Can the American Thyroid Association, K-Tirads, and Acr-Tirads Ultrasound Classification Systems Be Used to Predict Malignancy in Bethesda Category IV Nodules?

Impact of ultrasound elastography in evaluating Bethesda category IV thyroid nodules with histopathological correlation

Introduction

Fine needle aspiration (FNA) is the gold standard method recommended in the diagnosis of thyroid nodules. Bethesda IV cytology results are identified in 7-9% of nodules investigated through FNA, with reported malignancy rate in a wide range of 10-40%. The recommended treatment is either surgical or risk additional molecular testing before surgery. However, a large number of nodules belonging to this category (60-80%) are observed to be benign after surgical excision, which can put the patient at risk of unnecessary surgical morbidity. This study aimed to assess the diagnostic performance of conventional ultrasound, the ACR TI-RADS score and elastography in cases of Bethesda IV cytology on FNA.

Methods

We evaluated ninety-seven consecutive cases with Bethesda category IV results on FNA by using conventional B-mode ultrasound, qualitative strain or shear-wave elastography (Hitachi Preirus Machine, Hitachi Inc., Japan and Aixplorer Mach 30 Supersonic Imagine, Aix-en-Provence, France) and all nodules were classified according to the ACR TI-RADS system. Conventional ultrasound was used to categorize the nodules as potentially malignant based on the following features: hypoechogenicity, inhomogeneity, a taller than wide shape, irregular margins, presence of microcalcifications, an interrupted thyroid capsule and suspicious cervical lymph nodes. Elastography classified nodules with increased stiffness as suspicious for malignancy.

Results

We considered pathology results as the gold standard diagnosis, finding that 32 out of 97 nodules were carcinomas (33%) and 65 out of 97 were benign nodules (67%). The benign group included twenty cases of non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). Finally, we compared ultrasound data with pathology results, which showed that nineteen out of the 32 malignant nodules presented with increased stiffness on elastography (p=0.0002). On conventional ultrasound, we found that microcalcifications (p=0.007), hypoechogenicity and irregular margins (p=0.006) are features which can distinguish between benign and malignant nodules with statistical significance.

Discussion

Integrating elastography as a parameter of the ACR TI-RADS score in the evaluation of Bethesda category IV nodules showed a sensitivity of 90.62% in detecting thyroid cancer cases (p=0.006). We can conclude that elastographic stiffness as an addition to high risk features observed on conventional ultrasound improves the detection of malignant nodules in cases with Bethesda IV cytology.

Volume reduction rate of radiofrequency ablation in ≤ 2 cm Bethesda IV thyroid nodules

OBJECTIVE

This prospective observational study aimed to evaluate the efficacy of radiofrequency ablation (RFA) in treating ≤ 2 cm thyroid nodules with Bethesda IV cytology and C-TIRADS 4A categorization. Additionally, the factors influencing the completed absorption of ablation (CAA) were examined.

METHODS

A total of 62 cases with 62 nodules underwent ultrasound-guided RFA and were included in the study. The volume reduction rate (VRR), CAA, and incomplete absorption of ablation (IAA) were assessed at the 1st, 3rd, 6th, and subsequent 6-month follow-ups. Clinical and ultrasound features were compared between the CAA and IAA groups at the 12th month follow-up.

RESULTS

The average VRR at the 1st, 3rd, 6th, 12th month, and last follow-up were -88.6%, 16.0%, 59.7%, 82.0%, and 98.2%, respectively. More than half of the nodules achieved a 90% VRR after 1 year of RFA, with 88.7% demonstrating CAA at the end of the study (follow-up duration of 14 to 63 months). Nodules with grade 3 vascularity and those associated with chronic thyroiditis showed delayed CAA at the 12th month follow-up (p = 0.036 and 0.003, respectively).

CONCLUSION

RFA is an effective technique for treating ≤ 2 cm thyroid nodules with Bethesda IV cytology and C-TIRADS 4A categorization. Nodules with grade 3 blood supply and patients with chronic thyroiditis exhibited an impact on the completed absorption following RFA.

