Ultrasound malignancy risk stratification of thyroid nodules based on the degree of hypoechogenicity and echotexture

Malignancy risk stratification and subcategorization of K-TIRADS intermediate suspicion thyroid nodules: a retrospective multicenter study

PURPOSE

This study aimed to develop the ultrasonography (US) criteria for risk stratification of the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) 4 nodules, and to evaluate the diagnostic yield of a modified biopsy criterion in a multicenter cohort.

METHODS

In total, 1,542 K-TIRADS 4 nodules (≥1 cm) were included in the study. US criteria for the subcategorization of K-TIRADS 4 nodules were developed based on high-risk US features. The diagnostic yields and false referral rates of biopsy criterion 1 (size cut-off of 1 cm), biopsy criterion 2 (size cut-off of 1.5 cm), and modified biopsy criterion 3 (size cut-off of 1 cm for K-TIRADS 4B and 1.5 cm for K-TIRADS 4A) were evaluated.

RESULTS

The five high-risk US features (solid composition, marked hypoechogenicity, macrocalcification, punctate echogenic foci, and irregular margin) independently increased the malignancy risk of the K-TIRADS 4 nodules (P<0.001). The K-TIRADS 4 nodules could be subcategorized into higher- and lower-risk subcategories according to the number of high-risk US features: K-TIRADS 4B (≥2 US features) and K-TIRADS 4A (≤1 US feature). The modified biopsy criterion increased the diagnostic yield by 7.8% compared with criterion 2 and reduced the false referral rate by 15.3% compared with criterion 1 (P<0.001).

CONCLUSION

The K-TIRADS 4 nodules were subcategorized as K-TIRADS 4B and K-TIRADS 4A based on high-risk US features. The modified biopsy criterion 3 showed a similar diagnostic yield and reduced false referral rate compared to criterion 1.

Markedly hypoechoic: a new definition improves the diagnostic performance of thyroid ultrasound

OBJECTIVES

To determine the contribution of a modified definition of markedly hypoechoic in the differential diagnosis of thyroid nodules.

METHODS

A total of 1031 thyroid nodules were included in this retrospective multicenter study. All of the nodules were examined with US before surgery. The US features of the nodules were evaluated, in particular, the classical markedly hypoechoic and modified markedly hypoechoic (decreased or similar echogenicity relative to the adjacent strap muscles). The sensitivity, specificity, and AUC of classical/modified markedly hypoechoic and the corresponding ACR-TIRADS, EU-TIRADS, and C-TIRADS categories were calculated and compared. The inter- and intraobserver variability in the evaluation of the main US features of the nodules was assessed.

RESULTS

There were 264 malignant nodules and 767 benign nodules. Compared with classical markedly hypoechoic as a diagnostic criterion for malignancy, using modified markedly hypoechoic as the criterion resulted in a significant increase in sensitivity (28.03% vs. 63.26%) and AUC (0.598 vs. 0.741), despite a significant decrease in specificity (91.53% vs. 84.88%) (p < 0.001 for all). Compared to the AUC of the C-TIRADS with the classical markedly hypoechoic, the AUC of the C-TIRADS with the modified markedly hypoechoic increased from 0.878 to 0.888 (p = 0.01); however, the AUCs of the ACR-TIRADS and EU-TIRADS did not change significantly (p > 0.05 for both). There was substantial interobserver agreement (κ = 0.624) and perfect intraobserver agreement (κ = 0.828) for the modified markedly hypoechoic.

CONCLUSION

The modified definition of markedly hypoechoic resulted in a significantly improved diagnostic efficacy in determining malignant thyroid nodules and may improve the diagnostic performance of the C-TIRADS.

CLINICAL RELEVANCE STATEMENT

Our study found that, compared with the original definition, modified markedly hypoechoic significantly improved the diagnostic performance in differentiating malignant from benign thyroid nodules and the predictive efficacy of the risk stratification systems.

KEY POINTS

• Compared with the classical markedly hypoechoic as a diagnostic criterion for malignancy, the modified markedly hypoechoic resulted in a significant increase in sensitivity and AUC. • The C-TIRADS with the modified markedly hypoechoic achieved higher AUC and specificity than that with the classical markedly hypoechoic (p = 0.01 and  < 0.001, respectively).

