An integrated approach to the evaluation of metastatic bone disease

The radionuclide bone scan is the most effective whole body screening test for bone metastases. Conventional radiography, although relatively insensitive to the presence of bone metastases, is the best modality for characterizing them once they are detected in radionuclide scans. When the radionuclide bone scan and appropriate correlative radiographs are analyzed and reported together, false-positive scan findings are reduced, and scan specificity is increased. Valuable information on response to treatment may be obtained by correlating the changes seen in radiographs and radionuclide bone scans. CT or MR imaging may be useful for evaluating suspicious radionuclide bone scan findings that cannot be explained radiographically, and may influence the decision regarding the need for biopsy. CT can also be used to monitor needle-biopsy procedures. The use of CT or MR imaging is helpful in determining the local extent of metastatic disease when planning palliative surgery or radiotherapy. Although a positive diagnosis by needle biopsy is considered definitive, a negative result must be suspect and may eventually necessitate open surgical biopsy. An algorithmic approach to the workup of a possible skeletal metastasis is illustrated in Figure 12.