title: Opercular Index Score: a CT angiography-based predictor of capillary robustness and neurological outcomes in the endovascular management of acute ischemic stroke.
abstract: BACKGROUND
  Many CT angiography (CTA) collateral scoring systems are either subjective or complex and time consuming.
  
  
  OBJECTIVE
  To evaluate the correlation between a CTA collateral scoring system-the Opercular Index Score (OIS)-with neurological outcomes at 90 days following endovascular treatment for acute ischemic stroke (AIS) secondary to large vessel occlusion.
  
  
  METHODS
  Fifty-five patients with AIS due to distal internal carotid artery, M1, or proximal M2 occlusions who underwent endovascular treatment were included. OIS was retrospectively calculated from CTA images, reconstructed from CT perfusion imaging, as the ratio of opacified M3 opercular branches in the Sylvian fissure on the unaffected side to those on the stroke side and dichotomized into favorable (OIS≤2) and poor (OIS>2). The ability of OIS to predict good neurological outcomes (modified Rankin Scale score ≤2 at 90 days) was assessed using sensitivity, specificity, and area under the curve (AUC) with receiver operating characteristic analysis.
  
  
  RESULTS
  Thirty-five patients had a favorable OIS and 20 patients had a poor OIS. Patients with favorable OIS had an 80.0% (n=28) rate of good neurological outcomes compared with 15.0% (n=3) of patients with a poor OIS (p<0.0001). On multivariate logistic regression analysis adjusting for baseline National Institutes of Health Stroke Scale score, OIS, and device used, favorable OIS was the only variable independently associated with good neurological outcome (OR=17.2, 95% CI 3.8 to 104.3) and demonstrated a sensitivity of 90.3% and specificity of 70.8% with an AUC of 0.822.
  
  
  CONCLUSIONS
  OIS is a simple and practical non-invasive scoring system that can be used to predict collateral robustness and good neurological outcome among patients with AIS undergoing endovascular treatment.
authors.affiliation: Department of Radiology and Diagnostic Imaging, Beaumont Health System, Royal Oak, Michigan, USA.
authors.forename: Alexander
authors.identifier: http://orcid.org/0000-0002-3212-6084
authors.initials: A
authors.lastname: Copelan
authors.affiliation: Department of Radiology and Diagnostic Imaging, Beaumont Health System, Royal Oak, Michigan, USA.
authors.forename: Monzer
authors.initials: M
authors.lastname: Chehab
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Waleed
authors.initials: W
authors.lastname: Brinjikji
authors.affiliation: Department of Radiology, University of Michigan Health System, Ann Arbor, Michigan, USA.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Wilseck
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: David F
authors.initials: DF
authors.lastname: Kallmes
authors.affiliation: Department of Radiology and Diagnostic Imaging, Beaumont Health System, Royal Oak, Michigan, USA.
authors.forename: Jeffery
authors.initials: J
authors.lastname: Wilseck
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000601:surgery*; D002196:Capillaries / Q000000981:diagnostic imaging; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000601:surgery; D002533:Cerebral Angiography / Q000379:methods; D002560:Cerebrovascular Circulation / Q000502:physiology; D000072226:Computed Tomography Angiography / Q000379:methods*; D019468:Disease Management; D057510:Endovascular Procedures / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D020521:Stroke / Q000000981:diagnostic imaging* / Q000601:surgery*; D016896:Treatment Outcome
keywords: CT Angiography; Stroke; Thrombectomy