RESUMO
PURPOSE: Although both the subjective and physiological effects of abused psychotropic substances have been characterized, less is known about their effects on brain function. We examined the actions of intravenous diacetylmorphine (heroin), the most widely abused opioid, on regional cerebral blood flow (rCBF), as assessed by perfusion-weighted MR imaging (PWI) in a double-blind and placebo-controlled setting. MATERIAL AND METHODS: Eight male subjects dependent of diacetylmorphine (mean age 36 years, range: 26 to 44 years), who had participated in a clinical diacetylmorphine maintenance program, underwent PWI with gadolinium injection. At two sessions separated by 2-7 days, the participants were examined 80 s after intravenous administration of either diacetylmorphine or saline. rCBF in four regions of interest (amygdala, vermis of the cerebellum, anterior cingulated cortex and thalamus) was compared with heroin versus placebo. RESULTS: In the cerebellum, thalamus and cingulated cortex, there were no significant differences in perfusion values between diacetylmorphine and placebo. In the amygdala, perfusion values were 0.8+/-0.4 and 0.5+/-0.2 on the left, and 0.9+/-0.4 and 0.6+/-0.3 on the right, with diacetylmorphine and with placebo, respectively (t-test results were P=0.044 and P=0.033 on the left and right sides, respectively). Other differences in perfusion values between the drug and placebo did not reach statistical significance. CONCLUSION: Perfusion MRI demonstrated differences in brain hemodynamics induced by drug intake.