CLINICAL RELEVANCE STATEMENT

Our study has shown that radiofrequency ablation is an effective treatment for ≤ 2 cm thyroid nodules classified as Bethesda IV cytology. However, we identified that high vascularity of the nodule and chronic thyroiditis are adverse factors affecting the completed absorption of the ablation.

KEY POINTS

•Radiofrequency ablation (RFA) is an effective technique for treatment of ≤ 2 cm Bethesda IV category thyroid nodules. •Higher blood supply and chronic thyroiditis influence the completed absorption after RFA.

Examining the impact of several factors including COVID-19 on thyroid fine-needle aspiration biopsy

OBJECTIVE

The study explores various factors, including coronavirus disease 2019 (COVID-19) history and vaccination status, that influence the classification value of ultrasonography-guided thyroid fine needle aspiration biopsy (TFNAB) by comparing non-diagnostic (Bethesda-I) and diagnostic (Bethesda II-VI) results.

METHODS

We conducted a retrospective observational study in a high-volume tertiary care center involving patients who underwent TFNAB from November 2022 to April 2023. The study retrospectively analyzed the cytopathology of 482 thyroid nodules. Patients were categorized into non-diagnostic (n = 136) and Diagnostic groups (n = 346) based on TFNAB. A comprehensive set of parameters was examined, including demographic, anthropometric and clinical data, thyroid ultrasonography findings, COVID-19 history and immunization status.

RESULTS

The mean age was 55.1 ± 12.1 years in the non-diagnostic group and 53.5 ± 13 years in the Diagnostic group (p = .223). 75.7% (n = 103) of the non-Diagnostic group and 82.9% (n = 287) of the Diagnostic group were male (p = .070). The mean nodule longitudinal diameter of the Diagnostic group was significantly higher than that of the non-diagnostic group (p = .015). The TIRADS score of the nodules showed a statistical difference between the groups (p = .048). The groups had no significant differences regarding other ultrasonographic parameters and COVID-19-related variables.

CONCLUSION

It can be assumed that when the longitudinal diameter of the thyroid nodule is small and in TIRADS categories other than the TIRADS3 category, TFNAB is less likely to be diagnostic. However, future research may be needed to confirm these findings and uncover any long-term effects of COVID-19 or vaccines on thyroid nodule diagnostics.

Comparison of diagnostic performance of two ultrasound risk stratification systems for thyroid nodules: a systematic review and meta-analysis

OBJECTIVES

To assume the ideal cut-off values and diagnostic performance of two thyroid imaging reporting and data systems published by the Korean Thyroid Association/Korean Society of Thyroid Radiology (Korean TI-RADS) and the American Thyroid Association (ATA TI-RADS).

METHODS

Eighteen studies with 25,422 patients from PubMed, SCOPUS, Embase, Web of Science, and Cochrane Library databases up to August 2022. True and false positive and negative values with characteristics were extracted.

RESULTS

The highest area under the receiver operating characteristic curve (AUC) was 0.893 and 0.887 for Korean and ATA TI-RADS. High suspicion was judged as the best cut-off value with the highest AUC based on optimal sensitivity and specificity. In determining the risk of malignant thyroid nodules, high suspicion in Korean and ATA TI-RADS showed sensitivity as 71.3% and 73.5%, specificity as 7.9% and 86.4%, diagnostic odds ratios as 20.0289 and 20.9076, AUC as 0.893 and 0.887. There was no significant difference when directly comparing the diagnostic accuracy of both TI-RADS.

CONCLUSION

The two risk stratification systems had good diagnostic performance with high AUC and no significant differences. The ideal cut-off can depend on the medical condition or thyroid nodules, because the changes of cut-off point may reciprocally alter sensitivity and specificity.

