Validation and comparison of three newly-released Thyroid Imaging Reporting and Data Systems for cancer risk determination

Comparison of K-TIRADS, EU-TIRADS and ACR-TIRADS Guidelines for Malignancy Risk Determination of Thyroid Nodules

Background/Objectives: Thyroid nodules are commonly observed in neck ultrasonography. Most nodules are benign; hence, several nodules require biopsy to accurately identify the malignant ones. Numerous risk classification guidelines have been developed for thyroid nodules, varying in their indications for fine-needle aspiration biopsy (FNAB). The aim of this study is to evaluate the performances of three internationally recognized thyroid imaging reporting and data systems (TIRADS) for risk stratification of malignancy in comparison to one another. Methods: A total of 225 thyroid nodules with definitive FNAB cytology or histopathological diagnoses were included in this study. Various ultrasound (US) features were classified into categories based on three TIRADS editions. The guidelines were assessed regarding sensitivity, specificity, predictive values, and diagnostic accuracy to compare diagnostic value. Results: The American College of Radiology (ACR)-TIRADS demonstrated the best diagnostic accuracy (63.1%), the highest specificity (58.7%) and positive predictive value (36.3%), among three different TIRADS systems. Korean (K)-TIRADS exhibited the highest sensitivity (94.2%), negative predictive value (96.1%), and the most favorable negative likelihood ratio (0.13). The European (EU)-TIRADS had a sensitivity of 90.4%, specificity of 48.6%, and diagnostic accuracy of 58.2%, ranking between the other two guidelines across most parameters. Conclusions: The rigorous use of the guidelines established by each of the three TIRADS systems would have markedly reduced the number of FNABs performed. The comparison of the three guidelines in our study indicated that they are effective screening methods for identifying malignant thyroid nodules. Among them, K-TIRADS showed the most effective diagnostic performance in sensitivity, while ACR-TIRADS yielded the best specificity.

Multiparametric ultrasound evaluation of thyroid nodules

Thyroid nodules are common incidental findings. Most of them are benign, but many unnecessary fine-needle aspiration procedures, core biopsies, and even thyroidectomies or non-invasive treatments have been performed. To improve thyroid nodule characterization, the use of multiparametric ultrasound evaluation has been encouraged by most experts and several societies. In particular, US elastography for assessing tissue stiffness and CEUS for providing insight into vascularization contribute to improved characterization. Moreover, the application of AI, particularly machine learning and deep learning, enhances diagnostic accuracy. Furthermore, AI-based computer-aided diagnosis (CAD) systems, integrated into the diagnostic process, aid in risk stratification and minimize unnecessary interventions. Despite these advancements, challenges persist, including the need for standardized TIRADS, the role of US elastography in routine practice, and the integration of AI into clinical protocols. However, the integration of clinical information, laboratory information, and multiparametric ultrasound features remains crucial for minimizing unnecessary interventions and guiding appropriate treatments. In conclusion, ultrasound plays a pivotal role in thyroid nodule management. Open questions regarding TIRADS selection, consistent use of US elastography, and the role of AI-based techniques underscore the need for ongoing research. Nonetheless, a comprehensive approach combining clinical, laboratory, and ultrasound data is recommended to minimize unnecessary interventions and treatments.

Prospective Validation of Accuracy of American College of Radiologists- Thyroid Imaging Reporting and Data System (ACR-TIRADS) in Diagnosing Malignancy in Thyroid Nodule and a Prediction Score (TiPS) for Thyroid Malignancy

Introduction

Studies on diagnostic accuracy of revised ACR-TIRADS have been mostly retrospective and includes selection bias for surgery.

Methods

Consecutive subjects >12 years of age, with palpable or ultrasound-revealed thyroid nodule, were included in the study. Nodules of size >1 cm or TIRADS score 4 or 5 >5 mm underwent ultrasound-guided FNAC. All Bethesda 4, 5 and 6 nodules underwent thyroidectomy. Patients with Bethesda 3 nodules were given options of close follow up or surgery.

Results

There were 253 benign (Bethesda 2), 23 malignant (Bethesda 6) and 41 indeterminate (Bethesda 3,4,5) nodules. Among 41 indeterminate nodules, 19 underwent surgery of which 14 were malignant. 295 nodules had a definitive outcome (defined as final outcome variable); which could be a benign cytology report or a histopathology report. Proportion of thyroid cancer was 12.5%. ACR-TIRADS had a sensitivity of 100% and specificity of 60.5%, considering final outcome variable as gold standard and ACR-TIRADS 1-3 as test negative and score 4-5 positive. Lower age and higher serum TSH level were associated with malignancy (P < 0.05). Predictive scoring system was formulated with age, TSH, ACR-TIRADS and Bethesda. Cumulative score of 6 (IQR 4.5- 6.5) or above had a sensitivity and specificity of 96.2%, and 97.5% respectively and negative predictive value of 99.5%.

Conclusion

Owing to high sensitivity, ACR-TIRADS can be considered as a good tool to rule-out malignancy, but not to predict the same due to lower specificity. Cumulative scoring system had high diagnostic accuracy for prediction of malignancy risk and can be a useful tool for selecting nodules for surgery.

Cancer Risk in Thyroid Nodules: An Analysis of Over 1000 Consecutive FNA Biopsies Performed in a Single Canadian Institution

Objective: To determine the cancer risk in thyroid nodules using ACR TI-RADS. Methods: A retrospective analysis of all thyroid biopsies was performed over a 3-year period (2021 to 2023). Variables including gender, age, history of thyroid cancer or neck irradiation, nodule size and location, TR level, and sonographic features such as punctate echogenic foci (PEF), a very hypoechoic appearance, taller-than-wide shape, and suspected extrathyroidal extension were analyzed. Results: A total of 1140 nodules were assessed in 993 patients, including 740 females (74.5%) and 253 males (25.5%). The mean patient age was 57.1 ± 15.4 years. Variables significantly associated with nodule malignancy included (1) younger age, (2) a prior history of thyroid cancer or neck irradiation, (3) a higher TR level, (4) a taller-than-wide shape in nodules <1 cm, (5) PEF, (6) a very hypoechoic appearance, and (5) suspected extrathyroidal extension (p < 0.05). Gender, nodule location and size were not associated with a higher cancer risk (p > 0.05). Malignancy was found in 40.7% of TR5, 4.8% of TR4, 0.3% of TR3, and 0% of TR1 and 2 nodules. The odds ratios (ORs) for cancer were as follows: TR4 or 5, OR = 19; PEF, OR = 11; a very hypoechoic appearance, OR = 13.3; and suspected extrathyroidal extension, OR = 27.2 (p < 0.01). Conclusions: Higher TR levels, PEF, a very hypoechoic appearance, and suspected extrathyroidal extension are important features for predicting cancer risk. These findings affirm the effectiveness of ACR TI-RADS in nodule risk stratification.

Thyroid Nodule Characterization: Overview and State of the Art of Diagnosis with Recent Developments, from Imaging to Molecular Diagnosis and Artificial Intelligence

Ultrasound (US) is the primary tool for evaluating patients with thyroid nodules, and the risk of malignancy assessed is based on US features. These features help determine which patients require fine-needle aspiration (FNA) biopsy. Classification systems for US features have been developed to facilitate efficient interpretation, reporting, and communication of thyroid US findings. These systems have been validated by numerous studies and are reviewed in this article. Additionally, this overview provides a comprehensive description of the clinical and laboratory evaluation of patients with thyroid nodules, various imaging modalities, grayscale US features, color Doppler US, contrast-enhanced US (CEUS), US elastography, FNA biopsy assessment, and the recent introduction of molecular testing. The potential of artificial intelligence in thyroid US is also discussed.

The European Thyroid Imaging and Reporting Data System as a Remedy for the Overdiagnosis and Overtreatment of Thyroid Cancer: Results from the EUROCRINE Surgical Registry

BACKGROUND

The European Thyroid Imaging and Reporting Data System (EU-TIRADS) aims to reduce the overdiagnosis of thyroid cancer (TC) by guiding the selection of nodules for fine-needle aspiration biopsy (FNAB). This study sought to validate EU-TIRADS nodule selection criteria using data from EUROCRINE, an extensive international endocrine surgery registry.

METHOD

We reviewed indications for FNAB among patients with TC compared to those with benign disease who underwent surgery between March 2020 and March 2022, considering preoperative EU-TIRADS scores and dominant nodule size (FNAB is recommended in Category 5 (˃10 mm or ˂10 mm with suspicious lymph nodes), 4 (˃15 mm), and 3 (˃20 mm)). Patients were categorized into three risk groups: minimal risk (patients with papillary microcarcinoma), high risk (patients with pT3b stage or higher, pN1b, or pM1), and low-moderate risk (all other patients). We conducted a Receiver Operating Characteristic (ROC) analysis to assess the diagnostic accuracy of the EU-TIRADS.

RESULTS

We analyzed 32,008 operations. Approximately 68% of the surgical records included EU-TIRADS classifications. The EU-TIRADS exhibited diagnostic accuracy across high-volume sites, with a median ROC Area Under the ROC Curve (AUC) of 0.752, indicating its effectiveness in identifying malignancy. Among the cases, 7907 patients had TC. Notably, 55% of patients with TC underwent FNAB despite not initially meeting the EU-TIRADS criteria. These patients were distributed across the minimal- (58%), low-moderate- (36%), and high-risk (5.8%) categories. Of the patients with TC recommended for FNAB, 78% were deemed low-moderate risk, 21% high risk, and only 0.7% minimal risk.

CONCLUSION

The EU-TIRADS offers effective preoperative malignancy risk stratification. Promoting the proper use of the EU-TIRADS in clinical practice is essential to mitigate the overdiagnosis and overtreatment of low-risk TC.

Comprehensive Review of the Imaging Recommendations for Diagnosis, Staging, and Management of Thyroid Carcinoma

Thyroid cancer is the most common head and neck cancer (HNC) in the world. In this article, we comprehensively cover baseline, posttreatment, and follow-up imaging recommendations for thyroid carcinomas along with the eighth edition of the tumor, node, metastasis (TNM) staging system proposed by the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC). We include characterization and risk stratification of thyroid nodules on ultrasound (US) proposed by various international bodies. Management guidelines (depending upon the type of thyroid carcinoma) based on the international consensus recommendations (mainly by the American Thyroid Association) are also extensively covered in this article, including the role of a radioiodine scan. The management of recurrent disease is also briefly elucidated in this article. In addition, we cover the risk factors and etiopathogenesis of thyroid carcinoma along with the non-imaging diagnostic workup essential for thyroid carcinoma management, including the significance of genetic mutations. US is the diagnostic imaging modality of choice, with US-guided fine needle aspiration (FNA) being the procedure of choice for tissue diagnosis. The roles of computed tomography (CT), magnetic resonance imaging (MRI), and fluorodeoxyglucose positron emission tomography/CT (FDG-PET/CT) in thyroid carcinoma staging are also specified. Through this article, we aim to provide a comprehensive reference guide for the radiologists and the clinicians in the pursuit of optimal care for patients with thyroid carcinoma.

