title: Detection of incidental colorectal pathology on positron emission tomography/computed tomography.
abstract: BACKGROUND
  Positron emission tomography/computed tomography (PET/CT) is an important modality in cancer imaging. With its increasing availability and use, it is not uncommon to detect incidental focal colorectal18F-FDG uptake which poses a diagnostic challenge, as they may be associated with malignant or pre-malignant colorectal lesions. The aim of our study is to determine the proportion of these findings which represents true pathology.
  
  
  METHODS
  Patients with incidental focal colorectal18F-FDG uptake on PET/CT who subsequently underwent colonoscopy between January 2002 to September 2013 were identified from a prospective database in a tertiary referral centre. PET/CT results were correlated with colonoscopy and pathology results in these patients. Positive predictive values (PPVs) and 95% confidence intervals (CIs) of PET/CT in the detection of incidental colorectal pathology were calculated.
  
  
  RESULTS
  A total of 148 patients (92 men and 56 women), with a mean age 73 years (range of 36 to 93 years) were included in the study. A total of 170 foci of colorectal18F-FDG uptake were detected on PET/CT. Of these, 101 foci corresponded to a malignant or pre-malignant lesion (PPV 59%; 95% CI: 52-67%). On a per-patient analysis, 93 patients had at least one focus of colorectal18F-FDG uptake which corresponded to a pre-malignant or malignant lesion (PPV 63%; 95% CI: 54-71%).
  
  
  CONCLUSIONS
  Focal colorectal18F-FDG uptake on PET/CT is associated with a significant proportion of malignant or pre-malignant lesions. Further evaluation with colonoscopy is recommended.
authors: Department of Cancer Surgery, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
authors: Milton
authors: M
authors: Mui
authors: Department of Cancer Imaging, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
authors: Timothy
authors: T
authors: Akhurst
authors: Department of Cancer Surgery, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
authors: Satish K
authors: SK
authors: Warrier
authors: Department of Cancer Surgery, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
authors: A Craig
authors: AC
authors: Lynch
authors: Department of Cancer Surgery, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
authors: Alexander G
authors: AG
authors: Heriot
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000556:secondary*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012189:Retrospective Studies
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: colonoscopy; colorectal neoplasms; fluorodeoxyglucose F18
  ; incidental findings; positron-emission tomography