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:
Apr. 22, 1997
Filed:
May. 20, 1996
Volker Weissenberger, Moehrendorf, DE;
Peter Heubes, Poxdorf, DE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
In a method for avoiding image occlusions in nuclear magnetic resonance tomography apparatus that are operated with multi-echo sequences, at a time t.sub.0, a cross-magnetization in spins is generated in an examination subject with an excitation radio-frequency pulse. At times t.sub.1, t.sub.3, t.sub.5 . . . , at least two refocusing radio-frequency pulses that re-phase the cross-magnetization follow and read-out intervals follow at times t.sub.2, t.sub.4, t.sub.6 . . . The following condition is satisfied in at least one direction for the gradients G activated during the pulse sequence: ##EQU1## Even given quadratic gradient terms, thus, no phase difference occurs between a primary and a stimulated echo path. The presence of such a phase difference causes an image occlusion, and thus such occlusions are avoided by eliminating such a phase difference.