Background:
There is very limited data on the use of advanced neuroimaging to select patients with acute ischemic stroke and large vessel occlusion for intraarterial therapy beyond 6 hours from onset. Our aim is to report the outcome of patients with acute ischemic stroke and large artery occlusion who presented beyond 6 hours from onset, had favorable MRI imaging profile, and underwent mechanical embolectomy.
Methods:
This is a single institution retrospective study between December 1st, 2015, and July 30
th
, 2016 with acute ischemic stroke and anterior circulation large vessel occlusion (LVO) with ASPECTS of 6 or more and beyond 6 hours from symptoms onset. Favorable imaging profile was defined as 1) DWI lesion volume (as defined as apparent diffusion coefficient < 620 X 10-6 mm2/s) of 70 mL or less AND 2) Penumbra volume (as defined by volume of tissue with Tmax >6 sec) of 15 mL or greater AND 3) A mismatch ratio of 1.8 or more AND 4) Volume of tissue with perfusion lesion with Tmax > 10 sec is less than 100 mL. Good outcome was defined as a 90 day mRS≤2.
Results:
In the study period, 41 patients met the inclusion criteria; 22 (53.6%) had favorable imaging profile and underwent mechanical embolectomy. The median age was 75 years (59-92), 68.2% were females; the median time from last known normal to groin puncture was 684.5 minutes (range 363-1628) and the median admission NIHSS score was 17.5 (range 4-28). The rate of good outcomes in this series was similar to that in a patient level pooled meta-analysis of the recent endovascular trials (68.2% vs. 46.0%, p=0.07). The rate of good outcome matches that of the EXTEND-IA trial that selected patients using perfusion imaging (68.2% vs. 71.0%, p = 1.00). None of the patients in our cohort had symptomatic intracereberal hemorrhage.
Conclusion:
Advanced MR imaging may help select patients with acute ischemic stroke and anterior circulation large vessel occlusion for embolectomy beyond the treatment window used in most endovascular trials.
MR Imaging for Differentiating Contrast Staining from Hemorrhagic Transformation after Endovascular Thrombectomy in Acute Ischemic Stroke: Phantom and Patient Study
