Arterial-optimized 4D-flow MRI for quantifying flow and pulsatility in venous sinuses and large cerebral veins

A single, arterial-optimized 4D-flow MRI acquisition may enable fast assessment of both cerebral arterial and venous flow. However, arteries and veins require different velocity encoding (VENC) settings for optimal velocity-to-noise ratio (VNR). Consequently, venous measurements using arterial-optimized VENC settings are subject to reduced VNR and require further evaluation. This study compared cerebral venous flow and pulsatility assessments using a high-VENC (110 cm/s, adapted to the arterial system) and a low-VENC (40 cm/s, adapted to the venous system) 4D-flow MRI sequence at 3 Tesla. Flow and pulsatility index (PI) were calculated for cerebral veins, sinuses and internal jugular veins in 36 elderly volunteers (79 ± 5 years). The high-VENC acquisitions allowed visualization of nearly all venous structures. Mean flow differences were small and the correlation, strong, when comparing both acquisitions across sinuses (R = 0.90-0.99, difference = -8-7%) and cortical veins (R = 0.93, difference = - 6%). Inflow-outflow differences at the confluence of sinuses were similar between acquisitions. PI showed moderate to strong agreement except in the straight sinus. Both the vein of Galen and the jugular veins suffered from aliasing in the venous VENC acquisitions. In summary, this study demonstrated that a VENC setting adapted for the arterial cerebral circulation was feasible for studying cerebral venous flow and pulsatility.