Osteomyelitis.

The use of 111In-labelled granulocyte scintigraphy is recognized as a reliable method for detecting osteomyelitis and has similar sensitivity and significantly increased specificity compared to bone scintigraphy and 67Ga studies. Recent published work using pure granulocytes labelled with 111In tropolonate to detect osteomyelitis resulted in sensitivity of 100% and specificity of 92%. 99Tcm as an alternative granulocyte label offers advantages of convenience, lower radiation dose and higher image resolution. We have scanned 20 patients with suspected osteomyelitis using autologous granulocytes labelled with 99Tcm hexamethylpropyleneamineoxime (HMPAO), 12 of whom had prosthetic joints. The scan results were correlated with clinical, radiographic, microbiological and histological findings. Sensitivity was 100% and specificity was 93% which compares favourably with results obtained using 111In-labelled granulocytes. We believe that labelled granulocyte scintigraphy is a useful investigation in the diagnosis of osteomyelitis and that 99Tcm HMPAO appears to be at least as useful as 111In as the labelling agent.