JPH0374101B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a nuclear magnetic resonance imaging apparatus (hereinafter referred to as NMR), and particularly relates to a scanning method and a data processing method during diagnosis.

(Prior art) One of the characteristics of NMR images is that the concentration is not only the proton ¹ H density (hereinafter referred to as ρ), but also the relaxation times T ₁ and T ₂ and scans such as pulse sequences and RF pulse intervals. It is a function of parameters,
The purpose of this method is that images with various contrasts can be obtained by varying measurement parameters, and a variety of information regarding diseases can be obtained.

(Problems to be Solved by the Invention) However, it cannot be denied that it becomes difficult to compare clinical data with each other, and images lack objectivity.

As shown in the flowchart of FIG. 9, currently used imaging methods empirically select pulse sequences and scan parameters that provide a large image contrast depending on the target disease. Also,
For diseases for which there is no clinical case, as shown in the flowchart in Figure 10, multiple images are obtained by changing the imaging conditions, and the imaging conditions that produce image contrast are empirically correlated with the disease. There is. Not only is this method of accumulating clinical data inefficient, but in actual clinical practice, scans must be performed under a large number of imaging conditions, and furthermore, for diseases for which there is no past clinical data, it is difficult to obtain scans that provide optimal contrast. There are major practical problems, such as not being possible.

On the other hand, by performing inter-image calculations from multiple NMR images,
There are attempts to obtain objectively meaningful pure T ₁ and T ₂ images and use them for diagnosis. But T ₁ ,
It is important to note that not all diseases can be diagnosed from the _T2 value alone, and that the current _T1 and _T2 calculated images are based on the S/N ratio,
There are major problems such as poor accuracy of T ₁ and T ₂ values, making it impractical for practical use.

In view of these points, it is an object of the present invention to image all diseases under the same scan conditions and shorten the scan time, while at the same time ensuring that the physical meaning of the obtained images is clear and It is an object of the present invention to provide a nuclear magnetic resonance imaging apparatus capable of obtaining objective images with effective image contrast for diagnosis.

(Means for solving the problem) In order to achieve such an object, the present invention applies a high frequency pulse and a magnetic field to an object to generate a nuclear magnetic resonance signal, and uses this signal to detect the object. In a nuclear magnetic resonance imaging device designed to obtain tissue-related images, scanning is performed using a preset optimal pulse sequence and scan parameters, T ₁ , T ₂ , and ρ calculation images are calculated from the obtained data, and then pulse The present invention is characterized in that it is equipped with control and calculation means for resynthesizing images suitable for diagnosis in response to input from a console for selecting series and setting scan parameters.

(Example) The present invention will be explained in detail below with reference to the drawings. FIG. 1 is a diagram showing the configuration of essential parts of an embodiment of an NMR imaging device according to the present invention. In the figure, 1 is a magnet assembly, inside of which a space (hole) is provided for inserting an object, and a uniform static magnetic field H ₀ is applied to the object surrounding this space. A main magnetic field coil 2, and a gradient magnetic field coil 3 for generating a gradient magnetic field (consisting of an x gradient magnetic field coil, a y gradient magnetic field coil, and a z gradient magnetic field coil configured to be able to individually generate gradient magnetic fields). ), an RF transmitting coil 4 that provides high-frequency pulses to excite the spins of atomic nuclei within the object, and a receiving coil 5 that detects NMR signals from the object.

The main magnetic field coil is connected to the static magnetic field control circuit 15, Gx,
Gy, Gz each gradient magnetic field coil is gradient magnetic field control circuit 1
4, the RF transmitting coil is connected to the power amplifier 18, and the NMR signal receiving coil is connected to the preamplifier 19.
are connected to each.

13 is a controller that controls the sequence of generation of gradient magnetic fields and high-frequency magnetic fields.
Performs necessary control to capture the NMR signal into the waveform memory 21.

