Bone Scan vs. FDG-PET in Pediatric Sarcomas

Walter et. al compared ¹⁸F-FDG PET/CT and ^99mTc-MDP in 29 patients with bone and soft tissue sarcomas. They found that ^99mTc-MDP did not add any diagnostic value over ¹⁸F-FDG PET/CT. The superiority of ¹⁸F-FDG PET/CT is most pronounced in patients with Ewing sarcoma family of tumors, in whom tumor tends to infiltrate the bone marrow rather than the mineralized bone, and bone destruction is dominated by osteoclastic activity, rather than osteoblastic activity.

	18F-FDG PET/CT	99mTc-MDP
Sensitivity	100%	70%
Specificity	100%	95%
Accuracy	100%	82%

The image above is from a patient with Ewing sarcoma of the distal left femur. The primary lesion (black arrow) and bony metastases are clearly seen on the MIP image from the ¹⁸F-FDG PET study, while the bone scan only shows the uptake in the area of periosteal reaction (pink arrow) and a right anterior rib lesion that likewise was associated with cortical breakthrough and a periosteal reaction. MRI shows the primary lesion (black arrow), as well as metastases in the left and right femurs (blue arrows).

References

• Völker T, Denecke T, Steffen I, Misch D, Schönberger S, Plotkin M, Ruf J, Furth C, Stöver B, Hautzel H, Henze G, Amthauer H. Positron emission tomography for staging of pediatric sarcoma patients: results of a prospective multicenter trial. J Clin Oncol. 2007 Dec 1;25(34):5435-41.
• Walter F, Czernin J, Hall T, Allen-Auerbach M, Walter MA, Dunkelmann S, Federman N. Is there a need for dedicated bone imaging in addition to 18F-FDG PET/CT imaging in pediatric sarcoma patients? J Pediatr Hematol Oncol. 2012 Mar;34(2):131-6.