Image-Guided Sonography and Interventional Image Fusion

The propose of the project is the development of a prototype navigation system for image guided sonography and endosonography. The same image which is provided by the ultrasound (US) scan head of the endoscope is to be reconstructed from a three-dimensional CT or MRI dataset acquired prior to the intervention. To obtain the position and orientation of the instrument, we merge two methods: in the first step we use an electromagnetic tracking system (EMTS) to get the initial position and orientation of the instrument respective of the US scan head. Then optical registration procedure using the image provided by the video camera of the endoscope is performed. This provides higher accuracy. If the optical methods fails, the EMTS is used again to deliver the initial conditions to restart the optical registration procedure. For the registration of the patient in respect to the CT or MR volume dataset we want to apply an invasive method which is easier to handle for the interventionist. The clinical advantage that is expected from this technique is enhanced information content (basically, the physician sees the same view of the organ under consideration of three modalities) and the increased hit rate of endosonography biopsies.