Real-Time Ultrasonography and the Evaluation of Static Images Yield Different Results in the Assessment of EU-TIRADS Categories

The studies on the effectiveness of various TIRADS in the diagnostics of thyroid nodules differ in the method of ultrasound image assessment: real time (rtUS) vs. static ultrasonography (stUS). The aim of the study was to evaluate the impact of those two methods on the categorization of nodules in EU-TIRADS. Three experienced raters assessed 842 nodules in routine rtUS and reassessed with the use of sUS. Reproducibility of the assessment of malignancy risk features and categorization of nodules with EU-TIRADS was estimated with Krippendorff's alpha coefficient (Kα). The reproducibility of EU-TIRADS categories on sUS in relation to rtUS was in range 70.9-76.5% for all raters (Kα: 0.60-0.68) with the highest reproducibility for category 3 (80.0-86.5%) and the lowest for category 5 (48.7-77.8%). There was a total disagreement of the identification of microcalcifications on sUS in relation to rtUS, a strongly variable reproducibility of marked hypoechogenicity (12.5-84.6%, Kα: 0.14-0.48) and a tendency toward more frequent identification of the non-oval shape on sUS. The percentage of agreement for each pair of raters in assigning the EU-TIRADS category on sUS was in the range 71.6-72.3% (Kα: 0.60-0.62). The method of sonographic image evaluation influences the nodule's feature assessment and, eventually, the categorization within EU-TIRADS.

Concordance of the ACR TI-RADS Classification With Bethesda Scoring and Histopathology Risk Stratification of Thyroid Nodules

Importance

Although most thyroid nodules are benign, 10% to 15% of them harbor cancer. Thyroid ultrasonography is useful for risk stratification of nodules, and American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) classification provides recommendations for fine-needle aspiration cytology (FNAC) based on objective ultrasonographic features of these nodules.

Objective

To validate the concordance of ACR TI-RADS classification with Bethesda classification and histopathology.

Design, Setting, and Participants

This retrospective cohort study was performed to evaluate the concordance of ACR TI-RADS classification with Bethesda classification and histopathology and was conducted in Singapore General Hospital Outpatient Otolaryngology clinic in March 2021 to May 2021. Data analysis was performed in May 2021.

Main Outcomes and Measures

Results were deemed concordant when ACR TI-RADS recommendations aligned with Bethesda scores. Conversely, results were classified as nonconcordant with Bethesda scores and/or histopathology results when nodules that were recommended for FNAC yielded benign results or nodules that were not recommended for FNAC yielded malignant results.

Results

A total of 446 patients (370 women [83%]; mean [range] age, 60 [24-89] years) who underwent ultrasonography of the thyroid and ultrasonography-guided thyroid FNACs were identified. A total of 492 of 630 nodules (78.1%) were benign on FNAC (Bethesda II). Score 3 ACR TI-RADS nodules yielded the highest negative predictive values: 94.6% (95% CI, 92.9%-95.9%; P < .001) compared with Bethesda scoring and 100.0% (95% CI, 15.8%-100.0%; P = .003) compared with histopathology. Score 4 or 5 ACR TI-RADS nodules yielded positive predictive values of 2.8% and 16.2%, respectively, compared with Bethesda scoring and 6.1% and 66.7%, respectively, compared with histopathology. Small (<1.5 cm) ACR TI-RADS nodules of scores of 4 and 5 that were not recommended for FNAC yielded a malignant risk of 5.7% and 25.0% on Bethesda 5 and 6, respectively. On surgical excision, 5 of 46 (10.9%) ACR TI-RADS 4 nodules and 15 of 21 (71.4%) of ACR TI-RADS 5 nodules were confirmed to be malignant. Among nodules initially not recommended for FNAC, histopathology-proven cancer was found in 4 of 13 (30.7%) and 3 of 6 (50.0%) of nodules, respectively.

Conclusions and Relevance

These findings suggest that ACR TI-RADS score 3 nodules have a low risk of cancer and should be considered for FNAC only if nodules are 2.5 cm or larger. Patients with small (<1.5 cm) ACR TI-RADS 4 and 5 nodules should be appropriately counseled for FNAC to exclude cancer.

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.

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.

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.

