3-DIMENSIONAL VISUALIZATION OF VELOCITY PROFILES IN THE HUMAN MAIN PULMONARY-ARTERY WITH MAGNETIC-RESONANCE PHASE-VELOCITY MAPPING

Detailed data on blood velocity fields in the normal human main pulmon ary artery are an essential platform for discriminating physiologic fr om pathologic pulmonary flow patterns. Over the years, many studies ha ve revealed quite inconsistent data mainly because of lack of suitable measuring techniques. By using combined cardiac- and respiratory-trig gered magnetic resonance phase velocity mapping, very consistent data were obtained in 12 volunteers. In all subjects the location of the hi ghest axial velocities was shifted from the inferior-right toward the superior-left part of the vessel area during the right ventricular con traction, with rapidly decreasing velocities to the inferior right evo lving into retrograde flow in the deceleration phase. The mean tempora l velocity profile was consistently skewed with a low flow region also toward the inferior-right vessel wall. The magnetic resonance phase s hift method used in this study provided remarkably consistent high-qua lity data about human pulmonary artery velocity fields. This is most l ikely because of the use of combined cardiac and respiratory triggerin g.