Usefulness of PET-CT in the assessment of suspected recurrent colorectal carcinoma

Purpose: To evaluate the usefulness of PET/CT in detecting recurrent colorectal carcinoma (CRCR) in patients subsequent to colonic resection or rectal amputation and to compare it with the PET part of integrated FDG-PET/CT. Materials and methods: PET/CTs from 32 patients with suspected CRCR were studied. Histology, clinical follow-up and additional imaging served as the gold standard. The sensitivity, specificity, positive and negative predictive values (PPV, NPV), and accuracy of PET as well as integrated PET/CT were calculated and compared for each of (a) intra-abdominal extra-hepatic recurrences, (b) extra-abdominal and/or hepatic recurrences, and (c) any form of CRCR. Results: PPV, sensitivity, NPV, specificity and accuracy of PET in detecting intra-abdominal extrahepatic CRCR were, respectively, 85.7%, 85.7%, 88.9%, 88.9%, and 87.5% compared with 92.9%, 92.9%, 94.5%, 94.5%, and 93.8%, respectively, for PET/CT. The corresponding values for the detection of extra-abdominal and/or hepatic CRCR were 84.6%, 84.6%, 89.5%, 89.5%, and 87.5% for PET versus 100%, 92.3%, 95%, 100%, and 96.9% for PET/CT. For all forms of recurrence, the corresponding values for PET were 80%, 80%, 66.7%, 66.7%, and 75%, respectively, compared with 94.5%, 90%, 84.6%, 91.7%, and 90.6%, respectively, for PET/CT. Conclusion: PET/CT enhances the accuracy and specificity of diagnosis of CRCRa. PET/CT grows to reach prominent roles for imaging and restaging of patients after colorectal carcinoma resection. (C) 2012 Egyptian Society of Radiology and Nuclear Medicine. Production and hosting by Elsevier B.V. Open access under CC BY-NC-ND license.