17 is a gate modulation circuit, and 16 is a high frequency oscillator that generates a high frequency signal. Gate modulation circuit 17
appropriately modulates the high frequency signal output from the high frequency oscillator 16 using a control signal from the controller 13 to generate a high frequency pulse with a predetermined phase. This high frequency pulse is applied to the RF transmitting coil 4 through the RF power amplifier 18.

19 is a preamplifier that amplifies the NMR signal obtained from the detection coil 5; 20 is a phase detection circuit that phase-detects the NMR signal by referring to the output signal of the high-frequency oscillator; and 21 stores the phase-detected waveform signal from the preamplifier. In the waveform memory, here is A/
Contains a D converter.

11 is a computer that receives the signal from the waveform memory 21 and performs predetermined signal processing to obtain a tomographic image;
12 is a display device such as a television monitor that displays the obtained tomographic image.

Reference numeral 22 denotes a high-speed image processing device that completes image processing in, for example, a fraction of a second using a pipeline method or parallel processing. Note that this high-speed image calculation device 22 may be included on the computer 11 side and have an integrated configuration.

Reference numeral 30 denotes an operation console connected to the high-speed image processing device 22, which provides various information necessary for this device, such as scanning parameters such as pulse sequences and RF pulse intervals;
This is an input means for inputting other information.

Next, the procedure for creating a calculated image in such a configuration will be explained.

Here, three images obtained using the IR3SE method,
From a total of 7 images, 4 images obtained using the SR4SE method,
An example of calculating T ₁ , T ₂ , and ρ images will be explained.

In addition, the IR3SE method, as shown in Figure 2,
It is a pulse sequence based on the IRSE method {a pulse sequence that combines the Inversion Recovery method and the Spin Echo method},
In this method, a 180° pulse is repeatedly applied three times in one view to obtain three echo signals.

In addition, the SR4SE method is as shown in Figure 3.
It is based on the SRSE method (a pulse sequence that combines the Saturation Recovery method and the Spin Echo method), and is a multi-channel method that applies four 180° pulses to obtain four echo signals per view. This is the echo method.

The operation that characterizes the present invention will be mainly described below with reference to the scanning procedure shown in FIG.

(A) Optimized pulse sequences and scan parameters are set in advance. This device is programmed to scan with the set pulse sequences and scan parameters.
The same scan is used to image any disease.

However, the desired imaging region, such as the head, torso,
The scan parameters of the optimal pulse sequence change in relation to the legs, etc., and the scan conditions of the pulse sequence are determined as follows.

As a pulse sequence, T ₁ of the part to be imaged,
Within the range of T ₂ and ρ, the imaging time is short and the S/N is high.
Highly accurate T ₁ , T ₂ , and ρ calculation images can be obtained.
It is desirable to use a pulse sequence that combines the IR3SE method and the SR4SE method. The IR3SE method and
The optimal parameters in combination with the SR4SE method are determined as follows.

(1) About the pulse sequence In the pulse sequences shown in Figures 2 and 3, the interval between the 90° pulse and the center of the first echo signal T _s1 , the interval between the centers of each echo signal after the first echo signal T _s2 , 180 ₍₁₎ The interval T _d between the pulse and the 90° pulse and the repetition time T _r can be selected arbitrarily. These time managements are performed by the controller 13.

180° ₍₁₎ pulse is a 180° pulse for spin inversion, 180° ₍₂₎ is a 180° pulse for spin echo,
both to reduce pulse error.
90° _-45 /270° ₄₅ /90° _-45 composite pulses are used.

The number of 180° pulses for each view is determined by the IR3SE method.
Both SR4SE methods have even numbers.

Note that the suffix value attached to the frequency of the composite pulse represents the phase difference with the 90° excitation pulse, and these pulses are non-selective pulses.

The 90° pulse for excitation is a selective pulse,
It is Gaussian modulated.