Diagnostic Performance of ACR and Kwak TI-RADS for Benign and Malignant Thyroid Nodules: An Update Systematic Review and Meta-Analysis

(1) Background: To determine the optimal cut-off values of two risk stratification systems to discriminate malignant thyroid nodules and to compare the diagnostic performance; (2) Methods: True and false positive and negative data were collected, and methodological quality was assessed for forty-six studies involving 39,085 patients; (3) Results: The highest area under the receiver operating characteristic (ROC) curve (AUC) of ACR and Kwak TI-RADS were 0.875 and 0.884. Based on the optimal sensitivity and specificity, the highest accuracy values of ROC curves or diagnostic odds ratios (DOR) were taken as the cut-off values for TR4 (moderate suspicious) and 4B. The sensitivity, specificity, DOR, and AUC by ACR (TR4) and Kwak TI-RADS (4B) for malignancy risk stratification of thyroid nodules were 94.3% and 96.4%; 52.2% and 53.7%; 17.5185 and 31.8051; 0.786 and 0.884, respectively. There were no significant differences in diagnostic accuracy in any of the direction comparisons of the two systems; (4) Conclusions: ACR and Kwak TI-RADS had good diagnostic performances (AUCs > 85%). Although we determined the best cut-off values in individual risk stratification systems based on statistical assessment, clinicians can adjust the optimal cut-off value according to the clinical purpose of the ultrasonography because raising or lowering cut-points leads to reciprocal changes in sensitivity and specificity.

Malignancy risk stratification of thyroid nodules smaller than 10 mm with ACR-TIRADS, K-TIRADS, and ATA-2015 guidelines: a prospective study

Background

Small thyroid nodules (≤ 10 mm) are common findings in thyroid ultrasonography. The first purpose of this study was to compare the performance of three guidelines in the diagnosis of malignancy for small thyroid nodules. The second aim was to find the ultrasonographic characteristics potentially associated with the risk of malignancy. This prospective cross-sectional study was performed on the patients with a diagnosis of small thyroid nodules (≤ 10 mm), who were rereferred to the radiologists for sonography and FNA. Sonographic features were recorded and scored according to the American College of Radiology-Thyroid Imaging Reporting and Data System (ACR-TIRADS), American Thyroid Association (ATA-2015), and Korean-TIRADS (K-TIRADS). Finally, FNA was conducted and cytological findings were reported.

Results

In total, 287 thyroid nodules from 256 subjects (64 men and 192 women) were finally included in the study. The accuracy of ACR-TIRADS categories TR5 and TR4/5 was 88.9% and 72.1%, respectively. This rate for ATA-2015 classes high suspicion and intermediate suspicion/high suspicion was 88.9% and 82.6%, respectively. For K-TIRADS classes 5 and 4/5, the diagnostic accuracy was 89.6% and 82.9%, respectively. Significant direct associations were found between malignancy and punctate echogenic foci (odds ratio [OR] = 6.46), hypoechogenicity (OR = 6.39), ill-defined margin (OR = 4.38), and irregular margin (OR = 7.33).

Conclusion

The differences in the strength of the three guidelines in the prediction of the malignancy should be considered by clinicians and radiologists in the management of thyroid nodules smaller than 10 mm.

Correlation Between Ultrasound and Cytological Findings of Patients With Suspicious Thyroid Nodules: The King Hamad University Hospital Experience

Background Thyroid nodules are a common presentation in otolaryngology-head and neck clinics. The detection of thyroid nodules has increased significantly with the advancements in radiological technology such as computed tomography and ultrasound (US). The present study aims to improve the clinical practice and management of thyroid disorders by establishing correlations between US and cytological findings in the diagnosis of thyroid nodules. Methodology A retrospective cohort study was conducted at the King Hamad University Hospital (KHUH), Bahrain. A total of 189 cases met the study criteria. Pathological records for thyroid nodule fine needle aspiration (FNA) cytology and US features of sampled nodules from the patients were obtained. The cytological results were categorized into the Bethesda grading system, while the US features were organized into internationally accepted features using the Thyroid Imaging Reporting and Data System (TIRADS). Results The radiologic characteristics from US showed positive features largely for the composition (76.2%) and vascularity (59.3%). Very few showed echogenicity (6.9%). Most records indicated negatively for the shape (94.7%), margins (76.2%), echogenicity (63.5%), or echogenic foci (66.1%). Of the 47 cases in TIRADS 1 and 2, only two were found to be Bethesda 4 classification, showing that most of these nodules were benign. Among those with TIRADS 3 on US, 85% turned were benign (Bethesda 2), two of the remaining six were grade 3, and the other four were suspiciously malignant. Of the 100 cases in TIRADS 4 and 5, 63% were of Bethesda grade 2, and therefore, benign, 14% were mildly suspicious, and only 23% were in Bethesda grades 4-6. A significant positive correlation was noted between the TIRADS and Bethesda scores (r = 0.338, p ≤ 0.001). Conclusions If the thyroid nodules are classified properly by US using the TIRADS system, the probability of a nodule being malignant can be established with a certain level of confidence. The appropriate management of the nodule can be initiated avoiding unwarranted FNA procedures.

