Method for avoiding image occlusions in nuclear magnetic resonan

Details Method for avoiding image occlusions in nuclear magnetic resonan Method for avoiding image occlusions in nuclear magnetic resonan

1996-05-20

1997-04-22

Arana, Louis M.

Electricity: measuring and testing

Particle precession resonance

Using a nuclear resonance spectrometer system

324300, 324307, G01V 300

Patent

active

056232071

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.

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