JP4090576B2 - Ultrasonic diagnostic equipment - Google Patents

Description

【００１９】
が成立する。
ここで超音波探触子の移動速度ｖは、超音波伝播速度ｃと比べ十分に小さい（ｖ＜＜ｃ）ので、（１）式は、
【００２０】
【数２】

【００２１】
に近似できる。
また、移動量（移動距離）Ｌは、移動速度ｖの積分、すなわち、
Ｌ＝∫ｖ・ｄｔ ……（３）
により求められる。
ここで、（２）式中、超音波トランスデューサ２４から送波される超音波の中心周波数ｆ_O 、接触面２７への入射角θ、および超音波伝播速度ｃは既知であり、したがって超音波トランスデューサ２４で反射超音波を受信して得た受信信号に基づいて、例えばフーリエ変換により、その反射超音波の中心周波数ｆを求め、その求めた中心周波数ｆを（２）式に代入することにより、超音波振動子の、生体に対する相対的な移動速度ｖが求められ、（３）式に示すように、その移動速度ｖの積分（積算）により移動量（移動距離）Ｌが求められる。
後述する実施形態では、フーリエ変換および移動算出は、パルス／連続波ドプラ解析部４０１（図４参照）で実行される。
【００２２】
図３は、反射超音波の位相関係を示した図である。
図１に示す超音波トランスデューサ２４から接触面２７に向けて超音波が複数回（ここでは２回とする）送波され、接触面２７で反射して戻ってきた超音波をその超音波トランスデューサ２４で受信して得た複数（ここでは２つ）受信信号の波形が、それぞれ図３（Ａ），図３（Ｂ）であるとする。ここでは、定量的な説明は省略するが、それら２つの信号波形間の位相ψは、超音波探触子が生体に対し、図１に示すｘ方向に移動するかｘ’方向に移動するかに応じて反転し、その移動速度が速いほど位相ψが大きくずれる。したがってその位相を検出することによっても、超音波探触子の移動速度ｖ（移動方向を含む）を求めることができる。
この位相の検出、およびその検出された位相に基づく移動算出は、後述する実施形態では、カラードプラ解析部４０２で実行される。
以上で、本発明の特徴部分の原理的な説明を終了し、以下、本発明の実施形態について説明する。以下では、先ず、超音波診断装置の概要について説明し、次いで本発明の実施形態の特徴的な部分について説明する。
【００２３】
図４は、本発明の超音波診断装置の一実施形態を示すブロック図である。以下、各部の作用ないし機能の説明はあとにまわし、先ずは、この超音波診断装置の構成について説明する。
この超音波診断装置の本体部１０は、大別して、制御部１００、信号処理部２００、ディジタルスキャンコンバータ部３００、ドプラ処理部４００、表示制御部５００、生体信号アンプ部６００から構成されている。制御部１００は、ＣＰＵ部１０１とメモリ部１０２と、ビームスキャン制御部１０３からなり、ＣＰＵ部１０１には、操作パネル７０１、一体的に構成されたタッチパネル７０２とＥＬ表示器７０３、およびフロッピィディスク装置７０４が接続されている。
また、信号処理部２００は、送受信部２０１、受信ディレイ制御部２０２、ビームフォーマ部２０３、コントロールインターフェイス部２０４、演算部２０５、およびドプラシグナル処理部２０６から構成されており、コントロールインターフェイス部２０４と、送受信部２０１、受信ディレイ制御部２０２、およびドプラシグナル処理部２０６は、制御ライン２０７で結ばれている。また、コントロールインターフェイス部２０４と演算部２０５は制御ライン２０８で結ばれており、さらに、受信ディレイ制御部２０２とビームフォーマ部２０３は制御ライン２０９で結ばれている。信号処理部２００を構成する送受信部２０１には、超音波プローブ２０が、着脱自在に、ここでは最大４本まで接続される。
【００２４】
この超音波プローブ２０には、生体表面にあてがわれ、あるいは生体の体腔内に挿入される超音波探触子２１が備えられている。この超音波探触子２１はその目的に応じ、生体の体表にあてがわれる形態のものや生体の体腔内に挿入される形態のものなど様々な形態のものが存在する。この図１には一例として、生体１の体表にあてがわれる形態の超音波探触子２１が示されている。超音波探触子２１の、生体１への接触面に面して、複数の第１の超音波トランスデューサが配列された超音波トランスデューサアレイ２２１（本発明にいう第１の超音波トランスデューサアレイに相当する）と、第２の超音波トランスデューサ２４が装備されている。この第２の超音波トランスデューサ２４は、生体に接触する接触面との間に間隔を置いた超音波探触子の内部に配置されており、その接触面との間には、超音波の伝播を担う超音波伝播媒体が配備されている。詳細は後述する。
ディジタルスキャンコンバータ部３００には、白黒用スキャンコンバータ３０１、カラー用スキャンコンバータ３０２、およびスクロール用スキャンコンバータ３０３が備えられている。
また、ドプラ処理部４００には、パルス／連続波ドプラ解析部４０１とカラードプラ解析部４０２が備えられている。
また、表示制御部５００は、画像メモリ５００１を備えており、この表示制御部５００には、プリンタ７０５、ＶＴＲ（ビデオテープレコーダ）７０６、観察用テレビモニタ７０７、およびスピーカ７０８が接続されている。
また、生体信号アンプ部６００は、ここでは１つのブロックで示されており、この生体信号アンプ部６００には、ＥＣＧ電極ユニット７０９、心音マイク７１０、および脈波用トランスデューサ７１１が接続されている。
【００２５】
さらに、この超音波診断装置には、電源部８００が備えられている。この電源部８００は、商用電源に接続され、この超音波診断装置各部に必要な電力を供給する。
また、本体部１０は、ＣＰＵバス９０１を有しており、このＣＰＵバス９０１は、制御部１００を構成するＣＰＵ部１０１、メモリ部１０２、およびビームスキャン制御部１０３と、信号処理部２００を構成するコントロールインターフェイス部２０４と、ディジタルスキャンコンバータ部３００を構成する白黒用スキャンコンバータ３０１、カラー用スキャンコンバータ３０２、およびスクロール用スキャンコンバータ３０３と、ドプラ処理部４００を構成するパルス／連続波ドプラ解析部４０１およびカラードプラ解析部４０２と、さらに画像表示部５００とを接続している。また、この本体部１０は、エコーバス９０２を有しており、このエコーバス９０２は、信号処理部２００を構成する演算部２０５で生成される画像データを、ディジタルスキャンコンバータ部３００に供給する。また、ドプラ処理部４００を構成するパルス／連続波ドプラ解析部４０１およびカラードプラ解析部４０２で生成されたデータも、エコーバス９０２を経由してディジタルスキャンコンバータ部３００に供給される。さらに、この本体部１０は、ビデオバス９０３を有しており、このビデオバス９０３は、ディジタルスキャンコンバータ部３００を構成する白黒用スキャンコンバータ３０１、カラー用スキャンコンバータ３０２、およびスクロール用スキャンコンバータ３０３のいずれかで生成された画像データを表示制御部５００に伝達する。
【００２６】
操作パネル７０１は、多数のキーを備えたキーボード等からなり、この操作パネル７０１を操作するとその操作情報がＣＰＵ部１０１で検知され、その操作情報に応じた指令が、その指令に応じて、ビームスキャン制御部１０３、コントロールインターフェイス部２０４、ディジタルスキャンコンバータ部３００、ドプラ処理部４００、あるいは表示制御部５００に伝達される。
ＥＬ表示部７０３は、ＥＬ（Ｅｌｅｃｔｒｏ Ｌｕｍｉｎｅｓｃｅｎｃｅ）表示画面を有し、また、ＣＰＵ部１０１は、そのＥＬ表示部７０３のＥＬ表示画面に表示するＥＬ用線画を作成するＥＬ用線画作成部を兼ねており、そのＣＰＵ部１０１で生成されたＥＬ用線画がＥＬ表示部７０３のＥＬ表示画面上に表示される。そのＥＬ表示部７０３のＥＬ表示画面上にはタッチパネル７０２が備えられており、そのタッチパネル７０２に指で触れるとそのタッチパネル７０２上の指で触れた位置をあらわす位置情報がＣＰＵ部１０１に伝達される。このタッチパネル７０２およびＥＬ表示器７０３は、例えば、操作パネル７０１の操作により、この超音波診断装置に、ある１つのモードに関するパラメータを設定する旨指示すると、ＣＰＵ１０１により、その１つのモード用に設定すべき多数のパラメータ一覧がＥＬ表示部７０３に表示され、タッチパネル７０２を指で触れて所望のパラメータを設定するなど、この超音波診断装置への各種の指示を入力し易いように構成されたものである。
【００２７】
フロッピィディスク装置７０４は、図示しないフロッピィディスクが装脱自在に装填され、その装填されたフロッピィディスクをアクセスする装置であって、ＣＰＵ部１０１により、オペレータが操作パネル７０１やタッチパネル７０２の操作により行なった指示がそのフロッピィディスク装置７０４に装填されたフロッピィディスクに書き込まれ、この超音波診断装置への電源投入時、あるいは操作パネル７０１の操作により初期状態へのリセットが指示された時に、そのフロッピィディスク装置７０４に装填されたフロッピィディスクからそこに書き込まれている各種の指示情報がＣＰＵ部１０１に入力され、ＣＰＵ部１０１は、その指示情報に応じて各部を初期状態に設定する。これは、この超音波診断装置を稼働させるにあたって必要となる、操作パネル７０１やタッチパネル７０２から設定すべきパラメータ等が多数存在し、例えば電源投入のたびにそれら多数のパラメータ等を設定し直すのは極めて大変であり、このためフロッピィディスクに初期状態のパラメータ等を書き込んでおいて、電源投入時や初期状態へのリセットが指示された時には、そのフロッピィディスクに書き込まれているパラメータ等を読み込んでそれらのパラメータ等に応じて各部を設定することにより、パラメータ等の設定効率化を図るというものである。
【００２８】
制御部１００を構成するＣＰＵ部１０１は、上述のように、主としてマン・マシンインターフェイスの役割りを担っているのに対し、同じく制御部１００を構成するビームスキャン制御部１０３は、主として、この超音波診断装置による超音波の送受信のタイミング等、リアルタイム性が要求される制御を担当している。この超音波診断装置で超音波の送受信を行なう時には、信号処理部２００を構成する各部を制御するためのデータがビームスキャン制御部１０３からＣＰＵバス９０１を経由して信号処理部２００のコントロールインターフェイス部２０４に伝達され、このコントロールインターフェイス部２０４は、制御ライン２０７を経由して、送受信部２０１、受信ディレイ制御部２０２、およびドプラシグナル処理部２０６を制御し、また、このコントロールインターフェイス部２０４は、制御ライン２０８を介して演算部２０５を制御し、さらに受信ディレイ制御部２０２は、コントロールインターフェイス部２０４の制御を受けて、制御ライン２０９を介してビームフォーマ部２０３を制御する。信号処理部２００の各部の制御についての詳細は後述する。
制御部１００を構成するメモリ部１０２は、各種のプログラムや各種の制御データの格納領域であり、必要に応じてＣＰＵ部１０１やビームスキャン制御部１０３により参照される。
【００２９】
送受信部２０１には、超音波探触子２１を備えた超音波プローブ２０が接続されている。この超音波プローブに備えられる超音波探触子２１には、例えばリニア走査型超音波探触子、コンベックス走査型超音波探触子、セクタ走査型超音波探触子、また特殊な超音波探触子としては、体腔内に挿入されるタイプの超音波探触子、さらには、これら各種の超音波探触子について、使用される超音波の周波数の相違による種別等、多種類の超音波探触子が存在する。超音波プローブを本体部１０に装着するにはコネクタ（図示せず）が用いられるが、本体部１０側には超音波プローブを接続するためのコネクタが取り付けられており、前述したように、多種類の超音波探触子それぞれを備えた多種類の超音波プローブのうち最大４本まで同時装着が可能である。超音波プローブを本体部１０に装着すると、どの種類の超音波探触子を備えた超音波プローブが装着されたかをあらわす情報が本体部１０で認識できるように構成されており、その情報は、制御ライン２０７、コントロールインターフェイス部２０４、およびＣＰＵバス９０１を経由してＣＰＵ部１０１に伝えられる。一方、操作パネル７０１からは、この超音波診断装置を使用するにあたり、今回、本体部１０側のコネクタに接続された超音波プローブのうちどの超音波プローブを使用するか指示が入力される。その指示は、ＣＰＵバス９０１を経由してビームスキャン制御部１０３に伝えられ、そのビームスキャン制御部１０３から、使用する超音波プローブに応じたデータが、ＣＰＵバス９０１、コントロールインターフェイス部２０４、制御ライン２０７を経由して送受信部２０１に伝達され、送受信部２０１は、上記のようにして指示された超音波プローブ２０に対し、以下に説明するように高電圧パルスを送信してその超音波プローブに備えられた超音波探触子で超音波を送信し、その超音波探触子で受信された信号をその超音波プローブから受け取る。ここでは、図４に１つだけ示す超音波プローブ２０が超音波送受信のために選択されたものとする。
【００３０】
図４に示す超音波プローブ２０はいわゆるセクタ走査型の超音波探触子を備えた超音波プローブであり、その超音波探触子２１には、前述したように、配列された複数の第１の超音波トランスデューサからなる超音波トランスデューサアレイ２２１、および第２の超音波トランスデューサ２４が備えられており、超音波の送受信にあたっては、生体１の体表に、それら超音波トランスデューサアレイ２２１および第２の超音波トランスデューサ２４が装備された側の面（接触面）があてがわれる。尚、生体の体腔内に挿入される形態の超音波探触子の場合、その体腔内壁が、ここで説明している体表に相当する。
以下では、先ず、超音波トランスデューサアレイ２２１を用いた超音波の送受信に関する説明を行ない、その後第２の超音波トランスデューサ２４を用いた超音波の送受信に関する説明を行なう。
上記の接触面が生体１の体表にあてがわれた状態で、送受信部２０１から超音波トランスデューサアレイ２２１を構成する複数の超音波トランスデューサそれぞれに向けて超音波送信用の各高電圧パルスが印加される。複数の超音波トランスデューサそれぞれに印加される各高電圧パルスは、コントロールインターフェイス部２０４の制御により相対的な時間差が調整されており、それら相対的な時間差がどのように調整されるかに応じて、それら複数の超音波トランスデューサから、生体１の内部に延びる複数の走査線２のうちのいずれか一本の走査線に沿って、生体内部の所定深さ位置に焦点が結ばれた超音波パルスビームが送信される。
【００３１】
この送信される超音波パルスビームの属性、すなわち、その超音波パルスビームの方向、焦点の深さ位置、中心周波数等は、ビームスキャン制御部１０３からＣＰＵバス９０１を経由してコントロールインターフェイス部２０４に伝えられた制御データにより定まる。
この超音波パルスビームは生体１の内部を進む間にその１本の走査線上の各点で反射して超音波探触子２１に戻り、その反射超音波が超音波トランスデューサアレイ２２１を構成する複数の超音波トランスデューサで受信される。この受信により得られた複数の受信信号は、送受信部２０１に入力されて送受信部２０１に備えられた複数のプリアンプ（図示せず）でそれぞれ増幅された後ビームフォーマ部２０３に入力される。このビームフォーマ部２０３には、多数の中間タップを備えたアナログ遅延線（後述する）が備えられており、受信ディレイ制御部２０２の制御により、送受信部２０１から送られてきた複数の受信信号がアナログ遅延線のどの中間タップから入力されるかが切り換えられ、これにより、それら複数の受信信号が相対的に遅延されるとともに互いに電流加算される。ここで、それら複数の受信信号に関する相対的な遅延パターンを制御することにより、生体１の内部に延びる所定の走査線に沿う方向の反射超音波が強調され、かつ生体１の内部の所定深さ位置に焦点が結ばれた、いわゆる受信超音波ビームが形成される。ここで、超音波は、生体１内部を、信号処理の速度と比べてゆっくりと進むため、１本の走査線に沿う反射超音波を受信している途中で生体内のより深い位置に焦点を順次移動させる、いわゆるダイナミックフォーカスを実現することもでき、この場合、超音波パルスビーム１回の送信に対応する１回の受信の間であっても、その途中で時間的に順次に、受信ディレイ制御部２０２により、各超音波トランスデューサで得られた各受信信号が入力される、アナログ遅延線の各タップが切り換えられる。
【００３２】
この受信超音波ビームの属性、すなわち受信超音波ビームの方向、焦点位置等についても、ビームスキャン制御部１０３からＣＰＵバス９０１を経由してコントロールインターフェイス部２０４に伝えられ、さらに制御ライン２０７を経由して受信ディレイ制御部２０２に伝えられてきた制御データにより定められ、受信ディレイ制御部２０２はそのようにして伝えられてきた制御データに基づいて、ビームフォーマ部２０３を制御する。
尚、上記説明では、超音波トランスデューサには高電圧パルスを与え、超音波パルスビームを送信する旨説明したが、この場合、前述したように超音波は信号処理速度と比べるとゆっくりと生体内を進むため、超音波トランスデューサに高電圧パルスを印加した時点を起点とし、超音波トランスデューサで反射超音波を受信する時点までの時間により、その時点で得られた信号が生体内のどの深さ位置で反射した反射超音波に対応する信号であるかを知ることができる。すなわち、送信される超音波がパルス状のものであることにより、生体の深さ方向に分解能を持つことになる。通常は、このように、超音波トランスデューサには高電圧パルスが印加されるが、特殊な場合には、生体内の深さ方向に分解能を持たないことを許容し、超音波トランスデューサに連続的に繰り返す高電圧パルス列信号を印加して生体内に連続波としての超音波ビームを送信することもある。
ただし、以下においても、ドプラ処理部４００を構成するパルス／連続波ドプラ解析部４０１の説明の際に連続波に言及する場合を除き、パルス状の超音波ビームを送信するものとして説明する。
【００３３】
送受信部２０１およびビームフォーマ部２０３は、上記のようにして、生体１内部の複数の走査線２のそれぞれに沿って順次に超音波パルスビームの送信と受信とを繰り返し、これにより生成される、各走査線に沿う受信超音波ビームをあらわす信号が、演算部２０５に順次入力される。この演算部２０５では、入力された受信信号が対数圧縮され、検波され、さらに、操作パネル７０１を操作することにより指定された、生体１内部のどの深さ領域までの画像を表示するかという指定（つまり生体内部の浅い領域のみの画像を表示すればよいのか、あるいはどの程度深い領域までの画像を表示する必要があるかという指定）に応じたフィルタリング処理等が施され、さらにＡ／Ｄ変換によりディジタルの走査線データに変換される。
この演算部２０５で得られた走査線データは、エコーバス９０２を経由して、ディジタルスキャンコンバータ部３００を構成する白黒用スキャンコンバータ３０１に入力される。この白黒用スキャンコンバータ３０１では、表示用の各画素に対応したデータを生成するための補間演算処理が施されて表示用の画像データに変換され、その表示用の画像データがビデオバス９０３を経由して表示制御部５００に入力される。この表示制御部５００は、複数の走査線２で規定される生体断層面内の超音波反射強度分布によるＢモード像を観察用テレビモニタ７０７に表示する。その際、必要に応じて、操作パネル７０１から入力された患者名や撮影年月日、撮影条件等も、そのＢモード像に重畳されて表示される。このＢモード像として、生体１内部が動いている様子をあらわす動画像を表示することもでき、あるいは、ある時点における静止画像を表示することもでき、さらには、生体信号アンプ部６００からの同期信号に基づいて、人体の心臓の動きに同期した、その心臓の動きの、ある位相における画像を表示することもできる。また表示制御部５００には、前述したように画像メモリ５００１が備えられており、生成された画像データをその画像メモリ５００１に蓄積しておき、画像取得のための操作が終了した後で、その画像メモリ５００１から画像データを読み出して、観察用テレビモニタに画像を表示することもできる。
【００３４】
生体信号アンプ部６００には、生体１の心電波形を得るためのＥＣＧ電極ユニット７０９、心音をピックアップする心音マイク７１０、人体の脈をとらえる脈波用トランスデューサ７１１が接続されており、生体信号アンプ部６００では、これらのうちのいずれか１つもしくは複数のセンサに基づいて同期信号が生成され、表示制御部５００に送られる。
また表示制御部５００には、観察用テレビモニタ７０７のほか、プリンタ７０５、ＶＴＲ（ビデオテープレコーダ）７０６が接続されており、表示制御部５００は、オペレータからの指示に応じて、観察用テレビモニタ７０７に表示された画像をプリンタ７０５ないしはＶＴＲ７０６に出力する。
再度、信号処理部２００の説明から始める。
生体内部に延びるある一本の走査線上の超音波反射情報の時間変化を知ろうとするときは、オペレータからの指示に応じて、その関心のある一本の走査線に沿って超音波が繰り返し送受信され、その１本の走査線に沿う生体の受信超音波ビームをあらわすデータがエコーバス９０２を経由してスクロール用スキャンコンバータ３０３に入力される。このスクロール用スキャンコンバータ３０３は、縦方向にその１本の走査線に沿う生体の深さ方向の超音波反射強度分布、横軸が時間軸からなり時間軸方向にスクロールする画像（Ｍモード像）をあらわす画像データが生成され、ビデオバス９０３を経由して表示制御部５００に入力され、観察用テレビモニタ７０７に、その画像データに基づく画像が表示される。
【００３５】
尚、表示制御部５００は、白黒用スキャンコンバータ３０１から送られてきたＢモード像とスクロール用スキャンコンバータ３０３から送られてきたＭモード像とを横に並べる機能や、Ｂモード像に、後述するカラーモード像を重畳する機能も有しており、観察用テレビモニタ７０７には、オペレータからの指示に応じて、複数の画像が並べて表示され、あるいは複数の画像が重畳して表示される。
もう一度、信号処理部２００の説明に戻る。
信号処理部２００を構成するドプラシグナル処理部２０６は、基本的には、生体１内部の空間的な血流分布や、ある一点、ないしある１本の走査線上の血流速度を求めるための構成要素であり、このドプラシグナル処理部２０６では、ビームフォーマ部２０３で生成された受信超音波ビームをあらわす受信信号に、いわゆる直交検波が施され、さらにＡ／Ｄ変換によりディジタルデータに変換される。ドプラシグナル処理部２０６から出力された直交検波後のデータは、ドプラ処理部４００に入力される。ドプラ処理部４００には、パルス／連続波ドプラ解析部４０１とカラードプラ解析部４０２とが備えられている。ここでは、ドプラシグナル処理部２０６から出力されたデータは、カラードプラ解析部４０２に入力されるものとする。カラードプラ解析部４０２では、各走査線それぞれに沿って例えば８回ずつ超音波送受信を行なったときのデータに基づく自己相関演算により、オペレータにより指定された、Ｂモード画像上の関心領域（ＲＯＩ）内の血流の空間的な分布をあらわすデータが求められる。ＲＯＩ内の血流分布をあらわすデータは、エコーバス９０２を経由してカラー用スキャンコンバータ３０２に入力される。このカラー用スキャンコンバータ３０２では、そのＲＯＩ内の血流分布をあらわすデータが表示に適した画像データに変換され、その画像データは、ビデオバス９０３を経由して表示制御部５００に入力される。表示制御部５００では、白黒用スキャンコンバータ３０１から送られてきたＢモード像上のＲＯＩに、例えば超音波プローブ２０に近づく方向の血流を赤、遠ざかる方向の血流を青、それらの輝度で血流速度をあらわしたカラーモード像を重畳して、観察用テレビモニタ７０７に表示する。これにより、そのＲＯＩ内の血流分布の概要を把握することができる。
【００３６】
