title: The value of susceptibility-weighted imaging (SWI) in patients with non-neonatal hypoxic-ischemic encephalopathy.
abstract: OBJECTIVE
  In susceptibility-weighted imaging (SWI) in the normal brain, cortical veins appear hypointense due to paramagnetic properties of deoxy-hemoglobin. Global cerebral anoxia decreases cerebral oxygen metabolism, thereby increasing oxy-hemoglobin levels in cerebral veins. We hypothesized that a lower cerebral oxygen extraction fraction in comatose patients with non-neonatal hypoxic-ischemic encephalopathy (IHE) produces a pattern of global rarefied or pseudo-diminished cortical veins due to higher oxy-hemoglobin.
  
  
  OBJECTIVE
  (1) To investigate the topographic relationship between susceptibility effects in cortical veins and related diffusion restrictions on diffusion-weighted imaging (DWI) in patients with IHE. (2) To relate imaging findings to patterns of altered resting activity on surface EEG.
  
  
  METHODS
  Twenty-three IHE patients underwent MRI. EEG patterns were used to classify the depth of coma. Regional vs. global susceptibility changes on SWI and patterns of DWI restrictions were compared with the depth of coma.
  
  
  RESULTS
  All patients exhibited areas of restricted cortical diffusion and SWI abnormalities. The dominant DWI restrictions encompassed widespread areas along the precuneus, frontal and parietal association cortices and basal ganglia. For SWI, nineteen patients had generalized bi-hemispherical patterns, the EEG patterns correlated with coma grades III-V. Four patients had focal decreases of deoxy-hemoglobin following DWI restrictions; associated with normal EEGs.
  
  
  CONCLUSIONS
  Focal patterns of diamagnetic effects on SWI according to relative decreases in deoxy-hemoglobin due to reduced metabolic demand are associated with normal EEG in IHE patients. Global patterns indicated increased depth of coma and widespread cortical damage.
  
  
  CONCLUSIONS
  The results indicate a potential diagnostic value of SWI in patients with IHE.
authors.affiliation: University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland. Electronic address: franca.wagner@insel.ch.
authors.forename: Franca
authors.initials: F
authors.lastname: Wagner
authors.affiliation: Department of Intensive Care Medicine, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Matthias M
authors.initials: MM
authors.lastname: Haenggi
authors.affiliation: Department of Pediatric Intensive Care, University Children's Hospital, Inselspital, Bern, Switzerland.
authors.forename: Bendicht
authors.initials: B
authors.lastname: Wagner
authors.affiliation: Department of Neurology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Anja
authors.initials: A
authors.lastname: Weck
authors.affiliation: University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Weisstanner
authors.affiliation: Department of Neuropaediatrics, Development and Rehabilitation, University Children's Hospital, Inselspital, Bern, Switzerland.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Grunt
authors.affiliation: Department of Neurology and Neurosurgery, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Werner J
authors.initials: WJ
authors.lastname: Z'Graggen
authors.affiliation: University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Jan
authors.initials: J
authors.lastname: Gralla
authors.affiliation: University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Roland
authors.initials: R
authors.lastname: Wiest
authors.affiliation: University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Rajeev K
authors.initials: RK
authors.lastname: Verma
mesh_terms: D000328:Adult; D000368:Aged; D016887:Cardiopulmonary Resuscitation; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006323:Heart Arrest / Q000150:complications* / Q000628:therapy; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies
keywords: Coma; EEG; IHE; SWI