Accuracy of segmented MR velocity mapping to measure small vessel pulsatile flow in a phantom simulating cardiac motion

The purpose of this study was to investigate the accuracy of conventional, segmented, and echo-shared MR velocity mapping sequences to measure pulsati le flow in small moving vessels using a phantom with simulated cardiac moti on. The phantom moved either cyclically In-plane, through-plane, in- and th rough-plane, or was stationary. The mean error In average flow was -2% +/- 3% (mean +/- SD) for all sequences under all conditions, with or without ba ckground correction, as long as the region of interest (ROI) size was equal to the vessel cross-sectional size. Overestimation of flow as a result of an oversized ROI was less than 20%, and independent of field of view (FOV) and matrix, as long as the offset in angle between the imaging plane and fl ow direction was less than 10 degrees. Segmented velocity mapping sequences are surprisingly accurate In measuring average flow and render flow profil es in small moving vessels despite the blurring in the images due to vessel motion. (C) 2001 Wiley-Liss, Inc.