JP3335381B2 - Method and apparatus for magnetic resonance imaging - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic resonance imaging apparatus and, more particularly, to an operation technique for improving the setting efficiency of imaging conditions.

[0002]

2. Description of the Related Art In a magnetic resonance imaging, the quality of a reconstructed image, the imaging time, and the pulse sequence used in the imaging greatly vary. However, even for the same type of pulse sequence, the imaging conditions (field / pulse repetition time ( TR) Echo time (T
E), inversion recovery time (TI), slice thickness, number of slices, number of imaging matrices, number of signal additions, etc.) produce a large difference. Therefore, the operator considers the burden on the patient and, in order to obtain an image that allows the doctor to make an accurate diagnosis, carefully sets the imaging conditions for each patient, taking into account the imaging time, disease type, diagnostic site, and imaging area There is a need to.

Incidentally, there are various correlations between the conditions of each imaging, and arbitrary values cannot be set independently. For example, the number of slices can be set only up to a value equal to or less than a value determined from the pulse repetition time and the echo time. The operator must search for and set conditions closest to the desired imaging conditions under such constraints based on the correlation.

[0004]

Heretofore, the allowable setting range of each imaging condition cannot be known until an actual value is input. Therefore, there is a problem that it takes time and effort to set a desired imaging condition or the closest condition, and the operation becomes complicated.

The present invention has been made to solve the above problems.

It is an object of the present invention to provide a method and an apparatus for improving the setting efficiency of imaging conditions having a complicated correlation in a magnetic resonance imaging apparatus.

[0007]

A magnetic resonance imaging apparatus for arranging a subject in a magnetic field, applying a high-frequency magnetic field to the subject, and imaging the subject based on a nuclear magnetic resonance signal generated by the subject. Input means for inputting a plurality of mutually related parameters necessary for the imaging; calculating means for calculating a settable range of each parameter based on a correlation between the plurality of parameters; and a settable range of each parameter And a display means for displaying.

[0008]

According to the above means, imaging conditions and their settable ranges are displayed on the console or the like. When any of the imaging conditions is changed, a settable range is calculated for all the imaging conditions having a correlation, and a new settable range is displayed.

By referring to the displayed settable range, the operator can efficiently set desired imaging conditions or conditions closest to the desired imaging conditions without any trouble.

Thus, a desired nuclear magnetic resonance phenomenon is caused, and as a result, an image by magnetic resonance imaging can be obtained.

[0011]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a schematic block diagram of a magnetic resonance imaging apparatus according to one embodiment of the present invention.

The magnetic resonance imaging apparatus according to the present embodiment
An inspection unit 40 comprising a bed for a subject, a coil for generating a static magnetic field, a coil for generating a gradient magnetic field, a coil for generating a high frequency magnetic field, and a coil for generating a nuclear magnetic resonance signal, a static magnetic field power supply 41, a gradient magnetic field power supply 42, a high frequency magnetic field power supply 43, Signal receiving unit 44, pulse sequence control unit 45, console 46, arithmetic unit 47,
It comprises a storage device 48 and a display 49. The inspection unit 40 has a hole for inserting a subject inside.

In the case of performing imaging in FIG.
The subject is placed in the hole of the inspection unit 40 using the subject bed. Here, for the imaging conditions read from the storage device 48 and displayed on the display 49, the operator changes desired conditions and sets the imaging conditions. The pulse sequence control unit 45 controls the gradient magnetic field power supply 42 and the high frequency magnetic field power supply 43 according to the set imaging conditions, and
A nuclear magnetic resonance phenomenon is caused to a subject in the inside. The nuclear magnetic resonance signal generated by this is detected by the nuclear magnetic resonance signal detecting coil in the inspection unit 40 and amplified and
The signal is detected and sent to the arithmetic unit 47. The image reconstruction arithmetic processing is performed by the arithmetic unit 47, and the reconstructed image is displayed on the display 49.

The image quality of the reconstructed image and the imaging time in magnetic resonance imaging greatly differ depending on the pulse sequence and imaging conditions as described above, and it is necessary to set the imaging conditions in detail according to the patient's symptoms. In addition, the setting of imaging conditions
This must be done within the constraints of the correlation between the conditions.

In order to visualize this restriction in setting imaging conditions, in this embodiment, as shown in FIG. 1, a settable range of each imaging condition is displayed.

An item 10 of the imaging condition read from the storage device 48, its value 12, and a settable range 11 calculated from the correlation between the imaging conditions are displayed on the display 49.

When the number of slices desired by the operator is 10, the settable range of the number of slices is 1 to 12 in FIG.
Since the number of slices is 1, the operator can immediately set the number of slices to 10 and start imaging.

