Quantification of Regional Cerebral Blood Flow Using Diffusion Imaging With Phase Contrast

Background The perfusion‐related diffusion coefficient obtained from triexponential diffusion analysis is closely correlated with regional cerebral blood flow (rCBF), as assessed by arterial spin labeling (ASL) methods. However, this provides only a semiquantitative measure of rCBF, thereby making absolute rCBF quantification challenging. Purpose To obtain rCBF in a noninvasive manner using a novel diffusion imaging method with phase contrast (DPC), in which the total CBF from phase‐contrast (PC) MRI was utilized to convert perfusion‐related diffusion coefficients to rCBF values. Study Type Prospective. Subjects Eleven healthy volunteers (nine men and two women; mean age, 23.9 years) participated in this study. Field Strength/Sequence A 3.0 T, single‐shot diffusion echo‐planar imaging with multiple b ‐values (0–3000 s/mm 2 ), PC‐MRI , pulsed continuous ASL , and 3D T 1 ‐weighted fast field echo. Assessment rCBF and its correlations in the gray matter (GM) and white matter (WM) were compared between DPC and ASL methods. rCBF in the GM and WM and the GM/WM ratio were compared with the literature values obtained using [ 15 O]‐water positron emission tomography ( 15 O‐H 2 O PET). Statistical Tests Spearman's correlation coefficient and Wilcoxon signed‐rank test were used. Significance was set at P < 0.05. Results A significant positive correlation between DPC and ASL in terms of rCBF was observed in GM ( R = 0.9), whereas the correlation between the two methods was poor in WM ( R = 0.09). The rCBF in GM and WM and the GM/WM ratio obtained using DPC were consistent with the literature values assessed using 15 O‐H 2 O PET. The rCBF value obtained using DPC was significantly higher in the GM and WM than that using ASL. Data Conclusion DPC enabled noninvasive quantification of rCBF. Evidence Level 2 Technical Efficacy Stage 1.