Experimental estimates of the constants relating signal change to contrast concentration for cerebral blood volume by T2* MRI.

Estimates of cerebral blood volume (CBV) obtained from dynamic contrast T2(*)-weighted magnetic resonance imaging (MRI) tend to be significantly higher than values obtained by other methods. This may relate to the common assumption that the proportionality constants relating signal change to contrast concentration are equal in tissue and artery. To test this hypothesis and provide estimates for the ratio of those proportionality constants, the authors compared measurements of CBV by both MRI and computed tomography (CT) scans in nine healthy volunteers obtained using identical kinetic paradigms for the two imaging modalities.