ここで、オペレータにより、そのＲＯＩ内のある１点もしくはある１本の走査線上の血流を詳細に観察する旨の要求が入力されると、今度は送受信部２０１により、その関心のある一点を通る一本の走査線、もしくはその関心のある１本の走査線に沿う方向に多数回超音波の送受信が繰り返され、それにより得られた信号に基づいてドプラシグナル処理部２０６で生成されたデータが、ドプラ処理部４００を構成するパルス／連続波ドプラ解析部４０１に入力される。生体内のある一点の血流に関心があるときは、生体内にはパルス状の超音波ビームが送信され、ある１本の走査線上の広い範囲内で空間的に平均化された血流情報となることを許容しより速い流速範囲の血流情報を得たいときは、生体内には連続波としての超音波ビームが送信される。
パルス／連続波ドプラ解析部４０１では、ある１点もしくはある１本の走査線について多数回超音波送受信を行なうことにより得られたデータに基づくＦＦＴ（Ｆａｓｔ Ｆｏｕｒｉｅｒ Ｔｒａｎｓｆｏｒｍ）演算により、その一点の血流情報、あるいはその一本の走査線上で空間的に平均化された血流情報が得られる。このパルス／連続波ドプラ解析部４０１で得られた血流情報をあらわすデータは、エコーバス９０２を経由して、スクロール用スキャンコンバータ３０３に入力され、スクロール用スキャンコンバータ３０３では、縦軸が血流速度、横軸が時間軸からなり時間軸方向にスクロールする画像をあらわす画像データが生成される。この画像データは、ビデオバス９０３を経由して表示制御部５００に入力され、観察用テレビモニタ７０７上に、例えば白黒用スキャンコンバータ３０１から送られてきたＢモード像と並べられて表示される。
【００３７】
図５は、複数の超音波トランスデューサに印加される高電圧パルスの遅延パターンを示した概念図である。
配列された複数の超音波トランスデューサ２２のうち、配列の両端（Ａ），（Ｂ）に位置する超音波トランスデューサに高電圧パルスＰ_v を印加するとともに、配列の中央（Ｏ）よりに位置する超音波トランスデューサに、時間的に遅れた高電圧パルスＰ_v を印加する。このように、遅延パターンを持った高電圧パルスを複数の超音波トランスデューサ２２に印加することにより、生体内の所定の方向に延び、かつある深さ位置に焦点が形成された送信超音波パルスビームが形成される。
【００３８】
図６は、ビームフォーマ部における、受信超音波ビームの形成の仕方を示す原理説明図である。
ここでは、説明の簡単のため、複数のタップを備えた遅延線１００１ａ，…，１００１ｍ，…，１００１ｎと、制御信号に応じて受信信号の遅延線への入力ルートを切り換える選択スイッチ１００２ａ，…，１００２ｍ，…，１００２ｎとのペアが各超音波トランスデューサ２２ａに対応して備えられているものとする。各選択スイッチ１００２ａ，…，１００２ｍ，…，１００２ｎそれぞれには対応する超音波トランスデューサで得られた各１つの受信信号が入力され、各選択スイッチ１００２ａ，…，１００２ｍ，…，１００２ｎでは、その入力された受信信号が、遅延線の複数のタップのうちの、制御信号に応じたタップから遅延線に入力される。各遅延線は２００１ａ，…，２００１ｍ，…，２００１ｎは受信信号が入力されたタップに応じた遅延時間だけその入力された受信信号を遅延して加算器１００３に入力する。加算器１００３は、その加算器１００３に同時に入力された受信信号どうしを加算して、受信超音波ビームをあらわす受信信号を出力する。
なお、この図６では、解りやすさのため、受信信号の数と同数の、遅延線１００１ａ，…，１００１ｍ，…，１００１ｎと選択スイッチ１００２ａ，…，１００２ｍ，…，１００２ｎとのペアを備えるとともに、各遅延線１００１ａ，…，１００１ｍ，…，１００１ｎから出力された受信信号を互いに加算する加算器１０３を備えた構成について説明したが、実際には、多数のタップを備えた一本の遅延線に、複数の超音波トランスデューサで得られた複数の受信信号が、入力されるタップがそれぞれ制御されながら入力され、それら複数の受信信号がそれぞれ入力された各タップに応じた時間だけ遅延されると共にその遅延線内で互いに電流的に加算され、その一本の遅延線から、制御された遅延パターンに従って遅延を受けかつ互いに加算された受信信号が、直接に出力される。
【００３９】
図７は、遅延パターンと、走査線の方向と、焦点位置との関係を示した説明図である。
Ａ−Ｂ間に複数の超音波トランスデューサが配列されているものとし、Ａ−Ｂ間の中点をＯとする。このとき、各超音波トランスデューサに印加される高電圧パルスに、図７（Ａ）に示すようにＢ側に位置する超音波トランスデューサに対し長めの遅延時間を与えて各超音波トランスデューサに印加すると、中点ＯからＢ側に傾いた方向に延びる走査線に沿う送信超音波ビームが形成され、図７（Ｂ）に示すように、左右対称の遅延パターンを与えると中点Ｏから超音波トランスデューサの配列方向に対し垂直に延びる走査線に沿う送信超音波ビームが形成され、図７（Ｃ）に示すように、Ａ側に位置する超音波トランスデューサに対し長めの遅延時間を与えた高電圧パルスを印加すると、Ａ側に傾いた送信超音波ビームが得られる。また、同一の走査線に沿う送信超音波ビームであっても、高電圧パルスの遅延パターンに応じて焦点位置を定めることができる。具体的には、図７（Ａ）〜（Ｃ）に破線で示すように焦点を中心としてＡ−Ｂ間を結ぶ線分に接する円弧を描いて考える。各超音波トランスデューサから送信された超音波パルスがその円弧上に同時に到達すると、それらの超音波パルスは焦点に集まるように進む。したがって、例えば図７（Ｂ）のように焦点を形成する場合は、Ａ点およびＢ点に位置する超音波トランスデューサに同時に高電圧パルスが印加され、その高電圧パルスの印加によってＡ点およびＢ点に位置する超音波トランスデューサから発せられた超音波パルスがその円弧上に達したタイミングで、Ｏ点に位置する超音波トランスデューサに高電圧パルスが印加され、そのＯ点に位置する超音波トランスデューサから超音波パルスが送信される。こうすることにより、図７（Ｂ）に示す走査線に沿うとともに図７（Ｂ）に示す焦点位置で最も細いビーム径を有する送信超音波パルスビームが形成される。
【００４０】
ここで、Ａ−Ｂ間に配列された、超音波送信に用いられている複数の超音波トランスデューサは、例えば超音波探触子２１（図４参照）に装備された超音波トランスデューサアレイ２２１を構成する複数の超音波トランスデューサの一部であって、送信超音波パルスビームの形成に用いる複数の超音波トランスデューサからなる送信開口を、配列された超音波トランスデューサの配列方向に移動することにより、走査線を、その配列方向に平行移動させることができる。
このようにして、超音波探触子２１に配列された超音波トランスデューサアレイ２２１上の任意の点を始点として生体内の任意の方向に延びる走査線に沿うとともに、その走査線上の任意の点に焦点を持つ送信超音波ビームを得ることができる。
受信超音波ビームの形成についても上記の送信超音波ビームの場合と同様である。
すなわち、生体内で反射し各超音波トランスデューサに戻ってきた超音波を各超音波トランスデューサで受信することにより得られた各受信信号を、図７（Ａ）に示すように、Ｂ側の超音波トランスデューサで得られた受信信号に対し長めの遅延時間を与えた上で互いに加算すると、中点Ｏを始点としＢ側に傾いた走査線に沿う受信超音波ビームが形成され、図７（Ｂ）に示すように左右対称の遅延時間を与えた上で互いに加算すると、中点Ｏを始点として超音波トランスデューサの配列方向に対し垂直に延びる走査線に沿う受信超音波ビームが形成され、図７（Ｃ）に示すようにＡ側の超音波トランスデューサで得られた受信信号に対し長めの遅延時間を与えた上で互いに加算すると、点Ｏを始点としＡ側に傾いた走査線に沿う受信超音波ビームが得られる。また、同一の走査線に沿う受信超音波ビームであっても、遅延パターンに応じて焦点位置を定めることができる。具体的には、焦点で反射してそれぞれ各点Ａ，Ｏ，Ｂに向かう超音波は、焦点と各点Ａ，Ｏ，Ｂとを結ぶ各線分と、円弧との交点に同時に到達することになり、焦点で反射した超音波を各超音波トランスデューサで受信する時刻に差異が生じることになる。そこで焦点で反射した超音波が先に到達した超音波トランスデューサで得られた受信信号を、反射超音波が後から到達する超音波トランスデューサにその反射超音波が到達する迄の間遅延させた上で互いに加算すると、焦点を通る走査線に沿う方向に延び、かつその焦点で最も細く絞られた受信超音波ビームが形成されることになる。
【００４１】
ここで、送信の場合と同様、Ａ−Ｂ間に配列された、反射超音波の受信に用いられている複数の超音波トランスデューサは、例えば超音波探触子２１（図４参照）に装備された超音波トランスデューサアレイ２２１を構成する複数の超音波トランスデューサの一部であって、反射超音波の受信に用いる複数の超音波トランスデューサからなる受信開口を、配列された超音波トランスデューサの配列方向に移動することにより、走査線を、その配列方向に平行移動させることができる。
このようにして、送信および受信の双方について、超音波探触子２１に装備された超音波トランスデューサアレイ２２１上の任意の点を始点として生体内の任意の方向に延びる走査線に沿うとともにその走査線上の任意の点に焦点を持つ超音波ビームを得ることができる。
以上で、図４に示す超音波探触子２１に装備された、超音波トランスデューサアレイ２２１と第２の超音波トランスデューサ２４とのうち、超音波トランスデューサアレイ２２１を用いた超音波送受信に関する説明を終了し、次に第２の超音波トランスデューサ２４を用いた超音波送受信に関し説明する。
図４に示す超音波探触子２１に装備された第２の超音波トランスデューサ２４および周辺の部分は、前述した図１に示す構造を有するものであり、その第２の超音波トランスデューサ２４にも送受信部２０１から高電圧パルスが印加される。すると、その第２の超音波トランスデューサ２４から超音波パルスが送波され、生体との接触面２７で反射して戻ってきた超音波がその第２の超音波トランスデューサ２４で受信される。この第２の超音波トランスデューサ２４での超音波の受信により得られた受信信号（ここではこれを第２の受信信号と称する）は、前述した、超音波トランスデューサアレイ２２１での超音波受信により得られた受信信号（ここでこれを第１の受信信号と称する）と同様に、送受信部２０１に備えられたプリアンプ（図示せず）で増幅された後、ビームフォーマ２０３、およびドプラシグナル処理部２０６を経由してパルス／連続波ドプラ解析部４０１に入力される。ただし、ここでは第２の受信信号は図１に示す唯一の第２の超音波トランスデューサ２４で得られた受信信号であるため、ビームフォーマ部２０３では遅延加算は行なわれず、そのビームフォーマ部２０３は単に通過するだけである。
【００４２】
図８は、パルス／連続波ドプラ解析部４０１の内部構成を示すブロック図である。
ここには、本発明にいうドプラ偏移検出手段の一例に相当するフーリエ解析部４０１１、および本発明にいう移動算出手段の一例に相当する移動算出部４０１２が備えられている。
フーリエ解析部４０１１は、前述した第１の受信信号の場合と共通に使用される、ＦＦＴ（Ｆａｓｔ Ｆｏｕｒｉｅｒ Ｔｒａｎｓｆｏｒｍ）を行なうブロックである。第１の受信信号の場合、パルス／連続波ドプラ解析部４０１でＦＦＴ演算により血流情報が抽出され、エコーバス９０２を経由してディジタルスキャンコンバータ部へ送られる旨説明したが、このＦＦＴ演算による血流情報の抽出は、図８に示すブロック図中のフーリエ解析部４０１１が担当している。第２の受信信号の場合は、このフーリエ解析部４０１１では、第２の受信信号の中心周波数ｆ（前述の（２）式参照）が求められる。尚、フーリエ解析部４０１１では、第１の受信信号の場合も第２の受信信号の場合もＦＦＴ演算を行なう点に関しては共通であるが、第１の受信信号に基づく血流情報の抽出の場合と第２の受信信号の中心周波数の検出の場合とでは、それぞれの処理に適合するように、ＦＦＴ演算に先立つフィルタリング処理等の前処理等に関し相違がある。詳細は省略する。
【００４３】
フーリエ解析部４０１１で得られた第２の受信信号の中心周波数ｆをあらわすデータは、移動算出部４０１２に入力される。移動算出部４０１２では、フーリエ解析部４０１１で得られた第２の受信信号の中心周波数ｆと、既知の量である、第２の超音波トランスデューサ２４（図１参照）から送波された超音波の中心周波数ｆ₀ 、生体との接触面２７に対する角度θ、および超音波伝播媒体２６の超音波伝播速度ｃを用いて、前述した（２）式に基づく演算を行ない、超音波探触子２１の、生体１に対する相対的な移動速度ｖが求められ、さらに（３）式に基づく演算により、超音波探触子２１の、生体１に対する相対的な移動量（移動距離）Ｌが求められる。この移動演算部４０１２で求められた移動速度ｖおよび移動量Ｌをあらわすデータは、ＣＰＵバス９０１を経由してＣＰＵ部１０１に伝えられる。
図９は、カラードプラ解析部４０２の内部構成を示すブロック図である。この図９に示す構成要素中の移動算出部４０２２は、図８に示す移動算出部４０２１に代えて備えることができる。すなわち、図８に示す移動算出部４０２１と図９に示す移動算出部４０２２は、いずれか一方が備えられていればよい。
この図９には、本発明にいうドプラ偏移検出手段の一例に相当する自己相関演算部４０２１と、本発明にいう移動算出手段の一例に相当する移動算出部４０２２が備えられている。
自己相関演算部４０２１は、前述した第１の受信信号の場合と共通に使用される、自己相関演算を行なうブロックである。第１の受信信号の場合、このカラードプラ解析部４０２では、各走査線それぞれに沿って例えば８回ずつ超音波送受信を行なったときのデータに基づく自己相関演算によりＲＯＩ内の血流分布をあらわすデータを求め、エコーバス９０２を経由したディジタルスキャンコンバータ部３００に入力される旨説明したが、その自己相関演算による血流情報の抽出は、図９に示すブロック図中の自己相関演算部４０２１が担当している。自己相関は、基本的には、２つの波形（図３（Ａ）に示す波形と図３（Ｂ）に示す波形）相対的なずれ量を求める演算であり、２つの波形の間の位相ψを求めることに相当する。
【００４４】
第２の受信信号の場合は、この自己相関演算部４０２１で、第２の受信信号の位相ψが求められる。尚、図８に示すフーリエ解析部４０１１の場合と同様、この自己相関演算部４０２１においても、第１の受信信号に基づく血流情報の抽出の場合と第２の受信信号に基づく位相検出の場合とでは、それぞれの処理に適合するように、自己相関演算に先立つフィルタリング処理等の前処理等が異なっている。詳細は省略する。
自己相関演算部４０２１で得られた第２の受信信号の位相ψをあらわすデータは、移動算出部４０２２に入力される。この移動算出部４０２２では、位相ψに基づいて、超音波探触子２１の、生体１に対する相対的な移動速度ｖが求められ、さらに、その超音波探触子２１の、生体１に対する移動量（移動距離）Ｌが求められる。求められた移動速度ｖおよび移動量Ｌをあらわすデータは、ＣＰＵバス９０１を経由してＣＰＵ部１０１に伝えられる。
【００４５】
図１０は、本発明の超音波プローブに備えられた超音波探触子の一実施形態を示す図である。図２８，図２９を参照して説明した従来技術との相違点について説明する。
図１０に示す超音波探触子２０１には、図１に示す構造の、第２の超音波トランスデューサ２４および超音波伝播媒体２６が備えられている。この超音波トランスデューサ２４は信号線２５により超音波診断装置本体部と接続されている。この超音波探触子２１は、図２８，図２９に示す従来技術の説明において述べたように、人体１の肛門１ａから直腸１ｂ内に挿入されて前立腺の診断に用いられる超音波探触子である。図２８，図２９による従来技術の場合、超音波探触子２１を直腸１ｂ内に制御された挿入量だけ挿入するためにモータが備えられていたが、この図１０に示す超音波探触子２０の場合、第２の超音波トランスデューサ２４に超音波探触子２１の場合、第２の超音波トランスデューサ２４による超音波送受信により得られた第２の受信信号に基づいて超音波探触子２１の移動量を知ることができるため、モータ等挿入量を制御する手段は不要である。
ｓ図１１は、図４に示すメモリ部１０２に格納されたテーブルの一例を示す図、図１２は、一連の断層像を示す図である。
【００４６】
図１１に示すテーブルは、図１０に示す超音波探触子２１を用い、そのテーブルに記録された挿入量（移動量）ごとに断層像を生成することを指示するテーブルである。このテーブルは、オペレータによる操作パネル７０１の操作により、あらかじめ作成される。
図１０に示す超音波探触子２１の、直腸１ｂ内への挿入開始のタイミングで移動量（挿入量）をゼロにセットすると、その後、第２の超音波トランスデューサ２４による超音波送受信により挿入量（移動量）がモニタされ、その挿入量（移動量）がそのテーブルに記録された挿入量（移動量）に達するごとにトランスデューサアレイ２２１による超音波送受信が行なわれ、断層像が生成される。この制御は、ビームスキャン制御部１０３がメモリ部１０２に格納された、図１１に示すテーブルを参照し、さらにＣＰＵ部１０１に伝えられてきた挿入量（移動量）をあらわすデータを参照して、各部を制御することにより行なわれる。このようにして順次に生成された断層像は、観察用テレビモニタ７０７の表示画面７０７１上に、生成された各時点で表示されるとともに、表示制御部５００内の画像メモリ５００１に一旦格納され、断層像取得のための操作（超音波探触子２１を直腸内に挿入する操作等）が終了した後でも、観察用テレビモニタ７０７の表示画面７０７１上にそれらの断層像が表示される。このように、テーブルに記録された挿入量（移動量）ごとに断層像を生成するように構成すると、オペレータがいちいち断層像生成の指示を入力する手間が省かれ、操作性が向上する。
【００４７】
図１３は、超音波探触子の別の実施形態を示す図、図１４は、図１３に示す円Ａ内の拡大図である。
図１３に示す超音波探触子２１には、その超音波探触子を周回する方向に配列された複数の第１の超音波トランスデューサ２２，２２，……からなる第１の超音波トランスデューサアレイ２２１に加え、その超音波探触子２１の長手方向に配列された複数の第２の超音波トランスデューサ２４，２４，……からなる第２の超音波トランスデューサアレイ２４１が備えられている。
この超音波探触子２１はその外周にゴム製のカバー２９が配備されており、そのカバー２９の内部には、水などの超音波伝播媒体２６が充填され、第２の超音波トランスデューサアレイ２４と生体１との接触面２７（ここでは直腸１ｂの内壁１ｃとの接触面）との間に間隙が空けられている。尚、この図１３に示す実施形態の場合、第１の超音波トランスデューサアレイ２２１も接触面２７との間に間隙が空けられているが、この間隙は、第１の超音波トランスデューサアレイ２２１との関係では本質的なものではない。
【００４８】
第２の超音波トランスデューサアレイ２４では、図７を参照して説明した手法により、図１４に示すように、接触面２７に対し斜めに（角度θで）超音波が送受信され、超音波診断装置本体部側では、この斜めの超音波送受信により得られた、接触面２７で反射された超音波による第２の受信信号に基づいて、超音波探触子２１の、生体１に対する相対的な移動速度および移動量が求められる。尚、この場合、第２の超音波トランスデューサアレイ２４１を構成する複数の第２の超音波トランスデューサ２４，２４，……を用いるため、複数の第２の受信信号が得られ、したがってこれら複数の第２の受信信号は、図４に示すビームフォーマ部２０３で遅延加算が行なわれ、受信角度θの１つの第２の受信信号に統合される。
また、図１３に示す第２の超音波トランスデューサアレイ２４１は、超音波探触子２１の長手方向に広がる断層像（縦断層像と称する）を取得するための超音波送受信も担っており、この超音波探触子２１を用いると、第１の超音波トランスデューサアレイ２２１を用いた超音波送受信により得られる断層像（横断層像と称する）のほか、第２の超音波トランスデューサアレイ２４１を用いた超音波送受信により縦断層像を得ることができる。
【００４９】
図１５は、図１３に示す超音波探触子を備えた超音波プローブに適合した、超音波診断装置本体部の送受信部の構成を示すブロック図である。
図１５に示す送受信部２０１における送信信号生成部２０１１は、制御ライン２０７を経由して入力される制御データに応じて、図１３に示す第１の超音波トランスデューサアレイ２２１を構成する複数の第１の超音波トランスデューサ２２，２２，……、あるいは第２の超音波トランスデューサアレイ２４１を構成する複数の第２の超音波トランスデューサ２４，２４，……を駆動して、所定の走査線方向に送信される超音波ビームであって、さらに所定の深さ位置に焦点をもった超音波ビームを生成するための、相互の位相が制御された信号Ｐ_v （図５参照）を生成する。これらの信号は、超音波トランスデューサ駆動部２０１２により高電圧パルスに変換され、切替回路２０１３を経由して超音波探触子側に伝送される。この切替回路２０１３は、図１３に示す第１の超音波トランスデューサアレイ２２１と第２の超音波トランスデューサアレイ２４１のいずれを送受信部２０１に接続するかを切り替える回路であり、制御ライン２０７（図４参照）を経由して入力される制御データに応じてその切替えが行なわれる。
超音波探触子側で得られた受信信号は、切替回路２０１３を経由し、さらにプリアンプ２０１４を経由してビームフォーマ部２０３に伝達される。尚、ここでは信号線やプリアンプ２０１４等は、図示の繁雑さを避けるため信号１つ分のみ示されているが、それらは、同時に駆動され、あるいは超音波を同時に受信する超音波トランスデューサの数と同じ数だけ備えられている。
【００５０】
図１６は、図１３に示す超音波探触子を用いて生成される断層像をあらわした図であり、図１６（Ａ）は縦断層像、図１６（Ｂ）は横断層像である。
図１５に示す切替回路２０１３は、通常は、図１３に示す超音波探触子２１に装備された第２の超音波トランスデューサ２４１側に切り替えられており、超音波診断装置本体部では、その第２の超音波トランスデューサアレイ２４１を用いた超音波送受信により、超音波探触子２１の挿入量（移動量）のモニタと、図１６（Ａ）に示す縦断層像の取得が行なわれ、その縦断層像が観察用テレビモニタ７０７の表示画面７０７１上に表示される。
この切替回路２０１３は、超音波探触子２１の挿入量（移動量）が、例えば５ｍｍごと等、ある一定間隔の挿入量（移動量）に達する毎に第１の超音波トランスデューサアレイ２２１側に切り替わり、第１の超音波トランスデューサアレイ２２を用いた超音波送受信により得られた受信信号に基づいて、図１６（Ｂ）に示すような横断層像が生成される。この生成された横断層像は、その都度、リアルタイムでの画像確認に供するために短時間だけ、縦断層像に代わり観察用テレビモニタ７０７の表示画面７０７１に表示されるとともに、後の表示のために画像メモリ５００１（図４参照）に格納される。
【００５１】
画像メモリ５００１に格納された横断層像は、断層像取得の操作が終了した後画像の詳細観察のために読み出され、表示画面７０７１上に再度表示される。
尚、ここでは、縦断層像と横断層像を自動的に切り替える旨説明したが、オペレータによる操作パネル７０１の操作により、自在に切り替えたり、いずれかに固定しておくこともできる。
図１７は、超音波探触子のさらに異なる実施形態を示す斜視図、図１８は、図１７のＸ−Ｘに沿う模式断面図である。
この図１７に示す超音波探触子２１は、超音波ゼリー等が体表に塗られその超音波ゼリー等の媒体を介して腹壁等の体表に接触させて、人体内部の断層像を得るためのものである。この超音波探触子２１には、断層像を得るための超音波トランスデューサアレイ２２１の両側に、図１を参照して説明した構造、すなわち、図１８にその一方を示すように、体表への接触面に対し間隙を置いて斜めに配置された第２の超音波トランスデューサ２４と、超音波伝播媒体２６と、その超音波伝播媒体２６を閉じ込めておくためのカバー２８からなる構造を有している。この場合、図８あるいは図９に示す移動算出部４０１２，４０２２では、２つの第２の超音波トランスデューサ２４それぞれの超音波送受信により得られた２つの第２の受信信号それぞれに基づく各移動速度および各移動量が求められる。これら２つの第２の超音波トランスデューサ２４における超音波の送受信は、同時であって、２つの第２の受信信号それぞれを処理する回路を独立に持っていてもよく、あるいは、図１５を参照して説明したように切替回路を備えて、交互に行なってもよい。
