Evaluation of the accuracy of in-plane velocity measurements with segmented k-space magnetic resonance phase velocity mapping

The aim of this study was to evaluate the ability of segmented k-space magnetic resonance phase velocity mapping to accurately measure the in-plane flow velocity in an imaging slice. Straight PVC tubes were placed in a 1.5 Tesla clinical MRI scanner. The long axis of each tube was parallel to the z-axis of the scanner. In-plane velocity data were acquired in a sagittal slice placed along the long-axis of each tube at the vertical centerline. In addition, through-plane velocity data were acquired in a transverse slice. The two slices met along the vertical centerline of each tube. Each measurement was performed using two segmented sequences: one with seven and one with nine k-space lines per segment. A non-segmented acquisition was also performed to provide the reference velocity data for comparison. The in-plane velocity profiles were compared to the through-plane velocity profiles along the vertical centerline, showing both local and overall agreement (average differences lower than 10%), under both laminar and non-laminar flow and for all three sequences used. The results of this study show that segmented k-space acquisitions can provide accurate in-plane velocity data and have great clinical potential.