Application of such a 90° pulse or a 180° pulse is performed as follows. That is,
A predetermined 90° pulse obtained through the gate modulation circuit 17 under the control of the controller 13 or
180° pulse signal via power amplifier 18
Apply it to the RF transmitting coil 4 and apply it to the target object.
Generates an RF magnetic field.

On the other hand, the gradient magnetic field is as follows. The gradient magnetic field G _x in the x direction is a projection gradient, and a is a spoiler for eliminating noise outside the slice plane due to the 180° pulse.

The z-direction gradient magnetic field G _z is a slice gradient, the y-direction gradient magnetic field G _y is a warp gradient, and b is a spoiler for eliminating artifacts due to 180° pulse error. Further, c is a spoiler for removing correlation between views.

Application of each gradient magnetic field is controlled by a controller 13.

Each echo signal generated by the pulse sequence as described above is detected by the receiving coil 5. The spin echo signal detected by the receiving coil is stored in a waveform memory 21 via a preamplifier 19 and a phase detection circuit 20.

(2) Regarding the signal strength formula The signal strength formula for the IR3SE method is I ₀ = C _IR3 (T ₁ /T _r ) {1-2・exp(-T _d /T ₁ )
+2・exp(−T _r /T ₁ +T _s1 /T ₁ +3T _s2 /2T ₁ )−2・exp(−T _r /T ₁
+T _s1 /T ₁ +T _s2 /2T ₁ ) +2・exp(−T _r /T ₁ +T _s1 /2T ₁ )−exp(−T _r
/T ₁ )}・ρ, the first echo is I ₀・exp(−T _s1 /T ₂ ), the second echo is I ₀・exp(−T _s1 /T ₂ −T _s1 /T ₂ ), 3 echo is I ₀ · exp (−T _s1 /T ₂ −2T _s1 /T ₂ ).

The signal strength formula for the SR4SE method is I ₀ = C _SR4 (T ₁ /T _r ){1-2・exp(−T _r /T ₁ +T
_s1 /T ₁ +5T _s2 /2T ₁ ) +2・exp(−T _r /T ₁ +T _s1 /T ₁ +3T _s2 /2T ₁ ) −2・exp(−T _r /T ₁ +T _s1 /T ₁ +T _s2 /
2T ₁ ) +2・exp(−T _r /T ₁ +T _s1 /2T ₁ )−exp(−T _r /
T ₁ )}・ρ, the first echo is I ₀・exp(−T _s1 /T ₂ ), the second echo is I ₀・exp(−T _s1 /T ₂ −T _s2 /T ₂ ), the third The echo is _I0.exp ( _-Ts1 / _T2-2Ts2 / _T2 ) and the _fourth echo is _{I0.exp ( -Ts1} / _T2-3Ts2 / _T2 ).

Here, C _IR3 and C _SR4 are functions representing the influence of the slice shape, and are determined as follows.

Let F _o (T _r , T _s , T ₁ , T ₂ , ρ) be a signal strength expression that does not include the influence of slice shape.

(b) When the angle of magnetization tilted by a 90° pulse is α°, the signal strength is sin α / 1 + cos α if the pulse sequence consists of one 90° pulse and an odd number of 180° pulses.・exp(−T _r /T ₁ )
・F _o (T _r , T _s , T ₁ , T ₂ , ρ)...(1).

(b) If a Gaussian 90° pulse is used, α at a point at a distance z from the center of the slice becomes α=(π/2)·exp(−Z ² ) (2).

(c) By integrating equation (1) with respect to z using equation (2), the signal strength including the influence of the slice shape can be found, and the following equation is obtained.

F _o (T _r , T _s , T ₁ , T ₂ , ρ)∫sin {(π/2) exp
(−Z ² )}/1+cos {(π/2) exp(−Z ² )}exp(
−T _r /T ₁ ) dZ……(3) Since the integral of equation (3) is a function only of (T ₁ /T _r ), this value can be expressed as C _pdd ((T ₁ /T _r )
Write.

