title: Bone involvement in patients with lymphoma: the role of FDG-PET/CT.
abstract: OBJECTIVE
  To evaluate the diagnostic impact and clinical significance of FDG-avid bone lesions detected by FDG-PET/CT in patients with lymphoma.
  
  
  METHODS
  The study population comprised 50 consecutive patients (mean age 41.7+/-15.5 years; 27 female, 23 male; 41 staging, 9 restaging) with Hodgkin's disease (n=22) or aggressive non-Hodgkin's lymphoma (n=28) in whom FDG-avid bone lesions were detected by FDG-PET/CT. All patients had either direct biopsy of the FDG-avid bone lesion (n=18), standard bone marrow biopsy at the iliac crest (BMB; n=43) or both procedures (n=11). In 15 patients, additional MRI of the bone lesions was performed. All patients underwent FDG-PET/CT after the end of treatment. All CT images of FDG-PET/CT scans were analysed independently regarding morphological osseous changes and compared with FDG-PET results.
  
  
  RESULTS
  In the 50 patients, 193 FDG-avid lesions were found by PET/CT. The mean standardised uptake value was 6.26 (+/-3.22). All direct bone biopsies (n=18) of the FDG-avid lesions proved the presence of lymphomatous infiltration. BMB (n=43) was positive in 12 patients (27.9%). In CT, 32 of 193 (16.6%) lesions were detected without the PET information. No additional morphological bone infiltration was detected on CT compared with FDG-PET. All morphological bone alterations on CT scans persisted after the end of therapy. Additional PET/CT information regarding uni- or multifocal bone involvement resulted in lymphoma upstaging in 21 (42%) patients compared with the combined information provided by CT and BMB.
  
  
  CONCLUSIONS
  In patients with FDG-avid bone lesions, FDG-PET is superior to CT alone or in combination with unilateral BMB in detecting bone marrow involvement, leading to upstaging in a relevant proportion of patients.
authors.affiliation: Department of Nuclear Medicine, University Hospital Zurich, Zurich, Switzerland. niklaus.schaefer@usz.ch
authors.forename: Niklaus G
authors.initials: NG
authors.lastname: Schaefer
authors.forename: Klaus
authors.initials: K
authors.lastname: Strobel
authors.forename: Christian
authors.initials: C
authors.lastname: Taverna
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Hany
mesh_terms: D000293:Adolescent; D000328:Adult; D019046:Bone Marrow Neoplasms / Q000175:diagnosis*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008223:Lymphoma / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18