Imaging High-Speed Jets Using Rapid Ungated Fourier Velocity Encoding

Introduction: Accurate quantitation of the peak arterial jet velocity is crucial in assessing the severity of cardiovascular disease. The current “gold standard”, Doppler ultrasound, is highly sensitive to beam position and Doppler angle. Fourier velocity encoding (FVE) resolves the full velocity spectrum [1], but conventional gated methods [2-4] do not work well during arrhythmia and require long scan times. MR Doppler [5] gives good velocity distributions along a cylinder, but its long readout can cause signal degradation during highly accelerative flow. In this work, we developed an ungated FVE technique for imaging jet velocities that is fast and simple to apply. Through continuous velocity encoding and k-space data averaging, the sequence produces an accurate time-averaged velocity spectrum in just a few seconds.