title: Percentage insula ribbon infarction of >50% identifies patients likely to have poor clinical outcome despite small DWI infarct volume.
abstract: OBJECTIVE
  Large admission DWI infarct volume (>70 mL) is an established marker for poor clinical outcome in acute stroke. Outcome is more variable in patients with small infarcts (<70 mL). Percentage insula ribbon infarct correlates with infarct growth. We hypothesized that percentage insula ribbon infarct can help identify patients with stroke likely to have poor clinical outcome, despite small admission DWI lesion volumes.
  
  
  METHODS
  We analyzed the admission NCCT, CTP, and DWI scans of 55 patients with proximal anterior circulation occlusions on CTA. Percentage insula ribbon infarct (>50%, ≤50%) on DWI, NCCT, CT-CBF, and CT-MTT were recorded. DWI infarct volume, percentage DWI motor strip infarct, NCCT-ASPECTS, and CTA collateral score were also recorded. Statistical analyses were performed to determine accuracy in predicting poor outcome (mRS >2 at 90 days).
  
  
  RESULTS
  Admission DWI of >70 mL and DWI-percentage insula ribbon infarct of >50% were among significant univariate imaging markers of poor outcome (P < .001). In the multivariate analysis, DWI-percentage insula ribbon infarct of >50% (P = .045) and NIHSS score (P < .001) were the only independent predictors of poor outcome. In the subgroup with admission DWI infarct of <70 mL (n = 40), 90-day mRS was significantly worse in those with DWI-percentage insula ribbon infarct of >50% (n = 9, median mRS = 5, interquartile range = 2-5) compared with those with DWI-percentage insula ribbon infarct of ≤50% (n = 31, median mRS = 2, interquartile range = 0.25-4, P = .036). In patients with admission DWI infarct of >70 mL, DWI-percentage insula ribbon infarct did not have added predictive value for poor outcome (P = .931).
  
  
  CONCLUSIONS
  DWI-percentage insula ribbon infarct of >50% independently predicts poor clinical outcome and can help identify patients with stroke likely to have poor outcome despite small admission DWI lesion volumes.
authors.affiliation: From the Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.
authors.forename: V M
authors.initials: VM
authors.lastname: Timpone
authors.affiliation: From the Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.
authors.forename: M H
authors.initials: MH
authors.lastname: Lev
authors.affiliation: From the Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.
authors.forename: S
authors.initials: S
authors.lastname: Kamalian
authors.affiliation: From the Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.
authors.forename: L T
authors.initials: LT
authors.lastname: Morais
authors.affiliation: From the Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.
authors.forename: A M
authors.initials: AM
authors.lastname: Franceschi
authors.affiliation: From the Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.
authors.forename: L
authors.initials: L
authors.lastname: Souza
authors.affiliation: From the Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts. pschaefer@partners.org.
authors.forename: P W
authors.initials: PW
authors.lastname: Schaefer
mesh_terms: D000368:Aged; D002540:Cerebral Cortex / Q000473:pathology*; D002544:Cerebral Infarction / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D020521:Stroke / Q000473:pathology*; D016896:Treatment Outcome