International Expert Consensus on US Lexicon for Thyroid Nodules

Multiple US-based systems for risk stratification of thyroid nodules are in use worldwide. Unfortunately, the malignancy probability assigned to a nodule varies, and terms and definitions are not consistent, leading to confusion and making it challenging to compare study results and craft revisions. Consistent application of these systems is further hampered by interobserver variability in identifying the sonographic features on which they are founded. In 2018, an international multidisciplinary group of 19 physicians with expertise in thyroid sonography (termed the International Thyroid Nodule Ultrasound Working Group) was convened with the goal of developing an international system, tentatively called the International Thyroid Imaging Reporting and Data System, or I-TIRADS, in two phases: (phase I) creation of a lexicon and atlas of US descriptors of thyroid nodules and (phase II) development of a system that estimates the malignancy risk of a thyroid nodule. This article presents the methods and results of phase I. The purpose herein is to show what has been accomplished thus far, as well as generate interest in and support for this effort in the global thyroid community.

Does a three-degree hypoechogenicity grading improve ultrasound thyroid nodule risk stratification and affect the TI-RADS 4 category? A retrospective observational study

Objective

The aim of this study was to determine whether classifying hypoechogenicity in three degrees (mild, moderate, and marked) could improve the distinction between benign and malignant nodules and whether such an approach could influence Category 4 of the Thyroid Imaging Reporting and Data System (TI-RADS).

Materials and methods

In total, 2,574 nodules submitted to fine needle aspiration, classified by the Bethesda System, were retrospectively assessed. Further, a subanalysis considering solid nodules without any additional suspicious findings (n = 565) was performed with the purpose of evaluating mainly TI-RADS 4 nodules.

Results

Mild hypoechogenicity was significantly less related to malignancy (odds ratio [OR]: 1.409; CI: 1.086-1.829; p = 0.01), compared to moderate (OR: 4.775; CI: 3.700-6.163; p < 0.001) and marked hypoechogenicity (OR: 8.540; CI: 6.355-11.445; p < 0.001). In addition, mild hypoechogenicity (20.7%) and iso-hyperechogenicity (20.5%) presented a similar rate in the malignant sample. Regarding the subanalysis, no significant association was found between mildly hypoechoic solid nodules and cancer.

Conclusion

Stratifying hypoechogenicity into three degrees influences the confidence in the assessment of the rate of malignancy, indicating that mild hypoechogenicity has a unique low-risk biological behavior that resembles iso-hyperechogenicity, but with minor malignant potential when compared to moderate and marked hypoechogenicity, with special influence on the TI-RADS 4 category.

Subcategorization of intermediate suspicion thyroid nodules based on suspicious ultrasonographic findings

PURPOSE

This study compared the malignancy risk of intermediate suspicion thyroid nodules according to the presence of suspicious ultrasonographic (US) findings.

METHODS

From January 2014 to December 2014, 299 consecutive intermediate suspicion thyroid nodules in 281 patients (mean age, 50.6±12.5 years) with final diagnoses were included in this study. Two radiologists retrospectively reviewed the US findings and subcategorized the intermediate suspicion category into nodules without suspicious findings and nodules with suspicious findings, including punctate echogenic foci, nonparallel orientation, or irregular margins. The malignancy rates were compared between the two subcategory groups.

RESULTS

Of the 299 intermediate suspicion thyroid nodules, 230 (76.9%) were subcategorized as nodules without suspicious findings and 69 (23.1%) as nodules with suspicious findings. The total malignancy rate was 33.4% (100/299) and the malignancy rate of nodules with suspicious findings was significantly higher than that of nodules without suspicious findings (47.8% vs. 29.1%, P=0.004). In nodules with suspicious findings, the most common suspicious finding was punctate echogenic foci (48/82, 58.5%) followed by nonparallel orientation (22/82, 26.8%) and irregular margins (12/82, 14.6%). Thirteen nodules had two suspicious findings simultaneously. A linearly increasing trend in the malignancy rate was observed according to the number of suspicious US findings (P for trend=0.001).