【００５２】
図１９は、図１７に示す超音波探触子を体表にあてがって断層像を取得したときの、その断層像に対応づけてメモリ部１０２に格納されるデータを示す図、図２０は、図１７に示す超音波探触子の体表上での軌跡を示す模式図である。
ここでは、図１７に超音波探触子を用いて、一定時間間隔ごとに断層像が生成され、画像メモリ５００１（図４参照）に格納される。また各断層像の生成とともに、各断層像生成の時点における、２つの第２の超音波トランスデューサ２４それぞれにより得られた第２の受信信号それぞれに基づく移動量が求められ、画像データを特定する画像Ｎｏ．と対応づけられて、メモリ部１０２に、図１９に示すようなテーブルが作成される。このテーブルに格納されたデータは、図２０に示すように、各断層像生成タイミングにおける、体表上での図１７に示す超音波探触子の位置および姿勢をあらわしている。
このように、図１９に示すテーブルを作成することにより、超音波探触子の軌跡を知ることができる。このテーブルのデータは、後述するようにして、例えば超音波探触子の位置をあらわすマークとして表示画面上に表示される。
【００５３】
図２１は、図４に示す表示制御部５００の内部構成図である。
ここには、表示画面上に、断層像とともに線画を表示する構成が示されている。
ディジタルスキャンコンバータ部３００（図４参照）から送られてきた画像データは、画像メモリ５００１に一旦格納された後読み出されて画像合成部５００３に入力される。また、線画描画部５００２では、ＣＰＵバス９０１を経由して送られてくる線画描画用データに基づいて後述するような線画が描画され、画像合成部５００３に送られる。画像合成部５００３では、画像メモリ５００１からの画像データと線画描画部５００２からの線画が１つの画像に合成され、観察用テレビモニタ７０７にはその合成された画像が表示される。以下、各種の線画の例について説明する。尚、断層像自体については図１２および図１６に示されており、ここでは断層像自体についての図示は省略する。
【００５４】
図２２，図２３は、図１３に示す超音波探触子を用いて、その超音波探触子を直腸内に挿入しながら断層像を得るときの、その断層像と対応づけられた線画を示す図であり、図２２は、直腸内の深さと断層像の位置との対応を示す図、図２３は、直腸内の深さと、その直腸内に挿入された超音波探触子の位置との対応を示す図である。
図２２の横軸の数字は直腸内の深さ位置を示しており、図２２の深さ位置‘６’において縦に延びる直線は、現在取得されており、あるいは現在表示されている断層像の断層面位置を示している。このような表示を行なうと、オペレータは、現在の断層面位置を把握することができる。図２２の横軸‘０’の位置は、例えばオペレータが超音波探触子を直腸内に挿入開始したときにオペレータが指定してもよく、あるいは第２の超音波トランスデューサ２４での直腸内壁からの反射超音波を検出できた初期のタイミングを捉えて横軸‘０’の位置を自動的に決めてもよい。
【００５５】
図２３も、横軸は図２２と同様、直腸内の深さ位置を示しており、超音波探触子をあらわす図形が現在の直腸内への挿入量に対応した位置に示されている。
このような、超音波探触子の図形を表示すると、現在の挿入量が直感的に把握され、オペレータが誤って挿入し過ぎる等の事故の防止に役立つ。
【００５６】
図２４は、図１７に示す超音波探触子を用いて、その超音波探触子を体表にあてがいながら断層像を得たときの、人体に対する超音波探触子の位置を示す図、図２５、図２６は、表示画面上に表示される線画の各例を示す図である。
図２５、図２６の縦軸は、人体の腹部の縦方向の位置を示している。ここで、図２５（Ａ）の横に延びる直線は、超音波探触子２１が図２４（Ａ）の位置にあるときの断層像の位置を示しており、図２５（Ｂ）の矩形は、超音波探触子２１が図２４（Ｂ）のように人体１に対し斜めにあてがわれているときの断層像が含まれる領域を表わしている。
また、図２６（Ａ），（Ｂ）の矩形は、超音波探触子２１がそれぞれ図２４（Ａ），（Ｂ）のようにあてがわれているときの、超音波探触子の位置を示している。
このように、断層像の位置や超音波探触子の位置を表示することによって、断層像の取得にあたっては、表示画面を見ているだけで断層像や超音波探触子の位置を確認することができるため、人体に対する超音波探触子の位置を直接に確認する頻度を減らすことができ、断層像取得の後で断層像を表示する場合には、その表示された断層像が人体のどの位置の断層像であるかを容易に把握することができる。
【００５７】
図２７は、超音波探触子を移動させながら断層像を得ている際に表示される線画のもう１つの例を示す図である。
横軸は超音波探触子の移動速度を表わしており、ハッチングが付された棒グラフは現在の超音波探触子の移動速度、６０ｍｍ／ｓｅｃの位置に描かれた縦棒は、６０ｍｍ／ｓｅｃが移動速度の上限であることを意味している。
生体内を超音波が伝播する速度ｃ≒１５００ｍｍ／ｓｅｃの物理的制約から、１つの断層像を生成するには、様々な条件で変動するものの、およそ１／３０ｓｅｃ程度の時間を必要とする。そのため、超音波探触子の移動速度が速すぎると、５ｍｍ間隔あるいは２ｍｍ間隔といった所定の間隔で断層像を得ようとしても、その間隔では断層像を得ることが不可能となってしまう。そこで、操作パネル７０１から必要な断層像の生成間隔が入力された場合に、この図２７に示すように、超音波探触子の移動速度の上限を計算して断層像とともに表示する。さらに、ここでは、超音波探触子の移動速度（図２７のハッチングの部分）も表示し、移動速度の上限を超えないようにオペレータに対して注意を促す。このような表示を行ないながら、超音波探触子の移動量を求め、所定の移動間隔で断層像を得る。このような表示を行なうことで超音波探触子を速く動かしすぎることによる断層像の取得の失敗を未然に防止することができる。
ちなみに、１つの断層像を得るに１／３０ｓｅｃを必要とし、２ｍｍ間隔の断層像を得るためには、図２７に示すように６０ｍｍ／ｓｅｃが超音波探触子の移動速度の上限となる。
尚、図２７では、超音波探触子の移動速度とその移動速度の上限との双方が表示されているが、移動速度のみを表示してもよく、その移動速度の上限のみを表示してもよい。
【００５８】
図２８は、超音波探触子を移動させて、三次元的な断層像を得ている様子を表わす模式図である。この図２８には、解り易さのため、画像メモリ５００１を立体的に表現し、断層像の各画素のデータを格納する、画像メモリ５００１の各メモリ領域５００１ａを、その三次元断層像の各画素に対応する生体内の各分割領域にそのまま重畳させた状態の概念図が示されている。
ここでは、超音波探触子２１がｘ−ｘ’方向に移動しながら断層像が生成され、画像メモリ５００１に格納される。ここで、超音波探触子２１が一定距離移動するごとに断層像を生成する場合は、その生成された断層像に対応する断面に並ぶメモリ領域群にその断層像のデータを格納していくことで三次元断層像が生成される。一方、超音波探触子を移動させながら、一定時間間隔で断層像を生成する場合は、生成した断層像のデータを、その断層像を得たときの超音波探触子の移動量に応じた断面に格納する。超音波探触子を速く動かしすぎるとメモリ領域には順番には格納されないことになるが、超音波探触子２１をｘ−ｘ’方向に何回か往復させるうちに全てのメモリ領域を埋めることができる。
このようにして生成された三次元断層像は、その三次元断層像を構成する複数の二次元断層像を順次に表示し、あるいはそれら複数の二次元断層像のうちの特定の二次元断層像を表示するために用いてもよいが、その三次元断層像のまま、すなわち任意の方向から見た斜視図として、表示してもよい。
【００５９】
【発明の効果】
以上説明したように、本発明によれば、超音波探触子の、生体に対する相対移動を正確に検出することができる。
【図面の簡単な説明】
【図１】超音波探触子の、生体との接触部分を示す模式図である。
【図２】ドプラ偏移による周波数変化を示す模式図である。
【図３】反射超音波の位相関係を示した図である。
【図４】本発明の超音波診断装置の一実施形態を示すブロック図である。
【図５】複数の超音波トランスデューサに印加される高電圧パルスの遅延パターンを示した概念図である。
【図６】ビームフォーマ部における、受信超音波ビームの形成の仕方を示す原理説明図である。
【図７】遅延パターンと、走査線の方向と、焦点位置との関係を示した説明図である。
【図８】パルス／連続波ドプラ解析部の内部構成を示すブロック図である。
【図９】カラードプラ解析部の内部構成を示すブロック図である。
【図１０】本発明の超音波プローブに備えられた超音波探触子の一実施形態を示す図である。
【図１１】メモリ部に格納されたテーブルの一例を示す図である。
【図１２】一連の断層像を示す図である。
【図１３】超音波探触子の別の実施形態を示す図である。
【図１４】図１３に示す円Ａ内の拡大図である。
【図１５】図１３に示す超音波探触子を備えた超音波プローブに適合した、超音波診断装置本体部の送受信部の構成を示すブロック図である。
【図１６】図１３に示す超音波探触子を用いて生成される断層像をあらわした図である。
【図１７】超音波探触子のさらに異なる実施形態を示す斜視図である。
【図１８】図１７のＸ−Ｘに沿う模式断面図である。
【図１９】図１７に示す超音波探触子を体表にあてがって断層像を取得したときの、その断層像に対応づけてメモリ部に格納されるデータを示す図である。
【図２０】図１７に示す超音波探触子の体表上での軌跡を示す模式図である。
【図２１】表示制御部の内部構成図である。
【図２２】超音波探触子を直腸内に挿入しながら断層像を得るときの、その断層像と対応づけられた線画を示す図である。
【図２３】超音波探触子を直腸内に挿入しながら断層像を得るときの、その断層像と対応づけられた線画を示す例であり、図２２は、直腸内の深さと断層像の位置との対応を示す図である。
【図２４】超音波探触子を体表にあてがいながら断層像を作るときの、人体に対する超音波探触子の位置を示す図である。
【図２５】表示画面上に表示される線画の一例を示す図である。
【図２６】表示画面上に表示される線画の他の例を示す図である。
【図２７】超音波探触子を移動させながら断層像を得ている際に表示される線画のもう１つの例を示す図である。
【図２８】超音波探触子を移動させて、三次元的な断層像を得ている様子を表わす模式図である。
【図２９】前立腺診察用の超音波プローブに備えられた従来の超音波探触子の模式図である。
【図３０】図２９に示す超音波探触子の、その超音波探触子に装備された超音波トランスデューサアレイの部分を横切りにして示した模式図である。
【符号の説明】
１ 生体（人体）
２ 走査線
３ 断層面
１０ 本体部
２０ 超音波プローブ
２１ 超音波探触子
２２ａ 第１の超音波トランスデューサ
２３，２５ 信号線
２４ 第２の超音波トランスデューサ
２６ 超音波伝播媒体
２７ 接触面
２８，２９ カバー
１００ 制御部
１０１ ＣＰＵ部
１０２ メモリ部
１０３ ビームスキャン制御部
２００ 信号処理部
２０１ 送受信部
２０２ 受信ディレイ制御部
２０３ ビームフォーマ部
２０４ コントロールインターフェイス部
２０５ 演算部
２０７ 制御ライン
２２１ 第１の超音波トランスデューサアレイ
２４１ 第２の超音波トランスデューサアレイ
３００ ディジタルスキャンコンバータ部
３０１ 白黒用スキャンコンバータ
４００ ドプラ処理部
５００ 表示制御部
７０１ 操作パネル
７０７ 観察用テレビモニタ
２０１３ 切替回路
４０１１ フーリエ解析部
４０１２ 移動算出部
４０２１ 自己相関演算部
４０２２ 移動算出部
５００１ 画像メモリ
５００２ 線画描画部
７０７１ 表示画面[0001]
BACKGROUND OF THE INVENTION
The present invention was obtained while an ultrasonic probe equipped with an ultrasonic probe equipped with an ultrasonic transducer for transmitting and receiving ultrasonic waves was connected and repeated transmission and reception of ultrasonic waves using the ultrasonic probe. The present invention relates to an ultrasonic diagnostic apparatus that generates a tomographic image in a living body based on a received signal.
[0002]
[Prior art]
Conventionally, the above-described ultrasonic probe and ultrasonic diagnostic apparatus have been used for diagnosis of diseases inside a living body, particularly a human body.
In such an ultrasonic diagnostic apparatus, in order to grasp the spatial positional relationship of the ultrasonic tomogram with respect to the living body, it may be required to obtain the relative movement amount of the ultrasonic probe with respect to the living body. In particular, when it is necessary to grasp the three-dimensional structure in the living body, such as prostate volume measurement or fetal morphological diagnosis, measurement of this relative movement amount is required. Hereinafter, the prostate volume measurement will be described as an example.
FIG. 29 is a schematic diagram of a conventional ultrasound probe provided in an ultrasound probe for prostate examination, and FIG. 30 is provided in the ultrasound probe of the ultrasound probe shown in FIG. It is the schematic diagram which cut and showed the part of the ultrasonic transducer array.
The ultrasound probe 21 shown here is inserted into the rectum 1b from the anus 1a of the human body 1 when observing the prostate, has a cylindrical shape, and is disposed at the distal end side of the ultrasound probe 21. Are arranged in a direction that circulates around the cylindrical ultrasonic probe 21, and one ultrasonic transducer is formed by the plurality of ultrasonic transducers 22, 22,. An array 221 is configured.
[0003]
A wiring 23 is connected to each of the plurality of ultrasonic transducers 22, 22,... Constituting the ultrasonic transducer array 221. The wiring 23 is connected to an ultrasonic diagnostic apparatus main body (not shown), and voltage pulses for ultrasonic pulse transmission generated by the ultrasonic diagnostic apparatus main body are transmitted to the ultrasonic transducers 22. , 22,..., And further, the ultrasonic transducers 22, 22,... Yes.
Further, the base side of the ultrasonic probe 21 is connected to a motor 28, and when the motor 28 rotates in the directions of arrows A and A ', the ultrasonic probe 21 is inserted in the B direction. Or move in the direction of being pulled out in the B ′ direction.
Here, the ultrasonic probe 21 is inserted into the rectum 1b as shown in FIG. A, and an ultrasonic beam is transmitted from the ultrasonic transducer array 221 to the prostate 1d through the rectal wall 1c. The ultrasonic transducer array 221 receives the ultrasonic waves reflected back from the body and obtains a received signal.
Here, when transmitting and receiving ultrasonic waves using the ultrasonic transducer array 221, a plurality of ultrasonic transducers 22, 22,... Constituting the ultrasonic transducer array 221 are formed at a time as shown in FIG. Are transmitted and received using a plurality of ultrasonic transducers of a part of the ultrasonic transducers, and the ultrasonic transducers 21 having a cylindrical shape are cut into circles by performing a plurality of ultrasonic transducers in a different order. The ultrasonic reception signals relating to various directions in the tomographic plane 3 in the direction to be obtained are obtained. An ultrasonic probe main body (not shown) generates an ultrasonic tomographic image in the tomographic plane 3 based on these received signals.
[0004]
The above-described process for obtaining an ultrasonic tomographic image is performed while sequentially changing the amount of insertion of the ultrasonic probe 21 into the rectum to obtain a plurality of parallel tomographic images of the prostate 1d. The three-dimensional shape of the prostate 1d is obtained, the dimension of a predetermined portion of the three-dimensional shape is measured, and the dimension is applied to an empirical formula to calculate the prostate volume.
Here, when inserting the ultrasound probe 21 into the rectum 1b, the ultrasound probe 21 is placed in a chair, and the patient is seated in the chair and the ultrasound probe 21 is placed in the rectum of the patient. A method is adopted in which a tomographic image is acquired by inserting the contact 21 and rotating the motor 28 while changing the insertion amount by a certain amount.
