MRI evidence for cerebral microbleeds. Comparative histopathologic data and possible clinical implications

Increased use of gradient echo T2*-weighted gradient echo sequences in magn etic resonance imaging (MRI) of patients suffering from primary ICH called attention to foci of signal loss which were suggested to represent remnants of cerebral microbleeds. In a post mortem correlative MR and histopatholog ical study we provide support for this notion. We found areas of signal los s on gradient echo T2*-weighted sequences in 7 out of 11 brains of patients who had died of intracerebral hematoma. Histopathologically, these areas r epresented hemosiderin deposits indicating previous extravasation of blood. To provide data about the prevalence of these MRI findings in a healthy el derly population a subgroup of participants of the Austrian Stroke Preventi on Study was analyzed. We detected foci of signal loss on gradient echo T2* -weighted sequences in 18 out of 280 volunteers (6,4%). MR-based evidence o f previous microbleeds may indicate a potentially higher risk of suffering from intracerebral bleeding which could have therapeutic implications for t he treatment of acute stroke and for secondary prevention. This hypothesis will have to be tested in future prospective trials.