Comparative evaluation of shear wave elastography elasticity values in thyroid nodules with cytology results and TI-RADS scoring in differentiation of benign-malignant nodules

PURPOSE

The aim of this prospective study was to investigate the diagnostic performance of shear wave elastography (SWE) in differentiating benign and malignant thyroid nodules and their correlation with the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS).

METHODS

This prospective study included 370 thyroid nodules in 308 patients aged 18-70 years. All the patients underwent B-mode ultrasound (US), Doppler examination, and SWE and were given an ACR TI-RADS risk score before fine needle aspiration biopsy (FNAB) and/or surgery. The correlation between SWE parameters and ACR TI-RADS categories was investigated statistically and compared with histopathologic results. Additionally, the diagnostic performance of SWE was evaluated to distinguish malignant and benign thyroid nodules.

RESULTS

One hundred and thirty-five of the 370 thyroid nodules were malignant, and 235 nodules were benign. The mean shear wave velocity (SWV) value of the malignant nodules (3.70 ± 0.98 m/s) was statistically higher than that of the benign nodules (2.70 ± 0.37 m/s). The best cutoff value of the mean SWV for differentiating benign and malignant nodules was found to be 2.94 m/s (sensitivity 90.4%, specificity 89.9%, positive predictive value 81.3%, negative predictive value 94.1%, p < 0.001). The average score of the nodules according to the ACR TI-RADS was 3.57 ± 1.83 in benign nodules and 7.38 ± 2.69 in malignant nodules (p ≤ 0.001).

CONCLUSION

This study showed that combining SWE and TI-RADS improves the specificity of TI-RADS alone in differentiating benign and malignant nodules.

Accuracy of ultrasound in predicting thyroid malignancy: a comparative analysis of the ACR TI-RADS and ATA risk stratification systems

Objective

Thyroid nodules are very common in clinical practice, and ultrasound has long been used as a screening tool for their evaluation. Several risk assessment systems based on ultrasonography have been developed to stratify the risk of malignancy and determine the need for fine-needle aspiration in thyroid nodules, including the American Thyroid Association (ATA) system and the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS). The aim of this study was to compare the performance of the ATA and ACR TI-RADS systems in predicting malignancy in thyroid nodules based on the nodules' final histopathology reports.

Materials and methods

We performed a retrospective review of medical records to identify patients who underwent thyroid surgery at King Abdulaziz University from 2017 to 2022. The ultrasound features of the nodules with confirmed histopathology (benign versus malignant) were evaluated. Both ATA and ACR TI-RADS scores were documented.

Results

The analysis included 191 patients who underwent thyroid surgery and fulfilled the inclusion criteria. Hemithyroidectomy was performed in 22.5% of the patients, and total thyroidectomy was performed in 77.0% of them. In all, 91 patients (47.6%) were found to have malignant nodules on histopathology. We then compared the histopathology reports with the preoperative ultrasonographic risk scores. The estimated sensitivity and specificity in identifying malignant nodules were, respectively, 52% and 80% with the ATA system and 51.6% and 90% with the ACR TI-RADS system.

Conclusion

Both ATA and ACR TI-RADS risk stratification systems are valuable tools for assessing the malignancy risk in thyroid nodules. In our study, the ACR TI-RADS system had superior specificity compared with the ATA system in predicting malignancy among high-risk lesions.

Correct and Incorrect Recommendations for or against Fine Needle Biopsies of Hypofunctioning Thyroid Nodules: Performance of Different Ultrasound-based Risk Stratification Systems

PURPOSE

 To evaluate the recommendations for or against fine needle biopsy (FNB) of hypofunctioning thyroid nodules (TNs) using of five different Ultrasound (US) -based risk stratification systems (RSSs).

METHODS

 German multicenter study with 563 TNs (≥ 10 mm) in 534 patients who underwent thyroid US and surgery. All TNs were evaluated with ACR TI-RADS, EU-TIRADS, ATA, K-TIRADS 2016 and modified K-TIRADS 2021. A correct recommendation was defined as: malignant TN with recommendation for FNB (appropriate) or benign TN without recommendation for FNB (avoided). An incorrect recommendation was defined as: malignant TN without recommendation for FNB (missed) or benign TN with recommendation for FNB (unnecessary).

RESULTS

 ACR TI-RADS demonstrated the highest rate of correct (42.3 %) and lowest rate of incorrect recommendations (57.7 %). The other RRSs showed similar results for correct (26.5 %-35.7 %) and incorrect (64.3 %-73.5 %) recommendations. ACR TI-RADS demonstrated the lowest rate of unnecessary (73.4 %) and the highest rate of appropriate (26.6 %) FNB recommendation. For other RSSs, the rates of unnecessary and appropriate FNB were between 75.2 %-77.1 % and 22.9 %-24.8 %. The lowest rate of missed FNB (14.7 %) and the highest rate of avoided FNB (85.3 %) was found for ACR TI-RADS. For the other RSSs, the rates of missed and avoided FNB were between 17.8 %-26.9 % and 73.1 %-82.2 %. When the size cutoff was disregarded, an increase of correct recommendations and a decrease of incorrect recommendations was observed for all RSSs.

CONCLUSION

 The RSSs vary in their ability to correctly recommend for or against FNB. An understanding of the impact of nodule size cutoffs seems necessary for the future of TIRADS.

Diagnostic Performance of Thyroid Nodule Risk Stratification Systems: Comparison of ACR-TIRADS, EU-TIRADS, K-TIRADS, and ATA Guidelines

ABSTRACT

The purpose of this study was to compare the diagnostic performance of 4 different ultrasound-based risk scoring systems for thyroid nodules (TNs). This study consecutively included 256 patients (mean age: 43.98 ± 12.94 years, min-max: 18-89 years; 225 females, 31 males) with 266 TNs. Each nodule was evaluated and classified according to the American Thyroid Association (ATA), American College of Radiology (ACR), European Thyroid Association, and Korean Thyroid Imaging Reporting and Data System (ACR-TIRADS, EU-TIRADS, and K-TIRADS, respectively) before performing ultrasound-guided fine-needle aspiration biopsy. Pathological results were reported according to the Bethesda system. Outcomes of the 4 classification systems were compared with respect to Bethesda results. Twenty-eight (10.5%) nodules had malignant cytology results. Diagnostic performances of the scoring systems were comparable with similar area under the curve values according to the reference standards of category 5 of each scoring system. The sensitivity and specificity values of these guidelines were as follows: ACR-TIRADS, 60.7% and 95.4%; EU-TIRADS, 71.4% and 93.3%; ATA-2015, 71.4% and 93.3%; and K-TIRADS, 67.9% and 93.3%. The biopsy rate of malignant nodules was 57.1% for K-TIRADS and ATA, whereas this value was 46.4% for ACR and EU-TIRADS. ACR-TIRADS had the lowest unnecessary biopsy rate (141 of 238 benign nodules, 46%). The diagnostic performance of 4 risk stratification systems appears to be comparable, as shown by similar sensitivity, specificity, and area under the curve values. However, the ACR-TIRADS had slightly higher accuracy and necessitated fewer unnecessary biopsies for benign nodules.

Comparative Study of C-TIRADS, ACR-TIRADS, and EU-TIRADS for Diagnosis and Management of Thyroid Nodules

RATIONALE AND OBJECTIVES

Chinese Thyroid Imaging Reporting and Data Systems (C-TIRADS) was developed to provide a more simplified tool for stratifying thyroid nodules. Here we aimed to validate the efficacy of C-TIRADS in distinguishing benign from malignant and in guiding fine-needle aspiration biopsies in comparison with the American College of Radiology TIRADS (ACR-TIRADS) and European TIRADS (EU-TIRADS).

MATERIALS AND METHODS

This study retrospectively included 3438 thyroid nodules (≥10 mm) in 3013 patients (mean age, 47.1 years ± 12.9) diagnosed between January 2013 and November 2019. Ultrasound features of the nodules were evaluated and categorized according to the lexicons of the three TIRADS. We compared these TIRADS by using the area under the receiver operating characteristic curve (AUROC), the area under the precision-recall curve (AUPRC), sensitivity, specificity, net reclassification improvement (NRI), and unnecessary fine-needle aspiration biopsy (FNAB) rate.

RESULTS

Of the 3438 thyroid nodules, 707 (20.6%) were malignant. C-TIRADS showed higher discrimination performance (AUROC, 0.857; AUPRC, 0.605) than ACR-TIRADS (AUROC, 0.844; AUPRC, 0.567) and EU-TIRADS (AUROC, 0.802; AUPRC, 0.455). The sensitivity of C-TIRADS (85.3%) was lower than that of ACR-TIRADS (89.1%) but higher than that of EU-TIRADS (78.4%). The specificity of C-TIRADS (76.9%) was similar to that of EU-TIRADS (78.9%) and higher than that of ACR-TIRADS (69.5%). The unnecessary FNAB rate was lowest with C-TIRADS (21.2%), followed by ACR-TIRADS (41.7%) and EU-TIRADS (58.3%). C-TIRADS obtained significant NRI for recommending FNAB over ACR-TIRADS (19.0%, P < 0.001) and EU-TIRADS (25.5%, P < 0.001).

CONCLUSION

C-TIRADS may be a clinically applicable tool to manage thyroid nodules, which warrants thorough tests in other geographic settings.

Diagnostic efficiency among Eu-/C-/ACR-TIRADS and S-Detect for thyroid nodules: a systematic review and network meta-analysis

Background

The performance in evaluating thyroid nodules on ultrasound varies across different risk stratification systems, leading to inconsistency and uncertainty regarding diagnostic sensitivity, specificity, and accuracy.

Objective

Comparing diagnostic performance of detecting thyroid cancer among distinct ultrasound risk stratification systems proposed in the last five years.

Evidence acquisition

Systematic search was conducted on PubMed, EMBASE, and Web of Science databases to find relevant research up to December 8, 2022, whose study contents contained elucidation of diagnostic performance of any one of the above ultrasound risk stratification systems (European Thyroid Imaging Reporting and Data System[Eu-TIRADS]; American College of Radiology TIRADS [ACR TIRADS]; Chinese version of TIRADS [C-TIRADS]; Computer-aided diagnosis system based on deep learning [S-Detect]). Based on golden diagnostic standard in histopathology and cytology, single meta-analysis was performed to obtain the optimal cut-off value for each system, and then network meta-analysis was conducted on the best risk stratification category in each system.

