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ts e ri rr i ro imaging atter ab-ng in eld-rovascu-punctate perivas-reduced m to be a ing (7). bnormal-linked to changes frank tis-of wide-The sen-erin also ntify old diffusely orrhages ly appar-le by MRIndex terms: Brain, magnetic resonance; Cerebral hematoma; Cerebral hemorrhage AJNR Am J Neuroradiol 17:573–578, March 1996 Spontaneous bleeding into the brain paren-chyma without a sizable vascular malformation or neoplasm constitutes the most frequent mechanism of nontraumatic intracerebral hem-orrhage in the adult. Rupture of small arteries after damage from chronically increased blood pressure has been traditionally considered the most common cause of this primary intracere-bral hematoma (PICH) (1). However, the ab-sence of hypertension in more than 50 % of the patients with PICH (2, 3) also implies other causes, like amyloid angiopathy (4, 5). There-fore, the development of vessel wall changes that predispose patients to PICH may not be suspected before the hematoma occurs. Cerebral magnetic resonance (MR) has revealed clinically silent white m normalities, with most of these occurri erly patients and in patients with cereb lar risk factors (6, 7). Small hyperintensities result primarily from a cular reduction in myelin caused by vessel wall permeability (8, 9) and see frequent phenomenon of normal ag Larger and confluent areas of signal a ity, however, have been repeatedly microangiopathy. Reported tissue range from incomplete infarctions to sue necrosis in the center of areas spread high signal intensity (10–13). sitivity of MR imaging for hemosid provides the unique opportunity to ide hemorrhages (14, 15). In a setting of increased vascular fragility, small hem could occur when they are not clinical ent (16), but they should be detectab imaging, even in retrospect