Usefulness of Three Dimensional CT Scanning for Preoperative Diagnosis of Postoperative Paranasal Sinus Cysts
The surgical strategy for postoperative paranasal sinus cysts (POSC) is often difficult, even with helical CT and MRI images. Not only the number and location, but also the hardness (bony or soft) of the POSC wall is an important factor to determine surgical approaches. The existing instruments may be unable to resolve the problems above mentioned.We have tried to decide on the best surgical strategy for POSC in such difficult cases, using the new three dimensional CT scan (3D Accuitomo(r) Morita, Inc. Kyoto) that provides high resolution sagittal, coronal and axial slice views of complex postoperative structures of the paranasal sinuses. 512 frames of X ray pictures are taken by 3D CT, and transmitted to a personal computer (PC) as digital data, where the data are stored as mass volume data. Without being time consuming, the mass volume data can easily be sliced in parallel in selected planes to obtain the best CT images of interest on the PC. And we can therefore choose appropriate surgical approaches, such as an endoscopic endonasal or transantral method.Between October 2004 and April 2005, 8 patients with POSC were operated on with the aid of the 3D CT scan. The CT was very helpful for preoperative diagnosis of the disease.