title: Multimodal image registration of the scoliotic torso for surgical planning.
abstract: BACKGROUND
  This paper presents a method that registers MRIs acquired in prone position, with surface topography (TP) and X-ray reconstructions acquired in standing position, in order to obtain a 3D representation of a human torso incorporating the external surface, bone structures, and soft tissues.
  
  
  METHODS
  TP and X-ray data are registered using landmarks. Bone structures are used to register each MRI slice using an articulated model, and the soft tissue is confined to the volume delimited by the trunk and bone surfaces using a constrained thin-plate spline.
  
  
  RESULTS
  The method is tested on 3 pre-surgical patients with scoliosis and shows a significant improvement, qualitatively and using the Dice similarity coefficient, in fitting the MRI into the standing patient model when compared to rigid and articulated model registration. The determinant of the Jacobian of the registration deformation shows higher variations in the deformation in areas closer to the surface of the torso.
  
  
  CONCLUSIONS
  The novel, resulting 3D full torso model can provide a more complete representation of patient geometry to be incorporated in surgical simulators under development that aim at predicting the effect of scoliosis surgery on the external appearance of the patient's torso.
authors.affiliation: École Polytechnique de Montréal. 2500, chemin de Polytechnique, Montreal, H3T 1J4, Canada. rola.harmouche@polymtl.ca
authors.forename: Rola
authors.initials: R
authors.lastname: Harmouche
authors.forename: Farida
authors.initials: F
authors.lastname: Cheriet
authors.forename: Hubert
authors.initials: H
authors.lastname: Labelle
authors.forename: Jean
authors.initials: J
authors.lastname: Dansereau
mesh_terms: D059925:Anatomic Landmarks / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D011300:Preoperative Care / Q000379:methods*; D015203:Reproducibility of Results; D012600:Scoliosis / Q000175:diagnosis* / Q000601:surgery*; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods*; D060726:Torso / Q000000981:diagnostic imaging / Q000473:pathology