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Statistical Parametric Analysis of Cerebral Blood Flow in Vascular Dementia with Small-Vessel Disease Using 99mTc-HMPAO SPECT

Background: Subcortical ischemic vascular dementia (SVD) caused by small-artery disease is a major cause of dementia. It still remains unclear, however, whether SVD may present with localized regional cerebral blood flow (rCBF) changes. We aimed to clarify the local rCBF changes associated with dementia in patients with early-stage SVD. Methods: The subjects consisted of 15 patients with early-stage SVD [Mini Mental State Examination (MMSE) score: 20 ± 3.5] without apparent brain atrophy (SVD group), 11 patients without dementia with white matter lesions (non-dementia-WML group) and 16 age-matched controls. All the subjects were right-handed and underwent brain perfusion single photon emission computed tomography (SPECT), magnetic resonance imaging and cognitive function testing. Statistical analysis of the differences in the SPECT rCBF was performed by SPM2. The degree of severity of the WMLs was evaluated based on the Scheltens rating scale. Results: The results of SPM analysis revealed that the rCBF in the SVD group was significantly decreased in the pulvinar nuclei of the thalamus of both sides as compared with that in the controls, and in the left pulvinar nucleus as compared with that in the non-dementia-WML group. On the other hand, SPM analysis revealed no significant reduction in rCBF in the non-dementia-WML group as compared with that in the controls. The WMLs in the left parietal region were severer in the SVD group than in the non-dementia-WML group. Conclusions: In patients with early-stage SVD without apparent brain atrophy, significant rCBF reduction in the bilateral pulvinar nuclei as compared with that in normal controls, and in the left pulvinar nucleus as compared with that in patients without dementia with WMLs was found.