Gradient echo T2. weighted MRI has high sensitivity in detecting cerebral mic robleeds, which appear as small dot like hypointense lesions. Microbleeds are s trongly associated with intracerebral haemorrhage, hyperten...Gradient echo T2. weighted MRI has high sensitivity in detecting cerebral mic robleeds, which appear as small dot like hypointense lesions. Microbleeds are s trongly associated with intracerebral haemorrhage, hypertension, lacunar stroke and ischaemic small vessel disease, and have generated interest as a marker of b leeding prone microangiopathy. Microbleeds have generally been considered to be clinically silent; however, since they are located in widespread cortical and b asal ganglia regions and are histologically characterized by tissue damage, we h ypothesized that they would cause cognitive dysfunction. We therefore studied pa tients with microbleeds (n = 25) and a nonmicrobleed control group (n = 30) matc hed for age, gender and intelligence quotient. To avoid the confounding effects of coexisting cerebrovascular disease, the groups were also matched for the exte nt of MRI visible white matter changes of presumed ischaemic origin, location o f cortical strokes, and for the proportion of patients with different stroke sub types (including lacunar stroke). A battery of neuropsychological tests was used to assess current intellectual function, verbal and visual memory, naming and p erceptual skills, speed and attention and executive function. Microbleeds were m ost common in the basal ganglia but were also found in frontal, parieto occipit al, temporal and infratentorial regions. There was a striking difference between the groups in the prevalence of executive dysfunction, which was present in 60 %of microbleed patients compared with 30%of non microbleed patients (P = 0.03 ). Logistic regression confirmed that microbleeds (but not white matter changes) were an independent predictor of executive impairment (adjusted odds ratio = 1. 32, 95%confidence interval 1.01 1.70, P = 0.04). Patients with executive dysfu nction had more microbleeds in the frontal region (mean count 1.54 versus 0.03; P = 0.002) and in the basal ganglia (mean 1.17 versus 0.32; P = 0.048). There wa s a modest correlation between the number of microbleeds and the number of cogni tive domains impaired (r = 0.44, P = 0.03). This study provides novel evidence t hat microbleeds are associated with cognitive dysfunction, independent of the ex tent of white matter changes of presumed ischaemic origin, or the presence of is chaemic stroke. The striking effect of microbleeds on executive dysfunction is l ikely to result from associated tissue damage in the frontal lobes and basal gan glia. These findings have implications for the diagnosis of stroke patients with cognitive impairment, and for the appropriate use of antihypertensive and anti platelet treatments in these patients.展开更多
文摘Gradient echo T2. weighted MRI has high sensitivity in detecting cerebral mic robleeds, which appear as small dot like hypointense lesions. Microbleeds are s trongly associated with intracerebral haemorrhage, hypertension, lacunar stroke and ischaemic small vessel disease, and have generated interest as a marker of b leeding prone microangiopathy. Microbleeds have generally been considered to be clinically silent; however, since they are located in widespread cortical and b asal ganglia regions and are histologically characterized by tissue damage, we h ypothesized that they would cause cognitive dysfunction. We therefore studied pa tients with microbleeds (n = 25) and a nonmicrobleed control group (n = 30) matc hed for age, gender and intelligence quotient. To avoid the confounding effects of coexisting cerebrovascular disease, the groups were also matched for the exte nt of MRI visible white matter changes of presumed ischaemic origin, location o f cortical strokes, and for the proportion of patients with different stroke sub types (including lacunar stroke). A battery of neuropsychological tests was used to assess current intellectual function, verbal and visual memory, naming and p erceptual skills, speed and attention and executive function. Microbleeds were m ost common in the basal ganglia but were also found in frontal, parieto occipit al, temporal and infratentorial regions. There was a striking difference between the groups in the prevalence of executive dysfunction, which was present in 60 %of microbleed patients compared with 30%of non microbleed patients (P = 0.03 ). Logistic regression confirmed that microbleeds (but not white matter changes) were an independent predictor of executive impairment (adjusted odds ratio = 1. 32, 95%confidence interval 1.01 1.70, P = 0.04). Patients with executive dysfu nction had more microbleeds in the frontal region (mean count 1.54 versus 0.03; P = 0.002) and in the basal ganglia (mean 1.17 versus 0.32; P = 0.048). There wa s a modest correlation between the number of microbleeds and the number of cogni tive domains impaired (r = 0.44, P = 0.03). This study provides novel evidence t hat microbleeds are associated with cognitive dysfunction, independent of the ex tent of white matter changes of presumed ischaemic origin, or the presence of is chaemic stroke. The striking effect of microbleeds on executive dysfunction is l ikely to result from associated tissue damage in the frontal lobes and basal gan glia. These findings have implications for the diagnosis of stroke patients with cognitive impairment, and for the appropriate use of antihypertensive and anti platelet treatments in these patients.
