Steven Peti, Reza Fardanesh, Sivan Golan, William Simpson, Christopher Chin, Sasan Roayaie, Myron Schwartz, Daniel Labow and Lale Kostakoglu
Department of Radiology and Nuclear Medicine, The Mount Sinai Medical Center, One Gustave L. Levy Place, Box 1141 New York, NY 10029, USA.
Objectives: The aim of our study was to evaluate the incremental value of of 18
F-flouro-2-deoxyglucose (FDG) positron emission tomography (PET) performed with non-contrast enhanced computed tomography (non-ceCT) to the contrast enhanced CT (ceCT), and the advantage of combined evaluation over either modality alone in the detection of recurrent pancreatic carcinoma and cholangiocarcinoma.
Methods: A retrospective analysis was done on 47 patients with a history of pancreatic carcinoma (n=24) or cholangiocarcinoma (n=23), all of whom were referred for restaging with a FDG-PET/non-ceCT and a ceCT study during the follow- up period after first-line therapy. Histological and radiological follow-up were used to determine the accuracy of the imaging findings.
Results: A lesion-based analysis showed, when equivocal lesions were considered negative, that the sensitivity and specificity of PET/ceCT were 89.1% and 76.9% , respectively, whereas those of PET/non-ceCT were 71.4% and 80.8% , respectively, and those of ceCT were 63.9% and 84.6% , respectively. PET/ceCT had significantly higher sensitivity compared to PET/non-ceCT (p =0.0003) and ceCT alone (p=0.0003). When equivocal lesions were considered positive, the sensitivity and specificity of PET/ceCT were 93.3% and 69.2% , respectively, whereas those of PET/non-ceCT were 77.3% and 80.8% , respectively, and those of ceCT were 76.5% and 55.1% , respectively. Within the PET/ceCT group, negative reading increased specificity from 69.2% to 76.9% (p= 0.04), at no significant cost to sensitivity (decrease from 93.3% to 89.1% , p= 0.07).
Conclusions: PET/non-enhanced CT when interpreted together with ceCT, significantly improves sensitivity of restaging of pancreatic and cholangiocarcinomas at a minor expense to specificity. Our results provide evidence that ceCT and PET/CT are complementary tests that enhance the diagnostic accuracy of restaging in patients with pancreatic and cholangiocarcinomas.