title: Fluorine-18 fluorodeoxyglucose PET-CT for extranodal staging of non-Hodgkin and Hodgkin lymphoma.
abstract: OBJECTIVE
  We aimed to evaluate the role of fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) involving care-dose unenhanced CT to detect extranodal involvement in patients with non-Hodgkin and Hodgkin lymphoma.
  
  
  METHODS
  Lymphoma patients (35 Hodgkin lymphoma, 75 non-Hodgkin lymphoma) who were referred for 18F-FDG PET-CT imaging, following a diagnostic contrast-enhanced CT (CE-CT) performed within the last month, were included in our study. A total of 129 PET-CT images, and all radiologic, clinical, and pathological records of these patients were retrospectively reviewed.
  
  
  RESULTS
  In total, 137 hypermetabolic extranodal infiltration sites were detected by 18F-FDG PET-CT in 62 of 110 patients. There were no positive findings by CE-CT that reflected organ involvement in 40 of 137 18F-FDG-positive sites. The κ statistics revealed fair agreement between PET-CT and CE-CT for the detection of extranodal involvement (κ=0.60). The organs showing a disagreement between the two modalities were the spleen, bone marrow, bone, and thyroid and prostate glands. In all lesions that were negative at CE-CT, there was a diffuse 18F-FDG uptake pattern in the PET-CT images. The frequency of extranodal involvement was 51% and 58% in Hodgkin and non-Hodgkin lymphoma patients, respectively. There was a high positive correlation between the maximum standardized uptake values of the highest 18F-FDG-accumulating lymph nodes and extranodal sites (r=0.67) in patients with nodal and extranodal involvement.
  
  
  CONCLUSIONS
  18F-FDG PET-CT is a more effective technique than CE-CT for the evaluation of extranodal involvement in Hodgkin and non-Hodgkin lymphoma patients. PET-CT has a significant advantage for the diagnosis of diffusely infiltrating organs without mass lesions or contrast enhancement compared to CE-CT.
authors.affiliation: From the Department of Nuclear Medicine (Ö.Ö. e-mail: ozomur@yahoo.com, A.O, Y.C.), Ege University School of Medicine, İzmir, Turkey; the Department of Molecular Biology and Genetics (Y.B.), İzmir Institute of Technology, İzmir, Turkey.
authors.forename: Özgür
authors.initials: Ö
authors.lastname: Ömür
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Baran
authors.forename: Aylin
authors.initials: A
authors.lastname: Oral
authors.forename: Yeşim
authors.initials: Y
authors.lastname: Ceylan
mesh_terms: D000328:Adult; D003287:Contrast Media; D005260:Female; D019788:Fluorodeoxyglucose F18; D006689:Hodgkin Disease / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D064847:Multimodal Imaging; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18