Magnetic Resonance Imaging Detection of Microbleeds Before Thrombolysis

Abstract

Background-Hemorrhagic transformation (HT) is a major complication of thrombolytic treatment for acute ischemic stroke. Although a history of prior intracerebral hemorrhage diagnosed by head CT is a contraindication to thrombolysis, there are no guidelines or data regarding evidence of prior asymptomatic microbleeds visualized with T2*-weighted magnetic resonance imaging (MRI). Methods-Pretreatment T2*-weighted MRI sequences were retrospectively analyzed in all patients receiving intra-arterial thrombolytic therapy and undergoing a pretreatment MRI at our institution. The frequency and location of prior microbleeds was determined and compared with the frequency and location of secondary HT after therapy. Results-Five of 41 patients undergoing MRI before receiving intra-arterial thrombolytic therapy demonstrated evidence of prior microbleeds on the pretreatment MRI studies. Major symptomatic hemorrhage occurred in 1 of 5 patients with microbleeds compared with 4 of 36 patients without. Only 1 patient in the entire 41-patient cohort experienced any HT outside the acute ischemic field. In this patient, the symptomatic hemorrhage occurred directly at the site of a prior microbleed, contralateral to the acute ischemic event. Conclusions-Old silent microbleeds, visualized with T2*-weighted MRI sequences, may be a marker of increased risk of HT in patients receiving thrombolytic therapy for acute ischemic stroke. Pretreatment screening of thrombolytic candidates with these MRI sequences may be useful in the future to identify these patients.

Silent cerebral microbleeds associated with arterial stiffness in an apparently healthy subject

“…The wide clinical availability of this equipment has attracted much interest in asymptomatic cerebral MBs, with findings to date showing a frequent occurrence in patients with stroke, particularly those with intracerebral hemorrhage; [2][3][4] higher prevalence in patients with recurrent intracerebral hemorrhage than in those with a first episode; [5][6][7] and that their presence predicts bleeding after thrombolytic therapy 8 and antiplatelet drug administration in ischemic stroke. 9 These findings have in turn raised concerns that MBs may be a marker for future symptomatic cerebral hemorrhage.…”

Cerebral Microbleeds in Patients With Intracerebral Hemorrhage Are Associated With Previous Cerebrovascular Diseases and White Matter Hyperintensity, but Not With Regular Use of Antiplatelet Agents

“…Cerebral microbleeds are thought to be associated with the progression of small artery disease manifesting as bleeding and symptomatic intracerebral hemorrhage (ICH). 3,[7][8][9][10][13][14][15]18,[22][23][24]30,33) The prevalence of cerebral microbleeds in patients with ICH is thought to be around 60% in pooled analyses, which is higher than that in healthy adults (around 5%). 2,17) The presence of cerebral microbleeds appears to be linked to age, sex, history of cerebrovascular diseases, hypertension, diabetes mellitus, and use of antithrombotics.…”

Histological Analysis of Microbleed After Surgical Resection in a Patient With Moyamoya Disease -Case Report-

“…15) The incidence of cerebral microbleeds detected by gradient-echo T 2 * -weighted magnetic resonance (MR) imaging is significantly higher in patients with primary intracerebral hemorrhage, 6,10,16) ischemic stroke, 7,14) Alzheimer disease, 5) and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) 1,11) than in healthy individuals. 7,17,18) Microbleeds may be a potential risk factor of subsequent intracranial hemorrhage after ischemic stroke 2,14) and intraarterial thrombolytic therapy, 8) and are considered to be a general marker of various types of bleedingprone cerebral angiopathy. 19) We previously reported the incidence of asymptomatic microbleeds in patients with moyamoya disease 4) as 43-44% regardless of the onset type, which is significantly higher than that in healthy individuals.…”