Malignancy risk stratification of thyroid nodules: comparisons of four ultrasound Thyroid Imaging Reporting and Data Systems in surgically resected nodules

Ya-Ping He,Xiao-Long Li,Cheng-Yu Sun,Wei-Wei Ren,Kai-Rong Lei,Chong-Ke Zhao,Ying Wang,Xiao-Wan Bo,Dan Wang,Hui-Xiong Xu

doi:10.1038/s41598-017-11863-0

Abstract

To compare the efficiency of four different ultrasound (US) Thyroid Imaging Reporting and Data Systems (TI-RADS) in malignancy risk stratification in surgically resected thyroid nodules (TNs). The study included 547 benign TNs and 464 malignant TNs. US images of the TNs were retrospectively reviewed and categorized according to the TI-RADSs published by Horvath E et al. (TI-RADS H), Park et al. (TI-RADS P), Kwak et al. (TI-RADS K) and Russ et al. (TI-RADS R). The diagnostic performances for the four TI-RADSs were then compared. At multivariate analysis, among the suspicious US features, marked hypoechogenicity was the most significant independent predictor for malignancy (OR: 15.344, 95% CI: 5.313-44.313) (P < 0.05). Higher sensitivity was seen in TI-RADS H, TI-RADS K, TI-RADS R comparing with TI-RADS P (P < 0.05 for all), whereas the specificity, accuracy and area under the ROC curve (Az) of TI-RADS P were the highest (all P < 0.05). Higher specificity, accuracy and Az were seen in TI-RADS K compared with TI-RADS R (P = 0.003). With its higher sensitivity, TI-RADS K, a simple predictive model, is practical and convenient for the management of TNs in clinical practice. The study indicates that there is a good concordance between TI-RADS categories and histopathology.

Highlights

Thyroid nodule occurs in about 20% to 76% of the adult population with wide use of imaging modalities and the incidence increases with age[1, 2]
The latter has been widely used as a standard method to describe mammographic and US features of breast lesions to correlate with breast malignancies
We performed this retrospective study with surgical series of 1011 thyroid nodules (TNs) with an aim to compare the efficiencies of the four Thyroid Imaging Reporting and Data Systems (TI-RADS) classifcations in malignancy risk stratification of TNs, which would provide evidences to select an appropriate system under a special circumstance

Summary

Materials and Methods

This retrospective study was approved by our institutional review board and the requirement for informed consent from the patients was waived. Patients’ medical information including previous imaging results and histopathological results were blinded to the two reviewers. They were firstly asked to read carefully the four TI-RADSs until they understood the TI-RADSs and assessed the US characteristics defined by the authors. Independent two-sample t test was used to compare the continuous data including patient age and nodule size. Chi-square test was used to compare the categorical data including US features and patient sex. With adjustment for all variables, multivariate logistic regression analysis was performed to determine independent predictors for malignancy from the US characteristics that showed statistical significance. The cut-off value for each TI-RADS category, was obtained from receiver operating characteristic (ROC) analysis when Youden index was maximum, as well as sensitivity and specificity. Inter- and intra-observer agreement were assessed using the guideline of Landis and Koch for interpreting kappa values: slight agreement (0.00–0.20), fair agreement (0.21–0.40), moderate agreement (0.41–0.60), substantial agreement (0.61–0.80), and almost perfect agreement (0.80–1.00)[24]

Result

Discussion

Findings

Conclusion