NORMAL 3-DIMENSIONAL PULMONARY-ARTERY FLOW DETERMINED BY PHASE-CONTRAST MAGNETIC-RESONANCE-IMAGING

In this study, an application was developed to measure three-dimension al blood flow in the main, right, and left pulmonary arteries of seven healthy volunteers using phase contrast magnetic resonance imaging (M RI). Presently, no other noninvasive technique is capable of providing this information. Flow, mean velocity, kinetic energy, and cross-sect ional area were measured at multiple phases of the cardiac cycle and w ere consistent with previously reported values measured with one-dimen sional velocity encoded MRI and Doppler echocardiography. Additionally , axial, circumferential, and radial shear stresses neat the wall of t he vessel at multiple phases of the cardiac cycle were estimated using the in-plane velocities. All three shear stresses were relatively con stant along the vessel wall and throughout the cardiac cycle (-7 dyn/c m(2)). This three-dimensional characterization of normal pulmonary blo od flow provides a base line to which effects of altered pulmonary art ery flow patterns in disease can be compared. (C) 1998 Biomedical Engi neering Society.