CONCLUSION

Intermediate suspicion thyroid nodules with suspicious findings showed a higher malignancy rate than those without suspicious findings. Further management guidelines for nodules with suspicious findings should differ from guidelines for nodules without suspicious findings, even in the same US category.

[Clinical Application of the 2021 Korean Thyroid Imaging Reporting and Data System (K-TIRADS)]

In patients with thyroid nodules, ultrasonography (US) has been established as a primary diagnostic imaging method and is essential for treatment decision. The Korean Thyroid Imaging Reporting and Data System (K-TIRADS) is a pattern-based, US malignancy risk stratification system that can easily diagnose nodules during real-time ultrasound examinations. The 2021 K-TIRADS clarified the US criteria for nodule classification and revised the size thresholds for nodule biopsy, thereby reducing unnecessary biopsies for benign nodules while maintaining the appropriate sensitivity to detect malignant tumors in patients without feature of high risk thyroid cancer. Thyroid radiology practice has an important clinical role in the diagnosis and non-surgical treatment of patients with thyroid nodules, and should be performed according to standard practice guidelines for proper and effective clinical care.

Malignancy risk stratification of thyroid nodules according to echotexture and degree of hypoechogenicity: a retrospective multicenter validation study

Various risk stratification systems show discrepancies in the ultrasound lexicon of nodule echotexture and hypoechogenicity. This study aimed to determine the malignancy risk of thyroid nodules according to their echotexture and degree of hypoechogenicity. From June to September 2015, we retrospectively evaluated 5601 thyroid nodules with final diagnoses from 26 institutions. Nodules were stratified according to the echotexture (homogeneous vs. heterogeneous) and degree of hypoechogenicity (mild, moderate, or marked). We calculated the malignancy risk according to composition and suspicious features. Heterogeneous hypoechoic nodules showed a significantly higher malignancy risk than heterogeneous isoechoic nodules (P ≤ 0.017), except in partially cystic nodules. Malignancy risks were not significantly different between homogeneous versus heterogeneous nodules in both hypoechoic (P ≥ 0.086) and iso- hyperechoic nodules (P ≥ 0.05). Heterogeneous iso-hyperechoic nodules without suspicious features showed a low malignancy risk. The malignancy risks of markedly and moderately hypoechoic nodules were not significantly different in all subgroups (P ≥ 0.48). Marked or moderately hypoechoic nodules showed a significantly higher risk than mild hypoechoic (P ≤ 0.016) nodules. The predominant echogenicity effectively stratifies the malignancy risk of nodules with heterogeneous echotexture. The degree of hypoechogenicity could be stratified as mild versus moderate to marked hypoechogenicity.

Ultrasound-Guided Fine Needle Aspiration of Deep Thyroid Nodule: Is There a Correlation between the Nodule’s Depth and Nondiagnostic Results?

Objective

To evaluate whether thyroid nodule depth correlates with nondiagnostic results in ultrasound-guided fine needle aspiration cytopathology.

Background

Many factors correlate with nondiagnostic ultrasound-guided fine needle aspiration cytology (FNAC) results, including older age, macrocalcification, small-sized nodules, aspirin medication, and cystic portion in more than 50% of the thyroid nodules. However, there are few studies which have examined whether there is a relationship between the depth of nodules and the percentage of nondiagnostic results in cytology (Bethesda category I). We conducted this study in order to investigate if such a correlation exists.

Materials and Methods

FNAC was performed on 283 thyroid nodules between January 2019 and December 2020. Cytological analyses of the nodules were reviewed and sorted as nondiagnostic and diagnostic according to the Bethesda score. Patient files and ultra sound (US) scans were reviewed for clinical information (such as age, sex, and ethnic group) and sonographic features of nodules (such as depth, size, cystic portion, type of calcification, and echogenicity) and were compared between the nondiagnostic and diagnostic nodule results. The depth of a nodule was calculated as the shortest distance from the skin to the most superficial border of the nodule in the axial plane, using our medical center's computer program, which allows reviewing all saved shots of the US scan.

Results

Age, sex, and ethnicity were not significantly different between the nondiagnostic group and the diagnostic group (p > 0.05). Nodule diameter, cystic portion, calcification, and echogenicity were also not associated with the frequency of nondiagnostic results. The depth of nodules ≥9 mm was correlated with nondiagnostic US-guided FNA cytological results (OR = 2.55, p=0.018).