Evidence synthesis

This network meta-analysis included 88 studies with a total of 59,304 nodules. The most accurate risk category thresholds were TR5 for Eu-TIRADS, TR5 for ACR TIRADS, TR4b and above for C-TIRADS, and possible malignancy for S-Detect. At the best thresholds, sensitivity of these systems ranged from 68% to 82% and specificity ranged from 71% to 81%. It identified the highest sensitivity for C-TIRADS TR4b and the highest specificity for ACR TIRADS TR5. However, sensitivity for ACR TIRADS TR5 was the lowest. The diagnostic odds ratio (DOR) and area under curve (AUC) were ranked first in C-TIRADS.

Conclusion

Among four ultrasound risk stratification options, this systemic review preliminarily proved that C-TIRADS possessed favorable diagnostic performance for thyroid nodules.

Systematic review registration

https://www.crd.york.ac.uk/prospero, CRD42022382818.

Correlation of ACR TI-RADS and Patient Outcomes in a Real-World Cohort Presenting for Thyroid Ultrasonography

Context

The American College of Radiology Thyroid Image Reporting and Data System (ACR TI-RADS) was developed to predict malignancy risk in thyroid nodules using ultrasound features. TI-RADS was derived from a database of patients already selected for fine-needle aspiration (FNA), raising uncertainty about applicability to unselected patients.

Objective

We aimed to assess the effect of ACR TI-RADS reporting in unselected patients presenting for thyroid ultrasound in a real-world setting.

Methods

Records for all patients presenting for thyroid ultrasonography in Canterbury, New Zealand, were reviewed across two 18-month periods, prior to and after implementation of TI-RADS reporting. Patient outcomes were compared between the 2 periods. Malignancy rates were calculated for nodules 10 mm or larger with a definitive FNA or histology result.

Results

A total of 1210 nodules were identified in 582 patients prior to implementation of TI-RADS; 1253 nodules were identified in 625 patients after implementation of TI-RADS. TI-RADS category was associated with malignancy rate (0% in TR1 and TR2, 3% in TR3, 5% in TR4, 12% in TR5; P = .02); however, 63% of nodules were graded TR3 or TR4, for which malignancy rate did not meaningfully differ from baseline risk. After implementation of TI-RADS there was a small reduction in the proportion of patients proceeding to FNA (49% vs 60%; P < .01) or surgery (14% vs 18%; P < .05), with no difference in cancer diagnoses (3% vs 4%, not significant).

Conclusion

TI-RADS category is associated with malignancy rate and may alter clinical decision-making in a minority of patients; however, it is nondiscriminatory in the majority of nodules. In this study of unselected patients, nodules classified as TR5 and thus considered "highly suspicious" for cancer had only a modest risk of malignancy.

Diagnostic performance of the EU TI-RADS and ACR TI-RADS scoring systems in predicting thyroid malignancy

INTRODUCTION

Several ultrasound scoring systems have been developed to stratify the risk of malignancy of thyroid nodules, including ACR (American College of Radiology) and EU (European) TI-RADS. This study aimed to assess the diagnostic performance of these two classifications using histology as a reference standard.

METHODS

It was a single-centre, retrospective study including 156 patients who underwent thyroidectomy. Ultrasound data of 198 nodules (99 malignant nodules and 99 benign nodules) were analysed. Both classifications were applied for all nodules.

RESULTS

Ultrasound criteria associated with malignancy were solid composition (OR=7.81; p < 10^-3 ), hypoechoic character (OR=16.42; p < 10^-3 ), irregular contours (OR=7.47; p < 10^-3 ), taller-than-wide shape (OR=3.58; p = 0.02), microcalcifications (OR=3.02; p = .006) and the presence of cervical adenopathy (OR=3.89; p = .006). The prevalence of malignancy was 15.5%, 69% and 76.9% for EU TI-RADS categories 3, 4 and 5, respectively. It was 33.3%, 57% and 91.1% for ACR TI-RADS categories 3, 4 and 5, respectively. For category 5, EU TI-RADS and ACR TI-RADS had sensitivities of 60% and 41%, specificities of 82% and 96%, respectively. For categories 4 and 5 combined, the diagnostic performance of these two classification systems became comparable with a sensitivity of 89% and 86% for EU-TIRADS and ACR-TIRADS, respectively. The area under the ROC curve was 0.81 for the EU TI-RADS classification and 0.82 for the ACR TI-RADS classification.

CONCLUSIONS

EU TI-RADS and ACR TI-RADS scoring systems seem to be comparable in predicting malignancy in thyroid nodules.

Analysis of Thyroid Imaging Reporting and Data System Criteria and Its Correlation With the Pathological Results

Introduction Thyroid nodules are frequently encountered and may be discovered roughly in around 4-8% of individuals by clinical palpation. Aim The present study aims to analyze the Thyroid Imaging Reporting and Data Systems (TIRADS) classification and assess the validity of each criterion in predicting malignancy. Methods A prospective observational study was conducted at Sri Ramachandra Institute of Higher Education and Research from June 2020 to October 2021. Fifty patients who presented to the outpatient clinic with thyroid swelling got an ultrasound (USG) neck performed followed by either fine-needle aspiration cytology (FNAC) or thyroidectomy. They were included in the study and informed consent was obtained from all patients. Results Among 50 patients considered for the study, 36 were females. The mean age for malignant patients is 46 years with a standard deviation (SD) of 15, and for benign lesions is 47 years with an SD of 1. Most of the patients were TIRADS 4, which has a 56.2% risk of malignancy. The pathological results show a significant difference in ACR (American College of Radiology) TIRADS and echogenic foci between FNAC. The present study's solid composition showed a sensitivity of 25% and specificity of 75%, with an odds ratio of 0.90 in picking up malignant nodules. The shape of a nodule taller than wider, a malignant feature, showed a specificity of 92.3%. Punctate echogenic foci showed a sensitivity of 50% and specificity of 76.9% with a statistical significance of p-value 0.048. Conclusion TIRADS scoring avoids unessential invasive techniques for lower TIRADS scores. Certain criteria are more specific in recognizing malignant nodules. Proportional priority shall be given to certain criteria over others, and not all criteria should be considered.

Diagnostic Performance of Six Ultrasound Risk Stratification Systems for Thyroid Nodules: A Systematic Review and Network Meta-Analysis

BACKGROUND. Risk stratification systems for evaluating thyroid nodules on ultrasound use varying approaches to classify levels of suspicion for malignancy, leading to variable performance. OBJECTIVE. The purpose of this study was to perform a network meta-analysis comparing six risk stratification systems used to evaluate thyroid nodules on ultrasound in terms of their diagnostic performance for the detection of thyroid cancer. EVIDENCE ACQUISITION. Five bibliometric databases were searched for studies published through August 31, 2022, that compared at least two of six ultrasound risk stratification systems (the American Association of Clinical Endocrinologists, American College of Endocrinology, and Associazione Medici Endocrinologi [AACE/ACE/AME] system; American College of Radiology Thyroid Imaging Reporting and Data System [ACR TI-RADS]; the American Thyroid Association [ATA] risk stratification system; European Thyroid Association Thyroid Imaging Reporting and Data System [EU-TIRADS]; the Korean Thyroid Imaging Reporting and Data System [K-TIRADS] endorsed by the Korean Thyroid Association and the Korean Society of Thyroid Radiology; and the Thyroid Imaging Reporting and Data System developed by Kwak et al. [Kwak TIRADS]) in terms of their diagnostic performance for the detection of thyroid cancer, with cytologic or histologic evaluation used as a reference standard. The studies' risk of bias was evaluated using the Newcastle-Ottawa Scale. A meta-analysis of each system was performed to identify the risk category threshold that had the highest accuracy as well as the highest sensitivity and specificity at this threshold. Network meta-analysis was used to perform hierarchic ranking and identify the systems having the highest sensitivities and specificities at each system's most accurate threshold. EVIDENCE SYNTHESIS. The analysis included 39 studies with 49,661 patients. All studies were of fair (n = 17) or good (n = 22) quality. The most accurate risk category thresholds were class 3 (high risk) for the AACE/ACE/AME system, TR5 (highly suspicious) for ACR TI-RADS, EU-TIRADS 5 (high risk) for EU-TIRADS, 4c (moderate concern but not classic for malignancy) for Kwak TIRADS, K-TIRADS 5 (high suspicion) for K-TIRADS, and high suspicion for the ATA system. At these thresholds, the systems had sensitivity of 64-77% and specificity of 82-90%. Network meta-analysis identified the highest sensitivity and highest specificity for ACR TI-RADS, followed by K-TIRADS. CONCLUSION. Of six risk stratification systems, ACR TI-RADS had the highest diagnostic performance for the detection of thyroid nodules on ultrasound. CLINICAL IMPACT. This network meta-analysis can inform decisions regarding implementation of the risk stratification systems and can aid future system updates.

A prospective comparison of ACR-TIRADS and EU-TIRADS in thyroid nodule assessment for FNA-US

OBJECTIVE

Prospective data on the accuracy of ultrasound (US) classification systems in thyroid nodules are still scarce. The aim of this study is to compare the accuracy of the American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TIRADS) and European (EU)-TIRADS classification systems.

DESIGN AND PATIENTS

Consecutive patients with one or more thyroid nodule(s) who underwent fine-needle aspiration (FNA) under ultrasonographic guidance (FNA-US) were prospectively evaluated.

MEASUREMENTS

Clinical evaluation and US data were collected. The reference standard used for this study was FNA-US cytology and histopathological diagnosis.

RESULTS

A total of 186 thyroid nodules in 166 patients were evaluated, resulting in 168 nodules from 149 patients with conclusive benign or malignant results. Sensitivity, specificity, negative predictive value (NPV) and false negative (FN) were 100.0%, 28.7%, 100.0% and 0.0%, respectively, for ACR-TIRADS; and 90.0%, 19.1%, 96.8% and 9.1% (n = 1), respectively, for EU-TIRADS. The number of unnecessary FNA-US indicated by ACR-TIRADS was lower than EU-TIRADS (71.3% vs. 80.9%, p = .017), and the number of possibly avoided FNA-US was higher (26.7% vs. 17.8%). Using the same threshold of ACR-TIRADS to indicate FNA-US in EU-TIRADS 3 nodules (2.5 cm), there was an improvement in specificity (30.6%) and avoided FNA-US (28.6%). The best performance of both systems was demonstrated when FNA-US would be indicated only in highly suspicious nodules and/or in the presence of lymphadenopathy, with 85.7% and 89.3% of possibly avoided FNA-US for ACR-TIRADS and EU-TIRADS, respectively, without increasing FN.

