Low Dose CT Versus Contrast-Enhanced CT In FDG PET/CT Protocols For Staging/Restaging Of Malignancy

Abstract

Objective: Background: PET/CT combines functional and anatomical imaging, but the role of intravenous contrast-enhanced CT (ceCT) in integrated PET/CT protocols remains debated. While low-dose non-contrast CT is sufficient for attenuation correction and lesion localization, ceCT may improve staging accuracy, particularly in solid tumors.

Aim: To compare between non-contrast CT and ceCT in integrated PET/CT protocols in staging/restaging of malignant diseases to determine the added diagnostic value of IV contrast in tumor staging and restaging of malignant lesions.

Patients and methods: This was prospective research done from September 2021 to January 2023 in the Nuclear Medicine Unit (NEMROCK Center), Kasr Alainy Hospital, Cairo University, and a private facility collected data.

Results: Among 96 patients with solid tumors, PET/ceCT resulted in T stage upstaging in 23 (23.9%), N stage in 18 (18.7%), and M stage in 9 (9.5%), all statistically significant. Overall, PET/ceCT altered final staging in 31 patients (25.8%), predominantly intra-abdominal malignancies. In 24 lymphoma patients, only one case was upstaged.

Conclusion: PET/contrast-enhanced CT significantly improves staging accuracy in solid tumors, particularly intra-abdominal cancers, but provides minimal additional value in lymphoma. Routine CECT integration is recommended for solid tumors to guide management.