title: A new grading system of lumbar central canal stenosis on MRI: an easy and reliable method.
abstract: OBJECTIVE
  To introduce a new grading system of lumbar central canal stenosis, evaluate its reliabilities, and compare it to the cross-sectional area and anterior-posterior diameter of the dural sac.
  
  
  METHODS
  Lumbar central canal stenosis is defined as obliteration of the anterior CSF space in front of the cauda equina. Four musculoskeletal radiologists independently graded lumbar central canal stenosis by this new grading system based on separation degree of the cauda equina on T2-weighted axial images (grade 0 = no lumbar stenosis without obliteration of anterior CSF space; grade 1 = mild stenosis with separation of all cauda equina; grade 2 = moderate stenosis with some cauda equina aggregated; and grade 3 = severe stenosis with none of the cauda equina separated) in 81 patients to determine inter- and intra-reader reliability. One radiologist measured cross-sectional areas and anterior-posterior diameters and compared these to lumbar central canal stenosis grades.
  
  
  RESULTS
  Inter-reader reliabilities were substantial to almost perfect (ICC reliability = 0.730-0.953). Intra-reader reliability was almost perfect (kappa value = 0.863-0.900). Cross-sectional areas and anterior-posterior diameters were different according to grades at all levels (p = 0.000-0.049), except between grades 2 and 3 of L2-3. At L5-S1, only anterior-posterior diameter was different between grades 0 and 1 (p = 0.005) and between grades 0 and 2 (p = 0.022).
  
  
  CONCLUSIONS
  This new grading system may be helpful to clinicians for simple and practical evaluation of lumbar central canal stenosis and for communicating with each other.
authors.affiliation: Department of Radiology, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeongi-do, 464-707, South Korea. netty0523@hanmail.net
authors.forename: Guen Young
authors.initials: GY
authors.lastname: Lee
authors.forename: Young Lee
authors.initials: YL
authors.lastname: Guen
authors.forename: Joon Woo
authors.initials: JW
authors.lastname: Lee
authors.forename: Woo Lee
authors.initials: WL
authors.lastname: Joon
authors.forename: Hee Seok
authors.initials: HS
authors.lastname: Choi
authors.forename: Seok Choi
authors.initials: SC
authors.lastname: Hee
authors.forename: Kyoung-Jin
authors.initials: KJ
authors.lastname: Oh
authors.forename: Oh
authors.initials: O
authors.lastname: Kyoung-Jin
authors.forename: Heung Sik
authors.initials: HS
authors.lastname: Kang
authors.forename: Sik Kang
authors.initials: SK
authors.lastname: Heung
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008159:Lumbar Vertebrae; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013130:Spinal Stenosis / Q000473:pathology*