Accuracy of 16-channel multi-detector row chest computed tomography with thin sections in the detection of metastatic pulmonary nodules.

OBJECTIVES

The inaccuracy of conventional CT makes open thoracotomy and manual palpation inevitable in pulmonary metastasectomy. However, the introduction of multi-detector row CT technology made it possible to detect pulmonary nodules with a diameter of 1mm. The purpose of this study was to investigate the accuracy of 1mm thin-section 16-channel multi-detector row CT (TSMDCT) in the detection of metastatic pulmonary nodules.

METHODS

Twenty-seven patients who underwent pulmonary metastasectomy between November 2005 and September 2006 were included in the study. The primary tumors were colorectal cancer (n=11), renal cell carcinoma (n=5), osteosarcoma (n=3), hepatocellular carcinoma (n=3), thymic tumor (n=2), bladder cancer (n=1), thyroid cancer (n=1), and primitive neuroectodermal tumor (n=1). TSMDCT was performed in all patients in order to evaluate the location and number of metastatic nodules. The patients were divided into osteosarcoma and non-osteosarcoma groups, and the accuracy of TSMDCT was evaluated by comparison with the pathologic diagnosis of metastatic nodules.

RESULTS

A total of 117 nodules were detected preoperatively by TSMDCT scanning, and 198 nodules were resected during the operation. A total of 101 nodules were pathologically confirmed to be metastatic nodules. In the osteosarcoma group, the sensitivity, specificity, positive predictive value, and negative predictive value were 34%, 93%, 92%, and 38%, respectively. In the non-osteosarcoma group, the sensitivity, specificity, positive predictive value, and negative predictive value were 97%, 54%, 64%, and 96%, respectively. Subgroup analysis in the non-osteosarcoma group revealed that nodule size over 5mm, number of metastatic nodules less than five, and disease-free interval over 24 months showed 100% sensitivity by preoperative TSMDCT.

CONCLUSIONS

TSMDCT with 1mm thickness image reconstruction showed high detection rate of metastatic pulmonary nodules in the patients with non-osteosarcoma. In highly selected subgroups, TSMDCT detected all the metastatic nodules which manual palpation could detect. Further study on the application of TSMDCT in thoracoscopic metastasectomy should be performed.