Brain Imaging Techniques Applied to Chronically Solvent-Exposed Workers: Current Results and Clinical Evaluation

The application of neuroimaging techniques such as cerebral blood flow (CBF), single photon emission tomography (SPECT). X-ray computed tomography (CAT), and magnetic resonance imaging (MRI) on solvent-exposed workers and patients with toxic encephalopathy results in different and somewhat inconclusive pictures. The aim of this paper is to therefore critically review the current knowledge on chronic neurotoxicity of solvent exposures with respect to neuroimaging technique. CAT measurements of 86 house or construction painters, 82 spray painters, and 81 nonpainters showed no abnormal diffuse brain atrophy due to chronic solvent exposure after controlling for confounding variables such as age, alcohol consumption, or former disease. Correlation analyses did not show any consistent, biologically plausible exposure–effect relationship. Neuropsychologic test results did not correlate significantly with CAT parameters, whereas a strong age dependency exists. It is concluded that long-term exposure to solvent concentrations not exceeding permissible occupational limit values does not cause increased brain atrophy.