VIRTUAL ENDOSCOPY FOR PLANNING AND SIMULATION OF MINIMALLY INVASIVE NEUROSURGERY

OBJECTIVE: This article demonstrates the usefulness and the problems o f present-state software for virtual endoscopy as a tool for the plann ing and simulation of minimally invasive neurosurgical procedures. MET HODS: The software Navigator (General Electric Medical Systems, Buc, F rance) was applied for virtual endoscopic visualization of three-dimen sional magnetic resonance data sets of healthy volunteers and neurosur gical patients, using a clinical magnetic resonance scanner (1.5-T Sig na Hispeed; General Electric Medical Systems). Classical approaches fo r minimally invasive procedures were simulated. RESULTS: Virtual endos copy provided impressive three-dimensional views of intracranial and i ntracerebral cavities, with visualization of many anatomic details of the brain's inner and outer surfaces. The method proved to be especial ly suited for the simulation and planning of operations of intraventri cular lesions, for which the technical limitations of the present stat e of development of this method have fewer implications. However, the present state of technology, as described in this article, has two maj or shortcomings: 1) the blood vessels cannot be visualized together wi th the brain tissue and cranial nerves; and 2) different tissue compar tments cannot be stained in their original coloring, which would facil itate their recognition and thus orientation in space by anatomic land marks. Another important disadvantage at this stage is time consumptio n for many single working steps. CONCLUSION: Virtual endoscopy is a pr omising tool for teaching and training in intracranial neuroanatomy as well as for planning and simulation of minimally invasive (e.g., endo scopic), mainly intraventricular, operations. Direct clinical applicat ion is, at this stage of development, limited by several technical sho rtcomings of visualization and quantification of distances and modelin g of surfaces.