29 and 30 show an ultrasonic transducer array 221 including a plurality of ultrasonic transducers 22, 22,... Arranged in a one-dimensional direction around the cylindrical ultrasonic probe 21. However, the ultrasonic transducers are arranged two-dimensionally in a matrix, and the ultrasonic transducers arranged in such a two-dimensional manner are sequentially driven, so that they are perpendicular to the rectum 1b shown in FIG. It is also known to obtain a three-dimensional tomographic image without moving the ultrasonic probe 21 by sequentially performing a process of obtaining a tomographic image of the tomographic plane 3 in any direction while scanning in the longitudinal direction of the rectum. The method using an ultrasound probe in which ultrasound transducers are arranged two-dimensionally is not only for the diagnosis of the prostate, but the shape of the ultrasound probe is different, but an ultrasound probe is applied to the abdomen of a pregnant woman. It is also used for fetal morphological diagnosis transperitoneally.
[0005]
[Problems to be solved by the invention]
In the case of the prior art described with reference to FIGS. 29 and 30, even if the patient is commanded not to move while sitting on a chair, the patient may move with the insertion of the ultrasound probe 21 into the rectum 1b. Often, when the patient moves, the amount of insertion of the ultrasound probe 21 into the rectum 1b does not become constant even if the rotation amount of the motor 28 is controlled, and the human body of the ultrasound probe 21 does not move. It is difficult to accurately control the relative movement amount with respect to.
In the case of an ultrasonic probe in which ultrasonic transducers are two-dimensionally arranged, wiring to the electrodes provided in each of the two-dimensionally arranged ultrasonic transducers is complicated, and the number of ultrasonic transducers is extremely large. In order to increase the number of pulses, a high voltage for ultrasonic transmission is applied to each ultrasonic transducer on the ultrasonic diagnostic apparatus body side, and a reception signal obtained by the ultrasonic transducer is received. There is a problem that the number of channels becomes extremely large, and it takes a great deal of cost. In addition, there is a problem that the dimensions of the ultrasonic probe tend to increase and the operability is impaired.
In view of the above circumstances, an object of the present invention is to provide an ultrasonic diagnostic apparatus having a function of accurately detecting relative movement of an ultrasonic probe with respect to a living body.
[0006]
[Means for Solving the Problems]
The ultrasonic probe of the present invention that achieves the above object includes an ultrasonic probe equipped with an ultrasonic transducer that is responsible for transmission and reception of ultrasonic waves, and the ultrasonic probe is placed in contact with a living body, Ultrasound connected to an ultrasonic diagnostic apparatus main body for generating an image based on the received signal by transmitting an ultrasonic wave into the living body, receiving an ultrasonic wave reflected and returned from the living body, and obtaining a received signal In the acoustic probe,
The ultrasonic probe is
A first ultrasonic transducer array comprising a plurality of arranged first ultrasonic transducers for obtaining a tomographic image of a living body by ultrasonic waves;
It is provided with one or more second ultrasonic transducers arranged inside and spaced apart from the contact surface that comes into contact with the living body and transmitting and receiving ultrasonic waves obliquely with respect to the contact surface. It is characterized by.
In addition, the ultrasonic diagnostic apparatus of the present invention that achieves the above object includes an ultrasonic probe equipped with an ultrasonic transducer that transmits and receives ultrasonic waves, and the ultrasonic probe is in contact with a living body. An ultrasonic probe that transmits ultrasonic waves into the living body and receives ultrasonic waves reflected and returned from the living body is connected, and is obtained while repeating transmission and reception of ultrasonic waves using the ultrasonic probe. In the ultrasonic diagnostic apparatus for generating a tomographic image in a living body based on the received signal,
[0007]
A first ultrasonic transducer array comprising a plurality of arranged first ultrasonic transducers, wherein an ultrasonic probe provided in the ultrasonic probe obtains a tomographic image in a living body using ultrasonic waves; and And one or more second ultrasonic transducers arranged inside and spaced apart from the contact surface that contacts the living body and transmitting and receiving ultrasonic waves obliquely to the contact surface. ,
Transmitting / receiving means for transmitting and receiving ultrasonic waves to the first ultrasonic transducer array to obtain a first received signal, and further transmitting and receiving ultrasonic waves to the second ultrasonic transducer to obtain a second received signal;
A tomographic image generating means for generating a tomographic image based on the first received signal obtained by the transmitting / receiving means;
Display means for displaying the tomographic image generated by the tomographic image generating means;
A Doppler shift detecting means for detecting a displacement of the Doppler shift of the ultrasonic wave transmitted and received by the second ultrasonic transducer based on the second received signal obtained by the transmitting and receiving means;
Movement calculating means for obtaining a relative moving speed or moving amount of the ultrasonic probe relative to the living body based on the Doppler shift of the second received signal detected by the Doppler shift detecting means; It is characterized by.
An ultrasonic probe according to the present invention includes an ultrasonic probe including a second ultrasonic transducer that transmits and receives an ultrasonic wave obliquely inside a space between a contact surface that contacts a living body. When the ultrasonic probe moves, the ultrasonic wave reflected by the contact surface with respect to the ultrasonic wave transmitted by the second ultrasonic transducer undergoes Doppler shift, and the frequency and phase change.
[0008]
Therefore, in the ultrasonic diagnostic apparatus of the present invention, the Doppler shift of the reflected ultrasound is detected by the Doppler shift detection means, and the movement calculation means detects the Doppler shift of the ultrasonic probe based on the detected Doppler shift. Relative movement (relative movement speed or relative movement amount) with respect to the living body is obtained.
As described above, according to the present invention, since the Doppler shift caused by the direct interaction with the living body is based, even if the living body moves during the movement of the ultrasonic probe, the relative movement is accurately performed. Desired. Further, according to the present invention, the cost can be greatly reduced and the operability is improved as compared with the case where an ultrasonic probe in which a plurality of ultrasonic transducers are two-dimensionally arranged is employed.
Here, in the ultrasonic probe of the present invention and the ultrasonic diagnostic apparatus of the present invention, the ultrasonic probe is responsible for the propagation of ultrasonic waves interposed between the second ultrasonic transducer and the contact surface. It is preferable that an ultrasonic propagation medium is provided.
By providing such an ultrasonic propagation medium, the propagation of ultrasonic waves is made efficient.
Further, in the ultrasonic probe of the present invention and the ultrasonic diagnostic apparatus of the present invention, the one or more second ultrasonic transducers are inclined with respect to the contact surface inside the space spaced apart from the contact surface. It may consist of an ultrasonic transducer arranged in
[0009]
When such an ultrasonic transducer is equipped, ultrasonic waves can be directly transmitted and received obliquely.
Alternatively, in the ultrasonic probe of the present invention and the ultrasonic diagnostic apparatus of the present invention, the one or more second ultrasonic transducers are located in an interior spaced from the contact surface, A second ultrasonic transducer array including a plurality of ultrasonic transducers arranged in a direction different from the arrangement direction of the first ultrasonic transducers may be used.
It is known that when a voltage pulse whose phase is adjusted is applied to a plurality of arranged ultrasonic transducers, ultrasonic waves can be transmitted obliquely, and the present invention provides the second ultrasonic transducer array described above. And ultrasonic waves may be transmitted obliquely using the method described above. Further, when the second ultrasonic transducer array is provided, a tomographic image in the living body can be generated by the second ultrasonic transducer array.
In the ultrasonic probe of the present invention, the ultrasonic probe may include the one or more second ultrasonic transducers at a plurality of positions separated from each other. In the ultrasonic diagnostic apparatus of the present invention that employs a simple ultrasonic probe, the movement calculating means relates to each position where the one or more second ultrasonic transducers of the ultrasonic probe are provided. It is preferable to obtain a relative moving speed or moving amount.
[0010]
When the ultrasonic probe is provided with the second ultrasonic transducer at a plurality of positions, the relative movement in each pair can be detected, so that not only the parallel movement of the ultrasonic probe but also the rotation can be known. it can.
In the ultrasonic probe of the present invention and the ultrasonic diagnostic apparatus of the present invention, the ultrasonic probe has a cylindrical shape inserted into the body cavity of the living body, and constitutes the first ultrasonic transducer array. A plurality of first ultrasonic transducers arranged in a direction around the cylindrical ultrasonic probe, wherein the one or more second ultrasonic transducers are arranged on the contact surface. On the other hand, ultrasonic waves can be transmitted and received obliquely with respect to the longitudinal direction of the cylindrical shape of the ultrasonic probe.
This ultrasonic probe is suitable as an ultrasonic probe that is inserted into a body cavity, such as an ultrasonic probe that is inserted into the rectum and observes the prostate, and is an ultrasonic probe for a living body. The relative insertion speed or insertion amount can be accurately determined.
