The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 26, 1989
Filed:
Apr. 13, 1987
Hitachi, Ltd., Tokyo, JP;
Abstract
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.