Advances in stroke: Imaging 2013.

S ubstantial advances have been made during the past 2 years in various applications of neuroimaging in stroke. Because of limited space, a few major areas in imaging are highlighted here, including developments in selection for acute stroke therapies, hemorrhage, and recovery. Results from several clinical trials have provided important data about imaging selection, including the mismatch concept , for acute stroke reperfusion therapies. A post hoc analysis of the pooled EPITHET-DEFUSE (Echoplanar Imaging Thrombolytic Evaluation Trial and Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution Study) datasets found that alteplase in the 3-to 6-hour window attenuated infarct growth and increased reperfusion in mismatch patients compared with placebo. Clinical outcomes were associated with degree of reperfusion; however, there was no difference in mortality or outcome between treatment groups and no comparison with nonmismatch patients. Another secondary pooled analysis from all 3 of the des-moteplase trials suggested that defining mismatch with a minimum volume of 60 cc based on magnetic resonance imaging (MRI) alone showed a significant treatment effect for des-moteplase. 3 Additionally, in patients with a visible occlusion on noninvasive vessel imaging at baseline, the desmoteplase groups had greater rates of good clinical response. 4 A phase IIb, prospective, randomized, open-label blinded end point trial tested 2 doses of intravenous tenecteplase compared with alteplase within 6 hours of onset. 5 Only patients with a demonstrated target vessel occlusion and >20% mis-match on perfusion computed tomography were enrolled. Both coprimary end points were positive, with greater rates of reperfusion and greater improvement at 24 hours on the National Institute of Health Stroke Scale (NIHSS) score in the tenecteplase groups. DEFUSE 2 (Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution Study 2) was a prospective, cohort study of thrombectomy in patients with and without target mismatch. 6 In this study, patients with target mismatch had a greater likelihood of favorable clinical response, which was associated with reper-fusion. In contrast, MR RESCUE (Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy) was a randomized, controlled trial of thrombectomy versus standard care up to 8 hours from onset, with enrollment stratified by favorable penumbral or nonpenumbral pattern based on multi-modal computed tomography or MRI. 7 The trial failed to demonstrate that penumbral imaging selection improved outcomes for patients undergoing endovascular therapy for acute isch-emic stroke. Neutral results may have been partly because of low recanalization rates with first-generation thrombectomy devices and relatively …