Abstract
PURPOSE: Cerebral blood flow (CBF) is commonly measured by pseudo-continuous arterial spin labeling (PCASL) in human research, but recent advancements in methodology have limited data reuse. The object of this work is to harmonize two distinct PCASL techniques within a cohort with a wide range of CBF values. METHODS: Participants had two PCASL sequences collected within a single session: a single post-label delay sequence with a 2D echo-planar imaging (EPI) readout, " CBF2D,1PLD ", and a five post-label delay sequence with gradient and spin echo (GRASE) 3D readout, " CBF3D,5PLD ". Linear regression modeling to impute CBF3D,5PLD from CBF2D,1PLD , hemoglobin, and age were assessed within gray matter (GM) and white matter (WM) using leave-one-out cross-validation for prediction errors and confidence intervals. Within-subject coefficient of variation (wsCV) and inter-class correlation coefficient (ICC) were calculated using CBF3D,5PLD imputed vs. measured as pseudo test-retest pairs. RESULTS: Fifty participants, ages 8-45 (median 25) years, had usable CBF3D,5PLD and CBF2D,1PLD , including 17 participants with sickle cell disease (SCD), who were matched by age ( p = 0.90 ) and sex ( p = 0.16 ) to those without SCD. A multiple linear regression model including hemoglobin and age fit GM CBF ( R2adj. = 0.82 ; for WM CBF R2adj. = 0.78 ). The wsCV for CBF3D,5PLD was 9.1% for GM, 11.3% for WM. ICC was 0.89 for GM and 0.87 for WM. Models without age or hemoglobin fit slightly worse. CONCLUSION: Our study demonstrates feasibility to impute 3D-GRASE multi-PLD CBF from a 2D-EPI single-PLD technique, which promotes data sharing and harmonization.