Anterior choroidal artery infarction presenting as a progressive cognitivedeficit

Purpose: The authors describe a patient in whom neuroimaging using Tc-99m H MPAO SPECT, F-18 fluorodeoxyglucose (F-18 FDG) coincidence imaging, and mag netic resonance imaging (MRI) identified an anterior choroidal artery infar ction. Neuroimaging played a critical role in confirming this diagnosis, be cause the patient had symptoms of progressive cognitive decline and satisfi ed the National Institute of Neurological and Communicative Disorders and S troke-Alzheimer's Disease and Related Disorders Association criteria for Al zheimer's disease (AD). Methods: Tc-99m HMPAO brain SPECT was performed using a triple-head gamma c amera. F-18 FDG scanning was obtained 40 minutes after intravenous injectio n of 5 mCi F-18 FDG using a coincidence camera. A brain MRI scan was perfor med using a 1.5-Tesla scanner. Results: Tc-99m HMPAO SPECT showed focal hypoperfusion to the right parahip pocampal cortex. F-18 FDG coincidence imaging showed a more extensive reduc tion in glucose metabolism compared with SPECT. The MRI scan confirmed the presence of a small segmental choroidal artery infarction. The Tc-99m HMPAO and F-18 FDG scans were not consistent with AD. Conclusions: This case illustrates the value of the regional cerebral blood flow SPECT for evaluating memory impairment in the elderly. Decreased regi onal cerebral blood flow to the posterior temporoparietal region is consist ent with AD, whereas regional cerebral blood flow diminution in a vascular territory is consistent with vascular dementia. In this case, the patient w as clinically diagnosed with AD, and SPECT was performed to establish the b aseline regional cerebral blood flow before the cholinesterase inhibitor do nepezil was administered. An infarction was diagnosed on the regional cereb ral blood flow brain SPECT scan, which was later confirmed by MRI. Infarcti ons of the parahippocampal cortex may result in memory impairment, which ca n appear clinically similar to AD.