(d) Since C _pdd is a function only of T ₁ /T _r , it can be calculated by numerical integration within the required range of T ₁ /T _r .
Find C _pdd and use this value to calculate Codd as T ₁ /T _r
It can be found as a polynomial.

From the above, the signal strength formula F _s (T _r , T _s , T ₁ , T ₂ , ρ) including the influence of the slice format
is determined as the product of F _o and a coefficient C _pdd representing the influence of the slice shape.

F _s (T _r , T _s , T ₁ , T ₂ , ρ) = F _o (T _r , T _s ,
T ₁ , T ₂ , ρ) C _pdd (T ₁ /T _r ) Here, C _pdd is, for example, 0.2<T ₁ /T _r
<10.0, C _pdd = 8.1537E−6(T ₁ /T _r ) ⁶ −2.95086E−4(T ₁ /
T _r ) ⁵ +4.27675E-3 (T ₁ / T _r ) ⁴ -3.17902E-2 (T ₁ / T _r ) ³ +1.29262E-1 (T ₁ / T _r
) ² −2.8554E−1 (T ₁ /T _r ) + 1.0557 If the pulse sequence consists of one 90° pulse and an even number of 180° pulses, the effect of slice shape is not included. If the signal strength formula is F _o ,
When the angle at which the magnetization falls is α°, the signal strength is sinα/1−cosα·exp(−T _r /T ₁ )·F _o (4), which can be calculated in the same manner as in the above case.

For example, if a Gaussian 90° pulse is used, 0.2<T ₁ /T ₂ <10.0, and the coefficient C _eveo representing the influence of slice shape is C _eveo = −2.4203E−5 (T ₁ /T _r ) ⁵ +5 .6861E−4(T ₁
/T _r ) ⁴ −3.6523E−3 (T ₁ /T _r ) ³ −1.0071E−2 (T ₁ /T _r ) ² +3.2162E−1 (T ₁ /T _r )
+0.9178.

By using the signal strength equation that includes the influence of the slice shape determined here, systematic errors due to the slice shape can be removed.

The above is the calculation when using the Gaussian 90° pulse, but even when using other 90° pulses, the distance z from the center of the slice
If the angle α at which the magnetization falls due to the 90° pulse at the point is found, it can be calculated in the same way.

(3) Regarding systematic errors due to 90° pulse error If the 90° pulse becomes a β° pulse due to uniformity with RF pulse, etc., the obtained signal strength will be as described above.
As in the case of (2), it can be found by integrating equation (1) or (4) with respect to z using equation (5).

α＝β・exp(−z ² ) ……(5) If the coefficient representing this influence is C〓, then
Similar to C _pdd・C _eveo , C〓 is a function only of (T ₁ /T _r ), and its shape is determined by the odd number of 180° pulses.

The 180° pulse numbers of IR3SE and SR4SE are both even numbers, so if T _r is made equal, IR3SE and
C〓 of SR4SE matches. Therefore, the influence of the 90° pulse error is multiplied by C〓 for all images, and the only effect on the calculated values of T ₁ , T ₂ , and ρ is that C〓 is applied to the ρ value.

From the above, if T _r of IR3SE and SR4SE are made equal, systematic errors due to 90° pulse errors in T ₁ and T ₂ values can be removed.

Other effects of making T _r equal are as follows. Since the coefficient C _eveo representing the influence of the slice shape is also the same between IR3SE and SR4SE, the only systematic error due to the slice shape is the ρ value multiplied by C _eveo . Therefore, if it is not necessary to calculate the ρ value with high accuracy,
A normal signal strength formula that does not include the influence of slice shape may be used. It is also effective when the slice shape is unknown.

(4) Optimization of scan parameters The scan parameters that provide the best evaluation functions for T ₁ , T ₂ , and ρ calculated images of the human body are calculated using the law of error propagation. The signal strength formula uses (2) above.
The signal strength formula is used.

