Prostate perfusion mapping using Fourier-transform based velocity-selective arterial spin labeling: Choice of cutoff velocity and comparison with brain

PurposeTo develop velocity selective arterial spin labeling (VSASL) protocols for prostate blood flow (PBF) and prostate blood volume (PBV) mapping. MethodsFourier-transform based velocity-selective inversion and saturation pulse trains were utilized in VSASL sequences to obtain blood flow and blood volume weighted perfusion signal, respectively. Here four cutoff velocities (V-cut = 0.25, 0.50, 1.00, and 1.50 cm/s) for PBF and PBV mapping sequences were evaluated with a parallel implementation in brain for measuring cerebral blood flow (CBF) and cerebral blood volume (CBV) with identical 3D readout. This study was performed at 3T on eight young and middle-aged healthy subjects comparing both perfusion weighted signal (PWS) and temporal SNR (tSNR). ResultsIn contrast to CBF and CBV, the PWS of PBF and PBV were rather unobservable at V-cut of 1.00 or 1.50 cm/s and both PWS and tSNR of PBF and PBV considerably increased at the lower V-cut, indicating that blood moves much slower in prostate than in brain. Similar to the brain results, the tSNR of PBV-weighted signal was about two to four times over the corresponding values of PBF-weighted signal. The results also suggested a trend of reduced vascularity within prostate during aging. ConclusionFor prostate, a low V-cut of 0.25-0.50 cm/s seemed necessary for both PBF and PBV measurements to obtain adequate perfusion signal. As in brain, PBV mapping yielded a higher tSNR than PBF.

Automated summary

The purpose of this study was to develop velocity selective arterial spin labeling (VSASL) protocols for prostate blood flow (PBF) and prostate blood volume (PBV) mapping. Fourier-transform based velocity-selective inversion and saturation pulse trains were used to obtain blood flow and blood volume weighted perfusion signal in VSASL sequences. The study found that a low cutoff velocity of 0.25-0.50 cm/s was necessary for adequate perfusion signal in both PBF and PBV measurements in prostate.