The Added Value of (18) F-FDG Positron Emission Tomography/ Computed Tomography Compared to Contrast Enhanced Computed Tomography in the Detection and Assessment of Peritoneal Deposits of Colorectal Origin.

Abstract

Background: The challenge of diagnosing peritoneal carcinomatosis from colorectal cancer is notable in oncological imaging. This retrospective study aims to evaluate the effectiveness of contrast-enhanced Multi-Detector Computed Tomography (MDCT) versus Positron Emission Tomography-Computed Tomography using F18-fluorodeoxyglucose ((18F) FDG-PET/CT) in detecting peritoneal seeding.Aim of the Work: Our study seeks to highlight the diagnostic superiority of positron emission tomography/computed tomography over contrast-enhanced computed tomography in detecting peritoneal deposits originating from colorectal cancer in patients already diagnosed with the disease.Patients and Methods: We retrospectively evaluated 55 patients with colonic malignancy affecting any site from ileocecal valve till anus. They were reviewed for presence of the peritoneal deposits in FDG PET/CT and contrast enhanced CT. And the results were correlated to the tumor markers. The study was performed at the PET/CT unit in the radiology department of Ain shams university during the period between December / 2022 and October / 2023. Informed consent was obtained from all participants in the study.Results: of 55 known patients diagnosed with colorectal cancer with suspected peritoneal affection. The tumor marker was positive in 52 patients, and negative in 3 patients associated with PET-CT sensitivity of 90.8%, Specificity of 66.67% and accuracy of 78.5% and CT sensitivity of 69.23%, Specificity of 33.33% and accuracy of 51.3 % of Contrast enhanced CT scan. And these findings underscore the considerable superiority of PET/CT compared to traditional imaging modalities (contrast CT scan) in diagnosing peritoneal carcinomatosis.Conclusion: PET/CT outperforms contrast-enhanced CT in identifying peritoneal deposits, potentially reducing the need for laparotomies and enabling a more precise selection of patients suitable for adjuvant chemotherapy.