ARTERIAL TRACER INJECTION (Prepared by Dr Guillermo Contreras)
Asymmetric activity in upper extremities, with right arm having increased uptake in bone and soft tissues (whole body at left). An unnoticed arterial injection was done in this 62 year old man, in evaluation for Psoriatic Arthritis. A spot view of arms at center. Besides, increased uptake in shoulders, left elbow and knees, suggestive of inflammatory changes.
Bone scan was repeated 5 days later. The asymmetric findings are gone (right).
This is an artifact known as "glove phenomenon", which is not unfrequent. The image is explained by increased tracer delivery through blood flow, without any metabolic diffuse abnormality.References:
1 Mettler, Fred. Radionuclide Bone Imaging and Densitometry. Churchill-Livinstone, 1988. Pages. 24-25.