Time-Resolved Blood Flow Quantification Without Gating

Michael C. Langham¹, Jeremy Magland¹, Felix W. Wehrli¹

In MRI, gated phase-contrast (PC)-MRI is the standard approach to resolving pulsatile blood flow but arrhythmia (which is normal) can significantly affect accuracy and reproducibility since each phase-encoding takes one heartbeat. We describe a flow quantification technique with velocity-encoded projections where reference image is used to remove signals from the background, e.g. tissue, prior to taking phase difference. The projection method achieves temporal resolution of 20 ms without gating (prospective or retrospective). We demonstrate the technique by time-resolving the triphasic pulsatile blood flow in femoral artery of healthy subjects and show that results are consistent with PC-MRI.