Construction of Optimal Velocity Encoding for Cerebral Blood Flow Volume Measurement with Phase-Contrast MRA

Accurate velocity encoding is crucial for quantification of arterial inflow and venous outflow in intracranial diseases. The purpose of this study was to optimize the velocity encoding of phase-contrast (PC) MRA and quantify cerebral blood flow in normal volunteers.

Ten healthy volunteers were examined on a GE 1.5T MR system with 2D PCMRA sequence. The parameters of the sequence were as follows: TR 40ms, TE 6.6ms, flip angle 20°, slice thickness 4mm, matrix 256x256, field of view 140 mm. In each cardiac cycle, 40 images were obtained. Velocity encoding was set from 30 to 90 cm/sec at 10cm/sec interval for total of 7 scans per volunteer. The scan level was chosen at C2 perpendicular to the vessels of interest. Data were analyzed using CV Flow software on a GE Advantage Windows Workstation.