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

Abstract

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.