TOLUENE ABUSE - PHYSICAL BASIS FOR HYPOINTENSITY OF THE BASAL GANGLIAON T2-WEIGHTED MR-IMAGES

PURPOSE: To explain the hypointensity in the basal ganglia on T2-weigh ted magnetic resonance (MR) images of brains of toluene abusers. MATER IALS AND METHODS: Eight patients with histories of toluene abuse under went MR imaging. A bilayered model of dipalmitoylphosphatidylcholine ( DPPC; 100 mmol/L concentration) and varying concentrations of toluene was formed. The DPPC control and toluene-mixed bilayers underwent MR i maging. T1 and T2 were measured as a function of toluene and lipid con centrations. RESULTS: T2-weighted images of patients who had abused to luene showed marked hypointensity in the thalami and moderate hypointe nsity in the basal ganglia. Measurements of the DPPC-toluene phantom i ndicated that toluene-tainted lipid bilayers dramatically shortened T2 and had little effect on T1. By comparison, DPPC itself had little di scernible effect on either T1 or T2. CONCLUSION: This model suggests t hat partitioning of toluene into the lipid membranes of cells in cereb ral tissue may be responsible for the hypointensity of basal ganglia n oted on T2-weighted MR images of brains of toluene abusers.