| US 7,348,779 B2 | ||
| Magnetic resonance imaging method and system | ||
| Shouichi Miyawaki, Chiba (Japan); Hiroyuki Takeuchi, Chiba (Japan); and Yasumasa Saito, Chiba (Japan) | ||
| Assigned to Hitachi Medical Corporation, Tokyo (Japan) | ||
| Appl. No. 10/564,249 PCT Filed Jun. 08, 2004, PCT No. PCT/JP2004/007957 § 371(c)(1), (2), (4) Date Jan. 11, 2006, PCT Pub. No. WO2005/006979, PCT Pub. Date Jan. 27, 2005. |
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| Claims priority of application No. 2003-198595 (JP), filed on Jul. 17, 2003. | ||
| Prior Publication US 2006/0192558 A1, Aug. 31, 2006 | ||
| Int. Cl. G01V 3/00 (2006.01) | ||
| U.S. Cl. 324—320 [324/307] | 16 Claims |
| 1. A magnetic resonance imaging method comprising:
(1) a step for applying one or more pulses of the gradient magnetic field sequentially and detecting nuclear magnetic resonance
signals for reconstructing magnetic resonance images;
(2) a step for calculating a residual magnetic field being generated in the magnetic device by the applied gradient magnetic
field on the basis of the residual magnetic field response function that represents the relation between the strength of the
applied gradient magnetic field and the strength of the residual magnetic field being generated by the applied gradient magnetic
field; and
(3) a step for correcting the residual magnetic field calculated in the step (2) along with the application of each pulse
of the gradient magnetic field;
(4) a step for updating the residual magnetic field response function in accordance with the strength of each pulse of the
applied gradient magnetic field along with the application of the gradient magnetic field pulses,
wherein
the calculation in step (2) is executed to calculate the strength of the residual magnetic field upon every application of
the gradient magnetic field pulse in the process of executing the imaging sequence, and
the strength of the residual magnetic field calculated in step (2) is used to correct the residual magnetic field in step
(3) which changes the strength in accordance with every application of the gradient magnetic field pulse in the process of
executing the imaging sequence, and
updating of the residual magnetic field response function in step (4) is executed upon every application of the gradient magnetic
field pulse in the process of executing the imaging sequence, and
the calculation of the residual magnetic field in step (2) is executed by using the residual magnetic field response function
updated in step (4), and
the residual magnetic field response function, which is used in step (2) and updated in step (4), is stored in a storage means
and updated in real time and changes in accordance with every application of the gradient magnetic field pulse in the process
of executing the imaging sequence.
|