MRI Identifies Stroke Patients to Benefit From Thrombectomy

MRI plus clinical criteria improves assignment of stroke patients to endovascular treatment, according to a study published in JAMA Neurology.

Researchers from Massachusetts General Hospital in Boston sought to evaluate the effectiveness of MRI in helping select which patients with acute ischemic stroke would be candidates for thrombectomy.

A total of 103 patients received endovascular therapy during the study period, between January 1, 2012 and December 31, 2014. Seventy-two underwent diffusion weighted MRI followed by thrombectomy; 31 underwent CT screening only.

"Endovascular therapy has been proven to be effective and superior to other approaches for the treatment of severe strokes caused by the blockage of large brain arteries," senior author Gilberto González, MD, PhD, director of Neuroradiology in the MGH Department of Radiology, said in a release. "The critical question has been how to optimize its use to benefit the most patients while minimizing any harm."

The researchers prospectively classified the 72 patients who underwent MRI screening: 40 patients as likely to benefit (LBT) and 32 uncertain to benefit (UTB). The main outcomes and measures were 90-day modified Rankin Scale (mRS) score, with favorable defined as a 90-day mRS score of 2 or less.[[{"type":"media","view_mode":"media_crop","fid":"44377","attributes":{"alt":"Gilberto González, MD, PhD","class":"media-image media-image-right","id":"media_crop_734383373577","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"4954","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"float: right;","title":"Gilberto González, MD, PhD","typeof":"foaf:Image"}}]]

The results showed that reperfusion (71 of 103 patients) and prospective categorization as LTB (40 of 103 patients) were associated with favorable outcomes. Successful reperfusion positively affected the distribution of mRS scores of the LTB cohort, the researchers noted. Favorable outcomes were observed in 20 of the 27 patients in the LTB group (74.1%) who had successful reperfusion compared with eight of the 24 patients in the UTB group (33.3%) who had successful reperfusion. The ratio of treated to screened patients was 1:3.

"The next frontier to investigate is treatment six to 24 hours after stroke onset,” co-author Joshua Hirsch, MD, director of Endovascular Neuroradiology at MGH, said in the release. “Data we have accumulated over the past decade suggests that many patients may be successfully treated at this late stage, and MRI is the most powerful means to accurately identify these individuals. If that is true, there may be time to transfer patients who first present at regional hospitals to centers like the MGH that have the capability to conduct this type of screening program. While diffusion MRI is broadly available, only a few major institutions have recognized its critical role and made it available around the clock in emergent fashion for the evaluation of severe stroke patients."