The application of 18F-FDG coincidence imaging in detecting recurrent colorectal cancer

Objective: The aim of this study was to evaluate the value of 18F-fluorodeoxyglucose (FDG) coincidence imaging in detecting recurrent colorectal cancer. Methods: FDG coincidence imaging were performed in 56 patients with colorectal cancer. All had FDG coincidence imaging after their radical surgeries for at least six months. Imaging data was acquired and was reconstructed using iterative algorithm. 133Ba was used for attenuation correction. Results of FDG coincidence images were compared with CT scans and serum tumor marker carcinoembryonic antigen (CEA) during the corresponding period. Results: Of the 56 patients, 33 (58.9%) had recurrent disease, confirmed or endorsed by post-operation pathology, enteroscope, and(or) clinical follow-up. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of 18F-FDG coincidence imaging were 81.8% (27/33), 87.0% (20/23), 90.0% (27/30), 76.9% (20/26) and 83.9% (47/56), those of CT were 69.7% (23/ 33), 82.6% (19/23), 85.2% (23/27), 65.5% (19/29) and 75.0% (42/56), and those of CEA were 66.7% (22/33), 43.5% (10/23), 62.9% (22/35), 47.6% (10/21) and 57.1% (32/56) respectively. Conclusion: FDG coincidence imaging has the highest clinical value among FDG coincidence imaging, CT, and CEA in detecting recurrent colorectal cancer. (authors)