Visualization of experimental lung and bone metastases in live nude mice by X-ray micro-computed tomography.

The objective of this study was to evaluate the utility of micro-computed tomography (micro-CT) for the detection and monitoring of experimental lung and bone metastases in nude mice. Whole body micro-CT scans were performed in lung or bone metastasis-bearing nude mice under deep anesthesia. The volumes of individual lung metastases were estimated by micro-CT, and compared to direct measurements on excised tumors. The two data sets were highly correlated (p<0.0001). The smallest lung tumor detected was 0.85 mm in diameter. The progression of metastatic lung disease, including tumor growth and the development of pleural effusion, was visualized by serial micro-CT scans in live mice. In addition, multiple bony metastases, with both osteolytic and osteoblastic features, were successfully detected by micro-CT. Bone lesions identified by micro-CT were confirmed as metastases by histopathological examination. Micro-CT may be used as an accurate, noninvasive tool to detect and monitor experimental bone and lung metastases in intact live nude mice.