JPH0591988A - Mr imaging system - Google Patents

Abstract

PURPOSE:To provide an MR imaging system wherein a local presaturation can be treated. CONSTITUTION:A surface coil 12 is selected by means of a coil selector 11 to treat presaturation and then a body coil 13 is selected by means of a coil selector 11 to perform imaging. As a presaturation region which is independent from the image region can be formed thereby, only a specified position and blood flow can be observed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an MR imaging apparatus, and more particularly to an MR imaging apparatus capable of locally presaturating.

[0002]

2. Description of the Related Art Presaturation is generally used to prevent artifacts due to body movements and blood flow. For example, as shown in FIG.
A presaturation pulse is applied to each of the presaturation regions P1 and P2 upstream of the blood vessels a and b passing through 1 to make the blood flow flowing into the image region I1 non-signal and prevent artifacts. Further, as shown in FIG. 8, a presaturation pulse is applied to the presaturation region P3 upstream of the blood flow flowing into the image region I2 to make the blood flow in the blood vessels d and e non-signal and prevent artifacts.

Further, the presaturation is also used in MR angio to make the blood flow flowing in a direction different from the target direction unsignalized and to see only the blood flow in the target direction. For example, by applying a presaturation pulse only to the presaturation region P2 upstream of the blood vessel b shown in FIG.
Only see the blood flow of.

[0004]

In the conventional MR imaging apparatus, since the presaturation pulse is applied by the body coil, the presaturation region becomes flat as shown in FIGS. 7 and 8.

However, in such a flat presaturation region, for example, in the case of FIG.
Pre-saturation is applied to and at the same time, so the blood flow of blood vessel e is de-signaled in MR angio,
There is a problem that it is not possible to see only the blood flow of the blood vessel d.

Therefore, an object of the present invention is to provide an MR imaging apparatus capable of locally setting a presaturation region.

[0007]

In the MR imaging apparatus of the present invention, an imaging coil, a presaturation coil separate from the imaging coil, and a presaturation by the presaturation coil are performed before the imaging. It is characterized in that it is provided with a coil selection control means for selecting a coil so as to pick up an image with the use coil. For example, a body coil can be used as the imaging coil and a surface coil can be used as the presaturation coil. Conversely, a surface coil can be used as the imaging coil and a body coil can be used as the presaturation coil. It is also possible to use a surface coil as the imaging coil and another surface coil as the presaturation coil.

[0008]

In the MR imaging apparatus of the present invention, the imaging coil and the presaturation coil are separately provided, and the coils are selectively used by the coil selection control means. Therefore, for example, if the body coil is used as the imaging coil and the surface coil is used as the presaturation coil, it is possible to set the local presaturation region with respect to the flat image region. That is, in the case of FIG. 8, it becomes possible to presaturate only the blood vessel e to make the blood flow non-signal, and to see only the blood flow in the blood vessel d.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to the embodiments shown in the drawings. However, this does not limit the present invention. FIG. 1 is a block diagram of an MR imaging apparatus 1 according to an embodiment of the present invention. This MR
Description will be made assuming that the imaging apparatus 1 executes the MR angio scan sequence shown in FIG.
The computer 2 controls the overall operation based on the instruction from the console 18.

The sequence controller 3 operates the static magnetic field power supply 4 to generate the static magnetic field with the static magnetic field coil 5, and also operates the gradient magnetic field driving circuit 6 to generate the gradient magnetic field with the gradient magnetic field coil 7. Further, the gate modulation circuit 9 is controlled to modulate the RF signal generated by the RF generation circuit 8 into a presaturation pulse Pre-SAT, and the RF power amplification unit 1
Output from 0 to the coil selector 11.

The coil selector 11 is switched to the surface coil 12 side by the coil selector signal from the sequence controller 3 as shown by the solid line in FIG.
The presaturation pulse Pre-SAT is applied to the surface coil coil 12.

The surface coil 12 has, for example, a ring shape as shown in FIG. 3 and is installed in the vicinity of a blood vessel e (target site for presaturation) as shown in FIG. Since the presaturation region P4 formed by the surface coil 12 is only in the vicinity of the surface coil 12, only the blood flow of the blood vessel e is presaturated and made non-signal, but the blood flow of the blood vessel d is not presaturated.

The coil selector 11 is switched to the body coil 13 side as shown by the dotted line in FIG. 1 after presaturation by the coil selector signal from the sequence controller 3. The body coil 13 has a saddle shape as shown in FIG. 4, for example.

The sequence controller 3 controls the gate modulation circuit 9, modulates the RF signal generated by the RF oscillation circuit 8 into 90 ° and 180 ° pulses, and the RF power amplifier 10.
To the coil selector 11.

Since the coil selector 11 is switched to the body coil 13 side as described above, 90 °, 18
The 0 ° pulse is applied to the body coil 13. As a result, the image area I2 shown in FIG.
The NMR signal is received by the body coil 13. This NMR signal does not include the blood flow information of the blood vessel e, but includes the blood flow information of the blood vessel d.

The received NMR signal is transferred to the preamplifier 14
Is input to the phase detector 15 via the, and further input to the computer 2 via the AD converter 16. Calculator 2 is A
An image is reconstructed based on the NMR signal data obtained from the D converter 16 and displayed on the display device 17. According to the MR angio image thus obtained, only the blood vessel d can be seen without being obstructed by the blood vessel e.

FIG. 6 is an explanatory view of another embodiment of the MR imaging apparatus of the present invention. The neck coil NC shown in FIG. 6A is used in place of the surface coil 12 in FIG. 1, and the head coil HC is used in place of the body coil 13. As shown in (b) of FIG. 6, the presaturation region P should include three blood vessels of the four main blood vessels of the neck.
If 5 and P6 are set, only the remaining one blood vessel f can be seen.

As a further embodiment, in ordinary MR imaging that is not angio, an image in which a local presaturation region is set only in a part of the image region and the NMR signal from that part is suppressed is obtained. You can get what you get.

In yet another embodiment, a combination of a plurality of imaging coils and a presaturation coil is used to set a complicated presaturation region and image region.

[0020]

According to the MR imaging apparatus of the present invention, since the presaturation coil is provided separately from the imaging coil, presaturation can be performed in a presaturation region independent of the image region. Therefore, it becomes possible to see only a specific part and blood flow.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of an MR imaging apparatus of the present invention.

2 is an exemplary diagram of a sequence of MR angioscan by the MR imaging apparatus of FIG. 1. FIG.

FIG. 3 is an exemplary view of a surface coil.

FIG. 4 is an exemplary view of a body coil.

5 is an explanatory diagram for local presaturation by the MR imaging apparatus of FIG. 1. FIG.

FIG. 6 is an explanatory diagram of another embodiment of local presaturation by the MR imaging apparatus of FIG.

FIG. 7 is an explanatory diagram of a conventional presaturation.

FIG. 8 is another explanatory diagram of a conventional presaturation.

[Explanation of symbols]

 1 MR Imaging Device 2 Computer 3 Sequence Controller 11 Coil Selector 12 Surface Coil 13 Body Coil

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G01P 13/00 O 8708-2F 9118-2J G01N 24/04 Y 9118-2J 24/08 Y

Claims (1)

[Claims] 1. An imaging coil, a presaturation coil separate from the imaging coil, and presaturation with the presaturation coil, and then selecting the coil for imaging with the imaging coil. An MR imaging apparatus comprising a coil selection control means.