Computed tomography of pulmonary metastases from osteosarcoma: The less poor technique. A study of 51 patients with histological correlation

Background: The purpose is to evaluate the accuracy of computed tomography (CT) in the pulmonary staging of osteosarcoma. Patients and methods: Fifty-one patients presenting with osteosarcoma and a t initial CT considered metastatic to the chest had lung surgery. Two teams of two senior radiologists independently reviewed all CT examinations. The ir results were compared to the histological studies. Results: One hundred nineteen CT's were reviewed. The 2 teams found 247 and 268 nodules on the initial, and 143 and 146 nodules on the preoperative CT . Histological studies confirmed metastatic nodules in 29 patients. Two hun dred four nodules were excised and studied. One hundred nine were metastase s. The 22 patients without metastases had 53 negative nodules removed. In t he 29 patients with metastases, 151 nodules were removed, and 42 were non-m etastatic. The positive predictive value was 53% with regard to 'nodules', and 57% with regard to 'patients'. Only 4 out of 13 patients with one nodul e at surgery were metastatic, but all patients with more than 7 nodules wer e metastatic. The 46 cases with several available CT's, showed that no change in the numb er of nodules was more frequent in benign lesions. Other criteria revealed no significant difference. Conclusion: CT positive predictive value is limited, but as surgery is the only way to cure metastatic patients, CT will still be used as the referenc e technique until a more specific approach can be found.