Computer-aided diagnosis system for the evaluation of thyroid nodules on ultrasonography: Prospective non-inferiority study according to the experience level of radiologists

Objective: To determine whether a computer-aided diagnosis (CAD) system for the evaluation of thyroid nodules is non-inferior to radiologists with different levels of experience. Materials and Methods: Patients with thyroid nodules with a decisive diagnosis of benign or malignant nodule were consecutively enrolled from November 2017 to September 2018. Three radiologists with different levels of experience (1 month, 4 years, and 7 years) in thyroid ultrasound (US) reviewed the thyroid US with and without using the CAD system. Statistical analyses included non-inferiority testing of the diagnostic accuracy for malignant thyroid nodules between the CAD system and the three radiologists with a non-inferiority margin of 10%, comparison of the diagnostic performance, and the added value of the CAD system to the radiologists. Results: Altogether, 197 patients were included in the study cohort. The diagnostic accuracy of the CAD system (88.5%, 95% confidence interval [CI] = 82.7–92.5) was non-inferior to that of the radiologists with less experience (1 month and 4 year) of thyroid US (83.0%, 95% CI = 76.5–88.0; p < 0.001), whereas it was inferior to that of the experienced radiologist (7 years) (95.8%, 95% CI = 91.4–98.0; p = 0.138). The sensitivity and negative predictive value of the CAD system were significantly higher than those of the less-experienced radiologists were, whereas no significant difference was found with those of the experienced radiologist. A combination of US and the CAD system significantly improved sensitivity and negative predictive value, although the specificity and positive predictive value deteriorated for the less-experienced radiologists. Conclusion: The CAD system may offer support for decision-making in the diagnosis of malignant thyroid nodules for operators who have less experience with thyroid US.