FLOW QUANTITATION WITH ECHO-PLANAR PHASE-CONTRAST VELOCITY MAPPING - IN-VITRO ANTI IN-VIVO EVALUATION

We present a multishot echo-planar imaging (EPI) phase-contrast implem entation for how quantitation, The measurement accuracy of this techni que was evaluated in vitro and in vivo, a gated eight-shot EPI phase-c ontrast sequence (TR/TE = 16/7.4, 45 degrees flip angle), with a flow- phase interval of 32 msec and an in-plane resolution of 2 X 2 mm was i nitially evaluated in a pulsatile now phantom. Subsequently, EPI phase -contrast now measurements of the ascending and descending aorta, obta ined in 10 volunteers, were compared with now volume data acquired wit h a conventional cine phase-contrast sequence (TR/TE = 24/7, 45 degree s flip angle, 48-msec how-phase interval, 2 X 1 mm in-plane resolution ), Comparisons between flow measurements were made using data obtained with the now probe and cine phase contrast as the standard of referen ce for in vitro and in vivo measurements, respectively, EPI phase-cont rast sequences reduced data acquisition times tenfold compared with ci ne phase-contrast sequences. EPI: phase-contrast flow measurements cor related well with phantom now (r = .98, slope = 1.1) as well as with a ortic cine phase-contrast now volume determinations (r = .98). A 95% c onfidence interval of measurement differences between echo-planar and cine phase-contrast imaging, ranging from 2.0 to -1058 mL/min was comp uted, Ultrafast phase-contrast now measurements are possible. Multisho t EPI phase-contrast imaging provides high measurement accuracy in pul satile vessels while keeping the image acquisition interval short enou gh to be accomplished in a comfortable breath-hold.