title: A quantitative and reproducible method to assess cord compression and canal stenosis after cervical spine trauma: a study of interrater and intrarater reliability.
abstract: METHODS
  Reliability study.
  
  
  OBJECTIVE
  To assess the intrarater and interrater reliability of a recently described technique to measure of maximum canal compromise (MCC) and maximum spinal cord compression (MSCC) using digitized and magnified images in the setting of traumatic cervical spinal cord injury (SCI).
  
  
  BACKGROUND
  The extent of MCC and MSCC is of clinical and prognostic value in the setting of traumatic cervical SCI. However, concerns remain regarding the accuracy of measurements based on hard copy images. We hypothesized that the interrater and intrarater reliability of these assessments would be enhanced using magnified digitized images and software-based measurement tools.
  
  
  METHODS
  Midsagittal MRI and CT images of cervical spine were selected from 5 individuals with acute traumatic cervical SCI. Measurements of MCC using CT scan and T1-weighted MRI and measurements of MSCC based on T2-weighted MR images were independently estimated by 13 raters on 10 occasions.
  
  
  RESULTS
  The intrarater reliability for CT-MCC, T1-weighted MRI-MCC and T2-weighted MRI-MSCC was high in the 10 rounds in each patient. In addition, the mean intrarater interclass correlation coefficient was 0.72 +/- 0.05 for the CT-MCC, 0.70 +/- 0.07 for the T1-weighted MRI-MCC, and 0.68 +/- 0.11 for the T2-weighted MRI-MSCC. The mean interrater interclass correlation coefficients were 0.43 +/- 0.02 for the CT-MCC, 0.61 +/- 0.03 for the T1-weighted MRI-MCC, and 0.55 +/- 0.05 for the evaluation of T2-weighted MRI-MSCC.
  
  
  CONCLUSIONS
  Our study has demonstrated that the intrarater reliability for the instrument to assess MCC and MSCC in the setting of traumatic SCI was high. The interrater ICCs at a moderate level of reliability combined with our results using analysis of variance with post hoc tests indicate that the measurements of MCC and MSCC are reproducible, which supports the use of these radiologic parameters in the clinical and research settings.
authors.affiliation: Spinal Program, Krembil Neuroscience Centre, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada.
authors.forename: Julio C
authors.initials: JC
authors.lastname: Furlan
authors.forename: Michael G
authors.initials: MG
authors.lastname: Fehlings
authors.forename: Eric M
authors.initials: EM
authors.lastname: Massicotte
authors.forename: Bizhan
authors.initials: B
authors.lastname: Aarabi
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Vaccaro
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Bono
authors.forename: Ignacio
authors.initials: I
authors.lastname: Madrazo
authors.forename: Carlos
authors.initials: C
authors.lastname: Villanueva
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Grauer
authors.forename: David
authors.initials: D
authors.lastname: Mikulis
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009656:North America; D015588:Observer Variation; D011379:Prognosis; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D012815:Signal Processing, Computer-Assisted; D013117:Spinal Cord Compression / Q000175:diagnosis* / Q000209:etiology; D013119:Spinal Cord Injuries / Q000150:complications* / Q000473:pathology; D013130:Spinal Stenosis / Q000150:complications / Q000175:diagnosis* / Q000209:etiology; D014057:Tomography, X-Ray Computed