Here, the theoretical formula for signal strength and the T ₁ to be found,
A method for determining scan parameters that optimize the evaluation function of a calculated image from T ₂ and ρ values will be explained. Here, the sum of standard deviations normalized as an evaluation function, that is, ρ _T1 /T ₁ +σ _T2 /T ₂ +σ〓/ρ, where σ _T1 , σ _T2 , and σ〓 are the standard deviations of T ₁ , T ₂ , and ρ Use.

The scan parameters of the seven images are ₁ ,
〓 ₂ ,…, 〓 ₇ , the signal strength formula is F ₁ , F ₂ ,…, F ₇
Then, the covariance matrix V _T1T2 〓 of the values of T ₁ , T ₂ , and ρ calculated from the image by the least squares method is V _T1T2 〓 = (A ^T V ₁₂₃ ^-1 A) ^-1 However, V ₁₂₃ is the original The variance σ ² of the original image in the image covariance matrix is expressed as σ ² ∝n ^-1 T a ^-1 , where n is the average value and _{T a} is the sampling time, and A is becomes.

Therefore, the variance of the values of T ₁ , T ₂ , and ρ is V _T1T2 〓
It is found as the diagonal element of

From the above, the evaluation functions of the calculated image are 〓 ₁ , 〓 ₂ ,
…, 〓 ₇ , T _a1 , T _a2 , …, T _a7 , n ₁ , n ₂ , …, n ₇ is found as a function.

Based on this principle, appropriate scan parameters are determined by the following procedure.

Define the theoretical formula for signal strength.

The theoretical formula, the range of T ₁ , T ₂ , and ρ you want to measure,
From the variance of the original image, the evaluation function of the calculated image is determined as a function of the scan parameter.

In the above, since the evaluation function of the calculated image has been determined as a multivariable function of the scan parameters, the scan parameters that give the best evaluation function are determined by a method (such as the simplex method) that finds the extreme values of the multivariable function.

An example of the scan parameters obtained in this manner is as follows. In addition,
T _r in the IR3SE method and the SR4SE method are made equal.

When scanning with a total scan time of 600 seconds, in the IR3SE method T _r = 2.36 seconds T _d = 0.56 seconds T _s1 = 0.02 seconds T _s2 = 0.02 seconds Average number of times (AVE) = 1 In the SR4SE method, T _r = 2.36 seconds T _s1 = 0.02 seconds T _s2 = 0.079 seconds Average number of scans (AVE) = 1 In addition, if the total scan time is 300 seconds, in the IR3SE method, T _r = 1.18 seconds T _d = 0.41 seconds T _s1 = 0.02 Seconds T _s2 = 0.02 seconds Average count (AVE) = 1 In the SR4SE method, T _r = 1.18 seconds T _s1 = 0.02 seconds T _s2 = 0.074 seconds Average count (AVE) = 1 (5) With the scan parameter in (4) above Take an image.

That is, in the IR3SE method, echo signals are measured by scanning with the above parameters over predetermined views (the number of views is, for example, 127) that are different from each other of the warp gradient (gradient magnetic field G _y ). The measured echo signals are divided into first, second, and third echo signal groups, and each is reconstructed into two-dimensional images using the computer 11 to obtain three original images.

Next, in the SR4SE method, the warp gradient (gradient magnetic field G _y ) is scanned over different predetermined views (the number of views is, for example, 127) using the above parameters, and echo signals are similarly measured and stored in the waveform memory 21. . The obtained data is divided into first, second, third and fourth echo signal groups and similarly reconstructed into two-dimensional images using the computer 11 to obtain four original images.

(B) Using the seven original images obtained in (5) above, perform inter-image calculations and calculate T ₁ , T ₂ ,
A ρ calculation image is obtained (calculated by the computer 11).

In addition, in the above method, the gradient magnetic field G _x ,
The relationship between G _y and G _z and slice, projection, and warp is arbitrary.

In this way, the precise T ₁ , T ₂ , and ρ values of the portion corresponding to each pixel are found.