In this case, the one or more second ultrasonic transducers are composed of a plurality of second ultrasonic transducers arranged in the longitudinal direction of the cylindrical shape of the ultrasonic probe. The second ultrasonic transducer array may be used for calculating the relative movement speed or movement amount of the child relative to the living body and for generating the tomographic image extending in the longitudinal direction of the cylindrical shape of the ultrasonic probe. .
In the ultrasonic diagnostic apparatus of the present invention to which an ultrasonic probe having an ultrasonic probe provided with such a second ultrasonic transducer array is connected, the tomographic image generating means includes the first ultrasonic transducer. A first tomogram based on a first reception signal obtained by ultrasonic transmission / reception using an array and a second reception signal based on a second reception signal obtained by ultrasonic transmission / reception using the second ultrasonic transducer. It is preferable to be responsible for generating both tomographic images.
[0011]
When the second ultrasonic transducer array as described above is provided, when the ultrasonic probe is inserted into the body cavity, the insertion speed or the insertion amount can be accurately obtained, and the first ultrasonic transducer is obtained. It is possible to obtain both a tomographic image in the tomographic plane that divides the body cavity horizontally and a tomographic image in the tomographic image plane that divides the body cavity vertically by the array.
Further, in the case of the ultrasonic diagnostic apparatus to which the ultrasonic probe having the cylindrical ultrasonic probe inserted into the body cavity is connected, the movement calculating unit is configured to use the cylindrical shape of the ultrasonic probe. The tomographic image generation means is based on a first received signal obtained by ultrasonic transmission / reception using a first ultrasonic transducer array. It is preferable that the tomographic image is generated according to the movement amount obtained by the movement calculating means.
According to the movement amount obtained by the movement detection means, that is, by generating a tomographic image at a predetermined interval such as a 5 mm interval or every time the movement amount registered in advance in a table or the like is reached, the movement amount It is possible to obtain an accurate three-dimensional tomographic image in combination with accurate detection.
In addition, the ultrasonic probe has a cylindrical shape, and the first ultrasonic transducer array in which the first ultrasonic transducers are arranged in a direction around the cylinder, and the longitudinal direction of the ultrasonic probe In the ultrasonic diagnostic apparatus according to the present invention, the movement calculating means includes an ultrasonic probe when the second ultrasonic transducer array including a plurality of second ultrasonic transducers arranged in a line is provided. The longitudinal direction of the cylindrical shape is obtained with respect to the living body relative to the living body, and the display means generates a first received signal obtained by ultrasonic transmission / reception using the first ultrasonic transducer array. A first tomogram based on the second tomogram based on the second received signal obtained by ultrasonic transmission / reception using the second ultrasonic transducer array and It is preferable that the display is switched in accordance with the order obtained movement amount.
[0012]
By switching according to the amount of movement, the trouble of switching manually is saved, and the operability is improved.
Further, in the ultrasonic diagnostic apparatus of the present invention, the movement calculation means obtains a relative movement amount of the ultrasonic probe relative to the living body, and the display means obtains the movement amount obtained by the movement calculation means. Accordingly, it is preferable to display the tomographic image or the position of the ultrasonic probe relative to the living body.
By displaying the tomographic image or the ultrasonic probe, the position of the currently observed tomographic image with respect to the living body can be grasped, and further, for example, the ultrasonic probe is inserted into the body cavity of the living body. If it is of the type, it is useful for knowing the current insertion depth and preventing accidents such as accidental over-insertion.
Further, in the ultrasonic diagnostic apparatus of the present invention, the movement calculation means obtains a relative movement speed of the ultrasonic probe with respect to the living body, and the display means obtains the movement speed obtained by the movement calculation means. May be displayed.
For example, when generating a tomographic image for every certain amount of movement and obtaining a three-dimensional tomographic image, if the moving speed is too fast, it is impossible to generate a tomographic image for each predetermined amount of movement. It becomes. Therefore, for example, in such a case, by obtaining and displaying the moving speed of the ultrasonic probe, it is possible to prevent failure such as moving too quickly.
[0013]
Furthermore, in the ultrasonic diagnostic apparatus according to the present invention, the movement calculation means obtains a relative movement amount of the ultrasonic probe with respect to the living body, and the tomographic image generation means is obtained by the movement calculation means. An ultrasonic probe for generating a tomographic image based on the first received signal at a predetermined interval with respect to a moving amount, wherein the display means can generate a tomographic image at the predetermined interval. It is also a preferable form that the upper limit of the relative moving speed is displayed.
Displaying the upper limit of the moving speed also helps prevent failures caused by moving the ultrasonic probe too quickly.
Furthermore, in the ultrasonic diagnostic apparatus according to the present invention, the movement calculating means obtains a relative movement amount of the ultrasonic probe relative to the living body, and the tomographic image generating means uses the first received signal as the first received signal. The three-dimensional tomographic image is obtained by repeating the generation of the tomographic image based on it and obtaining the relative positional relationship between the tomographic images generated repeatedly based on the movement amount obtained by the movement calculating means. May be.
In the above description, the movement amount obtained by the movement amount calculation means is an explanation that the timing for generating a tomographic image is determined, for example, that a tomographic image is generated for every certain movement amount. However, the tomographic images are sequentially generated at regular time intervals, for example, and the movement amount calculated by the movement calculating means at the timing when each tomographic image is generated is recorded, and these tomographic images are synthesized to form a three-dimensional image. When obtaining tomographic images, the relative positional relationship between the tomographic images generated repeatedly based on the recorded movement amount may be obtained.
[0014]
With this configuration, a tomographic image for constructing a three-dimensional tomographic image can be obtained while reciprocating several times even if the ultrasonic probe is moved without much concern about the moving speed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Prior to the description of the embodiments of the present invention, first, the relative moving speed or moving amount with respect to the living body in the configuration that transmits and receives ultrasonic waves obliquely with respect to the contact surface with the living body, which is characteristic in the present invention, will be described. The principle to be obtained will be described.
[0016]
FIG. 1 is a schematic diagram showing a contact portion of an ultrasonic probe with a living body.
The contact surface 27 of the ultrasonic probe with respect to the living body is in contact with the body surface 1e of the living body or the body cavity inner wall 1c of the living body, and the ultrasonic wave is disposed inside the contact surface 27 with a space therebetween. The transducer 24 (second ultrasonic transducer according to the present invention) is disposed obliquely (angle θ) with respect to the contact surface 27.
Further, between the contact surface 27 and the ultrasonic transducer 24, for example, water, a sol-like or gel-like ultrasonic propagation medium 26 is filled. The boundary with the contact surface 27 is covered with a cover 28 such as rubber.
Here, an ultrasonic wave is transmitted obliquely (at an angle θ) toward the contact surface 27 by the ultrasonic transducer 24, and an ultrasonic wave reflected and returned from the contact surface 27 is received and a received signal (the present invention). Second received signal) is obtained. In addition, it is assumed that the ultrasonic probe moves relative to the living body in the illustrated xx ′ direction. At this time, the ultrasonic wave transmitted from the ultrasonic transducer 24 undergoes Doppler shift on the contact surface 27 due to the relative movement between the ultrasonic probe and the living body.
[0017]
FIG. 2 is a schematic diagram showing frequency changes due to Doppler shift.
The center frequency of the ultrasonic wave transmitted from the ultrasonic transducer 24 is f ₀ When the ultrasonic probe moves in the direction of the arrow x shown in FIG. 1 relative to the living body, the center frequency of the ultrasonic wave reflected by the contact surface 27 and returned to the ultrasonic transducer 24 is the frequency f. ₀ The frequency f closer to the higher frequency _H When the ultrasonic probe moves in the direction of the arrow x ′ shown in FIG. 1 relative to the living body, the center frequency of the ultrasonic wave reflected by the contact surface 27 and returned to the ultrasonic transducer 24 is Frequency f ₀ The frequency f closer to the lower frequency than _L To shift to.
Here, the center frequency of the ultrasonic wave transmitted from the ultrasonic transducer 24 is expressed as f. ₀ , F represents the center frequency of the ultrasonic wave reflected by the contact surface 27 and returned to the ultrasonic transducer 24, v represents the relative moving speed (including the moving direction) of the ultrasonic probe with respect to the living body, and the contact surface 27. When the incident angle of the ultrasonic wave to θ is θ (see FIG. 1) and the propagation speed of the ultrasonic wave in the ultrasonic propagation medium 26 is c,
[0018]
[Expression 1]

[0019]
Is established.
Here, since the moving velocity v of the ultrasonic probe is sufficiently smaller than the ultrasonic propagation velocity c (v << c), the equation (1) is
[0020]
[Expression 2]

[0021]
Can be approximated.
Further, the movement amount (movement distance) L is an integral of the movement speed v, that is,
L = ∫v · dt (3)
Is required.
Here, in equation (2), the center frequency f of the ultrasonic wave transmitted from the ultrasonic transducer 24 _O , The incident angle θ to the contact surface 27 and the ultrasonic wave propagation velocity c are known, and therefore the reflected ultrasonic wave is obtained based on the received signal obtained by receiving the reflected ultrasonic wave by the ultrasonic transducer 24, for example, by Fourier transform. By obtaining the center frequency f of the sound wave and substituting the obtained center frequency f into the equation (2), the relative moving speed v of the ultrasonic transducer with respect to the living body is obtained, as shown in the equation (3). In addition, the movement amount (movement distance) L is obtained by integration (integration) of the movement speed v.
In the embodiment to be described later, the Fourier transform and the movement calculation are executed by the pulse / continuous wave Doppler analysis unit 401 (see FIG. 4).
[0022]
FIG. 3 is a diagram showing the phase relationship of reflected ultrasonic waves.
Ultrasonic waves are transmitted from the ultrasonic transducer 24 shown in FIG. 1 toward the contact surface 27 a plurality of times (here, twice), and the ultrasonic waves reflected and returned from the contact surface 27 are returned to the ultrasonic transducer 24. Assume that the waveforms of a plurality of (here, two) received signals obtained by receiving in FIG. 3 are FIG. 3 (A) and FIG. 3 (B), respectively. Here, although a quantitative explanation is omitted, the phase ψ between the two signal waveforms is the ultrasonic probe moving in the x direction or the x ′ direction shown in FIG. The phase ψ shifts greatly as the moving speed increases. Therefore, the moving speed v (including the moving direction) of the ultrasonic probe can also be obtained by detecting the phase.
The phase detection and the movement calculation based on the detected phase are executed by the color Doppler analysis unit 402 in the embodiment described later.
Above, the fundamental description of the characteristic part of this invention is complete | finished, and embodiment of this invention is described hereafter. Below, the outline | summary of an ultrasonic diagnosing device is demonstrated first, and the characteristic part of embodiment of this invention is demonstrated next.
[0023]
FIG. 4 is a block diagram showing an embodiment of the ultrasonic diagnostic apparatus of the present invention. Hereinafter, the operation or function of each part will be described later. First, the configuration of this ultrasonic diagnostic apparatus will be described.
The main body 10 of this ultrasonic diagnostic apparatus is roughly composed of a control unit 100, a signal processing unit 200, a digital scan converter unit 300, a Doppler processing unit 400, a display control unit 500, and a biological signal amplifier unit 600. The control unit 100 includes a CPU unit 101, a memory unit 102, and a beam scan control unit 103. The CPU unit 101 includes an operation panel 701, an integrally configured touch panel 702, an EL display 703, and a floppy disk device. 704 is connected.
The signal processing unit 200 includes a transmission / reception unit 201, a reception delay control unit 202, a beamformer unit 203, a control interface unit 204, a calculation unit 205, and a Doppler signal processing unit 206. The transmission / reception unit 201, the reception delay control unit 202, and the Doppler signal processing unit 206 are connected by a control line 207. The control interface unit 204 and the calculation unit 205 are connected by a control line 208, and the reception delay control unit 202 and the beam former unit 203 are connected by a control line 209. Up to four ultrasonic probes 20 are detachably connected to the transmission / reception unit 201 constituting the signal processing unit 200, here.
[0024]
The ultrasonic probe 20 includes an ultrasonic probe 21 that is applied to the surface of a living body or inserted into a body cavity of the living body. There are various types of ultrasonic probe 21 depending on the purpose, such as a type applied to the body surface of a living body and a type inserted into a body cavity of a living body. As an example, FIG. 1 shows an ultrasonic probe 21 in a form applied to the body surface of a living body 1. An ultrasonic transducer array 221 in which a plurality of first ultrasonic transducers are arranged facing the contact surface of the ultrasonic probe 21 with the living body 1 (corresponding to the first ultrasonic transducer array according to the present invention). ), A second ultrasonic transducer 24 is provided. The second ultrasonic transducer 24 is disposed inside the ultrasonic probe with a space between the second ultrasonic transducer 24 and the contact surface that comes into contact with the living body. An ultrasonic propagation medium responsible for the above is deployed. Details will be described later.
The digital scan converter unit 300 includes a black and white scan converter 301, a color scan converter 302, and a scroll scan converter 303.
The Doppler processing unit 400 includes a pulse / continuous wave Doppler analysis unit 401 and a color Doppler analysis unit 402.
The display control unit 500 includes an image memory 5001, and a printer 705, a VTR (video tape recorder) 706, an observation television monitor 707, and a speaker 708 are connected to the display control unit 500.
The biological signal amplifier unit 600 is shown here as one block, and an ECG electrode unit 709, a heart sound microphone 710, and a pulse wave transducer 711 are connected to the biological signal amplifier unit 600.
[0025]
Further, the ultrasonic diagnostic apparatus is provided with a power supply unit 800. The power supply unit 800 is connected to a commercial power supply and supplies necessary power to each unit of the ultrasonic diagnostic apparatus.
The main body unit 10 includes a CPU bus 901, and the CPU bus 901 includes a CPU unit 101, a memory unit 102, a beam scan control unit 103, and a signal processing unit 200 that configure the control unit 100. Control interface unit 204, monochrome scan converter 301 constituting digital scan converter unit 300, color scan converter 302, scroll scan converter 303, and pulse / continuous wave Doppler analysis unit 401 constituting Doppler processing unit 400. In addition, the color Doppler analysis unit 402 and the image display unit 500 are connected. The main body unit 10 includes an echo bus 902, and the echo bus 902 supplies image data generated by the arithmetic unit 205 constituting the signal processing unit 200 to the digital scan converter unit 300. Data generated by the pulse / continuous wave Doppler analysis unit 401 and the color Doppler analysis unit 402 constituting the Doppler processing unit 400 is also supplied to the digital scan converter unit 300 via the echo bus 902. Further, the main unit 10 has a video bus 903, and the video bus 903 includes a monochrome scan converter 301, a color scan converter 302, and a scroll scan converter 303 that constitute the digital scan converter unit 300. The image data generated by either is transmitted to the display control unit 500.
[0026]
The operation panel 701 is composed of a keyboard or the like having a large number of keys. When the operation panel 701 is operated, the operation information is detected by the CPU unit 101, and a command corresponding to the operation information is transmitted to the beam according to the command. The data is transmitted to the scan control unit 103, the control interface unit 204, the digital scan converter unit 300, the Doppler processing unit 400, or the display control unit 500.
The EL display unit 703 has an EL (Electro Luminescence) display screen, and the CPU unit 101 also serves as an EL line drawing creation unit that creates an EL line drawing to be displayed on the EL display screen of the EL display unit 703. The EL line image generated by the CPU unit 101 is displayed on the EL display screen of the EL display unit 703. A touch panel 702 is provided on the EL display screen of the EL display unit 703. When the touch panel 702 is touched with a finger, position information indicating the position touched with the finger on the touch panel 702 is transmitted to the CPU unit 101. . When the touch panel 702 and the EL display 703 are instructed to set parameters related to a certain mode to the ultrasonic diagnostic apparatus by operating the operation panel 701, for example, the CPU 101 sets the parameters for that mode. A list of many parameters to be displayed is displayed on the EL display unit 703, and a desired parameter is set by touching the touch panel 702 with a finger. For example, various instructions to the ultrasonic diagnostic apparatus can be easily input. is there.
[0027]
The floppy disk device 704 is a device in which a floppy disk (not shown) is detachably loaded and accesses the loaded floppy disk. The CPU unit 101 is operated by the operator by operating the operation panel 701 or the touch panel 702. The instruction is written on the floppy disk loaded in the floppy disk device 704, and when the ultrasonic diagnostic apparatus is turned on or when the operation panel 701 is instructed to reset to the initial state, the floppy disk device Various instruction information written therein is input to the CPU unit 101 from the floppy disk loaded in 704, and the CPU unit 101 sets each unit to an initial state according to the instruction information. This is because there are a large number of parameters to be set from the operation panel 701 and the touch panel 702 necessary for operating the ultrasonic diagnostic apparatus. For example, each time the power is turned on, the large number of parameters must be reset. For this reason, the initial parameters etc. are written on the floppy disk, and when the power is turned on or the reset to the initial state is instructed, the parameters etc. written on the floppy disk are read and read. By setting each part according to the parameters, etc., the efficiency of setting the parameters, etc. is improved.
[0028]
As described above, the CPU unit 101 constituting the control unit 100 mainly plays the role of a man-machine interface, whereas the beam scan control unit 103 which also constitutes the control unit 100 is mainly composed of this super-machine. I am in charge of controls that require real-time performance, such as the timing of ultrasound transmission / reception by the ultrasound diagnostic apparatus. When ultrasonic waves are transmitted / received by this ultrasonic diagnostic apparatus, data for controlling each unit constituting the signal processing unit 200 is transmitted from the beam scan control unit 103 via the CPU bus 901 to the control interface unit of the signal processing unit 200. The control interface unit 204 controls the transmission / reception unit 201, the reception delay control unit 202, and the Doppler signal processing unit 206 via the control line 207, and the control interface unit 204 The calculation unit 205 is controlled via the line 208, and the reception delay control unit 202 controls the beamformer unit 203 via the control line 209 under the control of the control interface unit 204. Details of the control of each part of the signal processing unit 200 will be described later.
The memory unit 102 constituting the control unit 100 is a storage area for various programs and various control data, and is referred to by the CPU unit 101 and the beam scan control unit 103 as necessary.
