Technetium-99m-HMPAO brain SPECT evaluation of neurotoxicity due to manganese toxicity.

Abstract

We performed initial and follow-up regional cerebral blood flow (rCBF) studies using 99mTc-hexamethylpropyleneamine oxime (HMPAO) SPECT on a patient with manganese-induced central nervous system (CNS) neurotoxicity. The patient had a history of long-term exposure to manganese at the time of the first scan, while the follow-up scan was performed 9 mo after removal from the toxic environment. The patient's serum level of manganese was five- to tenfold greater than normal at the time of the initial rCBF brain SPECT scan. The rCBF brain SPECT scan demonstrated significantly decreased rCBF in the right caudate nucleus and both thalami. A MRI scan obtained at the same time was normal. The follow-up rCBF brain SPECT scan was normal. This report supports the utilization of functional rCBF brain SPECT imaging to provide objective evidence of a function CNS abnormality due to neurotoxicity at an early clinical stage. Our results emphasize that rCBF brain SPECT may provide a confirmational test to support the diagnosis of neurotoxicity in the appropriate clinical setting.