Comparative Study of ACR TI-RADS and ATA 2015 for Ultrasound Risk Stratification of Thyroid Nodules

OBJECTIVE

To study the adoption rate of the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) scoring system over a 3-year period in a community setting and compare its performance with that of the American Thyroid Association 2015 (ATA 2015) ultrasound risk scoring system.

STUDY DESIGN

Case series with prospective data collection and retrospective chart review.

SETTING

Large community-based practice with multiple satellite offices and a dedicated thyroid ultrasound clinic.

METHODS

All patients referred to the thyroid clinic between January 2018 and December 2020 for ultrasound-guided fine-needle biopsy were assigned an ATA 2015 risk score in a prospective manner immediately prior to biopsy. ACR TI-RADS scores were recorded through retrospective chart review of the radiologist report. Performance of the 2 systems was compared with cytology as the gold standard.

RESULTS

A total of 949 nodules underwent biopsy, of which 236 had available data for both scoring systems. There was a 33.8% increase in adoption of the ACR TI-RADS over the 3-year study period. The ATA 2015 guidelines yielded sensitivity and specificity of 81.6% and 54.5%, respectively, as opposed to 73.7% and 27.0% for the ACR TI-RADS.

CONCLUSION

In our community, there has been a gradual increase in adoption of the ACR TI-RADS, although the ATA 2015 risk scoring system has performed better.

Efficacy of Differential Diagnosis of Thyroid Nodules by Shear Wave Elastography-the Stiffness Map

BACKGROUND

Fine needle aspiration is the gold standard for differential diagnosis of thyroid nodules; however, the malignancy rate for indeterminate cytology is 20% to 50%.

OBJECTIVE

We evaluated the efficacy of shear wave elastography added to ultrasonography for differential diagnosis of thyroid nodules.

METHODS

We retrospectively reviewed the medical records of 258 consecutive patients. Thyroid nodules were divided into 4 categories according to maximum elasticity (EMax) and nodule depth/width (D/W) ratio: Category 1 (EMax ≥ 42.6 kPa; D/W < 0.9); Category 2 (EMax < 42.6 kPa; D/W < 0.9); Category 3 (EMax ≥ 42.6 kPa; D/W ≥ 0.9); and Category 4 (EMax < 42.6 kPa; D/W ≥ 0.9). The EMax cutoff value was set using receiver operating characteristic (ROC) curve analysis to predict nodular hyperplasia (NH) vs follicular neoplasm (FN). Cutoff value for nodule D/W ratio was set using ROC curve analysis for malignancy.

RESULTS

NH was the most prevalent pathology group in Category 1, FN in Category 2, and papillary thyroid carcinoma in Category 3. Category 3 demonstrated the highest rate of malignancy (81.8%) and had 55.4% sensitivity and 90% specificity for predicting malignancy. When assessing the benign pathology of NH in follicular patterned lesion, Category 1 demonstrated the highest NH prevalence of 88.9% (34/37) and had 73.9% sensitivity and 85.0% specificity.

CONCLUSION

The performance for malignancy was highest in Category 3 and predictive ability for benign pathology of NH in follicular lesion was highest in Category 1. The information of EMax and nodule D/W ratio was useful to predict the pathology of thyroid nodules.

Korean Thyroid Imaging Reporting and Data System: Current Status, Challenges, and Future Perspectives

The Korean Thyroid Imaging Reporting and Data System (K-TIRADS) is an ultrasound-based risk stratification system for thyroid nodules that has been widely applied for the diagnosis and management of thyroid nodules since 2016. This review article provides an overview of the use of the K-TIRADS compared with other risk stratification systems. Moreover, this review describes the challenges in the clinical application of the K-TIRADS, as well as future development directions toward the personalized management of patients with thyroid nodules.

