Comparison of different functional imaging modalities including FDG PET/CT and DWI-MRI with respect to their value in TNM staging of cholangiocarcinoma.

Objectives OBJECTIVES: To evaluate the role of FDG-PET/CT in TNM staging of cholangiocarcinoma(CCA). MRI and CT are considered superior to PET/CT in the initial detection and characterization of assessment for resectability of CCA. However PET/CT has many valuable advantages, which can make a clinical impact and are important to recognize. The relative advantages and disadvantages of different imaging modalities will be reviewed with a highlight on the values of functional versus anatomical imaging.

Methods Patients with a diagnosis of CCA who underwent FDG-PET/CT as well as CT or MRI were retrospectively reviewed. Imaging studies within one month of PET/CT were compared. Visual and semiquantitative analysis were performed. Our findings were also compared with current literature findings.

Results PET/CT can clinically impact staging and management by detecting distant unexpected metastasis and altering preoperative management resulting in upstaging in a significant percentage of cases(1,2). Another advantage of PET/CT is that it is more accurate in the diagnosis of recurrent CCA. Additionally semiquantitative analysis can differentiate benign from malignant stricture/thrombus. Disadvantages of PET/CT include the fact that its specific role in clinical use remains controversial. PET/CT is limited in evaluation of periductal infiltrating type CCA (3,4). Poor sensitivity for regional lymph node metastases with PET/CT has also been reported (4,5,2).

Conclusions FDG-PET/CT is a complementary tool to conventional cross-sectional imaging modalities (US, CT and MR) and enhances the accuracy of TNM staging of CCA. FDG-PET/CT data can modify clinical management and is valuable for treatment planning. It's specific role in the staging of CCA needs further research and elucidation. RESEARCH SUPPORT: 1. Ringe, K. I., & Wacker, F. (2015). Radiological diagnosis in cholangiocarcinoma: Application of computed tomography, magnetic resonance imaging, and positron emission tomography. Best Practice & Research Clinical Gastroenterology, 29(2), 253-265. 2. Albazaz R, Patel CN, Chowdhury FU, Scarsbrook AF. Clinical impact of FDG PET-CT on management decisions for patients with primary biliary tumours. Insights Imaging 2013;4:691e700. 3. Ayuso JR, Pages M, Darnell A. Imaging bile duct tumors: staging. Abdom Imaging 2013;38:1071e81. 4. Petrowsky H, Wildbrett P, Husarik DB, Hany TF, Tam S, Jochum W, et al. Impact of integrated positron emission tomography and computed tomography on staging and management of gallbladder cancer and cholangiocarcinoma. J Hepatol 2006;45:43e50. 5. Vilgrain V. Staging cholangiocarcinoma by imaging studies. HPB Oxf 2008;10:106e9.