A combined hematoxylin-eosin, alkaline phosphatase and high-resolution microradiographic study of lacunes.

Lacunar infarcts (lacunes) are small, cystic lesions of the brain in patients with hypertension and/or diabetes. In order to improve our understanding of the relationship between lacunes and their blood vessels, the alkaline phosphatase (AP) technique of microvascular staining and high-resolution microradiography were employed in a three-dimensional study of 31 lacunes from 15 hypertensive subjects. A second aim was to compare the usefulness of the techniques with that of routine hematoxylin-eosin (HE) stain employed by previous investigators. Arteries were traced throughout their course. The lesions identified included intimal hyperplasia, hyalinization and atherosclerosis with variable narrowing and occasional occlusions. The small arterioles in the lacune cavities supplied adjacent intact brain. The AP technique clearly distinguished true lacunar infarcts from dilated perivascular spaces. AP and microradiography were superior to HE in showing the three dimensional details with far fewer sections. Four different types of relationships were observed between nutrient arteries and their lacunes, indicating that patterns of vascular involvement can be elucidated in brains of subjects dying with lacunar syndromes by using special techniques such as AP. Such patterns can be correlated with clinical risk factors such as hypercholesterolemia, hypertension etc., singly and in combination. Our data suggest that the natural history of lacunar infarcts may be changing in two ways--the number of lacunes per patient may be diminishing and white matter involvement may be increasing. Possible explanations for these changes are suggested.