An important class of image guided interventional procedures are the so-called needle guided percutaneous interventions. The clinical procedures of interest are all needle guided embolisation, biopsies and ablation procedures in the domain of: vertrebroplasty, kyphoplasty, neuro biopsies in neoplastic cranial disease and percutaneous rhizotomy in trigeminal neuralgia.
Two of the most frequently used imaging techniques for the image guidance are ultrasonic (US) based and computer tomography (CT) based. The US guided procedures are characterized by an interactive needle advancement monitoring and relatively good real time visualization of anatomical soft tissue structures. However, this technique suffers from multiple drawbacks, relatively poor visualization of bony structures filled with air, poor visibility when bony anatomy is superimposed on the structure of interest, low signal quality in obese patients (subcutaneous fat), for example. The CT guided interventions provide high contrast resolution distortion-less images and good visualization of the anatomical structures. The disadvantage of the technique is poor patient access and room sterility issues. An intervention room equipped with a rotational X-ray device is much more suitable for such procedures, but for most of the procedures the contrast resolution of the X-ray device is not sufficient.
It is known from US2006/0215812, that preparations can be made for a puncture intervention using images obtained from Magneto-Resonance/Computer Tomography and rotational X-ray devices. Here as part of these preparations the target and start/entry points for the puncture have to be defined in the three-dimensional-volume set by indicating them in mutually orthogonal cross sectional slices. The problem with this process is that a tedious trial and error method must be followed to define/evaluate the resulting needle trajectory in the cross-sectional slices. In the context of rotational X-ray, this process is hindered by the fact that sometimes the actual entry point is difficult to locate because the skin may not always be visible within the reconstructed region of interest.
Furthermore usually some global constraints must be fulfilled, such as entering a cavity or avoiding or passing in between bone or vessel material that is sometimes difficult to evaluate on cross sectional slices.
Because the puncture preparations are performed just before the intervention i.e. directly after the rotational scan with a patient (who is not supposed to move) on the table, it is important that a fast and effective trajectory plan is available/obtained.