Prevalence and associations of MRI-demonstrated brain infarcts in elderly subjects with a history of transient ischemic attack - The Cardiovascular Health Study

Background and Purpose - MRI is more sensitive than CT, but the significanc e of brain abnormalities seen on MR images obtained in older subjects with transient ischemic attack (TIA) is not clear. We studied the prevalence and risk factors associated with MRI-demonstrated infarcts in elderly subjects with a history of TIA. Methods - Participants of the Cardiovascular Health Study, aged 65 years or more and without prior stroke, were studied with brain MRI (n = 3456). The prevalence of brain infarcts (greater than or equal to 3 mm) on MRI was de termined in subjects with and without TIA, The cardiovascular risk factors and clinical and subclinical cardiovascular disease associated with MRI inf arcts were studied in subjects with TIA. Results - Subjects with TLA (n = 100) had a higher prevalence of MRI infarc ts than subjects without TIA (46% versus 28%; P < 0.001), The unadjusted od ds ratio for having MRI infarcts in subjects with TIA was 2.20 (95% CI, 1.4 7 to 3.30) and remained significantly elevated after adjustments for risk f actors and cerebrovascular disease (odds ratio, 1.86; 95% CI, 1.23 to 2.83) , In subjects with TIA, diastolic blood pressure (P = 0.01) and internal ca rotid artery intima-media thickness (P = 0.01) were the only factors predic tive of the presence of MRI infarcts by stepwise logistic regression analys is. Conclusion - MRI infarcts are imaging manifestations of clinically importan t cerebrovascular disease in subjects with a history of TIA, given their in creased prevalence and positive association with increased diastolic blood pressure and internal carotid artery intima-media thickness.