title: Visual and quantitative comparison of (18)F-fluorodeoxyglucose PET/CT findings in the detection of pelvic tumor recurrence in colorectal cancer.
abstract: OBJECTIVE
  This study aimed to visually and quantitatively compare (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) imaging in determining postoperative pelvic recurrence in colorectal cancer (CRC).
  
  
  METHODS
  This retrospective analysis focused on 96 patients (age: mean 62.6 ± 10.5) with surgically resected CRC (time interval after surgery: 19.2 ± 20.4 months). The standard of reference was histopathologic confirmation (n = 27) or imaging follow-up (n = 69). For visual analysis, three independent nuclear physicians interpreted the PET/CT findings. For the quantitative analysis, the normalized standardized uptake values (nSUVs: nSUVmax, nSUVpeak, nSUVmean) were calculated by applying the mean SUV of a normal liver. We evaluated the areas under the receiver operating characteristic curves (AUCs) for all the quantitative parameters.
  
  
  RESULTS
  Of the 96 patients, 49 showed pelvic recurrence and 47 revealed no tumor recurrence. Sensitivity and specificity were 85.7 and 80.9 %, respectively, for visual analysis, and 65.3 and 83.0 %, respectively, for quantitative analysis. The AUC (0.766, CI: 0.668-0.846) of nSUVmax was largest comparing nSUVpeak and nSUVmean values, without significant difference (p value >0.316). Sensitivity of lesion detection was superior in visual analysis (p value = 0.02), but specificity was not significantly different (p = 0.80). After inclusive and exclusive combinations, sensitivity and specificity were slightly increased to 89.8 % (p = 0.54) and 91.5 % (p = 0.14), respectively.
  
  
  CONCLUSIONS
  Visual interpretation was superior to quantitative analysis in pelvic tumor recurrence in CRC. Though it was possible to improve diagnostic performance through combinatory analysis, the effect was not statistically significant.
authors.affiliation: Department of Nuclear Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, 22, 170 Beon-gil, Gwanpyeong-ro, Dongan-gu, Anyang-si, Gyeonggi-do, 14068, Korea. hshwang@hallym.or.kr.
authors.forename: Hee Sung
authors.initials: HS
authors.lastname: Hwang
authors.affiliation: Department of Nuclear Medicine, Hallym University Dongtan Sacred Heart Hospital, Hwaseong-si, Korea.
authors.forename: You Mie
authors.initials: YM
authors.lastname: Han
authors.affiliation: Department of Nuclear Medicine, Graduate School of Medicine, Yonsei University, Seoul, Korea.
authors.forename: Yun Jung
authors.initials: YJ
authors.lastname: Choi
authors.affiliation: Department of Radiology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang-si, Korea.
authors.forename: Sung Hye
authors.initials: SH
authors.lastname: Koh
authors.affiliation: Department of Surgery, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang-si, Korea.
authors.forename: Hyoung-Chul
authors.initials: HC
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000473:pathology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D010386:Pelvic Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D000072078:Positron Emission Tomography Computed Tomography; D012372:ROC Curve; D012008:Recurrence; D012189:Retrospective Studies
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: 18F-FDG PET/CT; Colorectal cancer; Locoregional neoplasm recurrence; Pelvic region