CONCLUSION

Both systems presented high sensitivity, but low specificity in selecting nodules for FNA-US. The use of nodular size for FNA-US selection is questioned.

Comparison of Various Ultrasound-Based Malignant Risk Stratification Systems on an Occasion for Assessing Thyroid Nodules in Hashimoto's Thyroiditis

Purpose

To compare the diagnostic performance and unnecessary ultrasound-guided fine-needle aspiration (US-FNA) biopsy rate of the 2015 American Thyroid Association (ATA), 2016 Korean Society of Thyroid Radiology (KSThR), and 2017 American College of Radiology (ACR) guidelines for patients with and without Hashimoto's thyroiditis (HT).

Patients and Methods

This retrospective study included 716 nodules from 696 consecutive patients, which were classified using the categories defined by the three guidelines: ATA, KSThR, and ACR. The malignancy risk in each category was calculated and the diagnostic performance and unnecessary fine-needle aspiration (FNA) rates of the three guidelines were compared.

Results

In total, 426 malignant and 290 benign nodules were identified. Patients with malignant nodules had lower total thyroxine levels and higher thyroid-stimulating hormone, thyroid peroxidase antibody, and thyroglobulin antibody levels than those without malignant nodules (all P<0.01). The margin difference was significant in non-HT patients (P<0.01), but comparable in HT patients (P=0.55). The calculated malignancy risks of high and intermediate suspicion nodules in the ATA and KSThR guidelines and moderately suspicious nodules in the ACR guidelines were significantly lower in non-HT patients compared with HT patients (P<0.05). The ACR guidelines showed the lowest sensitivity, highest specificity, and lowest unnecessary FNA rates in patients with and without HT. Compared to non-HT patients, HT patients had significantly lower unnecessary FNA rates (P<0.01).

Conclusion

HT was associated with a higher malignancy rate of thyroid nodules with intermediate suspicion according to the ATA, KSThR, and ACR guidelines. The three guidelines, especially ACR, were likely to be more effective and could allow a greater reduction in the percentage of benign nodules biopsied in patients with HT.

Diagnostic Performance of Various Ultrasound Risk Stratification Systems for Benign and Malignant Thyroid Nodules: A Meta-Analysis

BACKGROUND

To evaluate the diagnostic performance of ultrasound risk-stratification systems for the discrimination of benign and malignant thyroid nodules and to determine the optimal cutoff values of individual risk-stratification systems.

METHODS

PubMed, Embase, SCOPUS, Web of Science, and Cochrane library databases were searched up to August 2022. Sensitivity and specificity data were collected along with the characteristics of each study related to ultrasound risk stratification systems.

RESULTS

Sixty-seven studies involving 76,512 thyroid nodules were included in this research. The sensitivity, specificity, diagnostic odds ratios, and area under the curves by K-TIRADS (4), ACR-TIRADS (TR5), ATA (high suspicion), EU-TIRADS (5), and Kwak-TIRADS (4b) for malignancy risk stratification of thyroid nodules were 92.5%, 63.5%, 69.8%, 70.6%, and 95.8%, respectively; 62.8%, 89.6%, 87.2%, 83.9%, and 63.8%, respectively; 20.7111, 16.8442, 15.7398, 12.2986, and 38.0578, respectively; and 0.792, 0.882, 0.859, 0.843, and 0.929, respectively.

CONCLUSION

All ultrasound-based risk-stratification systems had good diagnostic performance. Although this study determined the best cutoff values in individual risk-stratification systems based on statistical assessment, clinicians could adjust or alter cutoff values based on the clinical purpose of the ultrasound and the reciprocal changes in sensitivity and specificity.

The clinical significance of the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) category 5 thyroid nodules: Not as risky as we think?

BACKGROUND

Although the prevalence of thyroid nodules is high, few prove to be malignant. Based on sonographic features, the American College of Radiology Thyroid Imaging Reporting and Data System categorizes malignancy risk of thyroid nodules with associated management recommendations for each category level. Malignancy rates among nodules with a highly suspicious Thyroid Imaging Reporting and Data System category 5 warrant examination in the context of additional risk stratification tools, including cytopathology and molecular testing.

METHODS

All patients who underwent fine-needle aspiration biopsy for Thyroid Imaging Reporting and Data System category 5 nodules from January 2018 to September 2021 in a large integrated academic health system were reviewed. Using the Bethesda System for Reporting Thyroid Cytopathology, categories V and VI were set as malignant. Molecular testing (ThyroSeq version 3; Rye Brook, NY) yielding ≥50% risk of malignancy was deemed positive and correlated with surgical pathology.

RESULTS

A total of 496 Thyroid Imaging Reporting and Data System category 5 nodules were identified. On fine-needle aspiration cytopathology, 61 (12.3%) were malignant. The breakdown included Bethesda System for Reporting Thyroid Cytopathology I, 15 (3%); II, 362 (73%); III, 52 (10.5%); IV, 5 (1%); V, 6 (1.3%); and VI, 55 (11.1%). Of Bethesda System for Reporting Thyroid Cytopathology III/IV nodules with molecular testing (n = 53), 24.5% yielded positive results. In total, 42 (8.5%) nodules underwent surgical resection, most of which were Bethesda System for Reporting Thyroid Cytopathology VI (n = 26, 61.9%). Of excised nodules, 33 (78.6%) nodules were malignant, 6 (14.3%) benign, and 3 (7.1%) noninvasive follicular thyroid neoplasm with papillary-like nuclear features. All Thyroid Imaging Reporting and Data System category 5 nodules with malignant cytology (Bethesda System for Reporting Thyroid Cytopathology V/VI) that underwent surgery were malignant on histopathology. On average, the total Thyroid Imaging Reporting and Data System points were higher in malignant nodules compared with benign (9.3 vs 7.3; P = .015). Moreover, benign nodules more frequently received Thyroid Imaging Reporting and Data System points when the radiologist was unable to determine composition or echogenicity (33% vs 3% among malignant nodules; P = .01).

CONCLUSION

Thyroid Imaging Reporting and Data System category 5 designation in thyroid nodules is associated with a lower risk of malignancy than previously reported. Benign and malignant nodules with Thyroid Imaging Reporting and Data System category 5 designation have discrepancies in certain Thyroid Imaging Reporting and Data System characteristics and individual points assigned, which may offer an opportunity for quality improvement and standardization measures in ultrasound reporting practices.

A new discriminant strategy combined with four TIRADS screening procedures increases ultrasound diagnostic accuracy-focusing on "wrong diagnostic" thyroid nodules

OBJECTIVE

To utilize the discrepancies of different TIRADS, including ACR-TIRADS, Kwak-TIRADS, C-TIRADS, and EU-TIRADS, to explore methods for improving ultrasound diagnostic accuracy.

METHODS

In total, 795 nodules with cytological or surgical pathology were included. All nodules were screened by the four TIRADS according to their diagnostic concordance (Screening procedures, SP). Discriminant strategy (DS) derived from predictor variables was combined with SP to construct the evaluation method (SP+DS). The diagnostic performance of the SP+DS method alone and its derivational methods and two-TIRADS combined tests was evaluated.

RESULTS

A total of 86.8% (269/310) malignant nodules and 93.6% (365/390) benign cases diagnosed by the four TIRADS simultaneously were pathologically confirmed, while 12.0% (95/795) nodules could not be consistently diagnosed by them. The criteria of DS were that iso- or hyper-echogenicity nodules should be considered benign, while hypo- or marked hypo-echogenicity nodules malignant. For 95 inconsistently diagnosed nodules screened by at least two TIRADS, DS performed best with an accuracy of 79.0%, followed by Kwak-TIRADS (72.6%). In the overall sample, the sensitivity and AUC were highest for the SP+DS method compared to the four TIRADS (91.3%, 0.895). Combining ACR-TIRADS and Kwak-TIRADS via parallel test resulted in significant improvements in the sensitivity and AUC compared to ACR-TIRADS (89.2% vs. 81.4%, 0.889 vs. 0.863). Combining C-TIRADS and DS in serial resulted in the highest AUC (0.887), followed by Kwak-TIRADS (0.884), while EU-TIRADS was the lowest (0.879).

CONCLUSIONS

For undetermined or suspected thyroid nodules, two-TIRADS combined tests can be used to improve diagnostic accuracy. Otherwise, considering the inconsistent diagnosis of two TIRADS may require attention to the echo characteristics to differentiate between benign and malignant nodules.

KEY POINTS

• The discrepancies in the diagnostic performance of different TIRADS arise from their performance on inconsistently diagnosed nodules. • ACR-TIRADS improves sensitivity via combining with Kwak-TIRADS in parallel (from 81.4 to 89.2%), while C-TIRADS increases specificity via combining with EU-TIRADS in serial (from 80.9 to 85.7%). • If the diagnostic findings of two TIRADS are inconsistent, echo characteristics will be helpful for the differentiation of benign and malignant nodules with an accuracy of 79.0%.

Changes in thyroid nodule cytology rates after institutional implementation of the Thyroid Imaging Reporting and Data System

BACKGROUND

The American College of Radiology Thyroid Imaging Reporting and Data System for ultrasound classification of malignancy risk was developed to better triage thyroid nodules for fine-needle aspiration biopsy. To examine further, we compared thyroid cytologic classification rates in nodules before and after institutional Thyroid Imaging Reporting and Data System implementation.

METHODS

Cytology diagnoses by Bethesda criteria (categories I-VI) from January 2014 to October 2021 were retrieved; observed changes in yearly category frequency were analyzed by linear regression; and pooled cohorts of pre- (2014-2018) and post-Thyroid Imaging Reporting and Data System (2019-2021) cytology call rates were compared.

RESULTS

Overall, 7,413 cytologic specimens were included (range/year 715-1,444). From 2014 to 2021, the proportion of benign (Bethesda category II) diagnosis per year declined stepwise from 49.7% to 19.4%, and atypia of undetermined significance/follicular lesion of undetermined significance (Bethesda category III) increased sequentially from 21.3% to 51.5%. Between 2014 and 2021, Bethesda category III diagnosis increased on average by 4.8% per year (95% confidence internal, 3.29-5.54; P < .001) and Bethesda category II results decreased on average by 4.4% per year (95% confidence interval, 6.29-3.42; P < .001). When comparing pre- and post-Thyroid Imaging Reporting and Data System, the proportion of Bethesda category II cytology results decreased (43.1% vs 21%; P = .001) while Bethesda category III (28.3% vs 47.7%; P = .002) and Bethesda category V (1.1% vs 1.7%; P = .015) results increased.

CONCLUSION

After implementation of American College of Radiology Thyroid Imaging Reporting and Data System ultrasound criteria, we observed a 2.5-fold decline in the rate of benign cytology and an increase in the proportion of atypia of undetermined significance/follicular lesion of undetermined significance results.

