Neuroimaging in Chronic MAP Users

Abstract

Chronic use of methamphetamine (MAP) produces persistent psychiatric symptoms in some users. Here, we present our four major findings, by using neuroimaging techniques, in the brain of chronic MAP users. 99mTc-HMPAO/SPECT showed persistent patchy deficits in cerebral blood flow without structural abnormalities on MRI, indicating that persistent functional changes occur in the users. A PET study with 11C-WIN-35,428 indicated significant and persistent reductions in dopamine transporter (DAT) density, which were correlated with both the duration of MAP use and severity of psychotic symptoms, in the striatum, nucleus accumbens, and prefrontal cortex. The DAT reduction may be associated with persistent psychiatric symptoms in the users. An MRS imaging study showed significant elevated choline/creatine but normal level of N-acetyl-aspartate/creatine in the striatum, implying altered membrane turnover without neuronal loss. On the other hand, a 11C- N-methylspiperone/PET study indicated no change in striatal D2 receptor density in abstinent MAP users, suggesting reversible changes in D2 receptors.