Changes of Regional Cerebral Blood Flow in Left Anterior Thalamic Infarction: Analysis of 99mTc-Ethyl Cysteinate Dimer (ECD) SPECT by using Statistical Parametric Mapping

ABSTRACT

BACKGROUND: The thalamus has multiple connections with areas of the cerebral cortex involved in arousal and cognition. Thalamic damage has been reported to be associated with variable neuropsychological dysfunctions and dementia. This study investigates the changes of regional cerebral blood flow (rCBF) by using SPM analysis of 99mTc-ECD SPECT and examining the neuropsychological abnormalities of 4 patients with anterior thalamic infarctions. METHODS: Four patients with left anterior thalamic infarctions and eleven normal controls were evaluated. K-MMSE and the Seoul Neuropsychological Screening Battery were performed within 2 days after stroke. The normalized SPECT data of 4 patients were compared to those of 11 controls for the detection of areas with decreased rCBF by SPM analysis. RESULTS: All 4 patients showed anterograde amnesia in their verbal memory, which was not improved by recognition. Dysexecutive features were occasionally present, such as decreased word fluency and impaired Stroop test results. SPM analysis revealed decreased rCBF in the left supramarginal gyrus, the superior temporal gyrus, the middle and inferior frontal gyrus, the medial dorsal and anterior nucleus of the left thalamus. CONCLUSIONS: The changes of rCBF in patients with left anterior thalamic infarctions may be due to the remote suppression on metabolism by the interruption of the cortico-subcortial circuit, which connects the anterior thalamic nucleus and various cortical areas. The executive dysfunction and dysnomia may be caused by the left dorsolateral frontal dysfunction of the thalamocortical circuit. Anterograde amnesia with storage deficit may be caused by the disruption of mamillothalamic tract.