[0029]
An ultrasonic probe 20 including an ultrasonic probe 21 is connected to the transmission / reception unit 201. Examples of the ultrasonic probe 21 included in the ultrasonic probe include a linear scanning ultrasonic probe, a convex scanning ultrasonic probe, a sector scanning ultrasonic probe, and a special ultrasonic probe. As the transducer, there are many types of ultrasonic probes that are inserted into body cavities, and various types of ultrasonic probes, such as types depending on the frequency of the ultrasonic waves used. There is a probe. A connector (not shown) is used to attach the ultrasonic probe to the main body unit 10, but a connector for connecting the ultrasonic probe is attached to the main body unit 10 side. Up to four of the various types of ultrasonic probes provided with each type of ultrasonic probe can be mounted simultaneously. When the ultrasonic probe is attached to the main body unit 10, information representing which type of ultrasonic probe is attached can be recognized by the main body unit 10, and the information is The data is transmitted to the CPU unit 101 via the control line 207, the control interface unit 204, and the CPU bus 901. On the other hand, when using this ultrasonic diagnostic apparatus, an instruction is input from the operation panel 701 as to which ultrasonic probe to use among the ultrasonic probes connected to the connector on the main body unit 10 side this time. The instruction is transmitted to the beam scan control unit 103 via the CPU bus 901, and data corresponding to the ultrasonic probe to be used is transmitted from the beam scan control unit 103 to the CPU bus 901, the control interface unit 204, the control line. The transmission / reception unit 201 transmits the high-voltage pulse to the ultrasonic probe 20 as described below by transmitting to the ultrasonic probe 20 instructed as described above. An ultrasonic wave is transmitted by the ultrasonic probe provided, and a signal received by the ultrasonic probe is received from the ultrasonic probe. Here, it is assumed that only one ultrasonic probe 20 shown in FIG. 4 is selected for ultrasonic transmission / reception.
[0030]
The ultrasonic probe 20 shown in FIG. 4 is an ultrasonic probe provided with a so-called sector scanning type ultrasonic probe, and the ultrasonic probe 21 includes a plurality of first probes arranged as described above. The ultrasonic transducer array 221 comprising the ultrasonic transducers and the second ultrasonic transducer 24 are provided. When transmitting / receiving ultrasonic waves, the ultrasonic transducer array 221 and the second ultrasonic transducer array 221 are placed on the body surface of the living body 1. The surface on which the ultrasonic transducer 24 is equipped (contact surface) is applied. Note that in the case of an ultrasonic probe that is inserted into a body cavity of a living body, the inner wall of the body cavity corresponds to the body surface described here.
In the following, first, description will be given regarding transmission / reception of ultrasonic waves using the ultrasonic transducer array 221, and then description regarding transmission / reception of ultrasonic waves using the second ultrasonic transducer 24 will be given.
In a state where the contact surface is applied to the body surface of the living body 1, each high voltage pulse for ultrasonic transmission is applied from the transmission / reception unit 201 to each of the plurality of ultrasonic transducers constituting the ultrasonic transducer array 221. Is done. Each high voltage pulse applied to each of the plurality of ultrasonic transducers has a relative time difference adjusted by the control of the control interface unit 204, and depending on how the relative time difference is adjusted, An ultrasonic pulse beam focused from the plurality of ultrasonic transducers at a predetermined depth position inside the living body along one of the scanning lines 2 extending inside the living body 1. Is sent.
[0031]
The attributes of the ultrasonic pulse beam to be transmitted, that is, the direction of the ultrasonic pulse beam, the depth position of the focus, the center frequency, and the like are sent from the beam scan control unit 103 to the control interface unit 204 via the CPU bus 901. Determined by the transmitted control data.
The ultrasonic pulse beam is reflected at each point on the single scanning line while traveling inside the living body 1 and returns to the ultrasonic probe 21, and the reflected ultrasonic waves form a plurality of ultrasonic transducer arrays 221. Is received by an ultrasonic transducer. A plurality of reception signals obtained by this reception are input to the transmission / reception unit 201, amplified by a plurality of preamplifiers (not shown) provided in the transmission / reception unit 201, and then input to the beamformer unit 203. The beamformer unit 203 is provided with an analog delay line (described later) having a large number of intermediate taps, and a plurality of received signals sent from the transmission / reception unit 201 are controlled by the reception delay control unit 202. Which intermediate tap of the analog delay line is input is switched, whereby the plurality of received signals are relatively delayed and current is added to each other. Here, by controlling the relative delay pattern related to the plurality of received signals, reflected ultrasonic waves in a direction along a predetermined scanning line extending inside the living body 1 are emphasized, and a predetermined depth inside the living body 1 is increased. A so-called received ultrasound beam is formed which is focused on the position. Here, since the ultrasonic wave travels slowly in the living body 1 as compared with the signal processing speed, the ultrasonic wave is focused on a deeper position in the living body while receiving the reflected ultrasonic wave along one scanning line. It is also possible to realize so-called dynamic focus that is moved sequentially. In this case, even during one reception corresponding to one transmission of an ultrasonic pulse beam, a reception delay is sequentially performed in the middle of the reception. The control unit 202 switches each tap of the analog delay line to which each reception signal obtained by each ultrasonic transducer is input.
[0032]
The attributes of the received ultrasonic beam, that is, the direction of the received ultrasonic beam, the focal position, and the like are also transmitted from the beam scan control unit 103 to the control interface unit 204 via the CPU bus 901, and further via the control line 207. The reception delay control unit 202 controls the beamformer unit 203 based on the control data transmitted in this manner.
In the above description, it has been described that a high voltage pulse is applied to the ultrasonic transducer and an ultrasonic pulse beam is transmitted. In this case, as described above, the ultrasonic wave slowly travels in the living body as compared with the signal processing speed. Therefore, depending on the time from when the high voltage pulse is applied to the ultrasonic transducer to the time when the reflected ultrasonic wave is received by the ultrasonic transducer, at which depth position in the living body the signal obtained at that time is It is possible to know whether the signal corresponds to the reflected reflected ultrasonic wave. That is, since the transmitted ultrasonic wave is pulsed, it has resolution in the depth direction of the living body. Normally, high voltage pulses are applied to the ultrasonic transducer in this way, but in special cases, it is allowed to have no resolution in the depth direction in the living body, and the ultrasonic transducer is continuously applied to the ultrasonic transducer. An ultrasonic beam as a continuous wave may be transmitted into the living body by applying a repeated high voltage pulse train signal.
However, in the following description, it is assumed that a pulsed ultrasonic beam is transmitted except for the case where continuous waves are mentioned in the description of the pulse / continuous wave Doppler analysis unit 401 constituting the Doppler processing unit 400.
[0033]
As described above, the transmission / reception unit 201 and the beamformer unit 203 sequentially transmit and receive ultrasonic pulse beams along each of the plurality of scanning lines 2 inside the living body 1 and are generated thereby. A signal representing the received ultrasonic beam along each scanning line is sequentially input to the calculation unit 205. In this calculation unit 205, the input received signal is logarithmically compressed and detected, and further, the designation of which depth region within the living body 1 is displayed, which is designated by operating the operation panel 701. Filtering processing or the like is performed according to (that is, designation of whether only an image of a shallow region inside the living body should be displayed or how deep an image needs to be displayed), and further A / D conversion To digital scanning line data.
The scanning line data obtained by the calculation unit 205 is input to the monochrome scan converter 301 constituting the digital scan converter unit 300 via the echo bus 902. In this black and white scan converter 301, an interpolation calculation process for generating data corresponding to each pixel for display is performed and converted into display image data, and the display image data passes through the video bus 903. And input to the display control unit 500. The display control unit 500 displays a B-mode image based on the ultrasonic reflection intensity distribution in the biological tomographic plane defined by the plurality of scanning lines 2 on the observation television monitor 707. At that time, the patient name, imaging date, imaging conditions, and the like input from the operation panel 701 are also superimposed and displayed on the B-mode image as necessary. As this B-mode image, a moving image representing a state in which the living body 1 is moving can be displayed, or a still image at a certain point in time can be displayed. Further, synchronization from the biological signal amplifier unit 600 can be displayed. Based on the signal, an image at a certain phase of the heart motion synchronized with the motion of the human heart can be displayed. The display control unit 500 is provided with the image memory 5001 as described above, and the generated image data is stored in the image memory 5001 and after the operation for image acquisition is completed, It is also possible to read image data from the image memory 5001 and display the image on the observation television monitor.
[0034]
The biological signal amplifier unit 600 is connected to an ECG electrode unit 709 for obtaining an electrocardiographic waveform of the living body 1, a heart sound microphone 710 for picking up heart sounds, and a pulse wave transducer 711 for capturing a human body pulse. The unit 600 generates a synchronization signal based on any one or a plurality of these sensors and sends it to the display control unit 500.
In addition to the observation television monitor 707, a printer 705 and a VTR (video tape recorder) 706 are connected to the display control unit 500, and the display control unit 500 is in accordance with an instruction from the operator. The image displayed on 707 is output to the printer 705 or VTR 706.
The description starts again with the signal processing unit 200.
When you want to know the time change of ultrasonic reflection information on a single scanning line extending inside the living body, the ultrasonic wave is repeatedly transmitted and received along the scanning line of interest according to the instructions from the operator. Then, data representing the reception ultrasonic beam of the living body along the one scanning line is input to the scroll scan converter 303 via the echo bus 902. This scroll scan converter 303 has an ultrasound reflection intensity distribution in the depth direction of the living body along the one scanning line in the vertical direction, and an image (M mode image) scrolling in the time axis direction with the horizontal axis being the time axis. Is generated and input to the display control unit 500 via the video bus 903, and an image based on the image data is displayed on the observation television monitor 707.
[0035]
Note that the display control unit 500 has a function of horizontally arranging the B-mode image sent from the monochrome scan converter 301 and the M-mode image sent from the scroll scan converter 303, or a B-mode image, which will be described later. It also has a function of superimposing a color mode image, and a plurality of images are displayed side by side or displayed in a superimposed manner on the observation television monitor 707 in accordance with an instruction from the operator.
Returning to the description of the signal processing unit 200 once again.
The Doppler signal processing unit 206 constituting the signal processing unit 200 is basically configured to obtain a spatial blood flow distribution inside the living body 1 and a blood flow velocity on a single point or a single scanning line. In this Doppler signal processing unit 206, so-called quadrature detection is performed on the reception signal representing the reception ultrasonic beam generated by the beam former unit 203, and further converted into digital data by A / D conversion. The data after quadrature detection output from the Doppler signal processing unit 206 is input to the Doppler processing unit 400. The Doppler processing unit 400 includes a pulse / continuous wave Doppler analysis unit 401 and a color Doppler analysis unit 402. Here, it is assumed that the data output from the Doppler signal processing unit 206 is input to the color Doppler analysis unit 402. In the color Doppler analysis unit 402, a region of interest (ROI) on the B-mode image designated by the operator by autocorrelation calculation based on data when ultrasonic transmission / reception is performed eight times along each scanning line, for example. Data representing the spatial distribution of blood flow in the interior is required. Data representing the blood flow distribution in the ROI is input to the color scan converter 302 via the echo bus 902. In the color scan converter 302, data representing the blood flow distribution in the ROI is converted into image data suitable for display, and the image data is input to the display control unit 500 via the video bus 903. In the display control unit 500, for example, the blood flow in the direction approaching the ultrasonic probe 20 is red, the blood flow in the direction away from the ROI on the B-mode image sent from the black and white scan converter 301 is blue, and the brightness thereof. A color mode image representing the blood flow velocity is superimposed and displayed on the observation television monitor 707. Thereby, the outline of the blood flow distribution in the ROI can be grasped.
[0036]
Here, when the operator inputs a request to observe in detail the blood flow on one point or one scanning line in the ROI, this time, the transmission / reception unit 201 selects one point of interest. Data generated by the Doppler signal processing unit 206 based on a signal obtained by repeating transmission / reception of ultrasonic waves many times in a direction along one scanning line passing through or one scanning line of interest. Is input to the pulse / continuous wave Doppler analysis unit 401 constituting the Doppler processing unit 400. When there is an interest in blood flow at a certain point in the living body, a pulsed ultrasonic beam is transmitted into the living body, and blood flow information spatially averaged within a wide range on a single scanning line. When it is desired to obtain blood flow information in a faster flow velocity range while allowing the above, an ultrasonic beam as a continuous wave is transmitted into the living body.
The pulse / continuous wave Doppler analysis unit 401 performs blood flow at one point by FFT (Fast Fourier Transform) calculation based on data obtained by performing ultrasonic transmission / reception many times for one point or one scanning line. Information or blood flow information spatially averaged on the single scanning line is obtained. Data representing blood flow information obtained by the pulse / continuous wave Doppler analysis unit 401 is input to the scroll scan converter 303 via the echo bus 902, and the vertical axis of the scroll scan converter 303 indicates the blood flow velocity. Then, image data representing an image scrolling in the time axis direction is generated in which the horizontal axis is a time axis. This image data is input to the display control unit 500 via the video bus 903 and displayed on the observation television monitor 707 along with the B-mode image transmitted from the black-and-white scan converter 301, for example.
[0037]
FIG. 5 is a conceptual diagram showing a delay pattern of high voltage pulses applied to a plurality of ultrasonic transducers.
Among the plural ultrasonic transducers 22 arranged, the high voltage pulse P is applied to the ultrasonic transducers located at both ends (A) and (B) of the arrangement. _v Is applied to the ultrasonic transducer located at the center (O) of the array, and the high voltage pulse P delayed in time is applied to the ultrasonic transducer. _v Is applied. In this way, by applying a high voltage pulse having a delay pattern to the plurality of ultrasonic transducers 22, a transmission ultrasonic pulse beam extending in a predetermined direction in the living body and having a focal point formed at a certain depth position. Is formed.
[0038]
FIG. 6 is a principle explanatory view showing how to form a reception ultrasonic beam in the beam former section.
Here, for the sake of simplicity of explanation, delay lines 1001a,..., 1001m,..., 1001n having a plurality of taps, and selection switches 1002a,. Assume that a pair of 1002m,..., 1002n is provided corresponding to each ultrasonic transducer 22a. Each of the selection switches 1002a,..., 1002m,..., 1002n receives one received signal obtained by the corresponding ultrasonic transducer, and each of the selection switches 1002a,. The received signal is input to the delay line from the tap corresponding to the control signal among the plurality of taps of the delay line. Each delay line 2001a,..., 2001m,..., 2001n delays the input received signal by a delay time corresponding to the tap to which the received signal is input and inputs it to the adder 1003. The adder 1003 adds the reception signals simultaneously input to the adder 1003 and outputs a reception signal representing a reception ultrasonic beam.
In FIG. 6, for ease of understanding, the same number of delay lines 1001a,..., 1001m,..., 1001n and selection switches 1002a,. , 1001m,..., 1001n have been described with respect to the configuration including the adder 103 that adds the received signals to each other, but in practice, a single delay line having a number of taps is provided. In addition, a plurality of reception signals obtained by a plurality of ultrasonic transducers are input while the input taps are controlled, and the plurality of reception signals are delayed by a time corresponding to each input tap. The delay lines add up to each other galvanically, receive a delay from the delay line according to the controlled delay pattern, and add to each other. Received signal is output directly.
[0039]
FIG. 7 is an explanatory diagram showing the relationship among the delay pattern, the scanning line direction, and the focal position.
A plurality of ultrasonic transducers are arranged between A and B, and O is a midpoint between A and B. At this time, when applying a long delay time to the ultrasonic transducer located on the B side as shown in FIG. 7A to the high voltage pulse applied to each ultrasonic transducer, A transmission ultrasonic beam is formed along a scanning line extending in a direction inclined from the middle point O toward the B side, and as shown in FIG. As shown in FIG. 7C, a transmission ultrasonic beam is formed along a scanning line extending perpendicular to the arrangement direction. As shown in FIG. 7C, a high-voltage pulse that gives a long delay time to the ultrasonic transducer located on the A side. When applied, a transmission ultrasonic beam tilted toward the A side is obtained. Further, even for transmission ultrasonic beams along the same scanning line, the focal position can be determined according to the delay pattern of the high voltage pulse. Specifically, as shown by broken lines in FIGS. 7A to 7C, a circular arc that touches a line segment connecting A and B with the focus at the center is considered. As the ultrasonic pulses transmitted from each ultrasonic transducer reach the arc simultaneously, the ultrasonic pulses travel to converge at the focal point. Therefore, for example, when forming a focal point as shown in FIG. 7B, a high voltage pulse is simultaneously applied to the ultrasonic transducers located at the points A and B, and the points A and B are applied by the application of the high voltage pulse. A high voltage pulse is applied to the ultrasonic transducer located at the point O at the timing when the ultrasonic pulse emitted from the ultrasonic transducer located at the point O reaches the arc, and the ultrasonic transducer located at the point O A sonic pulse is transmitted. By doing so, a transmission ultrasonic pulse beam having the narrowest beam diameter is formed along the scanning line shown in FIG. 7B and at the focal position shown in FIG. 7B.
[0040]
Here, the plurality of ultrasonic transducers used for ultrasonic transmission arranged between A and B constitute, for example, an ultrasonic transducer array 221 equipped in the ultrasonic probe 21 (see FIG. 4). A plurality of ultrasonic transducers used for forming a transmission ultrasonic pulse beam are moved in the arrangement direction of the arranged ultrasonic transducers, thereby moving a scanning line. Can be translated in the arrangement direction.
In this way, along the scanning line extending in any direction in the living body starting from an arbitrary point on the ultrasonic transducer array 221 arranged in the ultrasonic probe 21, and at an arbitrary point on the scanning line A transmitted ultrasound beam with a focus can be obtained.
The formation of the reception ultrasonic beam is the same as that of the transmission ultrasonic beam.
That is, as shown in FIG. 7 (A), the reception signals obtained by receiving the ultrasonic waves reflected in the living body and returning to the ultrasonic transducers by the ultrasonic transducers are converted into B-side ultrasonic waves. When a long delay time is given to the reception signals obtained by the transducers and added together, a reception ultrasonic beam is formed along a scanning line inclined from the middle point O to the B side, as shown in FIG. As shown in FIG. 7, when a symmetric delay time is given and added to each other, a reception ultrasonic beam is formed along a scanning line extending perpendicularly to the arrangement direction of the ultrasonic transducers from the middle point O as a starting point. As shown in C), when a long delay time is given to the received signals obtained by the ultrasonic transducer on the A side and added together, the received ultrasonic waves along the scanning line inclined from the point O to the A side. Over-time can be obtained. Further, even for reception ultrasonic beams along the same scanning line, the focal position can be determined according to the delay pattern. Specifically, the ultrasonic waves reflected at the focal point and directed to the respective points A, O, and B simultaneously reach the intersections of the line segments connecting the focal point and the respective points A, O, and B and the arc. Therefore, a difference occurs in the time at which the ultrasonic waves reflected at the focal point are received by the ultrasonic transducers. Therefore, after delaying the reception signal obtained by the ultrasonic transducer that the ultrasonic wave reflected at the focal point first arrived until the reflected ultrasonic wave arrived at the ultrasonic transducer that the reflected ultrasonic wave reached later When added together, a reception ultrasonic beam extending in the direction along the scanning line passing through the focal point and narrowed down at the focal point is formed.
