Silent cerebral infarction as a form of hypertensive target organ damage in the brain.

The incidence, number, size, and location of silent cerebral infarction on 0.1 T magnetic resonance imaging was investigated in 66 hypertensive patients (63 +/- 9 years old; mean +/- SD) and 42 age-matched normotensive subjects (61 +/- 9 years old) to determine the clinical significance of hypertension in silent cerebral infarction. Cerebrovascular risk factors and the severity of hypertensive changes in other major target organs were also investigated. The incidence of silent infarction in hypertensive patients (47%) tended to be higher than that of normotensive subjects (33%) and increased significantly with advancing age. In hypertensive patients, a significantly higher incidence of silent lesions was noted in patients with hypertensive changes in major target organs (72-73% in patients with organ involvement versus 33-39% in those without). The average number of lesions in hypertensive patients was significantly higher than that in normotensive subjects (6.0 versus 2.1), and the lesions in the hypertensive patients were more frequently detected in the brain areas supplied by perforating arteries than those in normotensive subjects (47% versus 24%). These results clearly demonstrate that silent cerebral infarction is frequently seen in older hypertensive patients, especially when moderate hypertensive changes are noted in major target organs, and suggest that hypertensive arterial changes play a crucial role in the occurrence of silent infarction.