Cerebral perfusion abnormalities in abstinent cocaine abusers: a perfusion MRI and SPECT study

Nuclear medicine studies found decreased regional cerebral blood flow (rCBF) in the cortex and deep gray matter of cocaine users. Perfusion magnetic resonance imaging (MRI), a non-radioactive technique, has not been applied to evaluate persistent rCBF abnormalities. Twenty-five abstinent cocaine users and 15 healthy subjects without a history of drug use were examined with perfusion MRI, using dynamic bolus-tracking, and single photon emission computed tomography (SPECT), using 133Xe-calibrated 99mTc-HMPAO. After coregistration of SPECT with MRI, the relative rCBF (from perfusion MRI and SPECT) and absolute rCBF (from SPECT) were determined in 10 brain regions in each hemisphere. There was a statistically significant interaction between drug use and brain region on SPECT alone (relative and absolute rCBF), and on SPECT and perfusion MRI combined, but not on perfusion MRI alone. There also was a significant interaction among gender, drug use, and brain region. Compared to the control subjects, cocaine users showed increased rCBF in the frontal white matter (+8.6%, P=0.02) and in the globus pallidus (+6.3%, P=0.05), and decreased rCBF in the putamen (-3.9%, P=0.04) and the temporal cortex (-2.4%, P=0.02). SPECT and perfusion MRI detect a regional pattern of rCBF abnormalities in cocaine users that is consistent across the two methods. The hypoperfusion in the cortex and deep gray matter of the cocaine users is consistent with previous results. The increased rCBF in the white matter of cocaine users may be due to the presence of reactive glia.