title: Role of ¹⁸F-FDG PET/CT in differentiation of a benign lesion and metastasis on the ribs of cancer patients.
abstract: OBJECTIVE
  Incidental 18-Fluoro-2-deoxyglucose positron emission tomography ((18)F-FDG) uptake in the ribs is a relatively common finding on positron emission tomography/computed tomography (PET/CT) images of cancer patients. This study examined the role of (18)F-FDG PET/CT in differentiating between benign lesions and metastases on the ribs.
  
  
  METHODS
  This study included 264 lesions in 172 PET/CT cases with underlying malignancy showing newly developed indeterminate (18)F-FDG rib uptake between June 2009 and May 2010. Patients with more than five FDG rib uptakes or hematologic malignancy were excluded. Malignancy was confirmed either histologically or by imaging studies, and clinical follow-up with serial images was at least 6 months. The maximum standardized uptake value (SUV(max)) of the rib lesion was recorded. The FDG uptake patterns (focal or segmental; discrete or non-discrete) and CT findings (evidence of fracture, soft tissue lesions, osteoblastic and/or osteolytic lesions) were recorded.
  
  
  RESULTS
  There were 206 benign lesions and 58 metastases. The SUV(max) was significantly higher in the metastatic group (3.0 ± 1.8) than in the benign group (2.5 ± 1.1), (P=.014). For the differential diagnosis between benign and metastatic lesions, the best SUV(max) cut-off was determined to be 2.4. Significant indicators for metastasis were a segmental FDG uptake pattern (OR=10.262, 95% CI 4.151-25.371), presence of an osteoblastic/-lytic lesion (OR=22.903, 95% CI 10.468 to 50.108) and the absence of fractures on CT (OR=291.629, 95% CI 39.09-2175.666).
  
  
  CONCLUSIONS
  SUV(max) alone is not sufficient to differentiate benign and metastatic rib lesions in cancer patients. The diagnostic accuracy can be further increased when findings of the CT part of PET/CT are considered.
authors.affiliation: Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Hyun Su
authors.initials: HS
authors.lastname: Choi
authors.affiliation: Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea. Electronic address: iryoo@catholic.ac.kr.
authors.forename: Ie Ryung
authors.initials: IeR
authors.lastname: Yoo
authors.affiliation: Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Hye Lim
authors.initials: HL
authors.lastname: Park
authors.affiliation: Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Eun Kyoung
authors.initials: EK
authors.lastname: Choi
authors.affiliation: Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Sung Hoon
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Soon Chun Hyang University Hospital, Bucheon city, Gyenggi-do, Korea.
authors.forename: Won Hyoung
authors.initials: WH
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D050723:Fractures, Bone / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000175:diagnosis*; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012272:Ribs / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Metastasis; PET/CT; Rib; SUVmax