Abstract #0422

Effect of Flip Angle Evolution on Flow Sensitivities in ECG-Gated Fast Spin Echo MRA Methods at 3T

Iliyana P. Atanasova^1,2, Pippa Storey¹, Ruth P. Lim¹, Jian Xu¹, Qin Chen³, Andrew Laine², Vivian S. Lee³

¹Department of Radiology , New York University Medical Center, New York, USA; ²Columbia University, New York, USA; ³Department of Radiology, New York University Medical Center, New York, USA

ECG-gated 3D fast spin-echo based techniques, which exploit differences in arterial and venous flow during systole and diastole, have been developed for non-contrast-enhanced MRA. We investigate the flow sensitivity of fast spin echo with constant (CFL) versus variable flip angle (VFL) echo-train evolutions at different stations of the peripheral vasculature. Out data demonstrate that velocity sensitivities depend on the flip angle magnitude, with shorter sensitivity range for lower flip angles. With the VFL approach near complete signal void occurs for velocities as low as 5 cm/s, which renders the technique suboptimal for imaging vessels where diastolic flow exceeds this threshold.