Estimation of Cerebral Blood Flow Using the Pulse Wave Amplitude in Brain MRI

Rationale and Objectives: First, to test the feasibility of cerebral blood flow (CBF) estimation using the pulse wave amplitude in flowrelated enhancement (FREE) brain MRI in comparison to pseudo-continuous arterial spin labeling (pCASL-MRI). Second, the potential for acceleration was evaluated retrospectively. Materials and Methods: 24 healthy study participants between 20 and 61 years had cerebral MRI. Perfusion imaging was performed with a balanced steady-state free precession sequence for FREE-MRI and with pCASL-MRI for comparison. Results: The value distribution of the estimated CBF showed a high overlap in the histogram between 0 and 20 mL/100 g/min. However, disparity of the values occurred with more values between 20 and 60 mL/100 g/min using pCASL-MRI and more high values > 60 mL/100 g/min applying FREE-MRI. A Kolmogorov-Smirnov test confirmed a differing probability distribution ( P = 0.62). The approximated CBF from FREE-MRI remained stable until only 50% of the acquired data was used. Values from using 40% of the data increased significantly compared to 90% or more ( P <= 0.05). Values within the white matter presented no significant change after data reduction. The global and voxel-wise correlation coefficients towards pCASL-MRI presented stability during data reduction of FREE-MRI. Conclusion: In conclusion, the proposed technique allows a rough approximation of the CBF compared to pCASL-MRI. Further sequence optimization must be achieved to improve the measurement of relatively lowly perfused tissues. Nevertheless, it offers large potential for imaging speed optimization and enables perfusion-weighted images similarly to the color Doppler mode in ultrasound.