title: Interobserver reliability of detecting lumbar intervertebral disc high-intensity zone on magnetic resonance imaging and association of high-intensity zone with pain and anular disruption.
abstract: METHODS
  Retrospective analysis of a spine imaging center's records of patients with chronic low back pain referred by tertiary care facilities.
  
  
  OBJECTIVE
  1) To assess the interobserver reliability of detecting lumbar intervertebral disc high-intensity zone on T2-weighted magnetic resonance imaging, and 2) to assess the relation between high-intensity zone and discography or post-computed tomography in symptomatic patients with low back pain.
  
  
  BACKGROUND
  Two of the three previous studies on this subject found an association between high-intensity zone and the presence of Grade 4 anular disruption with discographic reproduction of patients' exact low back pain.
  
  
  METHODS
  Records of patients with low back pain who had undergone lumbar spine discography injection and post-computed tomography from June 1995 to August 1996 were reviewed. Two independent observers were asked to identify the presence of an high-intensity zone from the T12-L1 disc to L5-S1 on T2-weighted magnetic resonance images. With this data, interobserver reliability was assessed with the kappa statistic. Concordant high-intensity zone results were then compared with the Dallas Discogram rating for anular disruption and to patients' subjective pain response to discography injection. With this data, the sensitivity, specificity, and predictive values of high-intensity zone for detecting disc disruption and pain response were calculated.
  
  
  RESULTS
  The interobserver reliability for detecting a high-intensity zone in a given disc was fair to good (kappa = 0.57; 95% confidence interval = 0.44, 0.70). The sensitivity of high-intensity zone for detecting Grade 4 anular disruption and exact pain was poor (31%) but its specificity was relatively high (90%). The positive predictive value of a high-intensity zone was low (40%) for a severely disrupted and exactly painful disc.
  
  
  CONCLUSIONS
  The interobserver reliability of detecting a high-intensity zone and the positive predictive value of the presence of a high-intensity zone for detecting a severely disrupted and exactly painful disc were much lower than previous studies have shown. The relatively low positive predictive value may be attributable to differences in sample characteristics or procedural variations, or suggest that a high-intensity zone is not indicative of exactly painful internal intervertebral disc disruption.
authors.affiliation: Division of Clinical Sciences, Los Angeles College of Chiropractic, California, USA.
authors.forename: B M
authors.initials: BM
authors.lastname: Smith
authors.forename: E L
authors.initials: EL
authors.lastname: Hurwitz
authors.forename: D
authors.initials: D
authors.lastname: Solsberg
authors.forename: D
authors.initials: D
authors.lastname: Rubinstein
authors.forename: D S
authors.initials: DS
authors.lastname: Corenman
authors.forename: A P
authors.initials: AP
authors.lastname: Dwyer
authors.forename: J
authors.initials: J
authors.lastname: Kleiner
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000000981:diagnostic imaging / Q000473:pathology*; D017116:Low Back Pain / Q000175:diagnosis* / Q000209:etiology; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013122:Spinal Diseases / Q000150:complications / Q000175:diagnosis*; D014057:Tomography, X-Ray Computed