LEUKOARAIOSIS AND CEREBRAL HYPOPERFUSION COMPARED IN ELDERLY NORMALS AND ALZHEIMERS DEMENTIA

Objective: To elucidate the pathogenesis of leuko-araiosis in patients with Alzheimer's disease by utilizing CT densitometry of the brain and measurements of local perfusion in order to quantify the extent of leuko-araiosis and local hypoperfusion compared with similar measurements made among age-matched normal volunteers. Design: Cross-sectional case-control study. Setting: Out-patient visits to a specialized laboratory located in a large hospital facility. Patients: Eighteen elderly patients with probable dementia of Alzheimer type (DAT, aged 71.8 +/- 5.1 years) and 17 neurologically and cognitively normal, age-matched volunteers (aged 68.2 +/- 9.6 years) were admitted to the study according to established criteria. Intervention: None Main Outcome Measures: Cerebral blood flow (mL/100 g brain/min estimated by the xenon inhalation CT-CBF method correlated with volume percentage ratio (%) measured by CT densitometry for leuko-araiosis, compared to normal white and gray matter. Results: Perfusion values for frontal and occipital white matter as well as frontal, parietal, temporal, and occipital cortex were all decreased in DAT patients. Ratios for leuko-araiosis to total brain tissue volumes were greater among patients with DAT compared with age-matched normal volunteers. White matter perfusion in zones of leuko-araiosis was decreased to a similar degree in both DAT and elderly normal volunteers. Conclusions: Perfusion is reduced to the same degree in regions of leuko-araiosis in elderly normals as in DAT patients, but the extent of leuko-araiosis is greater among DAT patients and presumably contributes to cognitive impairments.