Is There Any Direct Evidence of a Leak in Lacunar Stroke, Leukoaraiosis, or Dementia?
Several sources suggest that the blood-brain barrier fails with advancing age, in dementia, and in white matter disease. For example, an intravenously injected MR contrast agent, gadolinium-DTPA, leaked into the brain, particularly in the territory of the perforating arteries, more in maturity-onset diabetics and those with white matter hyperintensities than in controls. 47 Although another study of 10 patients with dementia failed to find evidence of leakage into the brain with gadolinium-enhanced MRI, a much less detailed imaging technique was used. 48 A study in 18 aging dogs, imaged after gadolinium-DTPA injection, found leakage in 1 dog with white matter hyperintensities on imaging and Alzheimer disease pathology. 49 Kwa et al 50 found indirect evidence of small-vessel endothelial failure in hypertensive patients in whom the degree of white matter hyperintensities correlated with the severity of retinal arterial changes. Wong et al 51 found that retinal microvascular abnormalities
