Conjugation and hybrid MR imaging

To evaluate the use of conjugation with hybrid magnetic resonance imaging techniques in order to reduce artifacts from inconsistencies introduced by T2 decay.

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.

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.

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.