title: The incidence and sites of Nasopharyngeal carcinoma (NPC) metastases on FDG PET/CT scans.
abstract: BACKGROUND
  The only investigation to determine if a whole body FDG PET/CT scan is helpful in the evaluation of NPC is a study from Stanford. In this study, 26 patients with whole body PET/CT, were evaluated for lesions below adrenals and showed that 7.7% of distant metastases were below adrenals. Our study comparing distant metastases below diaphragm with Stanford study to evaluate the need for whole body PET/CT.
  
  
  METHODS
  Reports of NPC patients in Singapore General Hospital were reviewed. The lesions were analyzed for total number and number below diaphragm. The lesions below the diaphragm were further analyzed if they were solitary or involved multiple areas and if any additional lesions were above diaphragm.
  
  
  RESULTS
  717 reports were included in final analysis. The number of FDG avid lesions in these reports was 709. Distant metastases represented 352 of the 709 lesions. The number of lesions below diaphragm was 152, of the lesions below diaphragm only 16 of lesions have no co-existing distant metastases above diaphragm. From these lesions, there were only 12 solitary lesions. The other 4 has concurrent metastases but all localized below diaphragm.
  
  
  CONCLUSIONS
  Compared to Stanford study, number of reports is more representative in this study and the yield is much lower (7.7% versus 2.26%). From the results of our study we can consider limiting the scan area from vertex to below diaphragm. However, the symptoms and clinical presentation of the patient will further direct the requesting physician in the area to be imaged.
authors: Department of Radiology/Nuclear Medicine and Molecular Imaging Division, Massachusetts General Hospital/Harvard Medical School, 55 Fruit Street, White 427, Boston, MA 02114, United States. Electronic address: he77@hotmail.com.
authors: Ammad Shanoon
authors: AS
authors: Al Tamimi
authors: Department of Nuclear Medicine and PET, Singapore General Hospital, Singapore.
authors: Sumbul
authors: S
authors: Zaheer
authors: Department of Nuclear Medicine and PET, Singapore General Hospital, Singapore.
authors: David Chee
authors: DC
authors: Ng
authors: RadLink Diagnostic Imaging, Singapore.
authors: Saabry
authors: S
authors: Osmany
mesh_terms: D000328:Adult; D002277:Carcinoma; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D012846:Singapore / Q000453:epidemiology; D014057:Tomography, X-Ray Computed / Q000379:methods*; D051598:Whole Body Imaging / Q000379:methods
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Diaphragm; Distant metastases; FDG PET/CT; Nasopharyngeal carcinoma