Likelihood of malignancy in thyroid nodules according to a proposed Thyroid Imaging Reporting and Data System (TI-RADS) classification merging suspicious and benign ultrasound features

Abstract

Objective: The aim of this study was to describe the ultrasound features of benign and malignant thyroid nodules and evaluate the likelihood of malignancy associated with each feature according to the Bethesda System for Reporting Thyroid Cytopathology and histopathology. With this analysis, we propose a new TI-RADS classification system. Materials and methods: The likelihood of malignancy from ultrasound features were assessed in 1413 thyroid nodules according to the Bethesda System for Reporting Thyroid Cytopathology and histopathological findings. A score was established by attributing different weights to each ultrasound feature evaluated. Results: Features positively associated with malignancy in bivariate analysis received a score weight of +1. We attributed a weight of +2 to features which were independently associated with malignancy in a multivariate analysis and +3 for those associated with the highest odds ratio for malignancy (> 10.0). Hence, hypoechogenicity (graded as mild, moderate or marked, according to a comparison with the overlying strap muscle), microcalcification and irregular/microlobulated margin received the highest weights in our scoring system. Features that were negatively associated with malignancy received weights of -2 or -1. In the proposed system a cutoff score of 2 (sensitivity 97.4% and specificity 51.6%) was adopted as a transition between probably benign (TI-RADS 3) and TI-RADS 4a nodules. Overall, the frequency of malignancy in thyroid nodules according to the categories was 1.0% for TI-RADS 3, 7.8% for TI-RADS 4a, 35.3% for TI-RADS 4b, and 84.7% for TI-RADS 5. Conclusion: A newly proposed TI-RADS classification adequately assessed the likelihood of malignancy in thyroid nodules. Arch Endocrinol Metab. 2017;61(3):211-21.

Advantages of the Korean Thyroid Imaging Reporting and Data System Combined with Contrast-Enhanced Ultrasound in Diagnosing Papillary Thyroid Microcarcinoma

“…A study by Ma found that ultrasound features are important predictors of PTMC, such as taller-than-wide shape, marked hypoechogenicity and poorly defined margin of the nodule, which is similar with the results of the present study (20). Our data demonstrated that the overall diagnostic performance of TI-RADS was a good US method, indicating that conventional US is still the most important US tool in evaluating PTMC (21).…”

“…This may be attributed to the small size of the nodules (diameter, ≤ 5 mm), which fail to form the tumor vascular beds and arteriovenous fistulas required to provide sufficient blood supply to the papillary thyroid carcinoma (25). This phenomenon may be partly ascribed to the complexity of microcirculation in tumor, unskilled operation, and lack of accepted standards or guidelines (21). Bartolotta et al (26) found that CEUS for thyroid is a viable technique, but overlapping findings seem to limit its potential in characterizing thyroid nodules.…”

High Rates of Underlying Thyroid Cancer in Patients Undergoing Thyroidectomy for Hyperthyroidism

“…1 In patients with hyperthyroidism because of toxic multinodular goiter or toxic solitary nodule, clinical situations that favor surgery are compression symptoms, concern for malignancy, or RAI uptake insufficient for therapy. 13 It is likely that the reported low risk of malignancy in hyperthyroidism is an underestimation of the actual risk with various recent studies demonstrating higher rates. [9][10][11] Given the increasing incidence of thyroid cancer and controversial nature of hyperthyroidism in the development of thyroid cancer, this study describes the incidence of malignancy and tumor characteristics in surgical patients with hyperthyroidism.…”

Assessment of Malignancy Risk in Thyroid Nodules Using a Practical Ultrasound Predictor Model: “Alpha Score”

“…Ultrasound assessment of thyroid nodules remains as the most important exam for the diagnosis approach due to its capacity of detecting potentially malignant thyroid nodules often not palpable and unsuspected. Up to 67% of the population may present a thyroid nodule, however, less than 10% are malignant [4] [5].…”

“…Numerous authors have submitted different TIRADS (Thyroid Reporting and Data System) that had been validated among a wide variety of population. Nevertheless, those systems are often criticized because of its lack of practicality or reproducibility, for this reason none of the current TIRADS classification systems has been universally accepted [4]…”