The purpose of this study was to investigate the usefulness of the ultrasonography as a screening test for thyroid diseases.

For 7 months, thyroid ultrasonography (7.5 MHz linear array) was performed prospectively by radiologists on 1,316 subjects who do not have a history of the thyroid disease. We analyzed the morphological abnormalities of thyroid gland and these were classified as the nodulal, cystic and diffuse types in accordance with the gender and ages of the patients. We performed ultrasound-guided fine needle aspiration in 21 patients who had sonographic features that were suggestive of malignant thyroid nodules. Physical examination was performed for all subjects by clinicians before the thyroid ultrasonography, and we compared the detectability of thyroid lesions between ultrasonography and physical examination.

Thyroidal abnormalities were detected in 94 (7.1%) of 1,316 subjects. Among the 94 patients, 72 (5.5%) showed as nodules, 18 (1.4%) showed as cysts and 4 (0.3%) showed as diffuse abnormalities. The result of the ultrasound-guided aspiration on 21 patient showed 4 malignant nodules, 16 benign nodules and 1 undetermined nodule. Physical examination detected abnormalities in only 12 patients (12.8%) of the 94 patients, which were showed as nodules, cysts and the diffuse type by ultrasonography.

Thyroid disease of the general population was relatively common and the detection rate with performing physical examination for the thyroid nodule, cyst and the diffuse type was lower than that for ultrasonography. Thyroid ultrasonography is a useful screening modality for detecting thyroid diseases.