In FIG. 1, when the number of slices desired by the operator is 15, the operator immediately determines that setting of the number of 15 slices is impossible by referring to the settable range of the number of slices. After increasing the TR, for example, within the allowable range of the imaging conditions desired by the operator, as shown in FIG. 2, it is confirmed that the settable range of the number of slices is 1 to 15, and the number of slices is reduced. Imaging can be started by setting 15 images.
At this time, even if the TR is increased within the range where the desired imaging condition is allowed by the operator, if the settable range of the number of slices is only 1 to 14, the operator sets the desired imaging condition. It is immediately possible to determine that the imaging condition is impossible, and the condition (slice number 1) that is closest to the desired imaging condition without unnecessary operation
(4 sheets), the imaging can be started.

In the above description, the display of the settable range of the imaging condition is performed according to the flow shown in FIG.

That is, in step 30, the storage device 48
Is displayed on the display 49. Step 31
Then, the settable range of all the imaging conditions is calculated, and in step 32, the calculated settable range is displayed on the display 49. Next, in step 33, it is checked whether or not imaging conditions have been set. If it has been set, imaging is performed in step 34. If not, it is checked in step 35 whether or not the imaging condition has been changed. If there is a change, a new settable range is calculated for all conditions correlated with the changed imaging condition, and the new settable range is displayed on the display 49 in step 32 in real time.

FIG. 5 shows an example of the correlation between the imaging conditions.

FIG. 5 shows TR and SE in the SE sequence.
This shows the correlation between TE and the number of slices.
The values of these conditions must satisfy Equation 1.

[Equation 1] TR ≧ (TE + t1 + t2 + t3) × the number of slices (t1, t2, and t3 vary depending on the slice thickness) The values of t1, t2, and t3 are unknown to the operator. Can not. Even if t1, t
Even if the values of 2 and t3 are known, it is very troublesome to calculate each time.

By displaying the settable range of the imaging condition of the present invention, the operator can immediately determine whether the desired imaging condition can be set.

If the setting is impossible, the conditions closest to the desired imaging conditions can be set efficiently by referring to the change in the settable range by appropriately changing the imaging conditions.

[0027]

As described above, according to the present invention,
By displaying the settable range, it is possible to improve the setting efficiency of imaging conditions having a complicated correlation.

[Brief description of the drawings]

FIG. 1 is a diagram showing display examples of imaging condition items, their values, and settable ranges according to an embodiment of the present invention.

FIG. 2 is a diagram showing display examples of imaging condition items, their values, and settable ranges when TR is changed in FIG.

FIG. 3 is a flowchart for calculating and displaying a settable range of imaging conditions.

FIG. 4 is a schematic block diagram of a magnetic resonance imaging apparatus according to one embodiment of the present invention.

FIG. 5 is a correlation diagram of imaging conditions.

[Explanation of symbols]

10 imaging condition item, 11 imaging condition value, 12 imaging condition settable range, 40 inspection unit, 41 static magnetic field power supply, 42 gradient magnetic field power supply, 43 high frequency magnetic field power supply, 44 ... Signal receiving unit, 45
... Pulse sequence control unit, 46 ... Operation console, 47 ... Computing device, 48 ... Storage device, 49 ... Display.

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yuji Enomoto 832-2 Nagakubo, Horiguchi, Katsuta-shi, Ibaraki Pref. Examiner, Hitachi Measurement Engineering Co., Ltd. Kosen Ito (56) JP-A-2-302897 (JP, A) JP-A-3-176765 (JP, A) JP-A-3-29641 (JP, A) JP-A-62-116711 (JP, U) Field (Int.Cl. ⁷ , DB name) A61B 5/055 JICST file (JOIS)

Claims (3)

(57) [Claims] A magnetic resonance imaging apparatus for arranging a subject in a magnetic field, applying a high-frequency magnetic field to the subject, and imaging the subject based on a nuclear magnetic resonance signal generated by the high frequency magnetic field. Required phases
Input means for inputting a plurality of interrelated parameters;
Each parameter is determined based on the correlation between the plurality of parameters.
Calculating means for calculating the settable range of the parameters;
Display means for displaying the settable range of data
A magnetic resonance imaging apparatus comprising: 2. The method according to claim 1, wherein the calculating means sets each of the parameters.
For the parameters set from the possible range, the correlation
Calculating the settable range again based on the relationship,
It is characterized by displaying the settable range reset to
The magnetic resonance imaging apparatus according to claim 1, wherein 3. The method according to claim 1, wherein the plurality of parameters include at least
Field of view, pulse repetition time, echo time, slice thickness,
3. The number of slices according to claim 1 or 2,
Magnetic resonance imaging equipment.