1. An Open-Source Solution for Interactive Acquisition, Processing and Transfer of Interventional Ultrasound Images
Jonathan Boisvert, David Gobbi, Siddharth Vikal, Robert Rohling, Gabor Fichtinger and Purang Abolmaesumi
Medical Image Analysis (MedIA) Laboratory
Queen’s University
Kingston, Ontario, Canada

2. Introduction Ultrasound is a very common interventional image modality
Open-interface machines makes it even more attractive to IGT developers
Often used with motion tracking devices.
Problem:
Acquisition, synchronization and transfer to existing IGT systems is more difficult than it should be.

3. Prior work Integrated navigation software such as:
CustusX1, IGSonic2, SonoNav3 or Stradx4.
Software frameworks such as:
IGSTK5
Slicer specific software development
A module for Slicer 2 initially developed by Boctor et al.6

4. Open-source software platform: Slicer
Sophisticated registration, data- fusion and visualization capabilities
Modular architecture
Multi-platform
Support for the new OpenIGTLink protocol

5. Architecture : SynchroGrab
Provide real-time ultrasound processing capabilities.
Delegate visualization, registration and navigation to an OpenIGTLink compatible software (Slicer).

6. Architecture : SynchroGrab
Provide real-time ultrasound processing capabilities.
Delegate visualization, registration and navigation to an OpenIGTLink compatible software (Slicer).

7. Architecture : SynchroGrab
Provide real-time ultrasound processing capabilities.
Delegate visualization, registration and navigation to an OpenIGTLink compatible software (Slicer).

8. Architecture : SynchroGrab
Provide real-time ultrasound processing capabilities.
Delegate visualization, registration and navigation to an OpenIGTLink compatible software (Slicer).

9. Architecture : SynchroGrab
Provide real-time ultrasound processing capabilities.
Delegate visualization, registration and navigation to an OpenIGTLink compatible software (Slicer).

10. Ultrasound image acquisition
SonixRP
Open interface
Access to pre-scan converted images, post-scan converted images, imaging parameters, RF raw-data, etc.
New vtk class “vtkSonixVideoSource”
Easy integration
Highly reusable

11. Using vtkSonixVideoSource
vtkSonixVideoSource *sonixGrabber = vtkSonixVideoSource::New();
sonixGrabber->SetSonixIP(" ");
sonixGrabber->SetImagingMode(BMode);
sonixGrabber-> SetAcquisitionDataType(udtBPost);
sonixGrabber->Record();
sonixGrabber->Stop();
sonixGrabber->Rewind();
// Process the first image here
sonixGrabber->Seek(1)
// Process the second image here
sonixGrabber->Delete();
Inherit from vtkVideoSource
Support many data types:
BPreScan, BPost 8 bit, BPost 32 bit, RF 16 bit, MPost 8 bit, Color+ B 32 bits

12. 3D Tracking Object oriented Extensible Multi-threaded
Circular buffers for transformations synchronization

13. Synchronization Tracking and ultrasound imaging
not performed at the same frequency.
Need to interpolate the poses (using spherical linear interpolation)

14. Synchronization Data preprocessing OS related
Hardware latency, pose computation, ultrasound image processing, and copy to user-space memory.
OS related
Context switching, memory swapping, etc.
Compensate for the mean lag

15. Synchronization vtkTaggedImageFilter
Compute the transformation associated with an image.
Two inputs: a vtkTrackerTool and a vtkImageAlgorithm object
vtkTaggedImageFilter *tagger = vtkTaggedImageFilter::New();
tagger->SetInput(sonixGrabber->GetOutput());
tagger->SetTrackerTool(trackerTool);
tagger->SetTemporalLag(xxx);
tagger->Update();
currentTransforms = tagger->GetTransform();
currentImage = tagger->GetOutput();

16. 3D Reconstruction Synchronized images and transformation
Combined to produce 3D volumes
Pixel-based reconstruction
Pixel nearest neighbors (PNN)
Pixel trilinear interpolation (PTL)

17. Reconstructing volumes
Just start the application using the command line
SynchroGrab --calibration-file _ Calibration.results --reconstruct-volume --nb-frames fps 5 --use-tracker-transforms

18. Communication with Slicer
Real-time acquisition using SynchroGrab.
Visualization with Slicer 3.
SynchroGrab --calibration-file _ Calibration.results --oigtl-transfert-images --nb-frames fps 5

19. Communication with Slicer

20. Conclusion & Future work
SynchroGrab
Acquisition and synchronization of tracking and ultrasound data
Can be used as a stand-alone command-line application.
Can be used in conjunction to an OpenIGTLink compliant software.
Development of temporal calibration protocols
Future support for 3D probes

21. References
T. Lango, G. A. Tangen, R. Marvik, B. Ystgaard, Y. Yavuz, J. H. Kaspersen, O. V. Solberg, and T. A. N. Hernes. Navigation in laparoscopy–prototype research platform for improved image-guided surgery. Minim Invasive Ther Allied Technol, 17(1):17–33, 2008.
BrainLAB (AG, Heimstetten, Germany). IGSonic.
Medtronic(Louisville, CO, U.S.). SonoNav.
Graham Treece, Richard Prager and Andrew Gee. Stradx/Stradwin.
Andinet Enquobahrie, Patrick Cheng, Kevin Gary, Luis Ibanez, David Gobbi, Frank Lindseth, Ziv Yaniv, Stephen Aylward, Julien Jomier, and Kevin Cleary. The image-guided surgery toolkit IGSTK: an open source C++ software toolkit. J Digit Imaging, 20 Suppl 1:21–33, 2007.
E. M. Boctor, A. Viswanathan, S. Pieper, M. A. Choti, R. H. Taylor, R. Kikinis, and G. Fichtinger. CISUS: an integrated 3D ultrasound system for IGT using a modular tracking API. Proceedings of the SPIE, volume 5367, pages 247–256, May 2004

22. Acknowledgments
Natural Sciences and Engineering Research Council (NSERC),
Canadian Institutes of Health Research (CIHR),
National Alliance in Medical Image Computing (NIH5U54EB ),
Fonds québécois de recherche sur la nature et les technologies.

23. Questions