[0041]
Here, as in the case of transmission, a plurality of ultrasonic transducers used for reception of reflected ultrasonic waves arranged between A and B are mounted on, for example, the ultrasonic probe 21 (see FIG. 4). A part of the plurality of ultrasonic transducers constituting the ultrasonic transducer array 221 is moved in the arrangement direction of the arranged ultrasonic transducers, and the reception openings including the plurality of ultrasonic transducers used for receiving the reflected ultrasonic waves are moved. By doing so, the scanning lines can be translated in the arrangement direction.
In this way, for both transmission and reception, along the scanning line extending in any direction in the living body, starting from an arbitrary point on the ultrasonic transducer array 221 equipped in the ultrasonic probe 21, the scanning is performed. An ultrasonic beam having a focal point at an arbitrary point on the line can be obtained.
The description of the ultrasonic transmission / reception using the ultrasonic transducer array 221 out of the ultrasonic transducer array 221 and the second ultrasonic transducer 24 installed in the ultrasonic probe 21 shown in FIG. Next, ultrasonic transmission / reception using the second ultrasonic transducer 24 will be described.
The second ultrasonic transducer 24 and the peripheral portion provided in the ultrasonic probe 21 shown in FIG. 4 have the structure shown in FIG. 1 described above, and the second ultrasonic transducer 24 also includes the second ultrasonic transducer 24. A high voltage pulse is applied from the transmission / reception unit 201. Then, an ultrasonic pulse is transmitted from the second ultrasonic transducer 24, and the ultrasonic wave reflected and returned by the contact surface 27 with the living body is received by the second ultrasonic transducer 24. A reception signal (herein referred to as a second reception signal) obtained by reception of ultrasonic waves by the second ultrasonic transducer 24 is obtained by ultrasonic reception by the ultrasonic transducer array 221 described above. After being amplified by a preamplifier (not shown) provided in the transmission / reception unit 201, the beamformer 203 and the Doppler signal processing unit 206 are amplified in the same manner as the received signal (hereinafter referred to as the first reception signal). Is input to the pulse / continuous wave Doppler analysis unit 401. However, here, since the second received signal is a received signal obtained by the only second ultrasonic transducer 24 shown in FIG. 1, the beamformer unit 203 does not perform delay addition, and the beamformer unit 203 It just passes.
[0042]
FIG. 8 is a block diagram showing an internal configuration of the pulse / continuous wave Doppler analysis unit 401.
Here, a Fourier analysis unit 4011 corresponding to an example of the Doppler shift detection unit according to the present invention and a movement calculation unit 4012 corresponding to an example of the movement calculation unit according to the present invention are provided.
The Fourier analysis unit 4011 is a block that performs FFT (Fast Fourier Transform) used in common with the case of the first reception signal described above. In the case of the first received signal, it has been described that blood flow information is extracted by FFT calculation in the pulse / continuous wave Doppler analysis unit 401 and sent to the digital scan converter unit via the echo bus 902. The flow information is extracted by the Fourier analysis unit 4011 in the block diagram shown in FIG. In the case of the second received signal, the Fourier analysis unit 4011 obtains the center frequency f of the second received signal (see the above-described equation (2)). In the Fourier analysis unit 4011, the FFT operation is common to both the first received signal and the second received signal, but in the case of blood flow information extraction based on the first received signal. There is a difference between the case of detecting the center frequency of the second received signal and the preprocessing such as filtering processing prior to the FFT operation so as to suit the respective processing. Details are omitted.
[0043]
Data representing the center frequency f of the second received signal obtained by the Fourier analysis unit 4011 is input to the movement calculation unit 4012. In the movement calculation unit 4012, the center frequency f of the second received signal obtained by the Fourier analysis unit 4011 and the ultrasonic wave transmitted from the second ultrasonic transducer 24 (see FIG. 1), which is a known amount. Center frequency f ₀ Using the angle θ with respect to the contact surface 27 with the living body and the ultrasonic propagation velocity c of the ultrasonic propagation medium 26, the calculation based on the above-described equation (2) is performed, and the ultrasonic probe 21 with respect to the living body 1 is performed. A relative moving speed v is obtained, and a relative moving amount (moving distance) L of the ultrasonic probe 21 with respect to the living body 1 is obtained by calculation based on the equation (3). Data representing the movement speed v and the movement amount L obtained by the movement calculation unit 4012 is transmitted to the CPU unit 101 via the CPU bus 901.
FIG. 9 is a block diagram illustrating an internal configuration of the color Doppler analysis unit 402. The movement calculation unit 4022 in the components shown in FIG. 9 can be provided instead of the movement calculation unit 4021 shown in FIG. That is, any one of the movement calculation unit 4021 illustrated in FIG. 8 and the movement calculation unit 4022 illustrated in FIG. 9 may be provided.
FIG. 9 includes an autocorrelation calculation unit 4021 corresponding to an example of the Doppler shift detection unit according to the present invention and a movement calculation unit 4022 corresponding to an example of the movement calculation unit according to the present invention.
Autocorrelation calculation section 4021 is a block for performing autocorrelation calculation, which is used in common with the case of the first reception signal described above. In the case of the first received signal, the color Doppler analysis unit 402 represents the blood flow distribution in the ROI by autocorrelation calculation based on data when ultrasonic transmission / reception is performed eight times along each scanning line, for example. Although it has been described that data is obtained and input to the digital scan converter unit 300 via the echo bus 902, blood flow information extraction by the autocorrelation calculation is performed by the autocorrelation calculation unit 4021 in the block diagram shown in FIG. is doing. The autocorrelation is basically an operation for obtaining a relative shift amount between two waveforms (the waveform shown in FIG. 3A and the waveform shown in FIG. 3B), and the phase ψ between the two waveforms. Is equivalent to
[0044]
In the case of the second received signal, the autocorrelation calculating unit 4021 obtains the phase ψ of the second received signal. As in the case of the Fourier analysis unit 4011 shown in FIG. 8, in the autocorrelation calculation unit 4021, blood flow information extraction based on the first reception signal and phase detection based on the second reception signal are performed. Are different in pre-processing such as filtering processing prior to autocorrelation calculation so as to suit each processing. Details are omitted.
Data representing the phase ψ of the second received signal obtained by the autocorrelation calculation unit 4021 is input to the movement calculation unit 4022. In the movement calculation unit 4022, the relative moving speed v of the ultrasonic probe 21 with respect to the living body 1 is obtained based on the phase ψ, and the moving amount of the ultrasonic probe 21 with respect to the living body 1 is further determined. (Movement distance) L is obtained. Data representing the obtained moving speed v and moving amount L is transmitted to the CPU unit 101 via the CPU bus 901.
[0045]
FIG. 10 is a diagram showing an embodiment of an ultrasonic probe provided in the ultrasonic probe of the present invention. Differences from the prior art described with reference to FIGS. 28 and 29 will be described.
An ultrasonic probe 201 shown in FIG. 10 includes a second ultrasonic transducer 24 and an ultrasonic propagation medium 26 having the structure shown in FIG. The ultrasonic transducer 24 is connected to the ultrasonic diagnostic apparatus main body by a signal line 25. As described in the description of the prior art shown in FIGS. 28 and 29, the ultrasonic probe 21 is inserted into the rectum 1b from the anus 1a of the human body 1 and used for diagnosis of the prostate. It is. 28 and 29, a motor is provided to insert the ultrasonic probe 21 into the rectum 1b by a controlled insertion amount. The ultrasonic probe shown in FIG. In the case of 20, in the case of the ultrasonic probe 21 in the second ultrasonic transducer 24, the ultrasonic probe 21 is based on the second received signal obtained by ultrasonic transmission / reception by the second ultrasonic transducer 24. Therefore, means for controlling the amount of insertion such as a motor is unnecessary.
FIG. 11 is a diagram showing an example of a table stored in the memory unit 102 shown in FIG. 4, and FIG. 12 is a diagram showing a series of tomographic images.
[0046]
The table shown in FIG. 11 is an instruction for generating a tomographic image for each insertion amount (movement amount) recorded in the table using the ultrasonic probe 21 shown in FIG. This table is created in advance by the operation of the operation panel 701 by the operator.
When the movement amount (insertion amount) of the ultrasonic probe 21 shown in FIG. 10 is set to zero at the start of insertion into the rectum 1b, the insertion amount is then transmitted by ultrasonic transmission / reception by the second ultrasonic transducer 24. (Movement amount) is monitored, and every time the insertion amount (movement amount) reaches the insertion amount (movement amount) recorded in the table, ultrasonic transmission / reception is performed by the transducer array 221 to generate a tomographic image. For this control, the beam scan control unit 103 refers to the table shown in FIG. 11 stored in the memory unit 102, and further refers to data representing the insertion amount (movement amount) transmitted to the CPU unit 101. This is done by controlling each part. The tomograms sequentially generated in this way are displayed on the display screen 7071 of the observation television monitor 707 at each time point generated and are temporarily stored in the image memory 5001 in the display control unit 500. Even after the operation for obtaining the tomographic image (such as the operation of inserting the ultrasonic probe 21 into the rectum) is completed, the tomographic images are displayed on the display screen 7071 of the observation television monitor 707. As described above, if the tomographic image is generated for each insertion amount (movement amount) recorded in the table, the operator is not required to input the instruction for generating the tomographic image one by one, and the operability is improved.
[0047]
FIG. 13 is a diagram showing another embodiment of the ultrasonic probe, and FIG. 14 is an enlarged view in a circle A shown in FIG.
The ultrasonic probe 21 shown in FIG. 13 includes a first ultrasonic transducer array including a plurality of first ultrasonic transducers 22, 22,... Arranged in a direction around the ultrasonic probe. In addition to 221, a second ultrasonic transducer array 241 comprising a plurality of second ultrasonic transducers 24, 24,... Arranged in the longitudinal direction of the ultrasonic probe 21 is provided.
The ultrasonic probe 21 is provided with a rubber cover 29 on the outer periphery thereof. The cover 29 is filled with an ultrasonic propagation medium 26 such as water, and the second ultrasonic transducer array 24. And a contact surface 27 between the living body 1 and a contact surface 27 (here, a contact surface with the inner wall 1c of the rectum 1b). In the case of the embodiment shown in FIG. 13, a gap is also formed between the first ultrasonic transducer array 221 and the contact surface 27, but this gap is separated from the first ultrasonic transducer array 221. The relationship is not essential.
[0048]
In the second ultrasonic transducer array 24, ultrasonic waves are transmitted and received obliquely (at an angle θ) with respect to the contact surface 27 as shown in FIG. 14 by the method described with reference to FIG. On the main body side, the relative movement of the ultrasonic probe 21 with respect to the living body 1 based on the second received signal by the ultrasonic wave reflected by the contact surface 27 obtained by the oblique ultrasonic wave transmission / reception. Speed and travel are required. In this case, since a plurality of second ultrasonic transducers 24, 24,... Constituting the second ultrasonic transducer array 241 are used, a plurality of second received signals are obtained. The two received signals are subjected to delay addition in the beamformer unit 203 shown in FIG. 4 and integrated into one second received signal having a reception angle θ.
Further, the second ultrasonic transducer array 241 shown in FIG. 13 is also responsible for ultrasonic transmission / reception for acquiring a tomographic image (referred to as a longitudinal tomographic image) spreading in the longitudinal direction of the ultrasonic probe 21. When the ultrasonic probe 21 is used, in addition to a tomographic image (referred to as a transverse layer image) obtained by ultrasonic transmission / reception using the first ultrasonic transducer array 221, a second ultrasonic transducer array 241 is used. A longitudinal tomographic image can be obtained by ultrasonic transmission / reception.
[0049]
FIG. 15 is a block diagram illustrating a configuration of a transmission / reception unit of an ultrasonic diagnostic apparatus main body unit that is suitable for an ultrasonic probe including the ultrasonic probe illustrated in FIG. 13.
The transmission signal generation unit 2011 in the transmission / reception unit 201 illustrated in FIG. 15 includes a plurality of first ultrasonic transducer arrays 221 illustrated in FIG. 13 according to control data input via the control line 207. , Or a plurality of second ultrasonic transducers 24, 24,... Constituting the second ultrasonic transducer array 241, and transmitted in a predetermined scanning line direction. And a phase-controlled signal P for generating an ultrasonic beam having a focal point at a predetermined depth position. _v (See FIG. 5). These signals are converted into high voltage pulses by the ultrasonic transducer drive unit 2012 and transmitted to the ultrasonic probe side via the switching circuit 2013. The switching circuit 2013 is a circuit for switching which of the first ultrasonic transducer array 221 and the second ultrasonic transducer array 241 shown in FIG. 13 is connected to the transmission / reception unit 201, and the control line 207 (see FIG. 4). The switching is performed in accordance with the control data input via).
The reception signal obtained on the ultrasonic probe side is transmitted to the beam former unit 203 via the switching circuit 2013 and further via the preamplifier 2014. Here, only one signal line, preamplifier 2014, and the like are shown for avoiding the complexity shown in the figure, but these are the number of ultrasonic transducers that are driven simultaneously or receive ultrasonic waves at the same time. The same number is provided.
[0050]
FIG. 16 is a diagram showing a tomographic image generated using the ultrasonic probe shown in FIG. 13. FIG. 16 (A) is a longitudinal tomographic image, and FIG. 16 (B) is a transverse layer image.
The switching circuit 2013 shown in FIG. 15 is normally switched to the second ultrasonic transducer 241 side mounted on the ultrasonic probe 21 shown in FIG. The ultrasonic transducer 21 uses the ultrasonic transducer array 241 to monitor the insertion amount (movement amount) of the ultrasonic probe 21 and acquire the longitudinal tomographic image shown in FIG. The layer image is displayed on the display screen 7071 of the observation television monitor 707.
This switching circuit 2013 is arranged on the first ultrasonic transducer array 221 side every time the insertion amount (movement amount) of the ultrasonic probe 21 reaches an insertion amount (movement amount) at a certain interval, for example, every 5 mm. Switching is performed, and a transverse layer image as shown in FIG. 16B is generated based on a reception signal obtained by ultrasonic transmission / reception using the first ultrasonic transducer array 22. The generated transverse layer image is displayed on the display screen 7071 of the observation television monitor 707 instead of the longitudinal tomographic image for a short period of time in order to provide real-time image confirmation each time, and for subsequent display. Is stored in the image memory 5001 (see FIG. 4).
[0051]
The transverse layer image stored in the image memory 5001 is read for detailed observation of the image after the operation for acquiring the tomographic image is completed, and is displayed again on the display screen 7071.
Here, it has been described that the longitudinal tomographic image and the transverse layer image are automatically switched, but can be freely switched or fixed to either by the operation of the operation panel 701 by the operator.
FIG. 17 is a perspective view showing still another embodiment of the ultrasonic probe, and FIG. 18 is a schematic cross-sectional view taken along line XX of FIG.
The ultrasonic probe 21 shown in FIG. 17 is coated with ultrasonic jelly or the like on the body surface, and is brought into contact with the body surface such as the abdominal wall through a medium such as the ultrasonic jelly to obtain a tomographic image inside the human body. Is for. The ultrasonic probe 21 has a structure described with reference to FIG. 1 on both sides of an ultrasonic transducer array 221 for obtaining a tomographic image, that is, as shown in FIG. The second ultrasonic transducer 24 is disposed obliquely with a gap with respect to the contact surface, an ultrasonic propagation medium 26, and a cover 28 for confining the ultrasonic propagation medium 26. ing. In this case, in the movement calculation units 4012 and 4022 shown in FIG. 8 or FIG. 9, the respective moving speeds based on the two second received signals obtained by the ultrasonic transmission / reception of the two second ultrasonic transducers 24 and Each amount of movement is determined. These two second ultrasonic transducers 24 transmit and receive ultrasonic waves at the same time, and may independently have a circuit for processing each of the two second received signals, or refer to FIG. As described above, a switching circuit may be provided to perform alternately.
[0052]
19 is a diagram showing data stored in the memory unit 102 in association with the tomographic image when the ultrasonic probe shown in FIG. 17 is applied to the body surface and a tomographic image is acquired. It is a schematic diagram which shows the locus | trajectory on the body surface of the ultrasonic probe shown in FIG.
Here, using the ultrasonic probe in FIG. 17, tomographic images are generated at regular time intervals and stored in the image memory 5001 (see FIG. 4). Further, along with the generation of each tomographic image, an amount of movement based on each of the second received signals obtained by each of the two second ultrasonic transducers 24 at the time of generating each tomographic image is obtained, and the image specifying the image data No. 19 is created in the memory unit 102 as shown in FIG. As shown in FIG. 20, the data stored in this table represents the position and orientation of the ultrasonic probe shown in FIG. 17 on the body surface at each tomographic image generation timing.
Thus, by creating the table shown in FIG. 19, the locus of the ultrasound probe can be known. The data of this table is displayed on the display screen as a mark representing the position of the ultrasound probe, for example, as will be described later.
[0053]
FIG. 21 is an internal block diagram of the display control unit 500 shown in FIG.
Here, a configuration for displaying a line drawing along with a tomographic image on the display screen is shown.
Image data sent from the digital scan converter unit 300 (see FIG. 4) is temporarily stored in the image memory 5001, read out, and input to the image composition unit 5003. Further, the line drawing unit 5002 draws a line drawing as described later based on the line drawing data sent via the CPU bus 901 and sends the line drawing to the image composition unit 5003. In the image composition unit 5003, the image data from the image memory 5001 and the line drawing from the line drawing unit 5002 are combined into one image, and the combined image is displayed on the observation television monitor 707. Hereinafter, examples of various line drawings will be described. Note that the tomographic image itself is shown in FIGS. 12 and 16, and the illustration of the tomographic image itself is omitted here.