Usability of EU-TIRADS in the Diagnostics of Hürthle Cell Thyroid Nodules with Equivocal Cytology

The aim of this study was to compare the diagnostic effectiveness of EU-TIRADS in two groups of nodules with equivocal cytology (categories III-V of Bethesda system), with and without Hürthle cells (HC and non-HC). The study included 162 HC and 378 non-HC nodules with determined histopathological diagnosis (17.9% and 15.6% cancers). In both groups calculated and expected risk of malignancy (RoM) for high, intermediate and benign risk categories of EU-TIRADS were concordant. RoM for low risk category was higher than expected in both groups, but especially in HC (HC: 13.9%, non-HC: 7.0%, expected: 2-4%). The majority of cancers in HC of that category were follicular thyroid carcinomas (FTC) and Hürthle cell thyroid carcinoma (HTC) (60.0% vs. non-HC: 16.7%). The diagnostic efficacy of EU-TIRADS was lower in HC (the area under the receiver operating characteristics curve (AUC): 0.621, sensitivity (SEN): 44.8%, specificity (SPC): 78.9% for high risk threshold) than in non-HC (AUC: 0.711, SEN: 61.0%, SPC: 77.7%). AUC was the highest for category V (AUC > 0.8, both groups) and the lowest for category IV (inefficient, both group). If intermediate risk category was interpreted as an indication for surgery, 25% of cancers from category III and 21.4% from category IV would not be treated in the HC group (0.0% and 7.4% from non-HC group, respectively). EU-TIRADS does not aid making clinical decisions in patients with cytologically equivocal HC nodules, particularly those classified into category IV of Bethesda System for Reporting Thyroid Cytopathology (BSRTC).

Diagnostic Value of Six Thyroid Imaging Reporting and Data Systems (TIRADS) in Cytologically Equivocal Thyroid Nodules

The aim was to compare the usefulness of selected thyroid sonographic risk-stratification systems in the diagnostics of nodules with indeterminate/suspicious cytology or unequivocal cytology in a population with a history of iodine deficiency. The diagnostic efficacy of ACR-TIRADS (the American College of Radiology Thyroid Imaging Reporting and Data Systems), EU-TIRADS (European Thyroid Association TIRADS), Korean-TIRADS, Kwak-TIRADS, AACE/ACE-AME-guidelines (American Association of Clinical Endocrinologists/ American College of Endocrinology-Associazione Medici Endocrinologi guidelines) and ATA-guidelines (American Thyroid Association guidelines) was evaluated in 1000 nodules with determined histopathological diagnosis: 329 FLUS/AUS (10.6% cancers), 167 SFN/SHT (11.6% cancers), 44 SM (77.3% cancers), 298 BL (benign lesions), 162 MN (malignant neoplasms). The percentage of PTC (papillary thyroid carcinoma) among cancers was higher in Bethesda MN (86.4%) and SM (suspicion of malignancy) nodules (91.2%) than in FLUS/AUS (57.1%, p < 0.005) and SFN/SHT (suspicion of follicular neoplasm/ suspicion of Hürthle cell tumor) nodules (36.8%, p < 0.001). TIRADS efficacy was higher for MN (AUC: 0.827-0.874) and SM nodules (AUC: 0.775-0.851) than for FLUS/AUS (AUC: 0.655-0.701) or SFN/SHT nodules (AUC: 0.593-0.621). FLUS/AUS (follicular lesion of undetermined significance/ atypia of undetermined significance) nodules assigned to a high risk TIRADS category had malignancy risk of 25%. In the SFN/SHT subgroup none TIRADS category changed nodule's malignancy risk. EU-TIRADS and AACE/ACE-AME-guidelines would allow diagnosing the highest number of PTC, FTC (follicular thyroid carcinoma), HTC (Hürthle cell carcinoma), MTC (medullary thyroid carcinoma). The highest OR value was for Kwak-TIRADS (12.6) and Korean-TIRADS (12.0). Conclusions: TIRADS efficacy depends on the incidence of PTC among cancers. All evaluated TIRADS facilitate the selection of FLUS/AUS nodules for the surgical treatment but these systems are not efficient in the management of SFN/SHT nodules.