ABNORMAL CEREBRAL METABOLISM IN POLYDRUG ABUSERS DURING EARLY WITHDRAWAL - A P-31 MR SPECTROSCOPY STUDY

Phosphorus magnetic resonance spectroscopy (P-31 MRS) at 1.5 T was per formed on nine polysubstance abusing men. All nine patients met DSM-II I-R criteria for concurrent cocaine and heroin dependence, were neurol ogically normal, were negative for the human immunodeficiency virus, a nd had normal clinical brain MRI scans. Patients were scanned 2-7 days after admission to a drug treatment unit, Eleven age-matched control subjects also were studied. The ISIS localized phosphorus spectra were obtained from a 5-cm thick axial brain slice and a 100-cc white matte r volume. In the brain slice, the phosphorus metabolite signal express ed as a percentage of total phosphorus signal was 15% higher for phosp homonoesters, 10% lower for nucleotide triphosphates (beta-NTP), and 7 % lower for total nucleotide phosphates in polydrug abusers compared w ith those in controls, Phosphodiesters, inorganic phosphate, phosphocr eatine, total phosphorus, pH, and free magnesium concentration were un changed, None of these parameters correlated with the methadone dose o r the number of days abstinence. Single photon emission computed tomog raphic imaging of a subgroup of the patients revealed abnormal cerebra l perfusion in 80% of the patients scanned. These data suggest that ce rebral high energy phosphate and phospholipid metabolite changes resul t from long term drug abuse and/or withdrawal and that these changes c an be detected and studied by P-31 MRS.