title: Monitoring for idiopathic scoliosis curve progression using surface topography asymmetry analysis of the torso in adolescents.
abstract: BACKGROUND
  At first visit and each clinical follow-up session, patients with adolescent idiopathic scoliosis (AIS) undergo radiographic examination, from which the Cobb angle is measured. The cumulative exposure to X-ray radiation justifies efforts in developing noninvasive methods for scoliosis monitoring.
  
  
  OBJECTIVE
  To determine the capability of the three-dimensional markerless surface topography (ST) asymmetry analysis to detect ≥5° progression in the spinal curvature in patients with AIS over 1-year follow-up interval.
  
  
  METHODS
  Cross-sectional study in a specialized scoliosis clinic.
  
  
  METHODS
  In this study, baseline and 1-year follow-up full torso ST scans of 100 patients with AIS were analyzed using three-dimensional markerless asymmetry analysis.
  
  
  METHODS
  Patients with ΔCobb≥5° and ΔCobb<5° were categorized into progression and nonprogression groups, respectively.
  
  
  METHODS
  The ST scan of each full torso was analyzed to calculate the best plane of symmetry by minimizing the distances between the torso and its reflection about the plane of symmetry. Distance between the torso and its reflection was measured and displayed as deviation color maps. The difference of ST measurements between two successive acquisitions was used to determine if the scoliosis has progressed at least 5° or not. The classification tree technique was implemented using the local deformity of the torso in the thoracic-thoracolumbar (T-TL) and lumbar (L) regions to categorize curves into progression and nonprogression groups. The change in maximum deviation and root mean square of the deviations in the torso were the parameters effective in capturing the curve progression. Funding for this research is provided by the Scoliosis Research Society, and Women and Children's Health Research Institute.
  
  
  RESULTS
  The classification model detected 85.7% of the progression and 71.6% of the nonprogression cases. The resulting false-negative rate of 4% for T-TL curves, representing the proportion of undetected progressions, confirmed that the technique shows promise to monitor the progression of T-TL scoliosis curves. Although 100% L curves with progression were detected using the deviation color maps of the torsos, because of the small number of analyzed L curves, further research is needed before the efficiency of the method in capturing the L curves with progression is confirmed.
  
  
  CONCLUSIONS
  Using the developed classification tree for the patients analyzed in this study, 43% of nonprogression cases between two visits would not have to undergo an X-ray examination.
authors.affiliation: Department of Civil and Environmental Engineering, University of Alberta, Markin/CNRL Natural Resources Engineering Facility, 9105 116th St, Edmonton, Alberta, Canada T6G 2W2. Electronic address: akomeili@ualberta.ca.
authors.forename: Amin
authors.initials: A
authors.lastname: Komeili
authors.affiliation: Department of Mechanical Engineering, University of Alberta, 4-9 Mechanical Engineering Building, Edmonton, Canada, AB T6G 2G8.
authors.forename: Lindsey
authors.initials: L
authors.lastname: Westover
authors.affiliation: Department of Physical Therapy, University of Alberta, 2-50 Corbett Hall, Edmonton, Alberta, Canada, T6G2G4.
authors.forename: Eric C
authors.initials: EC
authors.lastname: Parent
authors.affiliation: Department of Civil and Environmental Engineering, University of Alberta, Markin/CNRL Natural Resources Engineering Facility, 9105 116th St, Edmonton, Alberta, Canada T6G 2W2.
authors.forename: Marwan
authors.initials: M
authors.lastname: El-Rich
authors.affiliation: Department of Civil and Environmental Engineering, University of Alberta, Markin/CNRL Natural Resources Engineering Facility, 9105 116th St, Edmonton, Alberta, Canada T6G 2W2.
authors.forename: Samer
authors.initials: S
authors.lastname: Adeeb
mesh_terms: D000293:Adolescent; D003430:Cross-Sectional Studies; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D011859:Radiography; D012600:Scoliosis / Q000000981:diagnostic imaging*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging*; D060726:Torso / Q000000981:diagnostic imaging*
keywords: Adolescent idiopathic scoliosis; Asymmetry analysis; Classification tree; Disease progression; Monitoring; Surface topography