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Brain microhemorrhages detected on T2*-weighted gradient-echo MR images.

BACKGROUND AND PURPOSE
Multifocal microhemorrhages have been reported to be commonly found in the brain of patients with systemic hypertension and spontaneous brain hemorrhage. The factors associated with these lesions detected on T2*-weighted gradient-echo images were examined to determine whether these lesions serve to indicate different types of microangiopathy and to predict a patient's risk for symptomatic hemorrhage.


METHODS
The study population consisted of 2164 patients who underwent 2416 consecutive brain MR imaging studies performed during 3 years. The patients with intracerebral hemorrhages due to vascular malformations, neoplasms, trauma, or intracranial surgery and those with incomplete medical records were excluded; 2019 cases were analyzed.


RESULTS
The overall incidence of microhemorrhages was 9.8%, predominantly in the lentiform nucleus (n = 96), thalamus (n = 88), and cortical-subcortical region (n = 93). Presence of microhemorrhages had the highest significant correlation with history of hemorrhagic stroke (P <.0001); advancing age, hypertension, and prominent white matter hyperintensity on T2-weighted images had the next highest significant correlation. Cortical-subcortical microhemorrhages were more frequently observed in patients who had previous lobar hemorrhagic stroke (P <.005). Among 139 patients with microhemorrhages who could be clinically followed up for more than 1 month, four (2.9%) had new hemorrhagic stroke.


CONCLUSION
The presence of microhemorrhages may be not only a direct marker of bleeding-prone small-vessel diseases but also an indicator of different types of microangiopathy and a predictor of further hemorrhagic stroke.