SPURIOUS DUAL-ENERGY X-RAY ABSORPTIOMETRY IMAGES IN A PATIENT EXPOSEDTO THE CONTRAST AGENT THOROTRAST

A 69-year-old woman presented with a 20-year history of back pain and a 10 cm height loss. She had received an injection of the contrast age nt, Thorotrast, at age 23. There was no history of fluoride exposure. Multiple vertebral compression fractures were seen on radiographs. Dua l-energy X-ray absorptiometry (DXA) scans revealed high normal bone mi neral content on the spine and, on whole body scan, visualization of t he liver and spleen regions. Given the attenuation coefficient of thor ium and the thorium concentrations reported for liver, spleen and vert ebral bodies, it is likely that thorium was visualized in the liver an d spleen and that it caused spurious elevation in her DXA bone mineral content values.