Conclusions

Deep thyroid nodules correlated with nondiagnostic US-guided FNA cytological results. Further studies are needed for optimizing the approach to deep thyroid nodules in order to improve the efficacy of FNA in deep thyroid nodules.

Subacute thyroiditis paranchime heterogeneity may mask thyroid nodules and higher EU-TIRADS scores

PURPOSE

Nonhomogenous and ill-defined hypoechoic areas are typical ultrasonographic features of subacute thyroiditis (SAT). Evaluating a thyroid nodule accurately in this heterogeneous paranchime may be troublesome. This study aims to compare thyroid nodules, their characteristics, and European Thyroid Imaging and Reporting Data System (EU-TIRADS) categories at the time of the diagnosis and in the remission of SAT.

METHODS

Ultrasonographic features of SAT and characteristics and EU-TIRADS categories of thyroid nodules in the initial and control ultrasonography (US) of 350 patients with SAT have been evaluated in this retrospective observational study. Fine needle aspiration biopsy (FNAB) results and postsurgical data, if performed, have been estimated.

RESULTS

A hundred patients (28.6%) with SAT had thyroid nodules at the time of the diagnosis, while 152 (43.4%) patients had a nodule in remission US (p < 0.001). The number of thyroid nodules was found to be higher in the control US as against the initial US (p = 0.001). EU-TIRADS scores of the nodules in the remission US were significantly higher than the scores at the time of the diagnosis (p < 0.001). FNAB was performed in 23% of nodules observed in the remission US, and the rate of thyroid carcinoma within them was 3.3%.

CONCLUSION

Thyroid nodules, malignancy suspected features, and EU-TIRADS categories of them may not be appropriately evaluated due to heterogenous paranchime of SAT. Performing a control US examination after resolution of hypoechoic areas may be beneficial to avoid missing clinically significant nodules with high EU-TIRADS scores.

Ultrasonography of the thyroid, parathyroids, and beyond

Background

Ultrasonography has become an essential tool for the evaluation and management of thyroid and parathyroid diseases. Its applications extend beyond neck endocrine conditions to a multitude of pathologies within the head and neck region.

Objectives

Our study aimed to: (1) provide a broad review of neck ultrasonography and key findings in neck endocrine diseases; (2) support skilled performance office-based diagnostic ultrasonography and its varied applications.

Materials and methods

A review of the current literature was supplemented with clinical examples of key ultrasonographic findings.

Results

Current applications and key findings of ultrasonography in the diagnosis and management of neck endocrine conditions are reviewed.

Conclusion

Ultrasonography is a fundamental component in the evaluation and management of neck endocrine diseases. The reader is encouraged to use this review to enhance office-based performance and application of ultrasonography.

Video online

The online version of this article contains 11 additional videos. They are provided to illustrate some of the dynamic aspects of US performance. The article and the videos are available online (10.1007/s00106-022-01162-0). The videos can be found in the article back matter as “Electronic Supplementary Material”.

Non-Marked Hypoechogenic Nodules: Multicenter Study on the Thyroid Malignancy Risk Stratification and Accuracy Based on TIRADS Systems Comparison