(C) The console 30 has a parameter input section for the recombined image, from which parameters can be input. The high-speed image calculation device 22 calculates images of arbitrary pulse sequences and scan parameters at high speed using T ₁ , T ₂ , and ρ values, and the obtained images are displayed on the display device 12 .

For example, first select a pulse sequence for the IRSE method. Next, scan parameters T _d , T _s ,
Press the T _r setting button for an appropriate amount of time. Each T _d , T _s , and T _r are set corresponding to the pressing time length,
A recombined image with the set values is displayed. If you continue to press the T _r button, you will see that the image contrast changes as T _r changes, allowing you to find an image with the optimal contrast for diagnosis in real time.

Furthermore, images under conditions that cannot actually be realized, such as when T _r is infinite, and images that require a very long imaging time can also be easily obtained. In this calculation, the IRSE method uses the theoretical formula for the signal strength as I _IR = ρ・exp(−T _s /T ₂ ){1−2・exp(−T _d
/T ₁ )+2・exp(−T _r /T ₁ +T _s /2T ₁ ) −exp(−T _r /T ₁ )} is used. Other pulse sequences such as SR method,
Regarding the SE method, if the theoretical formula is programmed in advance, reconstructed images can be obtained in the same way.

Furthermore, it is also possible to identify diseases by resynthesizing fictitious images that are completely unrelated to the pulse sequence.
For example, a linear combination image of T ₁ , T ₂ , and ρ that maximizes Fisher's discriminant function can also be used. Furthermore, in this case, there are push buttons T ₁ , T ₂ , and ρ, which can be linearly combined with weights corresponding to the pressing times.

(Other Examples) The present invention is not limited to the above-mentioned embodiments, but can also be implemented as follows.

(1) Imaging conditions (pulse sequence, scan parameters) may be any that can obtain high S/N ratio, highly accurate T ₁ , T ₂ , and ρ calculation images in a short imaging time. This is because it is meaningless unless the resulting recombined image is of higher quality than the scanned image of the conventional method.

Other pulse sequences include the IRnSE method (n is an integer) and the FRmSE method (FR is an abbreviation for Fast Recovery method; a combination of the FR method and the SE method allows m
It is designed to obtain individual echo signals. In addition
The pulse sequence of the FR4SE method is as shown in FIG. ) may be used. Also, IR3SE
Not limited to the SR4SE method, but generally the IRnSE method.
The SRmSE method (n and m are integers) may be used.

Figure 6 shows the combinations of each pulse sequence and T ₁ , T ₂ ,
Regarding the sum of variance of the ρ coefficient images, Fig. 7 shows the sum of the variance of the T ₁ and T ₂ coefficient images in each pulse sequence.
The variance of the T ₁ and T ₂ values is shown, and FIG. 8 shows the number of images used for each pulse sequence and the sum of the variance of the T ₁ , T ₂ , and ρ calculation images, respectively.

Further, although the imaging conditions are the same for any disease, several scan programs are prepared and may be configured to be arbitrarily selectable for more effective scanning. In short, all diagnoses are based on the use of recombined images.

(Effects of the Invention) As explained above, the present invention has the following effects.

(1) Since all diseases are imaged using the same pulse sequence and scan parameters, there is no need for doctors to select imaging conditions. Therefore, uniform imaging is possible without knowing the relationship between the disease and the imaging conditions. Because the imaging conditions were incorrect, the disease could not be identified from the image, eliminating the need for wasteful operations such as rescanning. In addition, images of unknown diseases can be similarly imaged without any consideration. From this point of view, the present invention has a great effect on the widespread use of NMR devices when put into practical use.

(2) Some diseases conventionally require a long imaging time, but according to the present invention, the imaging time can be shortened.

(3) Since the same imaging conditions are used, there is objectivity between images and they can be compared with each other. If all NMR images are taken under the same imaging conditions, this would have revolutionary implications for information exchange and data accumulation.

