Naoto Yamanouchi

PURPOSE: To examine the brain damage of solvent abusers in Japan, where pure industrial toluene is frequently abused. METHODS: Twenty solvent abusers 17 to 33 years of age with 7.2 +/- 4.0 years of abuse were examined with a 1.5-T MR imaging system. RESULTS: White matter hyperintensities in cerebrum, brain stem, and cerebellum on T2-weighted images were found in seven cases. The extent of white matter change was most clearly shown on proton density-weighted images. The patients with restricted white matter change and intermediate white matter change showed white matter hyperintensities in the brain stem and cerebellum on T2-weighted images, in some cases, with additional hypointensities in the corresponding T1-weighted images. These patients had mainly abused pure toluene. The patients with diffuse white matter change showed obvious brain atrophy, including hippocampal atrophy and thinning of the corpus callosum. These patients had mainly abused lacquer thinner. CONCLUSION: There are some patients with restricted but severe enough change to cause the neurologic symptoms in specific regions, such as the brain stem and/or cerebellum, before the brain atrophy becomes apparent. This suggests that the restricted white matter change represents not only an early change of diffuse white matter change, but at least in some cases also represents a qualitatively different change than that of diffuse white matter change. We suggest that pure toluene has a possible relation to this qualitative difference.

To determine brain functional abnormality in systemic lupus erythematosus (SLE) patients with psychiatric symptoms, we evaluated 12 active SLE patients with or without psychiatric symptoms by means of [18F]2-fluoro-2-deoxy-D-glucose positron emission tomography (PET), magnetic resonance imaging and neuropsychological testing. Patients with psychiatric symptoms showed significantly poorer performance in tests which subserved attentional function. The PET study revealed that the psychiatric patients had significantly decreased regional cerebral metabolic rates for glucose in the prefrontal, inferior parietal and anterior cingulate regions. Prefrontal, inferior parietal and anterior cingulate dysfunction may be related to attentional deficits that are involved in various psychiatric symptoms in SLE. PET is an invaluable tool to reveal such brain functional abnormality seen in SLE patients with psychiatric symptoms.

MRI was performed in 7 patients with general paresis before or at a very early stage of treatment. A large dose of antibiotics, mainly penicillin, was given to all patients, and the effects of treatment, the patients' outcome, and MRI findings were investigated. Three of the 7 patients had MRI findings of atrophy of the medial temporal lobe including the hippocampus. In the medial temporal lobe atrophy group, a personality change or general dementia remained even after the treatment was completed, and outcome in social functioning was poor. Medial temporal lobe atrophy may be a poor prognostic sign in general paresis.