15 ORAL Does 18F-FDG PET/CT alter the management of patients with colorectal liver metastases?

Aims: To determine if 18F-FDG PET/CT provides additional information to routine multidetector spiral CT (MDCT), in assessment of colorectal liver metastases (CLM). Methods: A retrospective analysis of patients referred for assessment of CLM with 18F-FDG PET/CT was carried out. Only patients who underwent routine imaging with contrast enhanced MDCT within 2 weeks of the PET scan were included in the analysis. Imaging results were compared in terms of discordances in detection of hepatic / extraheptic disease and their subsequent influence on final management. Results: In total 32 patients (20 males, 12 females, with the median age of 63 years (range 28-82)) were included in the analysis. Indications for 18F-FDG PET/CT were for the assessment of indeterminate lesions found on MDCT in 7 patients (22%) and for further staging in the remaining 25 (78%). Overall, there were discordant findings between PET/CT and MDCT in 17 patients (53%). Of these, PET/CT provided additional information in 14 (43%), which consisted of excluding hepatic disease in 3 (9%), detecting additional liver metastases in 3 (9%) and detecting occult extraheptic disease in further 8 (25%) patients. The remaining discordances were due to 2 (6%) false negative liver lesions and one (3%) false positive mediastinal lesions found on PET/CT. Although 18F-FDG PET/CT provided additional information in 43% (14/32) of patients, this translated to a change in management of 34% (11/32). Conclusions: 18F-FDG PET/CT can provide additional information to MDCT, which can result in a change in management of up to 34% of patients with CLM.