title: Pitfalls of FDG-PET for the diagnosis of osteoblastic bone metastases in patients with breast cancer.
abstract: OBJECTIVE
  The purpose of this study was to investigate the pitfalls of using 2-[18F]-fluoro-2-deoxy-D: -glucose positron emission tomography (FDG-PET) for the evaluation of osteoblastic bone metastases in patients with breast cancer by comparing it with (99m)Tc-hydroxymethylene diphosphonate bone scintigraphy.
  
  
  METHODS
  Among the 89 breast cancer patients (mean age 59+/-15 years) who had undergone both FDG-PET and bone scintigraphy within 1 month between September 2003 and December 2004, 55 with bone metastases were studied. The bone metastases were visually classified by multi-slice CT into four types according to their degree of osteosclerosis and osteolysis-osteoblastic, osteolytic, mixed and invisible-and compared in terms of tracer uptake on FDG-PET or bone scintigraphy and SUV(mean) on FDG-PET. Differences in the rate of detection on bone scintigraphy and FDG-PET were analysed for significance by the McNemar test.
  
  
  RESULTS
  The sensitivity, specificity and accuracy of bone scintigraphy were 78.2%, 82.4% and 79.8% respectively, and those of FDG-PET were 80.0%, 88.2% and 83.1%, respectively, revealing no significant differences. According to the CT image type, the visualisation rate of bone scintigraphy/FDG-PET was 100%/55.6% for the blastic type, 70.0%/100.0% for the lytic type, 84.2%/94.7% for the mixed type and 25.0%/87.5% for the invisible type. The visualisation rates of bone scintigraphy for the blastic type and FDG-PET for the invisible type were significantly higher. The SUV(mean) of the blastic, lytic, mixed and invisible types were 1.72+/-0.28, 4.14+/-2.20, 2.97+/-1.98 and 2.25+/-0.80, respectively, showing that the SUV(mean) tended to be higher for the lytic type than for the blastic type.
  
  
  CONCLUSIONS
  FDG-PET showed a low visualisation rate in respect of osteoblastic bone metastases. Although FDG-PET is useful for detection of bone metastases from breast cancer, it is apparent that it suffers from some limitations in depicting metastases of the osteoblastic type.
authors.affiliation: Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan. tootuka@koto.kpu-m.ac.jp
authors.forename: Takako
authors.initials: T
authors.lastname: Nakai
authors.forename: Chio
authors.initials: C
authors.lastname: Okuyama
authors.forename: Takao
authors.initials: T
authors.lastname: Kubota
authors.forename: Kei
authors.initials: K
authors.lastname: Yamada
authors.forename: Yo
authors.initials: Y
authors.lastname: Ushijima
authors.forename: Keiko
authors.initials: K
authors.lastname: Taniike
authors.forename: Takako
authors.initials: T
authors.lastname: Suzuki
authors.forename: Tsunehiko
authors.initials: T
authors.lastname: Nishimura
mesh_terms: D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000556:secondary*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D010006:Osteoblasts / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013669:Technetium Tc 99m Medronate / Q000031:analogs & derivatives
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C024226:technetium Tc 99m hydroxymethylene diphosphonate; D013669:Technetium Tc 99m Medronate