Background and Objectives: The aim of the study was to evaluate the predictive value of the ultrasound criterion “non-marked hypoechogenicity” for malignancy and to determine whether classification of these nodules as TIRADS 3 could improve the overall accuracy of consequently adjusted M-TIRADS score. Materials and Methods: A total of 767 patients with 795 thyroid nodules were subject to ultrasonography examination and ultrasound-guided fine needle aspiration biopsy. Nodules were classified by Kwak TIRADS and modified (M-TIRADS) categories 4A, 4B, and 5 according to number of suspicious US features (marked hypoechogenicity, microlobulated or irregular margins, microcalcifications, taller-than-wide shape, metastatic lymph nodes). Non-marked hypoechoic nodules were classified as TIRADS 3. Results: Thyroid nodules were classified as TIRADS 2, 3, 4A, 4B, and 5 in 14.5, 57.5, 14.2, 8.1, and 5.7%, respectively. Only histopathologic results (125 nodules underwent surgery) and highly specific cytology results (Bethesda II, VI) were accepted as a standard of reference, forming a sub-cohort of 562/795 nodules (70.7%). Malignancy was found in 7.7%. Overall, M-TIRADS showed sensitivity/specificity of 93.02/81.31%, and for PPV/NPV, these were 29.2/99.29%, respectively (OR—18.62). Irregular margins showed the highest sensitivity and specificity (75.68/93.74%, respectively). In TIRADS 3 category, 37.2% nodules were isoechoic, 6.6% hyperechoic, and 52.2% hypoechoic (there was no difference of malignancy risk in hypoechoic nodules between M-TIRADS and Kwak systems—0.9 vs. 0.8, respectively). Accuracy of M-TIRADS classification in this cohort was 78.26% vs. 48.11% for Kwak. Conclusions: The non-marked hypoechoic nodule pattern correlated with low risk of malignancy; classification of these nodules as TIRADS 3 significantly improved the predictive value and overall accuracy of the proposed M-TIRADS scoring with malignancy risk increase in TIRADS 4 categories by 20%; and no significant alteration of malignancy risk in TIRADS 3 could contribute to reducing overdiagnosis, obviating the need for FNA.

A Proposed Heterogeneous Ensemble Algorithm Model for Predicting Central Lymph Node Metastasis in Papillary Thyroid Cancer

Purpose

To develop a heterogeneous ensemble algorithm model to precisely predict central lymph node metastasis (CLNM), which can provide a reference value on controversial topics of performing prophylactic central lymph node dissection for patients with papillary thyroid cancer (PTC).

Methods

The study included patients with PTC who underwent an initial thyroid resection in a single-center medical institution between January 2014 and December 2018. A total of 18 variables, including clinical features and ultrasound (US) features, were used in the univariate analysis, multivariate analysis, and feature selection and were also used to develop a heterogeneous ensemble model based on five basic machine learning models, including extreme gradient boosting, k-nearest neighbors, random forest, gradient boosting, and AdaBoost. Moreover, a partial dependent plot was used to explain the heterogeneous ensemble model.

Results

The area under the receiver operating characteristic curve of the heterogeneous ensemble algorithm model was 0.67, which is significantly better than that of the basic machine models in predicting CLNM. All machine learning models performed better than US. Based on multivariate analysis and receiver operating characteristic curve analysis, age ≤33 years, tumor size ≥0.8 cm, US-suspected CLNM, and microcalcification were risk factors for CLNM, and anti-thyroid peroxidase antibody and serum thyroglobulin levels were favorable factors for CLNM.

Conclusion

The proposed heterogeneous ensemble algorithm model may be optimal tool to predict CLNM by integrating clinical and US features.

Can sonographic features of microcalcification predict thyroid nodule malignancy? a prospective observational study

Background

The aim of this study was to investigate the diagnostic accuracy of microcalcification, as well as its associated sonographic features, for prediction of thyroid nodule malignancy.

We prospectively assessed the patients with thyroid nodule, who underwent ultrasound-guided fine-needle aspiration during 2017–2020 in Babol, northern Iran. The ultrasonographic characteristics of the nodules, as well as their cytological results, were recorded. We used regression analysis to evaluate the relation between sonographic findings and nodule malignancy. A receiver operator characteristics (ROC) analysis was also used to estimate the ability of ultrasound to predict the characteristic features of malignancy, as estimated by the area under the curve (AUC).

Results

Overall, 1129 thyroid nodules were finally included in the study, of which 452 (40%) had microcalcification. A significant positive association was found between nodule malignancy and microcalcification in both univariate (OR=3.626, 95% CI 2.258–5.822) and multivariable regression analyses (OR=1.878, 95% CI 1.095–3.219). In the nodules with microcalcification, significant positive relations were seen between malignancy and hypoechogenicity (OR=3.833, 95% CI 1.032–14.238), >5 microcalcification number (OR=3.045, 95% CI 1.328–6.982), irregular margin (OR=3.341, 95% CI 1.078–10.352), and lobulated margin (OR=5.727, 95% CI 1.934–16.959). The ROC analysis indicated that AUC for hypoechogenicity, >5 microcalcification number, irregular margin, and lobulated margin were 60%, 62%, 55%, and 60%, respectively, in predicting malignant thyroid nodules.

