REGIONAL CEREBRAL BLOOD-FLOW IMPROVES WITH TREATMENT IN CHRONIC COCAINE POLYDRUG USERS

Brain perfusion is abnormal in chronic cocaine users. To determine whe ther these perfusion abnormalities are reversible following treatment, we studied 10 cocaine-dependent polydrug users with Tc-99m-HMPAO SPEC T 2 to 3 days after admission to an inpatient treatment facility and a t 7 to 8 days and 17 to 29 days after abstinence from drugs. The patie nts also received buprenorphine, an opioid mixed agonist-antagonist, b eginning 10 days after admission and continuing to the end of the stud y. Imaging began 10-15 min after injection of Tc-99m-HMPAO (20 mCi) us ing an annular gamma camera system. MRI was performed during hospitali zation using a 1.5 Tesla system. SPECT and MRI were merged and five ax ial SPECT slices centered at the level of the basal ganglia were selec ted for analysis. Activity ratios were derived for cortical regions re lative to cerebellar activity and were corrected for linearity with re spect to regional cerebral blood flow. The cortical regions were class ified as abnormal (activity ratio < 0.6), borderline (0.6-0.72) and no rmal (> 0.72) based on the results of the first SPECT study. In abnorm al zones, regional cerebral blood flow (rCBF) increased 1 1.0% +/- 9.0 % at 7 to 8 days and 23.8% +/- 9.4% at 17 to 29 days after initiation of treatment. The increase in rCBF was 4.8% +/- 7.1% (7 to 8 days) and 11.1% +/- 8.0% (17 to 29 days) in borderline cortex and decreased 2.9 % +/- 6.3% (7 to 8 days) and increased only 2.7% +/- 13.4% (17 to 29 d ays) in normal cortex. The increase in rCBF did not vary significantly by location. The perfusion defects observed in chronic cocaine polydr ug users are partially reversible with short-term abstinence and bupre norphine treatment.