Skip to main content
  • Poster presentation
  • Open access
  • Published:

What is the importance of solitary focal bony FDG-uptake on 18F-FDG PET-CT of known cancer patients?


18F-FDG-PET-CT plays an important role in oncology staging. While the presence of multiple FDG-avid lesions on PET-CT in the context of known malignancy is generally considered metastases, the exact significance of solitary FDG-avid-lesions remains unknown. This study was undertaken to evaluate the significance of solitary bony lesions on PET-CT of oncology patients.


Retrospective review of 15,645 PET-CT studies was performed. Further evaluation of solitary bony FDG-avid lesions was carried out by conventional imaging, follow-up and biopsy studies. Spontaneous resolution on subsequent PET-CT without a change in therapy was considered benign while progression was considered malignant.


  1. 361

    (3%) cases were found to have single FDG-avid skeletal lesions, of which 16 were due to uptake at the primary bony malignancy, and 42 were not further-investigated/passed away, hence excluded. Of the remaining 303 lesions 276 (91%) were confirmed as metastases, 27 (9%) proven benign (10 by imaging, 5 by biopsy and12 by follow-up).

Of 276 metastases (SUVmax 9.6+/-6.6); 191 were lytic, 45 sclerotic, 21 mixed and 19 normal on CT. Of 27 benign (SUVmax 3.8+/-2.8); 2 were lytic, 7 sclerotic, 2 mixed and 16 normal on CT. PPV of PET-CT on lytic, sclerotic, mixed and normal lesions on CT are 99%, 87%, 91% and 54% respectively. There was significant difference in SUVmax between malignant/benign lesions (P<0.001).

PET-CT correctly upstaged in 83/303 (27%) cases, but incorrectly upstaged or suggested further investigation in 18/303 (6%) cases.


Solitary skeletal FDG-uptake on 18F-FDG-PET-CT in patients with known malignancy is just as significant as multiple skeletal FDG-uptake, carrying high risk of metastases.

Author information

Authors and Affiliations


Corresponding author

Correspondence to LI Sonoda.

Rights and permissions

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Sonoda, L., Lakhani, A. & Ghosh-Ray, S. What is the importance of solitary focal bony FDG-uptake on 18F-FDG PET-CT of known cancer patients?. cancer imaging 14 (Suppl 1), P6 (2014).

Download citation

  • Published:

  • DOI: