title: MRI evaluation of lumbar spinal stenosis: is a rapid visual assessment as good as area measurement?
abstract: BACKGROUND
  Lumbar spinal stenosis (LSS) is commonly assessed on MRI by measuring dural sac cross-sectional area (DSCA). A new method, morphological grading A-D, has recently been introduced as an alternative method.
  
  
  OBJECTIVE
  The aim of this study is to compare these two different methods for assessing LSS on MRI and study their reliability and intercorrelation.
  
  
  METHODS
  On pretreatment MRI of 84 patients, two experienced radiologists independently classified level L2/L3, L3/L4 and L4/L5 as no, relative or significant stenosis using both methods. Agreement was analyzed by weighted Kappa. The correlation between the two methods was analysed using Spearman correlation, and visualized in a box plot.
  
  
  RESULTS
  The interobserver agreement (95 % CI) was 0.69 (0.61-0.77) and 0.65 (0.56-0.74), respectively. The intraobserver agreements for DSCA were 0.77 (0.60-0.74) and 0.80 (0.66-0.93). On morphological grading A-D it was 0.78 (0.65-0.92) and 0.81 (0.68-0.94). The correlation coefficient between the two methods was 0.85 (p < 0.001). Grades C and D were under the limit value for significant stenosis using the DSCA.
  
  
  CONCLUSIONS
  The study shows that the inter- and intraobserver agreements of DSCA and morphological grading A-D were acceptable and their intercorrelation is strong. Both methods may be used in the MRI evaluation of LSS.
authors.affiliation: Department of Orthopaedic Surgery, Innlandet Hospital Trust, Anders Sandvigsgt 17, 2609, Lillehammer, Norway, greger.lonne@ntnu.no.
authors.forename: Greger
authors.initials: G
authors.lastname: Lønne
authors.forename: Bent
authors.initials: B
authors.lastname: Ødegård
authors.forename: Lars Gunnar
authors.initials: LG
authors.lastname: Johnsen
authors.forename: Tore K
authors.initials: TK
authors.lastname: Solberg
authors.forename: Kjell Arne
authors.initials: KA
authors.lastname: Kvistad
authors.forename: Øystein P
authors.initials: ØP
authors.lastname: Nygaard
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013130:Spinal Stenosis / Q000145:classification / Q000473:pathology*