Four sequential Tc-99m pyrophosphate (PYP) Imaging studies were performed in a 28-year-old man with high fever and exudate pharyngitis associated with renal failure. Radiotracer localization in the left ventricle (LV), lungs, kidneys, and skeletal muscles were seen in two, initial imaging studies. In the second and third imaging studies, area of increase in activity was seen in the left-sided bowel. In studies done two months later (in the third study), the radioactivity in the skeletal muscles was no longer seen. Studies obtained nine months (in the fourth study) after the first imaging showed less radio-tracer localization in the LV, lungs, and kidneys as compared to that seen in the Initial study. Myocardial necrosis and microcalcification were proved by LV biopsy. The exact mechanism of extraosseous bone-imaging agent localization is unknown. However, this phenomenon may be related to renal failure, rhabdomyolysis, hypercal-cemla, hyperphosphatemia, or elevated parathyroid hormone. The Tc-99m PYP imaging study is useful and sensitive in the detection of extraosseous tissue calcification and monitoring of the disease process.
From the Nuclear Medicine Division Veterans Administration and the University of Kentucky Medical Centers Lexington, Kentucky