Diagnostic performance of ACR-TIRADS, Korean TIRADS, and American Thyroid Association guidelines for risk stratification of thyroid nodules: a prospective study

BACKGROUND

In the present study, the first aim was to compare the accuracy of three guidelines in the diagnosis of thyroid nodule malignancy. The second purpose was to find sonographic features potentially associated with the risk of malignancy.

METHODS

In this cross-sectional study, we prospectively recruited patients referred with a diagnosis of thyroid nodule (≥ 1 cm) for fine-needle aspiration (FNA). Sonographic features were recorded and scored according to the American Thyroid Association (ATA-2015), the American College of Radiology-Thyroid Imaging Reporting and Data System (ACR-TIRADS), and the Korean TIRADS (K-TIRADS). FNA was conducted and cytological findings were reported.

RESULTS

A total of 984 thyroid nodules were ultimately included, of which 144 (14.6%) were malignant and 840 (85.4%) were benign. The accuracy of ACR-TIRADS categories TR5 and TR4/5 was 88.3% and 69.3%, respectively. This rate for ATA-2015 classes High suspicion and Intermediate suspicion/High suspicion was 87.9% and 80.4%, respectively. For K-TIRADS classes 5 and 4/5, the diagnostic accuracy was 88.0% and 80.6%, respectively. The rate of unnecessary FNA was highest with ATA-2015 and K-TIRADS guidelines (53.9% and 53.7%, respectively), followed by ACR-TIRADS (32.0%). Significant direct associations were observed between malignancy and hypoechogenicity (odds ratio [OR] 5.78), fine calcification (OR = 6.7), rim calcification (OR = 2.56), ill-defined margin (OR = 3.31), and irregular margin (OR = 6.95).

CONCLUSIONS

There are different strengths of ACR-TIRADS, K-TIRADS, and ATA-2015 guidelines in the prediction of malignant thyroid nodules, and clinicians and radiologists should consider these differences in the management of thyroid nodules.

Changes in Diagnostic Performance of Thyroid Cancer Screening before and after the Korean Thyroid Imaging Reporting and Data System Revision

Background: Since the era of “thyroid cancer epidemic,” many Korean academic societies discouraged the use of ultrasonography in healthy individuals and revised the Korean Thyroid Imaging Reporting and Data System to address the overscreening and overdiagnosis issues. This study aimed to evaluate the change in the diagnostic effectiveness of thyroid cancer screening over the last decade.Methods: This single-center, retrospective observational study analyzed the data of 125,962 thyroid nodules obtained during cancer screening at the health promotion center of Seoul National University Bundang Hospital from 2010 to 2019. Only 327 thyroid cancer cases pathologically confirmed by fine-needle aspiration (FNA) were included in the study. The strength of the association between the number of FNA and (1) the number of thyroid cancer diagnoses, (2) the positive predictive values (PPVs), and (3) the difference in PPV from the previous year were evaluated using Pearson’s correlation analysis.Results: The number of thyroid FNA biopsies as well as the thyroid cancer diagnoses decreased from 2010 to 2019 (166 to 48 [-71.1%] vs. 43 to 22 [-48.8%]). The PPV of FNA biopsies increased from 25.9% to 45.8% (+76.8%) and was negatively correlated with the number of FNA biopsies performed (R=-0.87, P<0.001). The difference in PPV from the previous year increased similarly but without statistical significance (R=-0.59, P=0.09).Conclusion: The diagnostic efficiency of thyroid cancer screening has increased over the last decade, as evidencedby the increasing PPV of FNA biopsies.

Validating and Comparing C-TIRADS, K-TIRADS and ACR-TIRADS in Stratifying the Malignancy Risk of Thyroid Nodules

The thyroid imaging reporting and data system (TIRADS) was proposed by experts for optimal ultrasound evaluation of malignancy risk of thyroid focal lesions. There are several versions of TIRADS, some of them have been validated sufficiently, and the others have not been well assessed. In this study, a recently launched Chinese version of TIRADS (C-TIRADS) for malignancy risk stratification of thyroid nodules was validated, and the performance was compared to that of the Korean TIRADS (K-TIRADS) and American College of Radiology(ACR) TIRADS (ACR-TIRADS). Archives of 2177 patients who had undergone thyroid ultrasound examination, coarse needle tissue biopsy and/or surgery were reviewed, and 1978 patients with 1982 thyroid nodules were assessed according to the three TIRADSs. The histopathology was taken as the golden standard. The results showed the 1982 thyroid nodules were consisted of 1306 benign nodules and 676 malignant nodules. The malignancy risk accounted for 1.09%, 2.14%, 10.34%, 49.28%, 88.19% and 85.29% of the total nodules that were categorised as C-TIRADS 2, 3, 4A, 4B, 4C and 5, respectively; 0.00%, 1.64%, 2.87%,18.71% and 82.22% of the total nodules that were categorised as ACR-TIRADS 1, 2, 3, 4 and 5, respectively; 0.85%, 3.27%, 24.27% and 80.96% of the total nodules that were categorised as K-TIRADS 2, 3, 4 and 5, respectively. The correlation between the category of TIRADS and percentile of malignancy was 0.94 in the C-TIRADS, 1.00 in the ACR-TIRADS, and 1.00 in the K-TIRADS, respectively. The highest values of accuracy(AUC) of ROC curves of C-TIRADS 4B, K-TIRADS 5 and ACR-TIRADS 5 were taken as the cut-off values for risk stratification, respectively. The sensitivity, specificity, positive and negative predictive values and AUC by C-TIRADS 4B, K-TIRADS 5 and ACR-TIRADS 5 for malignancy risk stratification of thyroid nodules were 90.83%, 84.23%, 74.88% and 94.66% and 0.88, respectively; 83.58%, 89.82%, 80.95%, 91.36% and 0.87, respectively; and 85.50%, 90.35%, 82.10%, 92.33% and 0.88, respectively (P>0.05 for all). We concluded that the C-TIRADS has excellent performance in the malignancy risk stratification of thyroid nodules by the optimized cut-off value, which is comparable to that in K-TIRADS and ACR-TIRADS.

The European Institute of Oncology Thyroid Imaging Reporting and Data System for Classification of Thyroid Nodules: A Prospective Study

Background: To evaluate the performance, quality and effectiveness of “IEO-TIRADS” in assigning a TI-RADS score to thyroid nodules (TN) when compared with “EU-TIRADS” and the US risk score calculated with the S-Detect software (“S-Detect”). The primary objective is the evaluation of diagnostic accuracy (DA) by “IEO-TIRADS”, “S-Detect” and “EU-TIRADS”, and the secondary objective is to evaluate the diagnostic performances of the scores, using the histological report as the gold standard. Methods: A radiologist collected all three scores of the TNs detected and determined the risk of malignancy. The results of all the scores were compared with the histological specimens. The sensitivity (SE), specificity (SP), and diagnostic accuracy (DA), with their 95% confidence interval (95% CI), were calculated for each method. Results: 140 TNs were observed in 93 patients and classified according to all three scores. “IEO-TIRADS” has an SE of 73.6%, an SP of 59.2% and a DA of 68.6%. “EU-TIRADS” has an SE of 90.1%, an SP of 32.7% and a DA of 70.0%. “S-Detect” has an SE of 67.0%, an SP of 69.4% and a DA of 67.9%. Conclusion: “IEO-TIRADS” has a similar diagnostic performance to “S-Detect” and “EU-TIRADS”. Providing a comparable DA with other reporting systems, IEO-TIRADS holds the potential of being applied in clinical practice.

Clinical diagnostic value of American College of Radiology thyroid imaging report and data system in different kinds of thyroid nodules

BACKGROUND

To evaluate the diagnostic value of American College of Radiology (ACR) score and ACR Thyroid Imaging Report and Data System (TI-RADS) for benign nodules, medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC) through comparing with Kwak TI-RADS.

METHODS

Five hundred nine patients diagnosed with PTC, MTC or benign thyroid nodules were included and classified into the benign thyroid nodules group (n = 264), the PTC group (n = 189) and the MTC group (n = 56). The area under the curve (AUC) values were analyzed and the receiver operator characteristic (ROC) curves were drawn to compare the diagnostic efficiencies of ACR score, ACR TI-RADS and KWAK TI-RADS on benign thyroid nodules, MTC and PTC.

RESULTS

The AUC values of ACR score, ACR TI-RADS and Kwak TI-RADS for distinguishing malignant nodules from benign nodules were 0.914 (95%CI: 0.886-0.937), 0.871 (95%CI: 0.839-0.899) and 0.885 (95%CI: 0.854-0.911), respectively. In distinguishing of patients with MTC from PTC, the AUC values of ACR score, ACR TI-RADS and Kwak TI-RADS were 0.650 (95%CI: 0.565-0.734), 0.596 (95%CI: 0.527-0.664), and 0.613 (95%CI: 0.545-0.681), respectively. The AUC values of ACR score, ACR TI-RADS and Kwak TI-RADS for the discrimination of patients with MTC, PTC or benign nodules from patients without MTC, PTC or benign nodules were 0.899 (95%CI: 0.882-0.915), 0.865 (95%CI: 0.846-0.885), and 0.873 (95%CI: 0.854-0.893), respectively.

CONCLUSION

The ACR score performed the best, followed ex aequo by the ACR and Kwak TI-RADS in discriminating patients with malignant nodules from benign nodules and patients with MTC from PTC.

Consistency of TI-RADS Reporting in Community-Based Imaging Centers vs. a Large Tertiary Hospital

OBJECTIVE

In our country, thyroid nodules are sonographically evaluated in health maintenance organization (HMO) imaging centers, and patients are referred to tertiary hospitals for ultrasound-guided fine needle aspiration (FNA) biopsy when indicated. We evaluated the concordance in Thyroid Imaging Reporting and Data System (TI-RADS) classification reporting between these sites.

METHODS

We conducted a retrospective cohort study reviewing the sonographic features of thyroid nodules evaluated both at the HMO and a large tertiary center between January 2018 and December 2019. The primary outcome was concordance between the TI-RADS classification at both sites. Additional endpoints included correlation of TI-RADS to the Bethesda category following FNA and correlation of TI-RADS with malignancy on final pathology at each site.

RESULTS

The records of 336 patients with 370 nodules were reviewed. The level of concordance was poor (19.8%), with 277 (74.8%) nodules demonstrating higher TI-RADS and 20 (5.4%) lower TI-RADS at the HMO compared to the hospital (p<0.001, weighted Kappa = 0.120). FNA results were available for 236 (63.8%) nodules. The Bethesda category strongly correlated with the hospital TI-RADS (p<0.001), yet not with HMO TI-RADS (p=0.123). In the 57 nodules surgically removed, a strong correlation was identified between malignancy on final pathology and TI-RADS documented at the hospital (p<0.001), yet not at the HMO (p=0.259).

