title: Comparison of MR imaging findings between extraligamentous and subligamentous disk herniations in the lumbar spine.
abstract: OBJECTIVE
  The method of treating an HIVD in the lumbar spine may depend on the integrity of the PLL. The purpose of this study was to analyze and compare the MR imaging findings of extraligamentous and subligamentous HIVDs in the lumbar spine.
  
  
  METHODS
  One hundred seventeen patients (M/F = 71:46; mean age, 47 years; age range, 15-79 years) underwent lumbar spine MR imaging and disk surgery (extraligamentous/subligamentous = 66:51) from May 2003 to November 2006. Two radiologists in consensus retrospectively reviewed all MR images, focusing on 10 criteria.
  
  
  RESULTS
  The following 5 criteria are suggestive of extraligamentous HIVD in the lumbar spine: 1) spinal canal compromised for more than half its dimension, 2) internal signal difference in the HIVD, 3) an ill-defined margin of the HIVD, 4) disruption of the continuous low-signal-intensity line covering the HIVD, and 5) the presence of an internal dark line in the HIVD (P < .05). When we combined these 5 MR imaging criteria, the sensitivity, specificity, accuracy, and odds ratio were 77.3%, 74.5%, 76.1%, and 9.93 (P < .0001).
  
  
  CONCLUSIONS
  Our proposed 5 MR imaging criteria will be helpful in differentiating extraligamentous and subligamentous HIVDs in the lumbar spine.
authors.affiliation: Department of Radiology, Seoul National University Bundang Hospital, Gyeongi-Do, South Korea.
authors.forename: K-J
authors.initials: KJ
authors.lastname: Oh
authors.forename: J W
authors.initials: JW
authors.lastname: Lee
authors.forename: B L
authors.initials: BL
authors.lastname: Yun
authors.forename: S T
authors.initials: ST
authors.lastname: Kwon
authors.forename: K-W
authors.initials: KW
authors.lastname: Park
authors.forename: J S
authors.initials: JS
authors.lastname: Yeom
authors.forename: H S
authors.initials: HS
authors.lastname: Kang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000473:pathology*; D008022:Ligaments / Q000473:pathology*; D008159:Lumbar Vertebrae / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult