Prevalence and patterns of soft tissue metastasis: detection with true whole-body F-18 FDG PET/CT

BMC Med Imaging. 2007 Dec 12:7:8. doi: 10.1186/1471-2342-7-8.


Background: The aim of this retrospective study was to report the prevalence and patterns of soft tissue (ST) metastasis detected with true whole-body (TWB) F-18 FDG PET/CT acquired from the top of the skull through the bottom of the feet and to compare such findings to that of the typically acquired skull-base to upper-thigh, thus limited whole-body (LWB) field of view (FOV).

Methods: TWB FDG-PET/CT scans were performed in 500 consecutive cancer patients. Suspected ST metastasis was verified by correlation with surgical pathology, other imaging modalities, or clinical follow-up.

Results: Nine out of 500 patients (1.8 %) had ST metastasis with a prevalence of 4/41 (9.8%) for melanoma, 2/60 (3.3%) for lung carcinoma, 2/88 (2.3%) for lymphoma and 1/13 (77%) for esophageal cancer. Those nine patients had a total of 41 ST lesions: 22 lesions within and 19 outside of LWB FOV. Of those 41 lesions, 19 (46%) were subcutaneous and 22 (54%) were muscular lesions. The presence of ST metastasis neither changed the staging nor the treatment in any of these patients. However, the ST lesions provided a biopsy site in 4 of the 9 patients (44%). Seven out of nine studied patients died of their disease within 1-22 months after ST metastasis was diagnosed.

Conclusion: The detection of ST metastasis may have prognostic implications, provide more accessible biopsy sites and help avoid invasive procedures. A LWB scanning may underestimate the true extent of ST metastasis since a significant percentage of ST metastasis (46%) occurred outside the typical LWB FOV.

MeSH terms

  • Adult
  • Aged
  • Biopsy
  • Female
  • Fluorodeoxyglucose F18
  • Humans
  • Image Interpretation, Computer-Assisted
  • Male
  • Middle Aged
  • Neoplasm Metastasis / diagnostic imaging
  • Prevalence
  • Prognosis
  • Radiopharmaceuticals
  • Retrospective Studies
  • Soft Tissue Neoplasms / diagnostic imaging
  • Soft Tissue Neoplasms / epidemiology
  • Soft Tissue Neoplasms / secondary*
  • Tomography, Emission-Computed*
  • Tomography, X-Ray Computed*
  • Whole Body Imaging


  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18