VIRTUAL ENDOSCOPY OF THE NOSE AND PARANASAL SINUSES

The purpose of this study was to evaluate the applicability of virtual endoscopy (VE) in the region of the nose and paranasal sinuses on the basis of volume-rendered spiral CT data. Forty-five patients underwen t a low-dose spiral CT of the sinuses. The data were transferred to a workstation running software for volume rendering (Easy Vision. Philip s Medical Systems, Eindhoven, The Netherlands). Six orthogonal views o f the maxillary sinuses and the nasopharynx and a fly-through movie of the nose were calculated. Two radiologists evaluated the coronal reco nstructions and virtual endoscopy with respect to detectability of pat hology using a checklist comprising 10 points. In 30 patients who unde rwent subsequent endoscopic surgery, surgeons were asked to rank the d egree of assistance of the preoperative virtual endoscopy. In general? virtual endoscopy was possible in all 45 patients. The mean time requ ired for path definition and movie calculation for virtual endoscopy w ere 8 ( +/- 2) min and 3 ( +/- 1) min, respectively. Overall, more ana tomical details were depicted on coronal reconstructions however, a hi gh degree of similarity between virtual endoscopy and the intraoperati ve impression was reported by the surgeons. We conclude that virtual e ndoscopy of the nose and paranasal sinuses may develop into a standard means to guide surgeons during endoscopic interventions.