[Evaluation of the clinical usefulness of ultrasonography in making a preoperative diagnosis of thyroid carcinoma].

Preoperative ultrasonographic findings of thyroid carcinoma were analysed in terms of their correlation with pathological features on the cut surface of surgically removed specimens, and the results were found to facilitate correct diagnosis. For this study, 414 patients with thyroid tumors, consisting of 172 with carcinomas and 242 with benign tumors, were examined by a 7.5 MHz high-resolutional real-time ultrasonography. Sonographic criteria for diagnosing thyroid carcinoma were newly proposed in this study. They were divided into major and minor criteria: The former were findings frequently observed in carcinoma, and the latter were findings observed in benign tumors but, rarely, in carcinoma also. By applying these criteria in thyroid patients, papillary carcinoma was diagnosed more correctly than follicular carcinoma, and solid carcinoma was more easily diagnosed than cystic carcinoma. Microcarcinomas, less than 10mm in maximum diameter, were frequently diagnosed by ultrasonography; 20 out of 36 were detected by these criteria. Intraglandular dissemination was also detected in 22 out of 87. From these studies, it was clear that the accuracy of ultrasonographic diagnosis for microcarcinoma and intraglandular dissemination was closely related to the size of the tumor. The diagnostic limitation was a maximum tumor diameter of 5mm. The superiority of ultrasonography to other diagnostic methods was also discussed.