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 implementation for how quantitation, The measurement accuracy of this technique was evaluated in vitro and in vivo, a gated eight-shot EPI phase-contrast 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 initially evaluated in a pulsatile now phantom. Subsequently, EPI phase-contrast now measurements of the ascending and descending aorta, obtained in 10 volunteers, were compared with now volume data acquired with a conventional cine phase-contrast sequence (TR/TE = 24/7, 45 degrees 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 reference for in vitro and in vivo measurements, respectively, EPI phase-contrast sequences reduced data acquisition times tenfold compared with cine phase-contrast sequences. EPI: phase-contrast flow measurements correlated well with phantom now (r = .98, slope = 1.1) as well as with aortic cine phase-contrast now volume determinations (r = .98). A 95% confidence interval of measurement differences between echo-planar and cine phase-contrast imaging, ranging from 2.0 to -1058 mL/min was computed, Ultrafast phase-contrast now measurements are possible. Multishot EPI phase-contrast imaging provides high measurement accuracy in pulsatile vessels while keeping the image acquisition interval short enough to be accomplished in a comfortable breath-hold.