RESPIRATORY AND POSTPRANDIAL CHANGES IN PORTAL FLOW-RATE - ASSESSMENTBY PHASE-CONTRAST MR-IMAGING

The objective of this study was to investigate the variability of seve ral different phase contrast (PC) magnetic resonance techniques and du plex Doppler imaging (DDI) for measuring portal now rate (PFR) with di fferent patterns of respiration before and after a standard meal, PFR was measured in nine normal volunteers in both fasting and postprandia l states, using both 2D and cine PC MR techniques. Two-dimensional PC technique was performed with and without breath-hold (BH). Four differ ent patterns of BH (relaxed maximal inspiration, expiration, Valsalva maneuver, and Muller or reversed Valsalva) were used, Cine PC techniqu e was performed without BH. DDI measurement of PFR was done in the fas ting state with relaxed inspiration, PFR measurements made by means of PC MR techniques varied, depending on BH method, and were systematica lly less than those obtained by DDI, PFR measured during inspiration w as significantly less than that measured during expiration and other r espiratory maneuvers (P < .03), PFR increased significantly after a me al for PC and Doppler measurements, with a range of mean increases of 24 to 74%, Two-dimensional PC MR imaging techniques yielded differing measurements of PFR, depending on whether they were done with or witho ut BH, as well as on the pattern of BH, PC mean measures of PFR were c onsistently less than those of DDI, The physiologic inspiratory decrea ses and postprandial increases of the PFR were evident from 2D and cin e PC MRI techniques, as well as with DDI.