Radiology, Vol 189, 891-895, Copyright © 1993 by Radiological Society of North America
Conjugation and hybrid MR imaging
H Avram, H Chen and L Kaufman
Diasonics Toshiba America MRI, Inc, South San Francisco, Calif.
PURPOSE: To evaluate the use of conjugation with hybrid magnetic resonance
imaging techniques in order to reduce artifacts from inconsistencies
introduced by T2 decay. MATERIALS AND METHODS: Two phantoms containing
either oil or water were used to study edge spread function (ESF) and
signal-to-noise ratio (S/N) for three hybrid acquisition strategies (low
pass, high pass, and ramp) in which a full set was acquired or with partial
acquisition and conjugation. RESULTS: With half the echoes providing
coverage of the same amount of k space, signal inconsistencies were reduced
by a factor of at least e. Conjugation improved ESF degradation, and
sequence efficiency increased by over 50%, which compensated for a loss in
S/N. CONCLUSION: The time saved with conjugation can be used to nearly
double the number of sections acquired for a given repetition time (TR) or
to obtain two simultaneous echoes instead of one, with reduction of
artifacts. Alternatively, the imaging time can be nearly halved for a given
TR and number of sections.
