Korean J Gastroenterol.  2013 Jun;61(6):319-326. 10.4166/kjg.2013.61.6.319.

Is It Useful to Perform Additional Colonoscopy to Detect Unmatched Lesion between Positron Emission Tomography/Computed Tomography and Colonoscopy?

  • 1Department of Internal Medicine, National Police Hospital, Seoul, Korea. jungjuno@nate.com
  • 2Department of Nuclear Medicine, National Police Hospital, Seoul, Korea.
  • 3Department of Pathology, National Police Hospital, Seoul, Korea.


Incidentally detected focal 18F-fluorodeoxyglucose (FDG) uptake was compared with colonoscopy. We investigated the characteristics of colon adenomas which were revealed on PET/CT. Then we identified whether additional colonoscopy was necessary in patients with lesions which were revealed on PET/CT but had no matched lesions on colonoscopy.
We retrospectively reviewed 95 patients who underwent colonoscopy within a 6 month interval after they had focal FDG uptake from January 2010 to May 2012 at National Police Hospital in Korea. Also, we analyzed 30 patients who underwent additional colonoscopy within 2 years after they had no matched lesions on primary colonoscopy.
PET/CT depicted 54.6% (41/75) of adenomas and adenocarcinomas. The PET visibility of colon adenoma was significantly associated with degree of dysplasia (p=0.027), histologic type (p=0.040), and the size (p=0.038). The positivity rate was increased with higher degree of dysplasia (low-grade dysplasia, 47%; high-grade dysplasia, 78%; adenocarcinoma, 100%) and villous patterns of histologic type (tubular, 46.8%; tubulovillous, 87.5%; villous, 100%). Patients with adenomas larger than 10 mm (87.5%) had higher detection rate compared to those with adenomas smaller than 10 mm (49.0%). Among the 30 patients who underwent additional colonoscopy, only one patient had a 6 mm sized tubular adenoma (low-grade dysplasia).
Incidental focal colonic uptake may indicate advanced adenoma or adenocarcinoma. Thus, it justifies performing colonoscopy for identifying the presence of colon neoplasms. However, in case of unmatched lesions between PET/CT and colonoscopy, there was little evidence that additional colonoscopy would yield benefits.


Positron-emission tomography and computed tomography; Colonic neoplasms; Colonoscopy

MeSH Terms

Adenocarcinoma/pathology/radiography/radionuclide imaging
Adenoma/pathology/radiography/radionuclide imaging
Colonic Neoplasms/pathology/*radiography/*radionuclide imaging
Colonic Polyps/pathology
Fluorodeoxyglucose F18/diagnostic use
Middle Aged
Multimodal Imaging
Positron-Emission Tomography
Radiopharmaceuticals/diagnostic use
Retrospective Studies
Tomography, X-Ray Computed
Fluorodeoxyglucose F18


  • Fig. 1. Flow diagram of patient dis-position and outcome.

  • Fig. 2. PET (A) and PET/CT (B) images showed an focal increased 18 F-fluoro-deoxyglucose uptake (A, black arrow; B, white arrow) at the sigmoid colon in a 51-year-old asymptomatic man. (C) A 20-mm sized adenocarcinoma of the sigmoid colon was observed and removed with colonoscopy.



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