Neuroimaging markers of hemorrhagic risk with stroke reperfusion therapy

Abstract

We sought to identify pretreatment neuroimaging markers associated with intracerebral hemorrhage (ICH) after reperfusion therapy for acute ischemic stroke. A literature review using available online medical literature databases was performed to identify noninvasive imaging markers correlated with ICH after reperfusion therapy. Key words, including different neuroimaging modalities such as noncontrast CT, multimodal CT, and MRI techniques, were queried. The review included randomized, controlled trials, post hoc studies, and institutional registries. Studies of IV as well as intra-arterial reperfusion therapies were considered. Articles were organized on the basis of imaging modality and type of treatment. Each imaging modality was given 1 of 3 grades for consideration of use in clinical practice (grade 1: a modality whose use for hemorrhage prediction is supported by randomized controlled trials or post hoc studies from prospective trials; grade 2: a modality that is largely available but requires further prospective validation; and grade 3: a modality which is rarely used and has limited clinical utility). Grade 1 imaging modalities included the size of infarction as seen on noncontrast CT or diffusion MRI. Higher hemorrhagic risk has been seen with larger infarctions, suggesting that these imaging modalities may be effective screening tests to exclude specific patients. Perfusion imaging using CT or MRI was considered to have a grade 2 recommendation, pending further validation. The use of xenon CT, radionuclide imaging, voxel-based MRI analysis, and blood-brain barrier disruption imaging still require further design improvements (grade 3). Future reperfusion trials require clearly defined protocols for imaging and determination of symptomatic ICH. Future trials may consider the use of perfusion imaging and the inclusion of patients without large territorial infarctions to accurately predict those at risk for ICH with reperfusion therapy.