Ultrasound Computer-Aided Diagnosis (CAD) Based on the Thyroid Imaging Reporting and Data System (TI-RADS) to Distinguish Benign from Malignant Thyroid Nodules and the Diagnostic Performance of Radiologists with Different Diagnostic Experience

Abstract

<strong>BACKGROUND</strong> The diagnosis of thyroid cancer and distinguishing benign from malignant thyroid nodules by junior radiologists can be challenging. This study aimed to develop a computer-aided diagnosis (CAD) system based on the Thyroid Imaging Reporting and Data System (TI-RADS) to distinguish benign from malignant thyroid nodules by analyzing ultrasound images to improve the diagnostic performance of junior radiologists. <strong>MATERIAL AND METHODS</strong> A modified TI-RADS based on a convolutional neural network (CNN) was used to develop the CAD system. This retrospective study reviewed 789 thyroid nodules from 695 patients and included radiologists with different diagnostic experience. Five study groups included the CAD group, the junior radiologist group, the intermediate-level radiologist group, the senior radiologist group, and the group in which the junior radiologist used the CAD system. The ultrasound findings were reviewed and compared with the histopathology diagnosis. <strong>RESULTS</strong> The CAD system for the diagnosis of thyroid cancer showed an accuracy of 80.35%, a sensitivity of 80.64%, a specificity of 80.13%, a positive predictive value (PPV) of 76.02%, a negative predictive value (NPV) of 84.12%, and an area under the receiver operating characteristic (ROC) curve (AUC) of 0.87. The accuracy of the junior radiologists in diagnosing thyroid cancer using CAD was similar to that of intermediate-level radiologists (79.21% vs. 77.57%; P=0.427). <strong>CONCLUSIONS</strong> The use of ultrasound CAD based on the TI-RADS showed potential for distinguishing between benign and malignant thyroid nodules and improved the diagnostic performance of junior radiologists.

Figure 1

Flowchart of the study protocol.

Figure 2

Flowchart of the proposed computer-aided diagnosis (CAD) system for thyroid nodule classification.

Figure 3

The ultrasound features of the Thyroid Imaging Reporting and Data System (TI-RADS) category of the thyroid nodules acquired using the computer-aided diagnosis (CAD) system. (A) The ultrasound features and the Thyroid Imaging Reporting and Data System (TI-RADS) category of a thyroid nodule acquired with the computer-aided diagnosis system (CAD). (B) The ultrasound features and TI-RADS Category of a thyroid nodule acquired in the group with the junior radiologist combined with the CAD system. The red font indicates the corrected ultrasound features of the thyroid nodule after the clinician and CAD combination. The triangle, plus sign, and dot on each receiver operating characteristic (ROC) curve indicate the performance of the junior radiologist, intermediate-level radiologist, and the senior radiologist, respectively. CAD – computer-aided diagnosis system; TI-RADS – Thyroid Imaging Reporting and Data System.

Figure 4

The accuracy of the computer-aided diagnosis (CAD) system. Senior, intermediate-level, and the junior radiologist combined with the CAD system for the classification of thyroid lesions as benign or malignant and the Thyroid Imaging Reporting and Data System (TI-RADS) categories. CAD – computer-aided diagnosis system; TI-RADS – Thyroid Imaging Reporting and Data System.

Figure 5

The sensitivity of the computer-aided diagnosis (CAD) system. Senior, intermediate-level, and the junior radiologist combined with the CAD system for the classification of thyroid lesions as benign or malignant and the Thyroid Imaging Reporting and Data System (TI-RADS) categories. CAD – computer-aided diagnosis system; TI-RADS – Thyroid Imaging Reporting and Data System.

Figure 6

The specificity of the computer-aided diagnosis (CAD) system. Senior, intermediate-level, and the junior radiologist combined with the CAD system for the classification of thyroid lesions as benign or malignant and the Thyroid Imaging Reporting and Data System (TI-RADS) categories. CAD – computer-aided diagnosis system; TI-RADS – Thyroid Imaging Reporting and Data System.

Figure 7

The receiver operating characteristic (ROC) curves for the performance of the computer-aided diagnosis (CAD) system and junior radiologist combined with the CAD system on the classification of thyroid nodules.