Detection of bone-marrow metastases using quantitative computed tomography.

A method is described for using quantitative computed tomography (CT) to detect subtle skeletal metastases not readily identified or precisely located by conventional methods. Four patients with intramedullary metastases are presented along with data from 13 control subjects. The results indicate that CT may demonstrate intramedullary changes that occur in skeletal metastases and that cannot be detected by other techniques. A difference in medullary CT number greater than 20 HU between limbs is abnormal. This asymmetry, however, is not specific for metastatic disease, and clinical judgment must be exercised in interpreting this finding.