Conclusion

The findings indicated that microcalcification can be a potential predictor of thyroid nodule malignancy. Also, the presence of irregular or lobulated margins, multiple intranodular microcalcification (>5 microcalcifications), and/or hypoechogenicity can improve the ability of microcalcification in distinguishing malignant from benign nodules.

A new prediction model for lateral cervical lymph node metastasis in patients with papillary thyroid carcinoma: Based on dual-energy CT

PURPOSE

The current study aimed to develop and validate a prediction model to estimate the independent risk factors for lateral cervical lymph node metastasis (LLNM) in papillary thyroid carcinoma (PTC) patients based on dual-energy computed tomography (DECT).

METHOD

This study retrospectively conducted 406 consecutive patients from July 2015 to June 2019 to form the derivation cohorts and performed internal validation. 101 consecutive patients from July 2019 to June 2020 were included to create the external validation cohort. Univariable and multivariable logistic regression analyses were used to evaluate independent risk factors for LLNM. A prediction model based on DECT parameters was built and presented on a nomogram. The internal and external validations were performed.

RESULTS

Iodine concentration (IC) in the arterial phase (OR 2.761, 95% CI 1.028-7.415, P 0.044), IC in venous phase (OR 3.820, 95% CI 1.430-10.209, P 0.008), located in the superior pole (OR 4.181, 95% CI 2.645-6.609, P 0.000), and extrathyroidal extension (OR 4.392, 95% CI 2.142-9.004, P 0.000) were independently associated with LLNM in the derivation cohort. These four predictors were incorporated into the nomogram. The model showed good discrimination in the derivation (AUC, 0.899), internal (AUC, 0.905), and external validation (AUC, 0.912) cohorts. The decision curve revealed that more advantages would be added using the nomogram to estimate LLNM, which implied that the lateral lymph node dissection was recommended.

CONCLUSIONS

DECT parameters could provide independent indicators of LLNM in PTC patients, and the nomogram based on them may be helpful in treatment decision-making.

Impact of the Hypoechogenicity Criteria on Thyroid Nodule Malignancy Risk Stratification Performance by Different TIRADS Systems

Simple Summary

This study is aimed at raising the question of the use of several TIRADS systems that stratify the risk of thyroid nodule malignancy. Approximately 5–20% of thyroid nodules are malignant, but most nodules are benign, and they are scored by FNA biopsy. One of the goals is to reduce the number of unnecessary FNA and the associated with-it possible complications for the patient and financial cost. Most TIRADS systems are based on the fact that one suspicious feature of a thyroid nodule classifies it as malignant, but there is a modified Kwak et al. system that is based on the count of malignant features. Therefore, this study is intended to estimate the specificity, sensitivity, and accuracy of the systems and, in the future, think about reducing the number of FNA biopsies. The result of this study can be important for all doctors who face thyroid changes, such as radiologists, ultrasonography specialists, and endocrinologists, those who must decide about the need for an FNA.

