Colored 3D-CT Reconstruction

Introduction: Planning of skull base surgery involves a large number of conventional pictures. Three-dimensional CT-reconstruction added a different perspective in demonstrating spatial relationships of bone, tumor and vessel in a single illustration. Methods: 70 patients with skull base lesions (63 neoplastic and 7 vascular) were examined with spiral CT and 3D-reconstruction preoperatively. The reconstruction both visualized the pathology in its relationship to the adjacent bone and vessels -labelled in different colors— and simulated the possible surgical approaches. A General Electric High Speed Advantage CT and a maximum of 95 ml intravenous contrast media were used. A Spiral CT covering the area of interest was performed and transformed to 1 mm slices. Reconstruction was done after transfering the data set to an Advantage Windows Workstation; this required about 3 to 5 minutes. Editing the 3D-reconstruction took between 20 minutes and 1.5 hours (average one (1) hour) depending on the pathology’s complexity. Results: Preoperative 3D-reconstruction of CT-data renders spatial representation of the lesion in relationship to neighboring structures using data usually acquired in preoperative routine. Complex anatomy is visualized with a handful of pictures including cinematografic presentations. Using the reconstructed 3D-computer model it was easily possible to compare different surgical approaches and its specific exposure. The short time necessary for reconstruction allows the application of this method as a routine preoperative procedure for selected skull base pathologies. Computing time of 1.5 hours in complex cases is acceptable due to the information gained with 3D-imaging. Since a preoperative CT in thin slices is mandatory in skull base surgery, no additional costs are caused. Conclusion: 3D-imaging in skull base surgery is a useful tool for visualizing complex anatomy and for finding the most feasible approach. It represents an application of “virtual surgery” in a standard hospital environment. Since CT data is acquired during preoperative routine, no additional examinations become necessary. We recommend this procedure as a routine preoperative procedure for selected skull base lesions.