Functional neuroimaging for clinical evaluation of mild‐to‐moderate toxic encephalopathic brain disease: A study of seven patients

Abstract

Purpose. Numerous studies have found that exposures to neurotoxins such as solvents, pesticides, heavy metals, carbon monoxide and mycotoxins can cause many neuropsychiatric deficits. Neuropsychological test batteries are often useful in diagnosing and treating neurotoxin exposed patients; however, these batteries have a number of shortcomings. Increasingly, brain scans with SPECT (Single Photon Emission Computed Tomography) are being used to diagnose neurotoxin‐exposed patients. The purpose of this study is to measure specific regional brain functional findings with SPECT on seven patients with various encephalopathic diseases and occupational and/or environmental chemical exposure.Design. Case series.Methods and materials. Detailed exposure/occupational histories were made of seven patients exposed to neurotoxins. Some patients had possible confounding factors such as a past history of alcohol abuse or mild trauma brain injury. SPECT scans were taken with a triple headed SPECT camera on patients injected with 99Tc‐HMPAO and brain blood perfusion was analysed digitally by the Hermes BRASS system.Results. A variety of significant hypoperfusion defects were seen in brain SPECT scans in six of these patients including frontal, parietal and cerebellar regions as well as thalamic hyperperfusion seen in six patients.Conclusions. With additional research and analytical refinement, SPECT studies have the potential to become an important tool for the differential diagnosis and treatment of encephalopathic patients with toxic chemical exposure.