发明名称 |
Nuclear magnetic resonance imaging apparatus |
摘要 |
A nuclear magnetic resonance imaging apparatus for deriving a signal from a moving part of an object to be imaged, includes a gradient magnetic field generator for applying a gradient magnetic field to the object; and a radio frequency magnetic field generator for applying a radio frequency magnetic field to the object to present a nuclear magnetic resonance phenomenon. Pulses of a 180 degree pulse method are generated to remove an adverse effect of ununiformity of a static magnetic field; two gradient magnetic fields having the same amplitude and grading oppositely to each other are applied at a certain time interval therebetween to the moving part of the object in the direction of motion of the moving object; a radio frequency magnetic field is generated by applying a pulse in the pulses of the 180 degree pulse method succeeding a 180 degree pulse at the time corresponding to the center of an echo signal generated by the 180 degree pulse, the radio frequency magnetic field making a nuclear spin vector at the stationary part of the object in parallel to the static magnetic field; a resonance signal is detected which is produced from the object upon application of the radio frequency magnetic field; the above process is performed to further obtain another resonance signal, reversing the polarities of the gradient magnetic fields; and a difference between the two resonance signals is derived as a signal from the moving part of the object.
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申请公布号 |
US4889127(A) |
申请公布日期 |
1989.12.26 |
申请号 |
US19870037855 |
申请日期 |
1987.04.13 |
申请人 |
HITACHI, LTD. |
发明人 |
TAKEDA, RYUZABURO;KOIZUMI, HIDEAKI;MIYAMOTO, YOSHIYUKI |
分类号 |
A61B10/00;A61B5/055;G01R33/48;G01R33/563 |
主分类号 |
A61B10/00 |
代理机构 |
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地址 |
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