Efficiency comparison of Kwak and ACR (2017) Thyroid Imaging Reporting and Data System(TI-RADS) classification: a polycentric retrospective study

Abstract

Objective To evaluate the diagnostic efficacy of Kwak and ACR(2017) thyroid imaging reporting and data systems(TI-RADS) for thyroid nodules. Methods Cases of thyroid nodule who underwent surgery from January 2015 to March 2018 in 15 hospitals in Sichuan province were collected and the ultrasonographic features of thyroid nodules were retrospectively analyzed by trained senior ultrasound physicians using Kwak and ACR TI-RADS classification methods. Totally, 12 712 thyroid nodules were observed, 7 023 thyroid nodules in 7 023 cases with complete ultrasound and surgical and pathological data were eventually enrolled in the study. Thyroid nodules with solid, hypoechoic or very hypoechoic, tall/wide ratio ≥1, margin ill-defined and microcalcification were classified as malignant signs of ultrasound. Malignant percentage was calculated and diagnostic tests were performed. Results ①There was a statistical difference between the benign and malignant nodules in the two types of TI-RADS classification (P<0.01). ②The area under ROC curve of Kwak and ACR in the diagnosis of malignant nodules were 0.89 and 0.84, respectively. The Youden index of Kwak and ACR were 0.66 and 0.57, respectively. ③Taking Kwak TI4B and ACR TR4 as critical points for malignancy, the sensitivity, specificity, positive predictive value and negative predictive value of Kwak TI4B were 75.0%, 90.9%, 83.2%, and 85.9%, respectively. The accuracy of Kwak TI4B was 84.9%; The sensitivity, specificity, positive predictive value and negative predictive value of ACR TR4 were 88.2%, 68.9%, 62.9%, and 90.8%, respectively. The accuracy of ACR TR4 was 76.2%. The Kappa value of Kwak TI4B and ACR TR4 was 0.52. The χ2 value of Kwak TI4B and ACR TR4 was 2 174.6 (P<0.01). Conclusions The diagnostic values of two TI-RADS classification methods for thyroid malignant nodules are high. The overall efficiency of Kwak TI-RADS classification method is better than that of ACR TI-RADS classification method. Key words: Ultrasonography; Thyroid nodule; Thyroid imaging reporting and data system; Kwak TI-RADS; ACR TI-RADS; Diagnostic efficiency