VASCULAR DEMENTIA OF BINSWANGERS TYPE - CLINICAL, NEURORADIOLOGICAL AND TC-99M-HMPAO SPET STUDY

In 24 patients with vascular dementia of Binswanger's type (VDBT) and 14 age-matched neurologically normal volunteers, we investigated the r elationship between clinical features, white matter lesions (leuco-ara iosis) and cerebral atrophy on computed tomographic (CT) scan, and reg ional cerebral blood flow, All subjects underwent the Mini-Mental Stat e Examination of Taiwan, version 1 (MMSE-T1), for assessing the severi ty of cognitive impairment. The patients were subdivided into two grou ps, one with mild to moderate (group I, MMSE-T1 scores: 11-24, n=11), and the other with severe dementia (group II, MMSE-T1 scores: below 10 , n=13), White matter degeneration was evaluated with densitometric me thods. Loss of brain parenchyma was estimated with seven linear measur ements (Evan's ratio, third ventricle ratio, width of temporal horn ti p, anterior-posterior length of temporal hem, anterior-posterior lengt h of Sylvian fissure and width of frontal interhemispheric fissure) by CT scans, Regional cerebral blood flow was determined with technetium -99m hexamethylpropylene amine oxime (HMPAO) single-photon emission to mography (SPET). In neuroimaging studies, subcortical leuco-araiosis w as localized at the frontal region in group I patients and scattered d iffusely in group II patients, Tc-99m-HMPAO SPET analysis revealed red uction of regional cerebral blood flow in the frontal lobe in group I patients and widespread reduction of regional cerebral blood flow in g roup II patients. A correlation between frontal leuco-araiosis and per fusion defect of the frontal pole was demonstrated in group I patients , showing findings typical of subcortical dementia. There was no diffe rence in frontal atrophic measurements between group I patients and co ntrols. Ratios of volumes of lost brain parenchyma and leuco-araiosis were significantly higher in group II patients than in the age-matched controls. corresponding to a diffuse cerebral perfusion defect, These results suggest that patients with VDBT have early frontal lobe invol vement with posterior progression, Patients with mild VDBT are more li kely to show reduction of frontal cerebral blood flow and leuco-araios is, while those with severe VDBT are more likely to have diffuse leuco -araiosis, cerebral hypoperfusion and brain atrophy.