title: FDG-PET and CT patterns of bone metastases and their relationship to previously administered anti-cancer therapy.
abstract: OBJECTIVE
  To assess (18)F-fluorodeoxyglucose (FDG) uptake in bone metastases in patients with and without previous treatment, and compare positive positron emission tomography (PET) with osteolytic or osteoblastic changes on computed tomography (CT).
  
  
  METHODS
  One hundred and thirty-one FDG-PET/CT studies were reviewed for bone metastases. A total of 294 lesions were found in 76 patients, 81 in untreated patients and 213 in previously treated patients. PET was assessed for abnormal FDG uptake localised by PET/CT to the skeleton. CT was evaluated for bone metastases and for blastic or lytic pattern. The relationship between the presence and pattern of bone metastases on PET and CT, and prior treatment was statistically analysed using the chi-square test.
  
  
  RESULTS
  PET identified 174 (59%) metastases, while CT detected 280 (95%). FDG-avid metastases included 74/81 (91%) untreated and 100/213 (47%) treated lesions (p<0.001). On CT there were 76/81 (94%) untreated and 204/213 (96%) treated metastases (p NS). In untreated patients, 85% of lesions were seen on both PET and CT (26 blastic, 43 lytic). In treated patients, 53% of lesions were seen only on CT (95 blastic, 18 lytic). Of the osteoblastic metastases, 65/174 (37%) were PET positive and 98/120 (82%), PET negative (p<0.001).
  
  
  CONCLUSIONS
  The results of the present study indicate that when imaging bone metastases, prior treatment can alter the relationship between PET and CT findings. Most untreated bone metastases are PET positive and lytic on CT, while in previously treated patients most lesions are PET negative and blastic on CT. PET and CT therefore appear to be complementary in the assessment of bone metastases.
authors.affiliation: Department of Nuclear Medicine, Rambam Health Care Campus, Haifa, 35254, Israel. o_israel@rambam.health.gov.il
authors.forename: Ora
authors.initials: O
authors.lastname: Israel
authors.forename: Anat
authors.initials: A
authors.lastname: Goldberg
authors.forename: Alicia
authors.initials: A
authors.lastname: Nachtigal
authors.forename: Daniela
authors.initials: D
authors.lastname: Militianu
authors.forename: Rachel
authors.initials: R
authors.lastname: Bar-Shalom
authors.forename: Zohar
authors.initials: Z
authors.lastname: Keidar
authors.forename: Ignac
authors.initials: I
authors.lastname: Fogelman
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D001859:Bone Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000556:secondary*; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000187:drug effects*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D000970:Antineoplastic Agents; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18