title: Visual and quantitative assessment of lateral lumbar spinal canal stenosis with magnetic resonance imaging.
abstract: BACKGROUND
  Lateral lumbar spinal canal stenosis is a common etiology of lumbar radicular symptoms. Quantitative measurements have commonly demonstrated better repeatability than visual assessments. We are not aware of any studies examining the repeatability of quantitative assessment of the lateral canal.
  
  
  OBJECTIVE
  To evaluate the repeatability of visual assessments and newly developed quantitative measurements of lateral lumbar spinal canal stenosis using magnetic resonance imaging (MRI).
  
  
  METHODS
  Twenty-eight patients with lateral lumbar spinal canal stenosis or prior spinal surgery with recurrent symptoms were imaged with MRI. A radiologist, a neurosurgeon and a spine research trainee graded visually and quantitatively subarticular (n = 188) and foraminal zones (n = 260) of the lateral spinal canal. Quantitative measurements included the minimal subarticular width and the cross-sectional area of the foramen.
  
  
  RESULTS
  The repeatability of visual assessment at the subarticular zone and foraminal zones between raters varied from 0.45-0.59 and 0.42-0.53, respectively. Similarly, the intraclass correlation coefficients for the quantitative measurements varied from 0.67-0.71 and 0.66-0.76, respectively. The intra-rater repeatability for the visual assessments of the subarticular and foraminal zones was 0.70 and 0.62, respectively, while the corresponding intraclass correlation coefficients for quantitative measurements were 0.83 and 0.81, respectively.
  
  
  CONCLUSIONS
  Inter-rater repeatability of visual assessments of lateral stenosis is moderate, whereas quantitative measurements of both subarticular width and the cross-sectional area of the foramen have substantial reproducibility and may be particularly useful for longitudinal studies and research purposes. The clinical value of these parameters requires further study.
authors.affiliation: University of Eastern Finland, School of Medicine, Institute of Clinical Medicine, Department of Clinical Radiology, Kuopio, Finland. petri.sipola@kuh.fi
authors.forename: Petri
authors.initials: P
authors.lastname: Sipola
authors.forename: Ville
authors.initials: V
authors.lastname: Leinonen
authors.forename: Riikka
authors.initials: R
authors.lastname: Niemeläinen
authors.forename: Timo
authors.initials: T
authors.lastname: Aalto
authors.forename: Ritva
authors.initials: R
authors.lastname: Vanninen
authors.forename: Hannu
authors.initials: H
authors.lastname: Manninen
authors.forename: Olavi
authors.initials: O
authors.lastname: Airaksinen
authors.forename: Michele C
authors.initials: MC
authors.lastname: Battié
mesh_terms: D000328:Adult; D000368:Aged; D006801:Humans; D008159:Lumbar Vertebrae / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D013130:Spinal Stenosis / Q000175:diagnosis / Q000473:pathology*