[0054]
22 and 23 show line drawings associated with a tomographic image when the ultrasonic probe shown in FIG. 13 is used and a tomographic image is obtained while the ultrasonic probe is inserted into the rectum. FIG. 22 is a diagram showing the correspondence between the depth in the rectum and the position of the tomogram, and FIG. 23 is the depth in the rectum and the position of the ultrasound probe inserted in the rectum. FIG.
The number on the horizontal axis in FIG. 22 indicates the depth position in the rectum, and the straight line extending vertically at the depth position “6” in FIG. 22 is the currently acquired or currently displayed tomographic image. The fault plane position is shown. By performing such display, the operator can grasp the current tomographic plane position. The position of the horizontal axis “0” in FIG. 22 may be specified by the operator when the operator starts inserting the ultrasonic probe into the rectum, or from the inner rectal wall of the second ultrasonic transducer 24. The position of the horizontal axis “0” may be automatically determined by capturing the initial timing at which the reflected ultrasonic wave can be detected.
[0055]
In FIG. 23 as well, the horizontal axis indicates the depth position in the rectum, as in FIG. 22, and the graphic representing the ultrasonic probe is shown at the position corresponding to the current amount of insertion into the rectum.
When such an ultrasonic probe graphic is displayed, the current insertion amount is intuitively grasped, which is useful for preventing accidents such as an operator's excessive insertion.
[0056]
FIG. 24 is a diagram showing the position of the ultrasonic probe with respect to the human body when a tomographic image is obtained using the ultrasonic probe shown in FIG. 17 while applying the ultrasonic probe to the body surface; 25 and 26 are diagrams illustrating examples of line drawings displayed on the display screen.
The vertical axis | shaft of FIG. 25, FIG. 26 has shown the position of the vertical direction of the abdominal part of a human body. Here, the straight line extending to the side of FIG. 25A indicates the position of the tomographic image when the ultrasonic probe 21 is at the position of FIG. 24A, and the rectangle of FIG. This represents a region including a tomographic image when the ultrasonic probe 21 is applied obliquely to the human body 1 as shown in FIG.
In addition, the rectangles in FIGS. 26A and 26B are positions of the ultrasonic probe when the ultrasonic probe 21 is applied as shown in FIGS. 24A and 24B, respectively. Is shown.
In this way, by displaying the position of the tomographic image and the position of the ultrasonic probe, when acquiring the tomographic image, the position of the tomographic image and the ultrasonic probe is confirmed simply by looking at the display screen. Therefore, the frequency of directly confirming the position of the ultrasound probe with respect to the human body can be reduced, and when displaying a tomographic image after acquiring a tomographic image, the displayed tomographic image is displayed on the human body. It is possible to easily grasp which position is the tomographic image.
[0057]
FIG. 27 is a diagram illustrating another example of a line drawing displayed when a tomographic image is obtained while moving the ultrasonic probe.
The horizontal axis represents the moving speed of the ultrasonic probe. The hatched bar graph indicates the current moving speed of the ultrasonic probe. The vertical bar drawn at a position of 60 mm / sec indicates the moving speed of 60 mm / sec. Means the upper limit of the moving speed.
The generation of one tomographic image due to the physical restriction of ultrasonic wave propagation speed c≈1500 mm / sec in a living body requires a time of about 1/30 sec although it varies under various conditions. For this reason, if the moving speed of the ultrasonic probe is too fast, it becomes impossible to obtain a tomographic image at a predetermined interval such as 5 mm or 2 mm. Therefore, when a necessary tomographic image generation interval is input from the operation panel 701, the upper limit of the moving speed of the ultrasonic probe is calculated and displayed together with the tomographic image as shown in FIG. Further, here, the moving speed of the ultrasonic probe (hatched portion in FIG. 27) is also displayed, and the operator is warned not to exceed the upper limit of the moving speed. While performing such display, the movement amount of the ultrasonic probe is obtained, and a tomographic image is obtained at a predetermined movement interval. By performing such display, it is possible to prevent a tomographic image acquisition failure caused by moving the ultrasonic probe too quickly.
Incidentally, 1/30 sec is required to obtain one tomographic image, and in order to obtain a tomographic image having an interval of 2 mm, 60 mm / sec is the upper limit of the moving speed of the ultrasonic probe as shown in FIG.
In FIG. 27, both the moving speed of the ultrasonic probe and the upper limit of the moving speed are displayed, but only the moving speed may be displayed, or only the upper limit of the moving speed is displayed. Also good.
[0058]
FIG. 28 is a schematic diagram showing a state in which a three-dimensional tomographic image is obtained by moving the ultrasonic probe. In FIG. 28, for ease of understanding, the image memory 5001 is three-dimensionally represented, and each memory area 5001a of the image memory 5001 storing data of each pixel of the tomographic image is shown in each of the three-dimensional tomographic images. A conceptual diagram is shown in a state where it is directly superimposed on each divided region in the living body corresponding to the pixel.
Here, a tomographic image is generated while the ultrasonic probe 21 is moving in the xx ′ direction and stored in the image memory 5001. Here, when a tomographic image is generated every time the ultrasonic probe 21 moves a certain distance, the data of the tomographic image is stored in a memory region group arranged in a cross section corresponding to the generated tomographic image. Thus, a three-dimensional tomographic image is generated. On the other hand, when generating a tomographic image at regular time intervals while moving the ultrasonic probe, the generated tomographic image data is determined according to the amount of movement of the ultrasonic probe when the tomographic image is obtained. Store in a cross section. If the ultrasonic probe is moved too fast, it will not be stored in the memory area in order. However, all the memory areas are filled while the ultrasonic probe 21 is reciprocated several times in the xx ′ direction. be able to.
The three-dimensional tomogram generated in this way sequentially displays a plurality of two-dimensional tomograms constituting the three-dimensional tomogram, or a specific two-dimensional tomogram among the plurality of two-dimensional tomograms. May be used to display the image, but may be displayed as a three-dimensional tomographic image, that is, as a perspective view viewed from an arbitrary direction.
[0059]
【The invention's effect】
As described above, according to the present invention, it is possible to accurately detect the relative movement of the ultrasonic probe with respect to the living body.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a contact portion of an ultrasonic probe with a living body.
FIG. 2 is a schematic diagram showing frequency change due to Doppler shift.
FIG. 3 is a diagram showing a phase relationship of reflected ultrasonic waves.
FIG. 4 is a block diagram showing an embodiment of the ultrasonic diagnostic apparatus of the present invention.
FIG. 5 is a conceptual diagram showing a delay pattern of high voltage pulses applied to a plurality of ultrasonic transducers.
FIG. 6 is a principle explanatory diagram showing how a reception ultrasonic beam is formed in a beam former unit.
FIG. 7 is an explanatory diagram showing a relationship among a delay pattern, a scanning line direction, and a focal position.
FIG. 8 is a block diagram showing an internal configuration of a pulse / continuous wave Doppler analysis unit.
FIG. 9 is a block diagram illustrating an internal configuration of a color Doppler analysis unit.
FIG. 10 is a diagram showing an embodiment of an ultrasonic probe provided in the ultrasonic probe of the present invention.
FIG. 11 is a diagram illustrating an example of a table stored in a memory unit.
FIG. 12 is a diagram showing a series of tomographic images.
FIG. 13 is a diagram showing another embodiment of the ultrasonic probe.
14 is an enlarged view in a circle A shown in FIG.
15 is a block diagram showing a configuration of a transmission / reception unit of an ultrasonic diagnostic apparatus main body that is suitable for an ultrasonic probe including the ultrasonic probe shown in FIG.
16 is a view showing a tomographic image generated using the ultrasonic probe shown in FIG.
FIG. 17 is a perspective view showing still another embodiment of the ultrasonic probe.
18 is a schematic cross-sectional view taken along the line XX of FIG.
FIG. 19 is a diagram illustrating data stored in a memory unit in association with a tomographic image when the tomographic image is acquired by applying the ultrasonic probe illustrated in FIG. 17 to the body surface.
20 is a schematic diagram showing a trajectory on the body surface of the ultrasonic probe shown in FIG.
FIG. 21 is an internal configuration diagram of a display control unit.
FIG. 22 is a diagram showing a line drawing associated with a tomographic image when a tomographic image is obtained while inserting an ultrasonic probe into the rectum.
FIG. 23 is an example showing a line drawing associated with a tomographic image when a tomographic image is obtained while inserting an ultrasonic probe into the rectum. FIG. It is a figure which shows a response | compatibility with a position.
FIG. 24 is a diagram showing the position of the ultrasound probe with respect to the human body when creating a tomographic image while applying the ultrasound probe to the body surface.
FIG. 25 is a diagram illustrating an example of a line drawing displayed on the display screen.
FIG. 26 is a diagram illustrating another example of a line drawing displayed on the display screen.
FIG. 27 is a diagram illustrating another example of a line drawing displayed when a tomographic image is obtained while moving an ultrasonic probe.
FIG. 28 is a schematic diagram showing a state in which a three-dimensional tomographic image is obtained by moving an ultrasonic probe.
FIG. 29 is a schematic diagram of a conventional ultrasound probe provided in an ultrasound probe for prostate examination.
30 is a schematic view of the ultrasonic probe shown in FIG. 29, with a portion of the ultrasonic transducer array equipped in the ultrasonic probe being traversed. FIG.
[Explanation of symbols]
1 Living body (human body)
2 scanning lines
3 Fault plane
10 Body
20 Ultrasonic probe
21 Ultrasonic probe
22a First ultrasonic transducer
23, 25 signal line
24 Second ultrasonic transducer
26 Ultrasonic propagation medium
27 Contact surface
28, 29 Cover
100 Control unit
101 CPU section
102 Memory part
103 Beam scan controller
200 Signal processor
201 Transceiver
202 Reception delay control unit
203 Beamformer section
204 Control interface part
205 arithmetic unit
207 Control line
221 First ultrasonic transducer array
241 Second ultrasonic transducer array
300 Digital scan converter
301 Black and white scan converter
400 Doppler processing section
500 Display controller
701 Operation panel
707 Television monitor for observation
2013 switching circuit
4011 Fourier analysis unit
4012 Movement calculation unit
4021 Autocorrelation calculation unit
4022 Movement calculation unit
5001 Image memory
5002 Line drawing unit
7071 display screen

Claims (5)

An ultrasonic probe equipped with an ultrasonic transducer for transmitting and receiving ultrasonic waves is provided, the ultrasonic probe is placed in contact with a living body, and ultrasonic waves are transmitted into the living body to transmit the ultrasonic wave within the living body. An ultrasonic probe that receives an ultrasonic wave reflected and returned is connected, and generates an in-vivo tomographic image based on a received signal obtained while repeating ultrasonic wave transmission / reception using the ultrasonic probe. In the ultrasonic diagnostic equipment,
A first ultrasonic transducer array comprising a plurality of arranged first ultrasonic transducers, wherein an ultrasonic probe provided in the ultrasonic probe obtains an in-vivo tomographic image by ultrasonic waves; and a plurality disposed within spaced between the contact surface in contact with the living body, one or more second ultrasonic transducers the contact surface with respect to transmitting and receiving ultrasonic waves obliquely, away from each other For each position ,
Transmitting / receiving means for transmitting and receiving ultrasonic waves to the first ultrasonic transducer array to obtain a first received signal, and further transmitting and receiving ultrasonic waves to the second ultrasonic transducer to obtain a second received signal;
A tomographic image generating means for generating a tomographic image based on the first received signal obtained by the transmitting / receiving means;
Display means for displaying the tomographic image generated by the tomographic image generating means;
A Doppler shift detecting means for detecting a Doppler shift of an ultrasonic wave transmitted and received by the second ultrasonic transducer based on a second received signal obtained by the transmitting and receiving means;
Movement calculating means for obtaining a relative moving speed or moving amount of the ultrasonic probe relative to the living body based on the Doppler shift of the second received signal detected by the Doppler shift detecting means. ,
The movement calculating means obtains a relative moving speed or moving amount with respect to the living body with respect to each position of the ultrasonic probe where the one or more second ultrasonic transducers are provided. A characteristic ultrasonic diagnostic apparatus. An ultrasonic probe equipped with an ultrasonic transducer for transmitting and receiving ultrasonic waves is provided, the ultrasonic probe is placed in contact with a living body, and ultrasonic waves are transmitted into the living body to transmit the ultrasonic wave within the living body. An ultrasonic probe that receives an ultrasonic wave reflected and returned is connected, and generates an in-vivo tomographic image based on a received signal obtained while repeating ultrasonic wave transmission / reception using the ultrasonic probe. In the ultrasonic diagnostic equipment,
A first ultrasonic transducer array comprising a plurality of first ultrasonic transducers arranged for obtaining an in-vivo tomographic image by an ultrasonic probe provided in the ultrasonic probe; and One or more second ultrasonic transducers disposed inside and spaced apart from the contact surface in contact with the living body to transmit and receive ultrasonic waves obliquely to the contact surface, the one or more Relative to the living body, wherein the second ultrasonic transducer comprises a plurality of second ultrasonic transducers arranged in the longitudinal direction of the cylindrical shape of the ultrasonic probe. A second ultrasonic transducer array serving both for calculating velocity or amount of movement and for generating a tomographic image extending in the longitudinal direction of the cylindrical shape of the ultrasonic probe;
Transmitting / receiving means for transmitting and receiving ultrasonic waves to the first ultrasonic transducer array to obtain a first received signal, and further transmitting and receiving ultrasonic waves to the second ultrasonic transducer to obtain a second received signal;
A tomographic image generating means for generating a tomographic image based on the first received signal obtained by the transmitting / receiving means;
Display means for displaying the tomographic image generated by the tomographic image generating means;
A Doppler shift detecting means for detecting a Doppler shift of an ultrasonic wave transmitted and received by the second ultrasonic transducer based on a second received signal obtained by the transmitting and receiving means;
Movement calculating means for obtaining a relative moving speed or moving amount of the ultrasonic probe with respect to the living body based on the Doppler shift of the second received signal detected by the Doppler shift detecting means. ,
The tomographic image generating means uses a first tomographic image based on a first received signal obtained by ultrasonic transmission / reception using the first ultrasonic transducer array, and an ultrasonic wave using the second ultrasonic transducer. ultrasonic diagnostic apparatus characterized in that responsible for the generation of both the tomographic image and the second tomographic image based on the second reception signal obtained by transmission and reception. The movement calculating means obtains a movement amount relative to the living body in the longitudinal direction of the cylindrical shape of the ultrasonic probe,
Said display means, said first tomographic image and the second tomographic images, according to claim 2, characterized in der Rukoto those displayed by switching in accordance with the movement amount obtained by said moving calculation means Ultrasound diagnostic equipment. An ultrasonic probe equipped with an ultrasonic transducer for transmitting and receiving ultrasonic waves is provided, the ultrasonic probe is placed in contact with a living body, and ultrasonic waves are transmitted into the living body to transmit the ultrasonic wave within the living body. An ultrasonic probe that receives an ultrasonic wave reflected and returned is connected, and generates an in-vivo tomographic image based on a received signal obtained while repeating ultrasonic wave transmission / reception using the ultrasonic probe. In the ultrasonic diagnostic equipment,
A first ultrasonic transducer array comprising a plurality of first ultrasonic transducers arranged for obtaining an in-vivo tomographic image by an ultrasonic probe provided in the ultrasonic probe; and And having one or more second ultrasonic transducers disposed inside and spaced apart from the contact surface contacting the living body and transmitting and receiving ultrasonic waves obliquely to the contact surface. ,
Transmitting / receiving means for transmitting and receiving ultrasonic waves to the first ultrasonic transducer array to obtain a first received signal, and further transmitting and receiving ultrasonic waves to the second ultrasonic transducer to obtain a second received signal;
A tomographic image generating means for generating a tomographic image based on the first received signal obtained by the transmitting / receiving means;
Display means for displaying the tomographic image generated by the tomographic image generating means;
A Doppler shift detecting means for detecting a Doppler shift of an ultrasonic wave transmitted and received by the second ultrasonic transducer based on a second received signal obtained by the transmitting and receiving means;
Movement calculating means for obtaining a relative moving speed or moving amount of the ultrasonic probe with respect to the living body based on the Doppler shift of the second received signal detected by the Doppler shift detecting means. ,
The movement calculating means calculates a relative moving speed of the ultrasonic probe with respect to a living body;
Wherein the display means, the ultrasonic diagnostic apparatus you characterized in that for displaying the moving velocity obtained by the moving calculation means. An ultrasonic probe equipped with an ultrasonic transducer for transmitting and receiving ultrasonic waves is provided, the ultrasonic probe is placed in contact with a living body, and ultrasonic waves are transmitted into the living body to transmit the ultrasonic wave within the living body. An ultrasonic probe that receives an ultrasonic wave reflected and returned is connected, and generates an in-vivo tomographic image based on a received signal obtained while repeating ultrasonic wave transmission / reception using the ultrasonic probe. In the ultrasonic diagnostic equipment,
A first ultrasonic transducer array comprising a plurality of first ultrasonic transducers arranged for obtaining an in-vivo tomographic image by an ultrasonic probe provided in the ultrasonic probe; and And having one or more second ultrasonic transducers disposed inside and spaced apart from the contact surface contacting the living body and transmitting and receiving ultrasonic waves obliquely to the contact surface. ,
Transmitting / receiving means for transmitting and receiving ultrasonic waves to the first ultrasonic transducer array to obtain a first received signal, and further transmitting and receiving ultrasonic waves to the second ultrasonic transducer to obtain a second received signal;
A tomographic image generating means for generating a tomographic image based on the first received signal obtained by the transmitting / receiving means;
Display means for displaying the tomographic image generated by the tomographic image generating means;
A Doppler shift detecting means for detecting a Doppler shift of an ultrasonic wave transmitted and received by the second ultrasonic transducer based on a second received signal obtained by the transmitting and receiving means;
Movement calculating means for obtaining a relative moving speed or moving amount of the ultrasonic probe with respect to the living body based on the Doppler shift of the second received signal detected by the Doppler shift detecting means. ,
The movement calculating means calculates a relative movement amount of the ultrasonic probe with respect to a living body;
The tomographic image generating means generates a tomographic image based on the first received signal at a predetermined interval with respect to the movement amount obtained by the movement calculating means;
Wherein the display means, the capable of producing a tomographic image at a predetermined interval, wherein the ultrasonic probe, ultrasonic you being a shall be displayed the upper limit of the relative movement speed with respect to the living body Diagnostic device.

Images