Fusion of single-photon emission computed tomographic (SPECT) and x-ray computed tomographic (CT) images can facilitate the direct comparison of function and anatomy by simultaneously displaying comparable cross-sectional images. A computer-assisted fusion method was used to prospectively evaluate 10 patients with suspected inflammatory disease complicated by an associated condition. CT images were transferred to the nuclear computer. Image fusion was accomplished with standard scaling, rotation, translation, and stretching transformations, using anatomic or external landmarks. SPECT-CT fusion correctly localized the inflammatory process in all 10 cases and facilitated percutaneous drainage or preoperative surgical planning in 6.