title: Ultrasound registration of the bone surface for surgical navigation.
abstract: OBJECTIVE
  To allow non-invasive registration of the bone surface for computer-assisted surgery (CAS), this investigation reports the development and evaluation of intraoperative registration using 2D ultrasound (US) images. This approach employs automatic segmentation of the bone surface reflection from US images tagged with the 3D position to enable the application of CAS to minimally invasive procedures.
  
  
  METHODS
  The US-based registration method was evaluated in comparison to point-based registration, which is the predominant method in current clinical use. The absolute accuracy of the US-based registration was determined using a phantom pelvis, with fiducial registration providing the ground truth. The relative accuracy was determined by an intraoperative study comparing the US registration to the point-based registration obtained as part of the HipNav experimental protocol.
  
  
  RESULTS
  The phantom pelvis study demonstrated equivalent accuracy between point- and US-based registration under in vitro conditions. In the intraoperative study, the US-based registration was sufficiently consistent with the point-based registration to warrant larger-scale clinical trials of this non-invasive registration method.
  
  
  CONCLUSIONS
  Ultrasound-based registration eliminates the need for physical contact with the bone surface as in point-based registration. As a result, non-invasive registration could fully unlock the potential of computer-assisted surgery, enabling development of the next generation of minimally invasive surgical procedures.
authors.affiliation: Center for Medical Robotics and Computer Assisted Surgery, The Robotics Institute, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA. da2q@andrew.cmu.edu
authors.forename: Devin V
authors.initials: DV
authors.lastname: Amin
authors.forename: Takeo
authors.initials: T
authors.lastname: Kanade
authors.forename: Anthony M
authors.initials: AM
authors.lastname: DiGioia
authors.forename: Branislav
authors.initials: B
authors.lastname: Jaramaz
mesh_terms: D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D066298:In Vitro Techniques; D007432:Intraoperative Period; D019060:Minimally Invasive Surgical Procedures; D010384:Pelvic Bones / Q000000981:diagnostic imaging* / Q000601:surgery; D019047:Phantoms, Imaging; D025321:Surgery, Computer-Assisted; D014463:Ultrasonography