Regional sensitivity and coupling of BOLD and CBV changes during stimulation of rat brain.

Functional MRI of rat brain was performed at 2 Tesla following intravenous injection of cocaine in order to 1) determine if changes in CBV and changes in BOLD signal were regionally coupled in brain parenchyma, and 2) compare the sensitivities of these imaging methods across different brain structures. Percent changes in CBV and BOLD relaxation rate were spatially and temporally coupled during this graded brain activation. The use of contrast agent increased functional sensitivity in all parenchymal brain structures, with a strong but predictable dependence on the resting-state blood volume fraction. Magn Reson Med 45:443-447, 2001.