Hippocampal magnetic resonance imaging abnormalities in cardiac arrest are associated with poor outcome

J Stroke Cerebrovasc Dis. 2013 Oct;22(7):899-905. doi: 10.1016/j.jstrokecerebrovasdis.2012.08.006. Epub 2012 Sep 18.

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.

Keywords: Cardiac arrest; coma; magnetic resonance imaging; prognosis.

MeSH terms

  • Aged
  • Coma / complications
  • Coma / mortality
  • Coma / pathology*
  • Female
  • Heart Arrest / complications
  • Heart Arrest / mortality
  • Heart Arrest / pathology*
  • Hippocampus / pathology*
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Prognosis