Neuronal Activity-Induced Cerebral Blood Volume Changes in Humans: Measurements with VASO and VERVE

Claire Cohalan¹, Jean J. Chen¹, G. Bruce Pike¹

The vascular-space-occupancy (VASO) technique targets changes in total cerebral blood volume (CBV), whereas the venous-refocusing for volume-estimation (VERVE) technique measures changes in venous CBV, which is more relevant for BOLD. In this work, ΔCBV measurements acquired in healthy humans using both techniques were compared. VASO produced a higher contrast-to-noise ratio and larger ΔCBV values than VERVE, as expected since VERVE measures only venous CBV changes. VERVE-based activation was more correlated with BOLD activation, since BOLD is sensitive to the venous compartment. Though the VASO technique is easier to implement, its signal potentially has many contributions other than CBV, and eliminating these contaminants is difficult, but necessary.