Effect of combining ultrasonography and ultrasound-guided fine-needle aspiration biopsy findings for the diagnosis of thyroid nodules.

OBJECTIVE: To assess the accuracy of ultrasonography and cytology in predicting malignancy in thyroid nodules. DESIGN: Prospective open study. SETTING: Thyroid centre, Japan. SUBJECTS: 329 nodules in 309 patients examined by a new ultrasound scanner and ultrasound-guided fine-needle aspiration biopsy. INTERVENTIONS: Comparison of ultrasonographic, cytological, and combined diagnosis with the histological diagnosis. MAIN OUTCOME MEASURES: Sensitivity, specificity, and accuracy of each diagnostic method. RESULTS: The sensitivity, specificity, accuracy were 84%, 87%, 85% for cytological diagnosis, and 82%, 91%, and 87% for ultrasonographic diagnosis. By using ultrasonographic diagnosis when cytological specimens were inadequate or gave false negative results, the sensitivity, specificity, and accuracy went up to 89%, 91%, and 90%, respectively. We could not diagnose follicular carcinomas accurately by combined cytology and ultrasonography. CONCLUSION: The combination of ultrasonography and cytology improves the accuracy of diagnosis of thyroid nodules, but is less effective with follicular tumours.