A NEW TECHNIQUE FOR CT MR FUSION FOR SKULL BASE IMAGING/

This paper presents our initial experience utilizing a new technique w hich allows CT and MR image fusion in patients with skull base lesions . Eleven patients with a variety of skull base lesion underwent CT and MR imaging prior to surgery. Both sets of images were coregistered us ing customized software. The CT and MR data sets were then combined an d viewing single interactive image format using a high-speed graphic c omputing system. Image fusion allowed simultaneous visualization of th e bony skull base anatomy (CT) and detailed soft tissue anatomy (MR) u sing a single image format. Combining both modalities was felt to prov ide a better assessment of the extent of lesions and improve understan ding of their relationship to adjacent bony neurovascular anatomy. Spe cifically, images fusion enhanced awareness of location of skull base lesions with respect to the cavernous sinuses, Gasserian ganglia, caro tid arteries, and jugular foramina. For tumors arising within the inte rnal auditory canal (IAC), fused images allowed better delineation of the lateral aspect of the lesion with respect to the fundus of the ASC . Thus, fusion of CT and MR studies provides a unique fusion is benefi cial for surgical planning and for treatment planning of complex skull base malignancies treated with radiotherapy.