A hybrid surface/image-based approach to facilitate ultrasound/CT registration

Seth Billings, Ankur Kapoor, Matthias Keil, Bradford J. Wood, Emad Boctor

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations


Registration of intra-operative ultrasound with preoperative CT is highly desirable as a navigational aid for surgeons and interventional radiologists. Image-based solutions generally achieve poor results due to substantially different image appearance of ultrasound and CT. A method is presented that uses surface information and tracked ultrasound to improve registration results. Tracked ultrasound is combined with surface and image-based registration techniques to register ultrasound to CT. Surface data is acquired using an optically tracked range sensor, for example time-of-flight camera. Range data is registered to CT using robust point-set registration; this registration provides an approximate transformation from tracker to CT coordinates. The ultrasound probe is also optically tracked. The probe position and surface-based registration provide a first estimate for the position of the ultrasound image in CT coordinates. This estimate is subsequently refined by a final image-based registration stage. Initial tests using Coherent Point Drift algorithm for registering surface data to CT show favorable results. Tests using both simulated and real time-of-flight range data have good convergence over a wide initial translation and rotation misalignment domain. Preliminary testing using time-of-flight surface data suggests that surface to CT registration may be useful as an initial guess enabling later more precise (but less robust) image based methods for registering ultrasound images to CT. We believe this method will enable image-based algorithms to robustly converge to an optimal registration solution.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2011
Subtitle of host publicationUltrasonic Imaging, Tomography, and Therapy
StatePublished - Jun 8 2011
EventMedical Imaging 2011: Ultrasonic Imaging, Tomography, and Therapy - Lake Buena Vista, FL, United States
Duration: Feb 13 2011Feb 14 2011

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


OtherMedical Imaging 2011: Ultrasonic Imaging, Tomography, and Therapy
Country/TerritoryUnited States
CityLake Buena Vista, FL


  • Coherent Point Drift
  • Cumulative Cross Residual Entropy
  • image registration
  • surface registration
  • time-of-flight
  • time-of-flight calibration
  • ultrasound/CT image fusion

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging


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