Case Author(s): J. Philip Moyers , . Rating: #D2, #Q4

Diagnosis: Diffuse soft tissue activity in a pattern consistent with a severe electrical injury

Brief history:

Status post trauma


Anterior and Posterior images from a Tc-99m pyrophosphate bone scan

View main image(bs) in a separate image viewer

Full history/Diagnosis is available below

Diagnosis: Diffuse soft tissue activity in a pattern consistent with a severe electrical injury

Full history:

This is a 36-year old man who is a worker for a local electric company who was standing next to an electrical truck with his right hand on the truck when the gantry of the truck hit a high tension power line. The patient suffered a severe electrical injury to the right arm with exit wounds at both feet. The patient was referred for a Tc-99m pyrophosphate study to evaluate for tissue necrosis and bone viability.


Diffuse soft tissue uptake is demonstrated in the proximal right arm extending to just below the right elbow. There is absent activity demonstrated below the right elbow consistent with radial and ulnar artery thrombosis due to severe electrical injury. Increased activity is demonstrated in both feet. There is, however, decreased activity in the left great toe.


Common radiopharmaceuticals include Tc-99m labeled phosphate analogues. These include Tc-99m pyrophosphate, methylene diphosphonate, and methylene hydroxydiphosphonate. Of these agents, MDP and MHDP have the most rapid blood clearance. Tc-99m pyrophosphate contains two phosphate residues. This agent is superior in localization in infarcted tissues to other bone agents commonly used today. Common causes of soft tissue uptake of radionuclide bone agents include metastatic adenocarcinoma such as breast cancer, GI metastases, and ovarian carcinoma. Calcification in dystrophic soft tissues or tumorous calcifications in patients with renal failure and chronic inflammatory change can also be causes for soft tissue uptake. Areas of infarction in muscle, brain, and heart may also be demonstrated on bone scintigraphy.

References: 1) Mettler FA. Essentials of Nuclear Medicine Imaging. 1991, 3rd edition. 2) Datz FL. Handbook of Nuclear Medicine, Mosby Yearbook Publishers, 1993, 2nd edition.


The patient had a right below-the- elbow, forearm amputation. The patient also had a left great toe amputation.

Major teaching point(s):

The Tc-99m pyrophosphate study was requested due to Tc-99m pyrophosphatešs greater localization in damaged tissues over Tc-99m MDP. The clinicians were interested in the extent of tissue necrosis. In this case, the soft tissue activity extended to the level of the right shoulder. Also, the lack of activity below the right elbow was consistent with radial and ulnar artery thrombosis at this level. The findings on this study were helpful to the clinicians in that a below-the-elbow amputation was performed, thus preserving some patient function in the right arm.

ACR Codes and Keywords:

References and General Discussion of Bone Scintigraphy (Anatomic field:Skeletal System, Category:Effect of Trauma)

Search for similar cases.

Edit this case

Add comments about this case

Read comments about this case

Return to the Teaching File home page.

Case number: bs035

Copyright by Wash U MO