title: Experience of diffusion tensor imaging and 1H spectroscopy for outcome prediction in severe traumatic brain injury: Preliminary results.
abstract: OBJECTIVE
  The objective of the study is to test whether multimodal magnetic resonance imaging can provide a reliable outcome prediction of the clinical status, focusing on consciousness at 1 year after severe traumatic brain injury (TBI).
  
  
  METHODS
  Single center prospective cohort with consecutive inclusions.
  
  
  METHODS
  Critical Care Neurosurgical Unit of a university hospital.
  
  
  METHODS
  Forty-three TBI patients not responding to simple orders after sedation cessation and 15 healthy controls.
  
  
  METHODS
  A multimodal magnetic resonance imaging combining morphologic sequences, diffusion tensor imaging (DTI), and H proton magnetic resonance spectroscopy (MRS) was performed 24 +/- 11 days after severe TBI. The ability of DTI and MRS to predict 1-year outcome was assessed by linear discriminant analysis (LDA). Robustness of the classification was tested using a bootstrap procedure.
  
  
  RESULTS
  Fractional anisotropy (FA) was computed as the mean of values at discrete brain sites in the infratentorial and supratentorial regions. The N-acetyl aspartate/creatine (NAA/Cr) ratio was measured in the thalamus, lenticular nucleus, insular cortex, occipital periventricular white matter, and pons. After 1 year, 19 (44%) patients had unfavorable outcomes (death, persistent vegetative state, or minimally conscious state) and 24 (56%) favorable outcomes (normal consciousness with or without functional impairments). Analysis of variance was performed to compare FA and NAA/Cr in the two outcome groups and controls. FA and MRS findings showed highly significant differences between the outcome groups, with significant variables by LDA being supratentorial FA, NAA/Cr (pons), NAA/Cr (thalamus), NAA/Cr (insula), and infratentorial FA. LDA of combined FA and MRS data clearly separated the unfavorable outcome, favorable outcome, and control groups, with no overlap. Unfavorable outcome was predicted with up to 86% sensitivity and 97% specificity; these values were better than those obtained with DTI or MRS alone.
  
  
  CONCLUSIONS
  FA and NAA/Cr hold potential as quantitative outcome-prediction tools at the subacute phase of TBI.
authors.affiliation: Department of Neuroradiology, University Hospital of Rouen, Rouen, France.
authors.forename: Eléonore
authors.initials: E
authors.lastname: Tollard
authors.forename: Damien
authors.initials: D
authors.lastname: Galanaud
authors.forename: Vincent
authors.initials: V
authors.lastname: Perlbarg
authors.forename: Paola
authors.initials: P
authors.lastname: Sanchez-Pena
authors.forename: Yann
authors.initials: Y
authors.lastname: Le Fur
authors.forename: Lamine
authors.initials: L
authors.lastname: Abdennour
authors.forename: Patrick
authors.initials: P
authors.lastname: Cozzone
authors.forename: Stéphane
authors.initials: S
authors.lastname: Lehericy
authors.forename: Jacques
authors.initials: J
authors.lastname: Chiras
authors.forename: Louis
authors.initials: L
authors.lastname: Puybasset
mesh_terms: D000328:Adult; D001930:Brain Injuries / Q000175:diagnosis*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D015601:Injury Severity Score; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011522:Protons; D013997:Time Factors; D055815:Young Adult
chemical_list: D011522:Protons