MRI APPARATUS

• US 20090118607A1
• Filed: 10/30/2008
• Published: 05/07/2009
• Est. Priority Date: 11/02/2007
• Status: Active Grant

• Current Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Original Assignee: Toshiba Medical Systems Corporation (Canon Inc.), Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Ookawa, Masashi
• Granted Patent: US 7,990,142 B2
• Time in Patent Office: Days
• US Class Current: 600/410
• CPC Class Codes: G01R 33/4828 Resolving the MR signals of different chemical species, e.g. water-fat imaging
• CPC Class Codes: G01R 33/5607 by reducing the NMR signal of a particular spin species, e.g. of a chemical species for fat suppression, or of a moving spin species for black-blood imaging

Abstract

An MRI apparatus has a waveform setting unit, an applying control unit, a reconstructing unit, and a display control unit. The waveform setting unit sets an asymmetric RF pulse Waveform. The applying control unit controls an application of a pulse in accordance with the RF pulse waveform. The reconstructing unit reconstructs an image based on a signal received by the application. The display control unit controls a display of the image.

Claims

1. An MRI apparatus comprising:

a waveform setting unit configured to set an asymmetric RF pulse waveform;

an applying control unit configured to control an application of a pulse in accordance with the RF pulse waveform;

a reconstructing unit configured to reconstruct an image based on a signal received by the application; and

a display control unit configured to control a display of the image.

2. The MRI apparatus according to claim 1, wherein the waveform setting unit sets the RF pulse waveform such that a decrease ratio of a flip angle after an excitation center is different from an increase ratio of a flip angle to the excitation center.

3. The MRI apparatus according to claim 1, wherein the waveform setting unit includes a first waveform setting unit configured to set a desired binomial pulse waveform which a number of waves is 3 or more, and a second waveform setting unit configured to generate and set a deformed binomial pulse waveform by deleting a deleted waveform included in the binomial pulse waveform and adding an flip angle calculated based on the deleted waveform to a rest of the waveform.

4. The MRI apparatus according to claim 3, wherein the second waveform setting unit forms the added waveform by using waves from a beginning to the excitation center in the binomial pulse waveform when the number of waves for forming the binomial pulse waveform is an odd number, while forms the added waveform by using waves from a beginning to shortly after the excitation center in the binomial pulse waveform when the number of waves for forming the binomial pulse waveform is an even number.

5. The MRI apparatus according to claim 3, wherein the second waveform setting unit generates the deformed binomial pulse waveform, because the second waveform setting unit matches total flip angles by uniformly adding the flip angle calculated based on the deleted waveform to the added waveform.

6. The MRI apparatus according to claim 3, wherein the second waveform setting unit generates the deformed binomial pulse waveform, because the second waveform setting unit matches total flip angles by proportionally adding the flip angle calculated based on the deleted waveform to the added waveform.

7. The MRI apparatus according to claim 1, wherein the applying control unit controls the application in accordance with a resonant frequency of free water.

8. The MRI apparatus according to claim 1, wherein the applying control unit controls the application in accordance with a resonant frequency of bound water.

9. The MRI apparatus according to claim 1, wherein the reconstructing unit receives an NMR signal from a multi coil in parallel by using the multi coil as an RF coil.

10. The MRI apparatus according to claim 1, wherein an RF coil is used as a multi coil from where the deformed binomial pulse is transmitted in parallel.

11. An MRI apparatus for generating an MRI image using a binomial pulse for a same nuclide excitation, comprising:

a waveform setting unit configured to generate and set a deformed binomial pulse waveform by deleting a portion of the binomial pulse waveform and adding an flip angle calculated based on the deleted waveform to a rest of the waveform if a number of waves of the binomial pulse waveform is 3 or more; and

an applying control unit configured to control application of a pulse in accordance with the deformed binomial pulse waveform set by the waveform setting unit.

12. An MRI apparatus for generating an MRI image using a binomial pulse for a same nuclide excitation, comprising:

a waveform setting unit configured to generate and set a deformed binomial pulse waveform by admeasuring an intensity or a flip angle which should be used for one waveform included in the binomial pulse waveform to the other waveform; and

an applying control unit configured to control application of a pulse in accordance with the deformed binomial pulse waveform set by the waveform setting unit.