title: Outcome prediction in patients after cardiac arrest: a simplified method for determination of gray-white matter ratio in cranial computed tomography.
abstract: OBJECTIVE
  Out-of-hospital cardiac arrest is a frequent cause of death in Europe. Hypoxic ischemic encephalopathy (HIE) often develops in initial survivors, and the question of treatment limitation arises in severely affected patients. To establish a poor prognosis with a high level of certainty, the use of a combination of prognostic parameters such as neurological examination, somatosensory evoked potentials, and neuron-specific enolase is common practice. A few recent studies suggest that gray-white matter ratio (GWR) determined from cranial computed tomography (CT) scans is an additional reliable predictor of poor prognosis. The standard GWR determination method involves measurements of 16 different regions of interest (ROIs). We tested whether a simplified method to obtain GWR has equivalent reliability for poor outcome prediction.
  
  
  METHODS
  We retrospectively analyzed 98 patients after cardiac arrest who had been treated with hypothermia. CT scans were obtained within the first 7 days after cardiac arrest. Neurological outcome was determined at intensive care unit discharge. Four different methods to obtain GWR were compared in a receiver-operating characteristic curve analysis with respect to their prognostic value for poor outcome prediction.
  
  
  RESULTS
  The simplest method using only four ROIs (putamen and internal capsule bilaterally) had the same prognostic value compared with the standard method using 16 ROIs. The simplified GWR predicted poor outcome with a sensitivity of 44 % at 100 % specificity.
  
  
  CONCLUSIONS
  Our results indicate that for poor outcome prediction in survivors of cardiac arrest, a simplified GWR determination is feasible and has the same reliability as the complex standard procedure.
authors.affiliation: Department of Neuroradiology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Gentsch
authors.forename: C
authors.initials: C
authors.lastname: Storm
authors.forename: C
authors.initials: C
authors.lastname: Leithner
authors.forename: T
authors.initials: T
authors.lastname: Schroeder
authors.forename: C J
authors.initials: CJ
authors.lastname: Ploner
authors.forename: B
authors.initials: B
authors.lastname: Hamm
authors.forename: E
authors.initials: E
authors.lastname: Wiener
authors.forename: M
authors.initials: M
authors.lastname: Scheel
mesh_terms: D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging; D005260:Female; D066128:Gray Matter / Q000000981:diagnostic imaging*; D006323:Heart Arrest / Q000150:complications / Q000000981:diagnostic imaging*; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000000981:diagnostic imaging* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D066127:White Matter / Q000000981:diagnostic imaging*