Differential Diagnosis of a "Super Scan" Appearance on Bone Scan

Super scan (superscan) refers to the diffuse skeletal uptake of MDP with resultant low or absent activity in the kidneys and bladder and high ratio of bone to soft tissue activity. Focal lesions in the skeleton may be obscured in some cases.

Differential considerations include:

• Metabolic disease: Renal osteodystrophy, osteomalacia, myelofibrosis. Often has a diffuse and homogeneous appearance on bone scan.
• Metastatic disease: Typically prostate, lung, and breast. May see some focal areas of increased uptake on bone scan.

This is a posterior view from a ^99mTc-MDP scan of a patient with colorectal cancer. There is diffusely increased radiotracer uptake in the thoracolumbar spine and poor visualization of the kidneys, consistent with a super scan.

More recently a super-superscan has been described, representing superimposed metastatic and metabolic superscan. This appearance may obscure recognition of osseous metastases.

References

• Liu Y. Super-superscan on a bone scintigraphy. Clin Nucl Med. 2011 Mar;36(3):227-8.
• Mettler FA and Guiberteau MJ. Chapter 9: Skeletal System. In Essentials of Nuclear Medicine Imaging. Fifth Edition. Saunders, Philadelphia. 2006