An Association Between Microbleeds And Stroke

[ Background and Purpose ] Cerebral microbleeds, which result from microangiopathic changes, may be hemorrhage-prone. Microbleeds are defined on gradient-echo T2*-weighted images as one or more rounded signal loss lesions with a diameter of 2 to 5mm, without surrounding edema. Pathologically, old microbleeds are hemosiderin deposits caused by minor extravasation of blood from fibrohyalinized small arterioles. Microbleeds are clinically silent, but could be found in many stroke patients, even in neurologically normal elderly individual.lt is revealed that microbleeds may be a predict factor of intracerebral hemorrhage, and are strongly associated with subsequent intracerebral hemorrhage among patients with acute ischemic stroke. Furthermore, there is a regionally association between them. This result should be taken into consideration when treating stroke patients with aspirin, anticoagulants and thrombolytic drugs. Recently, a lot of investigations have also been done to analyze how cerebral microbleeds to influence the development of stroke and whether microbleeds are linked with other associated vascular factors of stroke. These findings are still debated.Therefore, in order to investigate the influence of microbleeds on stroke, we examined the number , location and frequency of microbleeds using T2*-weighted gradient echo MRI, and studied the association between microbleeds and vascular factors of stroke such as hypertension, diabetes mellitus, hyperlipemia , previous stroke history and use of aspirin, et al. Furthermore, the associations between microbleeds and lacune, leukoariosis, stoke location were also analyzed respectively.[Methods] We included consecutively 83 patients with acute stroke, who were divided into two groups: Ischemic group(n=43) or hemorrhagic group(n=40), and compared the stroke study group with the cohort of non-stroke individuals who were older than 50 years(n=32). The number, location and frequency of microbleeds were examined using T2*-weighted gradient echo MRI, and stroke location, lacunes and leukoaraiosis were also evaluated. We recorded hypertension, diabetes mellitus, hyperlipemia, previous stroke history and use of aspirin for stroke patients. Microbleeds were categorized as being in the corticosubcortical area, the deep gray matter area, or the infratentorial area. Furthermore, microbleeds, lacune and leukoariosis were also graded respectively according to number. Statistical analysis was performed with the Statistical Package of Social Sciences(SPSS, inc).[Result] It was revealed that the frequency of microbleeds were 34.9% in ischemic group, 75.0% in hemorrhagic group and 9.4% in control group. The occurrence index of microbleeds was significantly highest in the basal ganglia including the thalami in all groups. Most of microbleeds were mild or moderate in ischemic group, compared with severe in hemorrhagic group. Microbleeds were more prevalent with hypertension and previous stroke history(p < 0.01).There were no significant relationships demonstrated between microbleeds and diabetes mellitus, hyperlipemia and use of aspirin(p>0.05). The degrees of the microbleeds was positively correlated with the severity of lacunes, and was closely correlated with the degree of leukoaraiosis(p<0.01). There was no significant difference when analyzed the location of microbleeds were ipsilateral or contralateral for stroke location(p>0.05). This study also revealed that the correspondence between stroke location and microbleeds topography in hemorrhagic group is significant higher than in ischemic group.[Conclusion] It was revealed that the frequency of microbleeds was were significantly high in stroke patients and was regional. There were clearly relationships demonstrated between microbleeds and hypertension, lacunes and leukoaraiosis. Our results suggest that microbleeds are closely associated with stroke, especially with intracerebral hemorrhage, and have a predictive role on hemorrhagic transform. Theincreasing recognition on microbleeds may promote further comprehension on the developmen...