title: Automatic model-based semantic registration of multimodal MRI knee data.
abstract: OBJECTIVE
  To propose a robust and automated model-based semantic registration for the multimodal alignment of the knee bone and cartilage from three-dimensional (3D) MR image data.
  
  
  METHODS
  The movement of the knee joint can be semantically interpreted as a combination of movements of each bone. A semantic registration of the knee joint was implemented by separately reconstructing the rigid movements of the three bones. The proposed method was validated by registering 3D morphological MR datasets of 25 subjects into the corresponding T2 map datasets, and was compared with rigid and elastic methods using two criteria: the spatial overlap of the manually segmented cartilage and the distance between the same landmarks in the reference and target datasets.
  
  
  RESULTS
  The mean Dice Similarity Coefficient (DSC) of the overlapped cartilage segmentation was increased to 0.68 ± 0.1 (mean ± SD) and the landmark distance was reduced to 1.3 ± 0.3 mm after the proposed registration method. Both metrics were statistically superior to using rigid (DSC: 0.59 ± 0.12; landmark distance: 2.1 ± 0.4 mm) and elastic (DSC: 0.64 ± 0.11; landmark distance: 1.5 ± 0.5 mm) registrations.
  
  
  CONCLUSIONS
  The proposed method is an efficient and robust approach for the automated registration between morphological knee datasets and T2 MRI relaxation maps.
authors.affiliation: Department of Phoniatrics and Pediatric Audiology, University Hospital Erlangen, Germany; Imaging & Therapy Division, Healthcare Sector, Siemens AG, Erlangen, Germany.
authors.forename: Ning
authors.initials: N
authors.lastname: Xue
authors.forename: Michael
authors.initials: M
authors.lastname: Doellinger
authors.forename: Jurgen
authors.initials: J
authors.lastname: Fripp
authors.forename: Charles P
authors.initials: CP
authors.lastname: Ho
authors.forename: Rachel K
authors.initials: RK
authors.lastname: Surowiec
authors.forename: Raphael
authors.initials: R
authors.lastname: Schwarz
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional; D007592:Joint Diseases / Q000175:diagnosis*; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D009068:Movement; D064847:Multimodal Imaging; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012660:Semantics
keywords: knee joint diseases; landmark detection; model-based semantic registration