Detection of heterotopic calcification with 99mTc-pyrophosphate in spinal cord injury patients.

Whole body 99mTc-pyrophosphate scans were obtained and correlated with skeletal radiographs for detection of heterotopic calcification in 122 spinal injury patients. There were 27 patients with recent injury (less than 6 months) and 95 with injury of 6 months to 25 years duration. Ectopic calcification was detected in 8 of the 27 patients (30%) with recent injury and in 32 of the 95 (34%) with injury of over 6 months duration. Ectopic calcification seen on radiographs were also seen on scans in all instances. The scan was a sensitive indicator of the ectopic calcification particularly at its early stage, and detected its presence before observable radiographic changes in 5 patients with injury of 1-3 months duration. In 3 of the 5 patients, the ectopic calcification mimicked deep vein thrombosis in presentation, and the scan was valuable in identifying the nature of the complication.