title: Who should undergo a colonoscopy among patients with incidental colon uptake on PET-CT?
abstract: OBJECTIVE
  To investigate the optimal cut-off of the maximum standard uptake value (SUVmax) for the detection of colorectal neoplasms and to suggest those for whom further colonoscopy is recommended among patients with incidental colonic uptake on positron emission tomography-computed tomography (PET-CT).
  
  
  METHODS
  In 306 patients who underwent colonoscopy within 3 months of receiving PET-CT between January and December 2009, measurements of the per-patient and per-lesion diagnostic performance of PET-CT for the detection of colonic neoplasms were obtained. Receiver operating characteristic (ROC) analysis was used to identify the SUVmax that provided a high probability of diagnosing malignancy and high-grade dysplasia.
  
  
  RESULTS
  The per-patient and per-lesion PET-CT detection sensitivities for malignancies were 93.3% (28/30; 95% confidence interval (CI) 76.5% to 98.9%) and 93.5% (29/31, 95% CI 77.2% to 98.9%), respectively; the sensitivities for high-grade dysplasia were both 90.0% (9/10; 95% CI 54.1% to 99.5%). As a criterion to specifically detect both malignancy and high-grade dysplasia on focal uptake, a SUVmax greater than 2.5 yielded a 92.3% per-lesion sensitivity and a 42.9% per-lesion positive predictive value (PPV). In the ROC curve analysis, a cut-off value of SUVmax = 5.8 was established, at which the sensitivity, PPV and positive likelihood ratio for diagnosing malignancy and high-grade dysplasia were 71.8% (28/39; 95% CI 54.9% to 84.5%), 84.8% (28/33; 95% CI 67.3% to 94.3%) and 6.9, respectively.
  
  
  CONCLUSIONS
  The optimal cut-off value to identify a malignancy or high-grade dysplasia was SUVmax = 5.8. However, to avoid missing a malignancy or high-grade dysplasia, a colonoscopy should be performed above a SUVmax = 2.5.
authors.affiliation: Department of Internal Medicine, Jeju National University Hospital, Jeju National University School of Medicine , Jeju , Korea.
authors.forename: Soo-Young
authors.initials: SY
authors.lastname: Na
authors.forename: Kyung-Jo
authors.initials: KJ
authors.lastname: Kim
authors.forename: Seungbong
authors.initials: S
authors.lastname: Han
authors.forename: Soyoung
authors.initials: S
authors.lastname: Jin
authors.forename: Jae Seung
authors.initials: JS
authors.lastname: Kim
authors.forename: Dong-Hoon
authors.initials: DH
authors.lastname: Yang
authors.forename: Kee Wook
authors.initials: KW
authors.lastname: Jung
authors.forename: Byong Duk
authors.initials: BD
authors.lastname: Ye
authors.forename: Jeong-Sik
authors.initials: JS
authors.lastname: Byeon
authors.forename: Seung-Jae
authors.initials: SJ
authors.lastname: Myung
authors.forename: Suk-Kyun
authors.initials: SK
authors.lastname: Yang
authors.forename: Jin-Ho
authors.initials: JH
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D003106:Colon / Q000473:pathology*; D003110:Colonic Neoplasms / Q000473:pathology*; D003113:Colonoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D012372:ROC Curve; D014057:Tomography, X-Ray Computed
keywords: PET-CT; colonoscopy; colorectal neoplasm; maximum standard uptake value