CONCLUSIONS

There is poor agreement between TI-RADS classification on ultrasound performed in the HMO compared to a tertiary hospital. The hospital TI-RADS strongly correlated with Bethesda category and final risk of malignancy unlike the HMO.

Malignancy risk of thyroid nodules: quality assessment of the thyroid ultrasound report

Background

Thyroid nodules are a challenge in clinical practice and thyroid ultrasonography is essential for assessing the risk of malignancy. The use of ultrasound-based malignancy risk classification systems has been recommended by several scientific societies but radiologist’s adherence to these guidelines may vary. The authors aimed to analyze the quality of the information provided by the thyroid ultrasound report, to assess the malignancy risk of thyroid nodules, in Portugal.

Methods

Multicenter and retrospective study, conducted in three of the five Portuguese NUTS2 corresponding to about 88.3% of the mainland population. We included 344 consecutive unselected participants aged ≥ 18 years who underwent thyroid ultrasonography in 2019. The description of six features of the dominant thyroid nodule was analyzed: maximum size, shape, margins, composition, echogenicity and echogenic foci. A utility score, including these six features, was used as an indicator of the report’s quality. A score of 4 was considered as a minimum value.

Results

Maximum diameter was reported for all nodules. Shape, margins, composition, echogenicity and echogenic foci were reported in 8.1%, 25.0%, 76.5%, 53.2% and 20.9%, respectively. Only 21.8% of the nodules had a score ≥ 4. At least one of four suspicious features, including marked hypoechogenicity, microcalcifications, irregular margins and non-oval shape, was identified in 8.7% of the nodules. Cervical lymph nodes’ status was reported in 93% of the exams. The risk category was only reported in 7.8% of the participants.

Conclusion

The adherence of Portuguese radiologists to a standardized reporting model and to an ultrasound-based malignancy risk stratification system is still low and has implications for the correct characterization of the malignancy risk of nodules and the decision to perform fine-needle aspiration biopsy.

Diagnostic Reliability of the American College of Radiology Thyroid Imaging Reporting and Data System in Royal Commission Hospital, Kingdom of Saudi Arabia

BACKGROUND: The American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) classified and predicted the risk of thyroid nodule malignancy with ultrasound scan scoring system. AIM: Hence, we aimed to investigate the value of the combined use of ultrasound ACR TI-RADS scoring and ultrasound-guided thyroid fine needle aspiration cytology (FNAC) based on the Bethesda System for Reporting Thyroid Cytology (TBSRTC) for assessing the accuracy tests of diagnosing low and high-risk thyroid nodules of ACR TI-RADS. METHODS: We enrolled 392 patients with thyroid nodules who underwent ultrasound scanning and scoring using the ACR TI-RADS classification along with ultrasound-guided thyroid FNAC and scoring with TBSRTC. The two methods were grouped as low and high risk of malignancy to evaluate the accuracy of ACR TI-RADS. RESULTS: Three hundred and ninety-two patients were enrolled in the study. The mean (Standard deviation [SD]) age was 46.03 (13.96) years, 332 (84.7%) were females and the mean (SD) of body mass index was 31.90 (22.32) kg/m2 and Vitamin D 17.65 (11.15) nmol/L. The mean (SD) for thyroid function test was 5.37 (44.16) mmol/L for thyroid-stimulating hormone, 1.48 (1.49) ng/dL for free thyroxine (FT4), and 2.69 (0.70) nmol/L for free triiodothyronine (FT3). Most of the participants were euthyroid (63.8%), but 28.6% had hypothyroidism and 7.7% had hyperthyroidism. The accuracy tests of ACR TI-RADS in relation to TBSRTC, were sensitivity (87.8%), specificity (65.2%), positive predictive value (29.8%), and negative predictive value (97%). The area under the curve = 0.590, 95% CI = 0.530–0.650, p ˂ 0.006. CONCLUSION: ACR TI-RADS is a simple, practical, and reliable scoring system for assessing thyroid nodule; it has a better overall diagnostic performance and the ability to exclude unnecessary FNAC with high negative predictive value.

The Diagnostic Efficacy of the American College of Radiology (ACR) Thyroid Imaging Report and Data System (TI-RADS) and the American Thyroid Association (ATA) Risk Stratification Systems for Thyroid Nodules

BACKGROUND

This study is aimed at evaluating the diagnostic efficacy of ultrasound-based risk stratification for thyroid nodules in the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) and the American Thyroid Association (ATA) risk stratification systems.

METHODS

286 patients with thyroid cancer were included in the tumor group, with 259 nontumor cases included in the nontumor group. The ACR TI-RADS and ATA risk stratification systems assessed all thyroid nodules for malignant risks. The diagnostic effect of ACR and ATA risk stratification system for thyroid nodules was evaluated by receiver operating characteristic (ROC) analysis using postoperative pathological diagnosis as the gold standard.

RESULTS

The distributions and mean scores of ACR and ATA rating risk stratification were significantly different between the tumor and nontumor groups. The lesion diameter > 1 cm subgroup had higher malignant ultrasound feature rates detected and ACR and ATA scores. A significant difference was not found in the ACR and ATA scores between patients with or without Hashimoto's disease. The area under the receiver operating curve (AUC) for the ACR TI-RADS and the ATA systems was 0.891 and 0.896, respectively. The ACR had better specificity (0.90) while the ATA system had higher sensitivity (0.92), with both scenarios having almost the same overall diagnostic accuracy (0.84).

CONCLUSION

Both the ACR TI-RADS and the ATA risk stratification systems provide a clinically feasible thyroid malignant risk classification, with high thyroid nodule malignant risk diagnostic efficacy.

Advanced Ultrasound Techniques for Differentiation of Benign Versus Malignant Thyroid Nodules: A Review

ABSTRACT

Grayscale ultrasound (US) is decisive in stratifying which thyroid nodules benefit from fine-needle aspiration to evaluate for malignancy. Unfortunately, a significant percentage of nodules remain indeterminate.Herein, we review the clinical considerations and diagnostic accuracy of advanced US, Doppler US, contrast-enhanced US, and US elastography techniques in the evaluation of indeterminate nodules.We conclude that these techniques may be used in combination with grayscale US to improve the assessment of lesion vascularity and tissue property.

Use of Diagnostic Criteria from ACR and EU-TIRADS Systems to Improve the Performance of Cytology in Thyroid Nodule Triage

Simple Summary

From a prospective series of 480 thyroid nodules, we compared the performances of the American College of Radiology (ACR) and the European Thyroid Association (EU) scoring systems in triaging thyroid nodules for fine-needle aspiration (FNA). FNA was recommended on 46.5% and 51.9% of the nodules using the ACR and EU-TIRADS scores, respectively. The ACR system demonstrated a higher specificity as compared to the EU-TIRADS (59.0% vs. 52.4%, p = 0.0012) in predicting ≥TIR3A/III (SIAPEC/Bethesda) nodules. Moreover, specific radiological features (i.e., echogenic foci and margins), combined with the cytological classes improved the specificity (97.5% vs. 91%, p < 0.0001) and positive predictive value (77.5% vs. 50.7%, p < 0.0001) of the cytology alone, maintaining an excellent sensitivity and negative predictive value.

Abstract

Objective: The American College of Radiology (ACR) and the European Thyroid Association (EU) have proposed two scoring systems for thyroid nodule classification. Here, we compared the ability of the two systems in triaging thyroid nodules for fine-needle aspiration (FNA) and tested the putative role of an approach that combines ultrasound features and cytology for the detection of malignant nodules. Design and Methods: The scores obtained with the ACR and EU Thyroid Imaging Reporting and Data Systems (TIRADS) from a prospective series of 480 thyroid nodules acquired from 435 subjects were compared to assess their performances in FNA triaging on the final cytological diagnosis. The US features that showed the highest contribution in discriminating benign nodules from malignancies were combined with cytology to improve its diagnostic performance. Results: FNA was recommended on 46.5% and 51.9% of the nodules using the ACR and EU-TIRADS scores, respectively. The ACR system demonstrated a higher specificity as compared to the EU-TIRADS (59.0% vs. 52.4%, p = 0.0012) in predicting ≥ TIR3A/III (SIAPEC/Bethesda) nodules. Moreover, specific radiological features (i.e., echogenic foci and margins), combined with the cytological classes improved the specificity (97.5% vs. 91%, p < 0.0001) and positive predictive values (77.5% vs. 50.7%, p < 0.0001) compared to cytology alone, especially in the setting of indeterminate nodules (TIR3A/III and TIR3B/IV), maintaining an excellent sensitivity and negative predictive value. Conclusions: The ACR-TIRADS system showed a higher specificity compared to the EU-TIRADS in triaging thyroid nodules. The use of specific radiological features improved the diagnostic ability of cytology.

A beneficial role of computer-aided diagnosis system for less experienced physicians in the diagnosis of thyroid nodule on ultrasound

Ultrasonography (US) is the primary diagnostic tool for thyroid nodules, while the accuracy is operator-dependent. It is widely used not only by radiologists but also by physicians with different levels of experience. The aim of this study was to investigate whether US with computer-aided diagnosis (CAD) has assisting roles to physicians in the diagnosis of thyroid nodules. 451 thyroid nodules evaluated by fine-needle aspiration cytology following surgery were included. 300 (66.5%) of them were diagnosed as malignancy. Physicians with US experience less than 1 year (inexperienced, n = 10), or more than 5 years (experienced, n = 3) reviewed the US images of thyroid nodules with or without CAD assistance. The diagnostic performance of CAD was comparable to that of the experienced group, and better than those of the inexperienced group. The AUC of the CAD for conventional PTC was higher than that for FTC and follicular variant PTC (0.925 vs. 0.499), independent of tumor size. CAD assistance significantly improved diagnostic performance in the inexperienced group, but not in the experienced groups. In conclusion, the CAD system showed good performance in the diagnosis of conventional PTC. CAD assistance improved the diagnostic performance of less experienced physicians in US, especially in diagnosis of conventional PTC.

Comparison of Korean vs. American Thyroid Imaging Reporting and Data System in Malignancy Risk Assessment of Indeterminate Thyroid Nodules

BACKGROUND

The management of cytologically indeterminate thyroid nodules is challenging for clinicians. This study aimed to compare the diagnostic performance of the Korean Thyroid Imaging Reporting and Data Systems (K-TIRADS) with that of the American College of Radiology (ACR)-TIRADS for predicting the malignancy risk of indeterminate thyroid nodules.

METHODS

Thyroid nodules diagnosed by fine-needle aspiration (FNA) followed by surgery or core needle biopsy at a single referral hospital were enrolled.

