title: Reliability of the Goutallier classification in quantifying muscle fatty degeneration in the lumbar multifidus using magnetic resonance imaging.
abstract: OBJECTIVE
  The purpose of this study was to investigate the reliability of the Goutallier classification system (GCS) for grading muscle fatty degeneration in the lumbar multifidus (LM) using magnetic resonance imaging (MRI) examinations.
  
  
  METHODS
  Lumbar spine MRI scans were obtained retrospectively from the radiology department imaging system. Two examiners (a chiropractic diagnostic imaging resident and a board certified chiropractic radiologist with 30 years of experience) independently graded each LM at the L4/5 and L5/S1 intervertebral level. ImageJ pixel analysis software (version 1.47; National Institutes of Health, Bethesda, MD) was used independently by 2 observers to quantify the percent fat of the LM and allow correlation between LM percent fat and GCS grade. Twenty-five subject MRIs were randomly selected. Magnetic resonance imaging scans were included if they were obtained using a 1.5 T imaging system and were excluded if there was evidence of spinal infection, tumor, fracture, or postoperative changes. For all tests, P < .05 was defined as significant.
  
  
  RESULTS
  Intraobserver reliability grading LM fat ranged from a weighted κ (κw) of 0.71 to 0.93. Mean interobserver reliability grading LM fat was κ(w), 0.76 to κ(w), 0.85. There was a significant (P < .001) correlation between LM percent fat and GCS grade. Furthermore, interobserver reliability in determining percent fat was between intraclass correlation coefficient, 0.73 to intraclass correlation coefficient, 0.90.
  
  
  CONCLUSIONS
  In this study, the GCS was reliable in grading LM fatty degeneration and correlated positively with a quantified percent fat value. In addition, ImageJ software (National Institutes of Health) was reliable between raters when quantifying LM percent fat.
authors.affiliation: Diagnostic Imaging Resident, Department of Radiology, Logan University, Chesterfield, MO. Electronic address: Patrick.battaglia@logan.edu.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Battaglia
authors.affiliation: Research Fellow, Adjunct Professor, Department of Radiology, Logan University, Chesterfield, MO; Research Fellow, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Maeda
authors.affiliation: Diagnostic Imaging Fellow, Department of Radiology, Logan University, Chesterfield, MO.
authors.forename: Aaron
authors.initials: A
authors.lastname: Welk
authors.affiliation: Chief Information Officer, Department of Information Technology Services, Logan University, Chesterfield, MO.
authors.forename: Brad
authors.initials: B
authors.lastname: Hough
authors.affiliation: Chair, Department of Radiology, Logan University, Chesterfield, MO.
authors.forename: Norman
authors.initials: N
authors.lastname: Kettner
mesh_terms: D000273:Adipose Tissue / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008161:Lumbosacral Region; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data; D008875:Middle Aged; D009133:Muscular Atrophy / Q000145:classification* / Q000473:pathology*; D015588:Observer Variation; D064170:Paraspinal Muscles; D015203:Reproducibility of Results; D012189:Retrospective Studies
keywords: Low-Back Pain; Magnetic Resonance Imaging; Skeletal Muscle