title: Semi-automated stereoradiographic upper limb 3D reconstructions using a combined parametric and statistical model: a preliminary study.
abstract: OBJECTIVE
  Quantitative assessment of 3D clinical indices may be crucial for elbow surgery planning. 3D parametric modeling from bi-planar radiographs was successfully proposed for spine and lower limb clinical investigation as an alternative for CT-scan. The aim of this study was to adapt this method to the upper limb with a preliminary validation.
  
  
  METHODS
  CT-scan 3D models of humerus, radius and ulna were obtained from 20 cadaveric upper limbs and yielded parametric models made of geometric primitives. Primitives were defined by descriptor parameters (diameters, angles...) and correlations between these descriptors were found. Using these correlations, a semi-automated reconstruction method of humerus using bi-planar radiographs was achieved: a 3D personalized parametric model was built, from which clinical parameters were computed [orientation and projections on bone surface of trochlea sulcus to capitulum (CTS) axis, trochlea sulcus anterior offset and width of distal humeral epiphysis]. This method was evaluated by accuracy compared to CT-scan and reproducibility.
  
  
  RESULTS
  Points-to-surface mean distance was 0.9 mm (2 RMS = 2.5 mm). For clinical parameters, mean differences were 0.4-1.9 mm and from 1.7° to 2.3°. All parameters except from angle formed by CTS axis and bi-epicondylar axis in transverse plane were reproducible. Reconstruction time was about 5 min.
  
  
  CONCLUSIONS
  The presented method provides access to morphological upper limb parameters with very low level of radiation. Preliminary in vitro validation for humerus showed that it is fast and accurate enough to be used in clinical daily practice as an alternative to CT-scan for total elbow arthroplasty pre operative evaluation.
authors: Laboratoire de Biomécanique, Arts et Metiers ParisTech, 151 Boulevard de l'Hopital, 75013, Paris, France.
authors: F
authors: F
authors: Lebailly
authors: L V P C
authors: LV
authors: Lima
authors: A
authors: A
authors: Clairemidi
authors: B
authors: B
authors: Aubert
authors: S
authors: S
authors: Guerard
authors: Y
authors: Y
authors: Chaibi
authors: J
authors: J
authors: de Guise
authors: C
authors: C
authors: Fontaine
authors: W
authors: W
authors: Skalli
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D005260:Female; D006801:Humans; D006811:Humerus / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D015233:Models, Statistical; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*; D034941:Upper Extremity / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*