Intersubject Variability in Cerebral Blood Flow is Great than Structural Variability

Yufen Chen¹, Hengyi Rao¹, John A. Detre¹

Cerebral blood flow (CBF) is tightly coupled to brain metabolism and is known to be modulated by age and gender. But little is known about intersubject variability in CBF, which may be reflective of individual phenotypic differences. Here, we retrospectively analyzed arterial spin labeling (ASL) data from 136 subjects to test the hypothesis that metabolic variance exceeds structural variance. F-tests showed gray matter (GM) CBF had higher variance than GM volume. Linear model of age and gender showed reduced R² fit to GM CBF compared to GM volume, suggesting the presence of additional sources of variability.