Cholangiocarcinomas are not simple to image because they are located in an area of multiple other organs and there is often associated inflammation and anatomic variation. There are also only a few studies of PET for cholangiocarcinomas and conclusions vary. In a study by Kim et al, FDG PET was not found to be specific enough in detecting hilar cholangiocarcinomas, an observation ascribed to small tumor size or to fibrous or mucinous components of the lesion . Most peripheral cholangiocarcinomas show ring-shaped FDG uptake due to excessive desmoplastic response within the tumor and neovascularity at the periphery. However, these findings are not specific to cholangiocarcinomas, since any lesion with central necrosis can mimic this pattern. Fritscher-Ravens et al  found FDG PET more useful in detecting metastases to lymph nodes, the liver, and other distant sites. However, they could not differentiate malignant from benign lesions, since false-positive FDG uptake was seen in granulomatous inflammatory lesions and there were false-negative results in non-FDG-avid mucinous cholangiocarcinomas. NCCN on pp GAL-2-4 only lists CT scans and MRI.  The 2012 Bristish update of 2012 does not mention PET. The 2014 guidelines byBridgewater et al says: “Prior to surgical resection,PETscanning may be con-

sidered to help rule out an occult primary as well as to rule out otherwise occult metastatic disease.“.

A recent consensus statement concluded: “PET-CT is recommended in the preoperative staging of intrahepatic and extrahepatic CCA.” In regard to restaging, PET is not well established and NCCN does not list PET in its guidelines

S. Breitenstein, C. Apestegui, and P.-A. Clavien, Positron emission tomography (PET) for cholangiocarcinoma, HPB (Oxford). 2008; 10(2): 120121.

Jadvar H, Henderson RW, Conti PS. F-18]fluorodeoxyglucose positron emission tomography and positron emission tomography: computed tomography in recurrent and metastatic cholangiocarcinoma. J Comput Assist Tomogr. 2007;31:2238.

Garcea G, Ong SL, Maddern GJ. The current role of PET-CT in the characterization of hepatobiliary malignancies.HPB (Oxford). 2009 Feb;11(1):4-17.

Olthof SC, Othman A, Clasen S, Schraml C, Nikolaou K, Bongers M. Imaging of Cholangiocarcinoma. Visc Med. 2016;32(6):402410.

Rahnemai-Azar AA, Pandey P, Kamel I, Pawlik TM. Monitoring outcomes in intrahepatic cholangiocarcinoma patients following hepatic resection. Hepat Oncol. 2016;3(4):223–239.

NCCN, Cholangiocarcinoma, 2019

A 2010 guideline by Laperrier says: “Positron emission tomography (PET) is not recommended for the determination of diagnosis or grading in gliomas. A recommendation cannot be made for or against the use of PET or positron emission tomography/computed tomography (PET/CT) in the assessment of patients with recurrent gliomas because of insufficient evidence. Positron emission tomography (PET) is not recommended for the determination of diagnosis or grading in gliomas. A recommendation cannot be made for or against the use of PET for the assessment of treatment response in gliomas because of insufficient evidence. A recommendation cannot be made for or against the use of PET or positron emission tomography/computed tomography (PET/CT) in the assessment of patients with recurrent gliomas because of insufficient evidence. Positron emission tomography (PET) is not recommended for the determination of diagnosis or grading in gliomas. A recommendation cannot be made for or against the use of PET for the assessment of treatment response in gliomas because of insufficient evidence. A recommendation cannot be made for or against the use of PET or positron emission tomography/computed tomography (PET/CT) in the assessment of patients with recurrent gliomas because of insufficient evidence.”
It is not clinically appropriate in terms of type, frequency, extent, site and duration and considered effective for the condition in question as per literature and guidelines

Read the Professional version here.