RESULTS

Among 200 thyroid nodules, 78 (39.0%) nodules were classified as indeterminate by FNA (Bethesda category III, IV, and V), and 114 (57.0%) nodules were finally diagnosed as malignancy by surgery or core needle biopsy. The area under the curve (AUC) was higher for FNA than for either TIRADS system in all nodules, while all three methods showed similar AUCs for indeterminate nodules. However, for Bethesda category III nodules, applying K-TIRADS 5 significantly increased the risk of malignancy compared to a cytological examination alone (50.0% vs. 26.5%, P=0.028), whereas applying ACR-TIRADS did not lead to a change.

CONCLUSION

K-TIRADS and ACR-TIRADS showed similar diagnostic performance in assessing indeterminate thyroid nodules, and K-TIRADS had beneficial effects for malignancy prediction in Bethesda category III nodules.

Diagnostic Performance of Kwak, EU, ACR, and Korean TIRADS as Well as ATA Guidelines for the Ultrasound Risk Stratification of Non-Autonomously Functioning Thyroid Nodules in a Region with Long History of Iodine Deficiency: A German Multicenter Trial

Germany has a long history of insufficient iodine supply and thyroid nodules occur in over 30% of the adult population, the vast majority of which are benign. Non-invasive diagnostics remain challenging, and ultrasound-based risk stratification systems are essential for selecting lesions requiring further clarification. However, no recommendation can yet be made about which system performs the best for iodine deficiency areas. In a German multicenter approach, 1211 thyroid nodules from 849 consecutive patients with cytological or histopathological results were enrolled. Scintigraphically hyperfunctioning lesions were excluded. Ultrasound features were prospectively recorded, and the resulting classifications according to five risk stratification systems were retrospectively determined. Observations determined 1022 benign and 189 malignant lesions. The diagnostic accuracies were 0.79, 0.78, 0.70, 0.82, and 0.79 for Kwak Thyroid Imaging Reporting and Data System (Kwak-TIRADS), American College of Radiology (ACR) TI-RADS, European Thyroid Association (EU)-TIRADS, Korean-TIRADS, and American Thyroid Association (ATA) Guidelines, respectively. Receiver Operating Curves revealed Areas under the Curve of 0.803, 0.795, 0.800, 0.805, and 0.801, respectively. According to the ATA Guidelines, 135 thyroid nodules (11.1%) could not be classified. Kwak-TIRADS, ACR TI-RADS, and Korean-TIRADS outperformed EU-TIRADS and ATA Guidelines and therefore can be primarily recommended for non-autonomously functioning lesions in areas with a history of iodine deficiency.

The New Era of TIRADSs to Stratify the Risk of Malignancy of Thyroid Nodules: Strengths, Weaknesses and Pitfalls

Simple Summary

The aim of this review is to provide the reader with a comprehensive overview of thyroid imaging and reporting data systems used for thyroid nodules, so as to understand how nodules are scored with all existing systems. Both ultrasound based risk stratification systems and indications for fine-needle aspirations are described. Systems are compared by analyzing their strengths and weaknesses. Studies show satisfactory sensitivities and specificities for the diagnosis of malignancy for all systems, and none of them have shown a real significant advantage over the others in terms of raw diagnostic value. Interobserver agreement is also very similar for all systems, fairly adequate to robust. Dimensional cut-offs for fine-needle aspiration are quite similar and all RSSs seem to reduce effectively the number of unnecessary FNAs. Merging all existing systems in a common international one is desirable.

Abstract

Since 2009, thyroid imaging reporting and data systems (TI-RADS) have been playing an increasing role in the field of thyroid nodules (TN) imaging. Their common aims are to provide sonologists of varied medical specialties and clinicians with an ultrasound (US) based malignancy risk stratification score and to guide decision making of fine-needle aspiration (FNA). Schematically, all TI-RADSs scores can be classified as either pattern-based or point-based approaches. The main strengths of these systems are their ability (i) to homogenize US TN descriptions among operators, (ii) to facilitate and shorten communication on the malignancy risk of TN between sonologists and clinicians, (iii) to provide quantitative ranges of malignancy risk assessment with high sensitivity and negative predictive values, and (iv) to reduce the number of unnecessary FNAs. Their weaknesses are (i) the remaining inter-observer discrepancies and (ii) their insufficient sensitivity for the diagnosis of follicular cancers and follicular variant of papillary cancers. Most common pitfalls are degenerating shrinking nodules and confusion between individual and coalescent nodules. The benefits of all TI-RADSs far outweigh their shortcomings, explaining their rising use, but the necessity to improve and merge the different existing systems remains.

Thyroid Nodules in Patients with Acromegaly: Frequency According to the ACR TI-RADS Classification and its Relationship with Disease Activity

PURPOSE

In our study, we aimed to determine the frequency of thyroid nodules in patients with acromegaly according to the American College of Radiology (ACR) Thyroid Imaging, Reporting and Data System (TI-RADS) classification and its relationship with acromegaly disease activity.

METHODS

A total of 56 patients with acromegaly and age, sex, and body mass index matched with 56 healthy control subjects were included in our study. Thyroid-stimulating hormone, free thyroxine, and anti-thyroperoxidase antibody levels of patients and control subjects were measured. In addition, patients and healthy controls were evaluated by ultrasonography to determine thyroid structure, thyroid volume, and thyroid nodules and to make ACR TI-RADS classification.

RESULTS

Thyroid nodules were present in 31 (55.4%) of 56 patients in the acromegaly group and 20 (35.7%) of 56 subjects in the control group, and the frequency of thyroid nodules was significantly higher in the acromegaly group (p=0.038). The mean number of nodules in the acromegaly group and control group was 1.27±1.43 and 0.48±0.73, respectively, and the mean number of nodules was significantly higher in the acromegaly group (p=0.003). The number of patients with TI-RADS 1, TI-RADS 2, and TI-RADS 4 nodules in the acromegaly group was higher than the control group (p=0.026, p=0.049, p=0.007, respectively). No difference was found in terms of cytological findings between those who have undergone FNAB in the acromegaly group and control group.

CONCLUSION

In our study, we found that the frequency of thyroid nodules, the number of thyroid nodules, and the number of TI-RADS 1, TI-RADS 2, and TI-RADS 4 nodules increased in patients with acromegaly. There was no significant difference between acromegaly disease activity and thyroid nodule frequency, number of thyroid nodules, and TI-RADS classifications.

Comparison of Thyroid Risk Categorization Systems and Fine-Needle Aspiration Recommendations in a Multi-Institutional Thyroid Ultrasound Registry

OBJECTIVES

The aim of this study was to compare how often fine-needle aspiration (FNA) would be recommended for nodules in unselected, low-risk adult patients referred for sonographic evaluation of thyroid nodules by ACR Thyroid Imaging Reporting and Data System (TI-RADS), the American Thyroid Association guidelines (ATA), Korean Thyroid Imaging Reporting and Data System (K-TIRADS), European Thyroid Imaging Reporting and Data System (EU-TIRADS), and Artificial Intelligence Thyroid Imaging Reporting and Data System (AI-TIRADS).

METHODS

Seven practices prospectively submitted thyroid ultrasound reports on adult patients to the ACR Thyroid Imaging Research Registry between October 2018 and March 2020. Data were collected about the sonographic features of each nodule using a structured reporting template with fields for the five ACR TI-RADS ultrasound categories plus maximum nodule size. The nodules were also retrospectively categorized according to criteria from ACR TI-RADS, the ATA, K-TIRADS, EU-TIRADS, and AI-TIRADS to compare FNA recommendation rates.

RESULTS

For 27,933 nodules in 12,208 patients, ACR TI-RADS recommended FNA for 8,128 nodules (29.1%, 95% confidence interval [CI] 0.286-0.296). The ATA guidelines, EU-TIRADS, K-TIRADS, and AI-TIRADS would have recommended FNA for 16,385 (58.7%, 95% CI 0.581-0.592), 10,854 (38.9%, 95% CI 0.383-0.394), 15,917 (57.0%, 95% CI 0.564-0.576), and 7,342 (26.3%, 95% CI 0.258-0.268) nodules, respectively. Recommendation for FNA on TR3 and TR4 nodules was lowest for ACR TI-RADS at 18% and 30%, respectively. ACR TI-RADS categorized more nodules as TR2, which does not require FNA. At the high suspicion level, the FNA rate was similar for all guidelines at 68.7% to 75.5%.

CONCLUSION

ACR TI-RADS recommends 25% to 50% fewer biopsies compared with ATA, EU-TIRADS, and K-TIRADS because of differences in size thresholds and criteria for risk levels.

Matrix 3D ultrasound-assisted thyroid nodule volume estimation and radiofrequency ablation: a phantom study

Background

Two-dimensional (2D) ultrasound is well established for thyroid nodule assessment and treatment guidance. However, it is hampered by a limited field of view and observer variability that may lead to inaccurate nodule classification and treatment. To cope with these limitations, we investigated the use of real-time three-dimensional (3D) ultrasound to improve the accuracy of volume estimation and needle placement during radiofrequency ablation. We assess a new 3D matrix transducer for nodule volume estimation and image-guided radiofrequency ablation.

Methods

Thirty thyroid nodule phantoms with thermochromic dye underwent volume estimation and ablation guided by a 2D linear and 3D mechanically-swept array and a 3D matrix transducer.

Results

The 3D matrix nodule volume estimations had a lower median difference with the ground truth (0.4 mL) compared to the standard 2D approach (2.2 mL, p < 0.001) and mechanically swept 3D transducer (2.0 mL, p = 0.016). The 3D matrix-guided ablation resulted in a similar nodule ablation coverage when compared to 2D-guidance (76.7% versus 80.8%, p = 0.542). The 3D mechanically swept transducer performed worse (60.1%, p = 0.015). However, 3D matrix and 2D guidance ablations lead to a larger ablated volume outside the nodule than 3D mechanically swept (5.1 mL, 4.2 mL (p = 0.274), 0.5 mL (p < 0.001), respectively). The 3D matrix and mechanically swept approaches were faster with 80 and 72.5 s/mL ablated than 2D with 105.5 s/mL ablated.

Conclusions

The 3D matrix transducer estimates volumes more accurately and can facilitate accurate needle placement while reducing procedure time.

Diagnostic performance rates of the ACR-TIRADS and EU-TIRADS based on histopathological evidence

PURPOSE

In this study, we aimed to assess the effectiveness of malignancy stratification algorithms of the American College of Radiology (ACR) and European Thyroid Association (ETA) in the delineation of thyroid nodules using a database of nodules that were unequivocally diagnosed by means of histopathological examination and meticulously matched with the imaged nodules.

