PURPOSE: To describe the signal void dots found on T2-weighted magnetic resonance (MR) images of the brain in hypertensive patients. MATERIALS AND METHODS: Conventional T2-weighted MR images of 11 patients with hypertensive intracerebral hemorrhage (ICH), 14 with lacunar infarction and 11 comprising a normal control group aged over 60 were analyzed with regard to the presence, location, number and size of signal void dots. We also evaluated their relationship to hypertension. We performed time-of-flight or phase contrast MR angiography, gradient echo pulse sequences, or conventional cerebral angiography in some hypertensive ICH patients and compared them with corresponding T2-weighted images. RESULTS: Signal void dots were found in all patients with hypertensive ICH. Six of 14 patients with lacunar infarction showed these dots; all six suffered from hypertension. The dots were located in the thalami, pons and basal ganglia, and were measured as 1 to 4 mm in diameter, mostly 2 mm; they looked larger on gradient echo images. In the normal control group there were no signal void dots, and on MR or conventional angiography, no vascular ectasia was noted at the site corresponding to the signal void dots. CONCLUSION: Signal void dots were not considered to be part of the normal aging process, but appeared to be closely related to hypertension and ICH. The dots were thought to be due to the susceptibility effect of blood degradation product rather than to flow artifact or enlarged vessels. The thrombosed microaneurysm with or without surrounding microleakage of blood may explain the nature of signal void dots on T2-weighted images of hypertensive brain.