title: Incidental findings on integrated PET/CT that do not accumulate 18F-FDG.
abstract: OBJECTIVE
  The purpose of this study was to report the prevalence of abnormalities that do not show increased 18F-FDG uptake on the CT component of integrated PET/CT in patients with non-small cell lung cancer.
  
  
  METHODS
  Images from all PET/CT studies performed consecutively between April and October 2003 on patients with non-small cell lung cancer were retrospectively reviewed. All abnormalities present on the CT component of the PET/CT scans that did not show abnormally increased 18F-FDG uptake were documented.
  
  
  RESULTS
  Three hundred twenty-one patients with non-small cell lung cancer (179 men, 142 women; mean age, 67 years; age range, 38-91 years) underwent initial staging (198/321 [62%]) or restaging (123/321 [38%]) PET/CT imaging during the study period. In 263 (82%) of the patients, CT showed 1,231 abnormalities that were not 18F-FDG avid. The abnormalities were located in the thorax (n = 650), abdomen and pelvis (n = 444), head and neck (n = 69), and bony skeleton (n = 68). In total, 298 (24%) of the abnormalities that were not 18F-FDG avid were located outside the range of a standard thoracic CT scan. The clinical importance of these abnormalities was classified as major (n = 48 [4%]), moderate (n = 465 [38%]), or minor (n = 718 [58%]). Four (1%) of the patients had findings of major clinical importance that did not show increased 18F-FDG uptake and were previously unsuspected.
  
  
  CONCLUSIONS
  Among patients with non-small cell lung cancer undergoing PET/CT, there is a high prevalence of CT abnormalities that do not show correlative 18F-FDG avidity but that may be clinically important.
authors.affiliation: Department of Thoracic Imaging, M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Unit 0371, Houston, TX 77030-4095, USA. john.bruzzi@di.mdacc.tmc.edu
authors.forename: John F
authors.initials: JF
authors.lastname: Bruzzi
authors.forename: Mylene T
authors.initials: MT
authors.lastname: Truong
authors.forename: Edith M
authors.initials: EM
authors.lastname: Marom
authors.forename: Osama
authors.initials: O
authors.lastname: Mawlawi
authors.forename: Donald A
authors.initials: DA
authors.lastname: Podoloff
authors.forename: Homer A
authors.initials: HA
authors.lastname: Macapinlac
authors.forename: Reginald F
authors.initials: RF
authors.lastname: Munden
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000556:secondary; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted; D033162:Incidental Findings; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011859:Radiography; D019275:Radiopharmaceuticals; D014055:Tomography, Emission-Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18