An Experimental Study for Minimum Level of Decalcification to Detect the Osteolytic Bone Metastasis of Long Bone on Plain Radiography

BACKGROUND: In 1951, Ardran reported that metastatic bone lesions could be detectable on plain radiography with 30% to 50% of decalcification. Authors performed experimental study for minimum level of decalcification to detect the osteolytic bone metastasis of long bone with recent technique of radiographs. METHODS: One pair of fibula and humerus from two cadavers was cut into specimen 1 inch in length. Distal half of specimen was dipped into hydrochloride (HCl) with 15 min interval. All 16 specimens were checked by film-type radiography (FR), computed radiography (CR), digital radiography (DR). To exclude inter-observer's variance, 3 radiologists evaluated images. Calcium amount before and after decalcification was measured and expressed in percentage of decalcification. RESULTS: Osteolytic changes were detectable with 11% to 16% of decalcification for fibula and 3% to 8% for humerus on plain radiography with FR, CR, and DR. CONCLUSIONS: Our study showed that minimum of 3% and maximum of 16% of decalcification is necessary when osteolytic metastatic bone lesions of long bone could be detected on plain radiography.