(4) Since diagnosis is made using recombined images, the best image contrast is always obtained, and diagnosis is made quickly and accurately.

(5) In conventional devices, the hardware was complicated because scanning could be performed freely with various pulse sequences and scan parameters, but in the present invention, only one imaging condition (or a small number of imaging conditions) is required.
Therefore, the hardware can be simplified.

(6) It can treat all kinds of diseases and complex diseases. Since the imaging conditions under which maximum contrast can be obtained differ depending on the type of disease, this was difficult with conventional devices, but with the present invention, images under any conditions can be obtained by recombining images.

(7) In addition to morphological diagnosis using image contrast, highly accurate T ₁ , T ₂ , and ρ values can be obtained.
Pathological diagnosis is also possible from this biological information.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the main part configuration of an embodiment of the nuclear magnetic resonance imaging device according to the present invention, FIG. 2 is a diagram showing a pulse sequence of the IR3SE method, and FIG. 3 is a diagram showing a pulse sequence of the SR4SE method. Figure 4 shows the scan procedure, Figure 5 shows the pulse sequence of the FR4SE method, and Figure 6 shows the combinations of each pulse sequence.
Diagram showing the sum of variance of T ₁ , T ₂ , and ρ calculation images, 7th
The figure shows the T ₁ and T ₂ calculation images for each pulse sequence.
Figure 8 shows the number of images used for each pulse sequence and the sum of the variance of T _{1 ,} T ₂ and ρ calculation images. Figures 9 _and 10 show the conventional 2 is a flowchart for explaining the scanning procedure of FIG. DESCRIPTION OF SYMBOLS 1... Magnet assembly, 2... Main magnetic field coil, 3... Gradient magnetic field coil, 4... RF transmitting coil, 5... Receiving coil, 11... Computer, 12... Display, 13... Controller ,1
4... Gradient magnetic field control circuit, 15... Static magnetic field control circuit, 16... High frequency oscillator, 17... Gate modulation circuit, 18... Power amplifier, 19... Preamplifier, 20... Phase detection circuit, 21... Waveform memory, 30...operation console.

Claims (1)

[Scope of Claims] 1. A nuclear magnetic resonance imaging apparatus that applies high-frequency pulses and a magnetic field to a target object to generate nuclear magnetic resonance signals, and uses the signals to obtain images regarding the tissue of the target object, comprising: Within the T1, T2, and ρ range of the desired part, the imaging time is short, the S/N ratio is high, and the T1 is highly accurate.
Using the pulse sequence that yields T2 and ρ calculation images and the scan parameters determined by the method below, the same scan region is imaged with the same scan for the purpose of imaging any disease. From the obtained data, T1, T2,
What is claimed is: 1. A nuclear magnetic resonance imaging apparatus comprising control and calculation means having a function of obtaining a ρ calculation image and resynthesizing the images according to an input signal from an operation console. Note: Define the theoretical formula for signal strength. Using this theoretical formula, the range of T1, T2, and ρ to be measured, and the variance of the original image, the evaluation function of the calculated image is determined as a multivariable function of the scan parameter. A scan parameter that provides the best evaluation function is determined by a method of determining the extreme value of a multivariable function. 2. A claim characterized in that the pulse sequence used during the scanning is configured to use the IRnSE method and the SRmSE method (n and m are integers), or the IRnSE method and the FRmSE method (n and m are integers). Item 1
The nuclear magnetic resonance imaging device described in . 3 As the pulse sequence used during the scan, the IR3SE method and the SR4SE method, or the IR3SE method and the
The nuclear magnetic resonance imaging apparatus according to claim 1, characterized in that it is configured to use the FR4SE method. 4. The console is configured so that it is possible to select a pulse sequence and continuously vary scan parameter settings during image resynthesis, and to enable settings such that the resynthesized image display follows in real time. The nuclear magnetic resonance imaging apparatus according to claim 1.