title: Hippocampal magnetic resonance imaging abnormalities in cardiac arrest are associated with poor outcome.
abstract: BACKGROUND
  The role of neuroimaging in assessing prognosis in comatose cardiac survivors appears promising, but little is known regarding the import of particular spatial patterns. We report a specific spatial imaging abnormality on magnetic resonance imaging (MRI) that portends a poor prognosis: bilateral hippocampal hyperintensities on diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) sequences.
  
  
  METHODS
  Eighty sequential comatose cardiac arrest patients underwent MRI scans. Qualitative and quantitative regional analyses were performed. Patients were categorized as HIPPO(+) (n = 18) or HIPPO(-) (n = 62) based on whether they had bilateral hippocampal hyperintensities. Poor outcome was defined by a modified Rankin Scale (mRS) score ≥4 at 6 months.
  
  
  RESULTS
  Patients with bilateral hippocampal abnormalities had a higher frequency of poor outcome (P = .032). HIPPO(+) patients suffered more severe cerebral injury, with lower whole brain apparent diffusion coefficient values (P = .043) and a greater number of affected regions on DWI (P = .001) and FLAIR (P = .001) than HIPPO(-) patients. The hippocampal approach was 100% specific for a poor prognosis; only 1 patient survived and remained in a vegetative state.
  
  
  CONCLUSIONS
  Bilateral hippocampal hyperintensities on MRI may be a specific imaging finding that is indicative of poor prognosis in patients who suffer global hypoxic-ischemic injury. More research on the prognostic significance of this and similar neuroimaging patterns is indicated.
authors.affiliation: Department of Neurology at Yale University School of Medicine, New Haven, Connecticut; Department of Neurology at Massachusetts General Hospital, Boston. Electronic address: david.greer@yale.edu.
authors.forename: David M
authors.initials: DM
authors.lastname: Greer
authors.forename: Patricia D
authors.initials: PD
authors.lastname: Scripko
authors.forename: Ona
authors.initials: O
authors.lastname: Wu
authors.forename: Brian L
authors.initials: BL
authors.lastname: Edlow
authors.forename: James
authors.initials: J
authors.lastname: Bartscher
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Sims
authors.forename: Erica E C
authors.initials: EE
authors.lastname: Camargo
authors.forename: Aneesh B
authors.initials: AB
authors.lastname: Singhal
authors.forename: Karen L
authors.initials: KL
authors.lastname: Furie
mesh_terms: D000368:Aged; D003128:Coma / Q000150:complications / Q000401:mortality / Q000473:pathology*; D005260:Female; D006323:Heart Arrest / Q000150:complications / Q000401:mortality / Q000473:pathology*; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011379:Prognosis