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:
Sep. 13, 1994
Filed:
Apr. 23, 1993
Gerrit H Van Yperen, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
In a spin-echo magnetic resonance sequence a phase encoding gradient magnetic field (39) is applied after the 180.degree. rephasing pulse (32.sub.1). After detection of the spin-echo signal (33) the position dependent phases are compensated for by applying a further gradient magnetic field (39'), identical in size but opposite in sign. The phase difference (.phi..sub.32,1 -.phi..sub.31,1) between the RF-pulses (31.sub.1,32.sub.1) applied within a sequence is constant over the sequences. With no position dependent effects left at the end of a sequence the next sequence can be started immediately following the earlier one. A repetition time TR substantially shorter than the spin-spin relaxation time T.sub.2 is feasible, thereby developing a steady state of the magnetization. A TR of 50 ms or less can be obtained, as well as strong signals for long T.sub.2 substances and good T.sub.2 contrast. RF spoiling by changing phases of RF-pulses in subsequent sequences can destroy the T.sub.2 signal and provide images with pure T.sub.1 contrast.