Magnetic resonance imaging method and apparatus

Patent metadata

Field	Value
Publication number	US-9658306-B2
Application number	US-201314074038-A
Country	US
Kind code	B2
Filing date	Nov 7, 2013
Priority date	Dec 5, 2012
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

A magnetic resonance imaging (MRI) method and apparatus are provided including a signal acquirer, a resonance frequency acquirer, and an RF driver. The signal acquirer is configured to acquire a free induction decay (FID) signal or an echo signal to generate a magnetic resonance image of a portion of an area of a subject. The resonance frequency acquirer is configured to acquire a resonance frequency of the portion of the area from the acquired FID signal. The RF driver is configured to generate a refocusing RF pulse having the acquired resonance frequency. The signal acquirer, the resonance frequency acquirer and the RF driver are configured to acquire and generate in each of sections of an RF pulse sequence.

First claim

What is claimed is:

1. A magnetic resonance imaging (MRI) method, comprising:
acquiring a resonance frequency of a portion of an area of a subject from a free induction decay (FID) signal by performing a transform of the acquired FID signal and determining a frequency with a peak value according to the transform; and
applying a refocusing radio frequency (RF) pulse comprising the resonance frequency to acquire an echo signal to generate a magnetic resonance image of the portion of the area,
wherein the acquiring of the resonance frequency and the applying of the refocusing RF pulse are performed in each of sections, corresponding to a repetition time, of an RF pulse sequence, and wherein the resonance frequency is used to generate the refocusing RF pulse in a same section and to generate an excitation RF pulse in a next section, the next section corresponding to a next repetition time.

2. The MRI method as recited in claim 1 , further comprising:
applying an excitation RF pulse to acquire the FID signal, wherein the excitation RF pulse of a next section of each of the sections has the resonance frequency acquired in each of the sections of the RF pulse sequence.

3. The MRI method as recited in claim 1 , wherein two refocusing RF pulses of each of the sections of the RF pulse sequence have the resonance frequency acquired in each of the sections of the RF pulse sequence.

4. The MRI method as recited in claim 1 , wherein the acquiring of the resonance frequency is performed in real-time.

5. The MRI method as recited in claim 1 , wherein the acquiring of the resonance frequency comprises:
acquiring the FID signal of the portion of the area in response to an applied excitation RF pulse,
performing Fourier Transform of the acquired FID signal,
determining a frequency having a peak value from a frequency spectrum of the acquired FID signal according to the Fourier Transform, and
acquiring the determined frequency having the peak value as the resonance frequency of the portion of the area.

6. The MRI method as recited in claim 1 , further comprising:
configuring the RF pulse sequence to be a spin echo or a fast spin echo.

7. The MRI method as recited in claim 1 , further comprising:
configuring an excitation RF pulse to acquire the FID signal to be a 90° RF pulse, and the refocusing RF pulse to be 180° RF pulse.

8. The MRI method as recited in claim 1 , further comprising:
configuring the predetermined area to be a 2-dimensional (2D) cross-section of the subject or a 3-dimensional (3D) sub-volume.

9. A computer program embodied on a non-transitory computer readable medium, the computer program being configured to control a processor to perform the MRI method of claim 1 .

10. A magnetic resonance imaging (MRI) apparatus, comprising:
a signal acquirer configured to acquire a free induction decay (FID) signal or an echo signal to generate a magnetic resonance image of a portion of an area of a subject;
a resonance frequency acquirer configured to acquire a resonance frequency of the portion of the area from the acquired FID signal by performing a transform of the acquired FID signal and determining a frequency with a peak value according to the transform; and
an RF driver configured to generate a refocusing RF pulse having the acquired resonance frequency,
wherein the signal acquirer, the resonance frequency acquirer and the RF driver are configured to acquire and generate in each of sections, corresponding to a repetition time, of an RF pulse sequence, and wherein the resonance frequency is used to generate the refocusing RF pulse in a same section and to generate an excitation RF pulse in a next section, the next section corresponding to a next repetition time.

11. The MRI apparatus as recited in claim 10 , wherein the RF driver uses the acquired resonance frequency to generate an excitation RF pulse of a next section of each of the sections.

12. The MRI apparatus as recited in claim 10 , wherein the RF driver uses the resonance frequency acquired in each of the sections to generate at least two refocusing RF pulses of each of the sections.

13. The MRI apparatus as recited in claim 10 , wherein the resonance frequency acquirer acquires the resonance frequency in real-time.

14. The MRI apparatus as recited in claim 10 , wherein the resonance frequency acquirer comprises:
a converter configured to perform Fourier Transform of the acquired FID signal,
a determiner configured to determine a frequency having a peak value from a frequency spectrum of the acquired FID signal according to the Fourier Transform to acquire the resonance frequency of the portion of the area, and
a storage configured to store the acquired FID signal and the acquired resonance frequency.

15. The MRI apparatus as recited in claim 10 , wherein the RF pulse sequence is a spin echo or a fast spin echo.

16. The MRI apparatus as recited in claim 10 , wherein an excitation RF pulse to acquire the FID signal is a 90° RF pulse, and the refocusing RF pulse is 180° RF pulse.

17. The MRI apparatus as recited in claim 10 , wherein the predetermined area is a 2D cross-section of the subject or a 3D sub volume.

18. The MRI method as recited in claim 1 , further comprising determining whether the RF pulse sequence is completely applied to generate the magnetic resonance image of the predetermined area, and in response to a negative determination, using the same acquired resonance frequency to generate an excitation RF pulse in a next section of the RF pulse sequence.

Assignees

• Samsung Electronics Co Ltd

Inventors

• Son Jong-Bum
• Lee Seong-Deok
• Yi Jaemock

Classifications

• G01R33/56563 Primary

  caused by a distortion of the main magnetic field B0, e.g. temporal variation of the magnitude or spatial inhomogeneity of B0 (G01R33/56509, G01R33/56518, G01R33/56536 take precedence) · CPC title

• A61B5/055 Primary

  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging · CPC title