METHODS

A total of 165 patients having 251 thyroid nodules with histopathologically proven definitive diagnoses during a 5-year period were included in this study. All patients had preoperatively undergone ultrasonography (US) examination, and US characteristics of the thyroid nodules were retrospectively analyzed and assigned in compliance with the thyroid imaging reporting and data system categories recommended by the ACR (ACR-TIRADS) and ETA (EU-TIRADS). The diagnostic effectiveness in the delineation of thyroid nodules and unnecessary fine-needle aspiration (FNAB) rates were evaluated.

RESULTS

Overall, 189 nodules (75.30%) were diagnosed as benign, while 62 nodules (24.70%) were reported to be malignant based on histopathological assessment. Sensitivity and specificity rates were 71% and 75% for ACR-TIRADS and 73% and 80% for EU-TIRADS. The area under the curve values were 0.78 and 0.80 for ACR-TIRADS and EU-TIRADS, respectively. The unnecessary FNAB rates were 61% for ACR-TIRADS and 64% for EU-TIRADS as per the recommended criteria of each algorithm.

CONCLUSION

The diagnostic performance of both malignancy stratification systems was signified to be moderate and sufficient in a cohort of nodules with definite histopathological diagnosis. In light of our results, we demonstrated the strengths and weaknesses of the ACR- and EU-TIRADS for physicians who should be familiar with them for optimal management of thyroid nodules.

Ultrasound-Based Indications for Thyroid Fine-Needle Aspiration: Outcome of a TIRADS-Based Approach versus Operators' Expertise

BACKGROUND

Thyroid nodule image reporting and data systems (TIRADS) provide the indications for fine-needle aspiration (FNA) based on a combination of nodule sonographic features and size. We compared the TIRADS-based recommendations for FNA with those based on the personal expertise of qualified US investigators in the diagnosis of thyroid malignancy.

METHODS

Seven highly experienced ultrasound (US) investigators from 4 countries evaluated, online, the US video recordings of 123 histologically verified thyroid nodules. Technical resources provided the operators with a diagnostic approach close to the real-world practice. Altogether, 4,305 TIRADS scores were computed. The combined diagnostic potential of TIRADS (TIRSYS) and the personal recommendations of the investigators (PERS) were compared against 3 possible goals: to recognize all malignant lesions (allCA), nonpapillary plus non-pT1 papillary cancers (nPnT1PCA), or stage II-IV cancers (st2-4CA).

RESULTS

For allCA and nPnT1PCA, TIRSYS had lower sensitivity than PERS (69.8 vs. 87.2 and 83.5 vs. 92.6%, respectively, p <0.01), while in st2-4CA the sensitivities were the same (99.1 vs. 98.6% and TIRSYS vs. PERS, respectively). TIRSYS had a higher specificity than PERS in all 3 types of cancers (p < 0.001). PERS recommended FNA in a similar proportion of lesions smaller or larger than 1 cm (76.9 vs. 82.7%; ns).

CONCLUSIONS

Recommendations for FNA based on the investigators' US expertise demonstrated a better sensitivity for thyroid cancer in the 2 best prognostic groups, while TIRADS methodology showed superior specificity over the full prognostic range of cancers. Thus, personal experience provided more accurate diagnoses of malignancy, missing a lower number of small thyroid cancers, but the TIRADS approach resulted in a similar accuracy for the diagnosis of potentially aggressive lesions while sparing a relevant number of FNAs. Until it is not clearly stated what the goal of the US evaluation is, that is to diagnose all or only clinically relevant thyroid cancers, it cannot be determined whether one diagnostic approach is superior to the other for recommending FNA.

Establishment of an Ultrasound Malignancy Risk Stratification Model for Thyroid Nodules Larger Than 4 cm

Background

The incidence and mortality of thyroid cancer, including thyroid nodules > 4 cm, have been increasing in recent years. The current evaluation methods are based mostly on studies of patients with thyroid nodules < 4 cm. The aim of the current study was to establish a risk stratification model to predict risk of malignancy in thyroid nodules > 4 cm.

Methods

A total of 279 thyroid nodules > 4 cm in 267 patients were retrospectively analyzed. Nodules were randomly assigned to a training dataset (n = 140) and a validation dataset (n = 139). Multivariable logistic regression analysis was applied to establish a nomogram. The risk stratification of thyroid nodules > 4 cm was established according to the nomogram. The diagnostic performance of the model was evaluated and compared with the American College Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS), Kwak TI-RADS and 2015 ATA guidelines using the area under the receiver operating characteristic curve (AUC).

Results

The analysis included 279 nodules (267 patients, 50.6 ± 13.2 years): 229 were benign and 50 were malignant. Multivariate regression revealed microcalcification, solid mass, ill-defined border and hypoechogenicity as independent risk factors. Based on the four factors, a risk stratified clinical model was developed for evaluating nodules > 4 cm, which includes three categories: high risk (risk value = 0.8-0.9, with more than 3 factors), intermediate risk (risk value = 0.3-0.7, with 2 factors or microcalcification) and low risk (risk value = 0.1-0.2, with 1 factor except microcalcification). In the validation dataset, the malignancy rate of thyroid nodules > 4 cm that were classified as high risk was 88.9%; as intermediate risk, 35.7%; and as low risk, 6.9%. The new model showed greater AUC than ACR TI-RADS (0.897 vs. 0.855, p = 0.040), but similar sensitivity (61.9% vs. 57.1%, p = 0.480) and specificity (91.5% vs. 93.2%, p = 0.680).

Conclusion

Microcalcification, solid mass, ill-defined border and hypoechogenicity on ultrasound may be signs of malignancy in thyroid nodules > 4 cm. A risk stratification model for nodules > 4 cm may show better diagnostic performance than ACR TI-RADS, which may lead to better preoperative decision-making.

Comparing ultrasound assessment of thyroid nodules using BTA U classification and ACR TIRADS measured against histopathological diagnosis

INTRODUCTION

The British Thyroid Association (BTA) recommends ultrasound assessment of thyroid nodules using the U classification. The American College of Radiologists (ACR) recommend assessment with the Thyroid Imaging Reporting and Data System (TIRADS). We conduct the first UK study to compare these two systems.

METHODS

Ultrasound (US) reports of patients who underwent surgical excision of thyroid nodules over a 10-year period in one UK centre were reviewed. US findings were collected, and the classifications were retrospectively applied. The systems were compared to histopathological diagnosis.

RESULTS

308 nodules in 296 patients are included. 135 nodules (43.8%) were malignant. U classification showed sensitivity of 88.1% in recommending FNA, significantly higher than TIRADS at 73.3% (p = .0002). The U classification showed specificity of 41.6%, significantly lower than TIRADS at 64.2% (p=<0.0001). PPV between classifications at equivalent levels showed no significant difference at U3/TR-3 (p=.81), U4/TR-4 (p=.30) or U5/TR-5 (p=.90).

DISCUSSION

Classification systems enable risk stratification of potentially malignant thyroid nodules. This study shows BTA U classification has a higher sensitivity but lower specificity than TIRADS.

Comparison of British Thyroid Association, American College of Radiology TIRADS and Artificial Intelligence TIRADS with histological correlation: diagnostic performance for predicting thyroid malignancy and unnecessary fine needle aspiration rate

Objectives:

To compare diagnostic performance of British Thyroid Association (BTA), American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TIRADS) and Artificial Intelligence TIRADS (AI-TIRADS) for thyroid nodule malignancy. To determine comparative unnecessary fine needle aspiration (FNA) rates.

Methods:

218 thyroid nodules with definitive histology obtained during 2017 were included. Ultrasound images were reviewed retrospectively in consensus by two subspecialist radiologists, blinded to histopathology, and nodules assigned a BTA, ACR-TIRADS and AI-TIRADS grade. Nodule laterality and size were recorded to allow accurate histopathological correlation and determine which nodules met criteria for FNA.

Results:

77 (35.3%) nodules were malignant. Deeming ultrasound Grade 4–5 as test-positive and 1–2 as test-negative, sensitivity and specificity for BTA was 98.28 and 42.55%, for ACR-TIRADS: 95.24 and 40.57% and for AI-TIRADS: 93.44 and 45.71%. FNA was indicated in 101 (71.6%), 67 (47.5%) and 65 (46.1%) benign nodules utilising BTA, ACR-TIRADS and AI-TIRADS respectively. The unnecessary FNA rate was significantly higher with BTA (46.3%) compared to ACR-TIRADS (30.7%) and AI-TIRADS (29.8%) p < 0.001.

Conclusion:

BTA, ACR-TIRADS and AI-TIRADS had similar diagnostic performance for predicting thyroid nodule malignancy with sensitivity >93% for all systems when considering ultrasound Grade 4–5 as malignant and Grade 1–2 as benign. ACR-TIRADS and AI-TIRADS both had a significantly lower rate of recommended FNA in benign nodules compared to BTA.

Advances in knowledge:

BTA, ACR-TIRADS and AI-TIRADS have comparable diagnostic performance with high sensitivity but relatively low specificity for predicting thyroid nodule malignancy in this cohort using histology as gold-standard. Using Grade 1–2 as benign and 4–5 as malignant there were more false negatives with TIRADS but this improved when taking other features into account while BTA had a significantly higher rate of unnecessary FNA.

The ultrasound risk stratification systems for thyroid nodule have been evaluated against papillary carcinoma. A meta-analysis

Thyroid imaging reporting and data systems (TIRADS) are used to stratify the malignancy risk of thyroid nodule by ultrasound (US) examination. We conducted a meta-analysis to evaluate the pooled cancer prevalence and the relative prevalence of papillary, medullary, follicular thyroid cancer (PTC, MTC, and FTC) and other malignancies among nodules included in studies evaluating their performance. Four databases were searched until February 2020. Original articles with at least 1000 nodules, evaluating the performance of at least one TIRADS among AACE/ACE/AME, ACR-TIRADS, ATA, EU-TIRADS, or K-TIRADS, and reporting data on the histological diagnosis of malignant lesions were included. The number of malignant nodules, PTC, FTC, MTC and other malignancies in each study was extracted. For statistical pooling of data, a random-effects model was used. Nine studies were included, evaluating 19,494 thyroid nodules. The overall prevalence of malignancy was 34% (95%CI 21 to 49). Among 6162 histologically proven malignancies, the prevalence of PTC, FTC, MTC and other malignancies was 95%, 2%, 1%, and 1%, respectively. A high heterogeneity was found for all the outcomes. A limited number of studies generally conducted using a retrospective design was found, with possible selection bias. Acknowledging this limitation, TIRADSs should be regarded as accurate tools to diagnose PTC only. Proposed patterns and/or cut-offs should be revised and other strategies considered to improve their performance in the assessment of FTC, MTC and other malignancies.