title: Brain-shift compensation by non-rigid registration of intra-operative ultrasound images with preoperative MR images based on residual complexity.
abstract: OBJECTIVE
  Compensation for brain shift is often necessary for image-guided neurosurgery, requiring registration of intra-operative ultrasound (US) images with preoperative magnetic resonance images (MRI). A new image similarity measure based on residual complexity (RC) to overcome challenges of registration of intra-operative US and preoperative MR images was developed and tested.
  
  
  METHODS
  A new two-stage method based on the matching echogenic structures such as sulci is achieved by optimizing the residual complexity value in the wavelet domain between the ultrasound image and the probabilistic map of the MR image. The proposed method is a compromise between feature-based and intensity-based approaches. Evaluation was performed using a specially designed brain phantom and an in vivo patient data set.
  
  
  RESULTS
  The results of the phantom data set registration confirmed that the proposed objective function outperforms the accuracy of adapted RC for multi-modal cases by 48 %. The mean fiducial registration error reached 1.17 and 2.14 mm when the method was applied on phantom and clinical data sets, respectively.
  
  
  CONCLUSIONS
  This improved objective function based on RC in the wavelet domain enables accurate non-rigid multi-modal (US and MRI) image registration which is robust to noise. This technology is promising for compensation of intra-operative brain shift in neurosurgery.
authors.affiliation: Image-Guided Intervention Group, Research Centre of Biomedical Technology and Robotics, RCBTR, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: P
authors.initials: P
authors.lastname: Farnia
authors.forename: A
authors.initials: A
authors.lastname: Ahmadian
authors.forename: T
authors.initials: T
authors.lastname: Shabanian
authors.forename: N D
authors.initials: ND
authors.lastname: Serej
authors.forename: J
authors.initials: J
authors.lastname: Alirezaie
mesh_terms: D000465:Algorithms; D001921:Brain / Q000473:pathology / Q000601:surgery*; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D009038:Motion; D019635:Neurosurgical Procedures / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014463:Ultrasonography