Abstract

Background: Various Thyroid Imaging and Reporting data systems (TIRADS) are used worldwide for risk stratification of thyroid nodules. Their sensitivity is high, while the specificity is suboptimal. The aim of the study was to compare several TIRADS systems and evaluate the effect of hypoechogenicity as a sign of risk of malignancy on the overall assessment of diagnostic accuracy. Methods: The prospective study includes 274 patients with 289 thyroid nodules to whom US and risk of malignancy were assessed according to four TIRADS systems—European (EU-TIRADS), Korean (K-TIRADS), TIRADS by American College of Radiology (ACR TIRADS), and modified Kwak et al. TIRADS (L-TIRADS) systems, in which mild hypoechogenicity is not included in malignancy risk suggestive signs. For all thyroid nodules, a fine needle aspiration (FNA) biopsy was performed and evaluated according to the Bethesda system. For all systems, diagnostic accuracy was calculated. Results: Assessing the echogenicity of the thyroid nodules: from 81 of isoechogenic nodules, 2 were malignant (2.1%), from 151 mild hypoechogenic, 18 (12%) were malignant, and from 48 marked hypoechogenic nodules, 16 (33%) were malignant. In 80 thyroid nodules, mild hypoechogenicity was the only sign of malignancy and none appeared malignant. Assessing various TIRADS systems on the same cohort, sensitivity, specificity, PPV, NPV, and accuracy, firstly for EU-TIRADS, they were 97.2%; 39.9%; 18.7%; 99.0%, and 73.3%, respectively; for K-TIRADS they were 97.2%; 46.6%; 20.6%; 99.2%, and 53.9%; for ACR-TIRADS they were 97.2%; 41.1%, 19.0%; 99.0%, and 48.0%, respectively; finally, for L-TIRADS they were 80.6%; 72.7%; 29.6%; 96.3%, and 73.3%. Conclusions: This comparative research has highlighted that applying different TIRADS systems can alter the number of necessary biopsies by re-categorization of the thyroid nodules. The main pattern that affected differences was inconsistent hypoechogenicity interpretation, giving the accuracy superiority to the systems that raise the malignancy risk with marked hypoechogenicity, at the same time with minor compensation for sensitivity.

Systematic review and meta-analysis of ultrasonic elastography in the diagnosis of benign and malignant thyroid nodules

Background

In recent years, ultrasound elastography (USE) has been the main diagnostic technique for benign and malignant thyroid nodules. However, it cannot display the blood flow signals of nodules with smaller diameters clearly, which decreases its diagnostic accuracy.

Methods

Chinese and English databases were searched using "ultrasonic elastography", "benign and malignant thyroid nodules", and "diagnose" as the search terms. RevMan 5.3 software was used for meta-analysis.

Results

A total of 11 randomized controlled trials (RCTs) were included. Eight articles analyzed clinical symptoms, and the heterogeneity test results were Chi² =7.46, df=7, I²=6%, and P=0.38; and Z=11.44, OR =14.58, 95% confidential interval (CI): 9.21-23.07, and P<0.01. The diagnostic efficacy of USE was analyzed in 8 articles, and the heterogeneity test results were Chi² =3.03, df=7, I²=0%, and P=0.88; and Z=6.33, OR =7.47, 95% CI: 4.01-13.93, and P<0.01. The pathological diagnosis results of randomized controlled trials were analyzed in 10 literatures, and the heterogeneity test results were Tau² =0.78, Chi² =20.97, df=9, I²=57%, and P=0.01; and Z=7.27, OR =14.67, 95% CI: 7.11-30.27, and P<0.01. After meta-analysis, the combined sensitivity was 72.26% (95% CI: 0.625-0.764) and the combined specificity was 95.35% (95% CI: 0.815-0.943). The area under the receiver operating characteristic curve (AUC) was 0.857.

Conclusions

This meta-analysis confirmed that USE shows high sensitivity and specificity in diagnosing benign and malignant thyroid nodules, which could reduce the false negative rate (FNR) and false positive rate (FPR), showing high clinical diagnostic value.

2021 Korean Thyroid Imaging Reporting and Data System and Imaging-Based Management of Thyroid Nodules: Korean Society of Thyroid Radiology Consensus Statement and Recommendations

Incidental thyroid nodules are commonly detected on ultrasonography (US). This has contributed to the rapidly rising incidence of low-risk papillary thyroid carcinoma over the last 20 years. The appropriate diagnosis and management of these patients is based on the risk factors related to the patients as well as the thyroid nodules. The Korean Society of Thyroid Radiology (KSThR) published consensus recommendations for US-based management of thyroid nodules in 2011 and revised them in 2016. These guidelines have been used as the standard guidelines in Korea. However, recent advances in the diagnosis and management of thyroid nodules have necessitated the revision of the original recommendations. The task force of the KSThR has revised the Korean Thyroid Imaging Reporting and Data System and recommendations for US lexicon, biopsy criteria, US criteria of extrathyroidal extension, optimal thyroid computed tomography protocol, and US follow-up of thyroid nodules before and after biopsy. The biopsy criteria were revised to reduce unnecessary biopsies for benign nodules while maintaining an appropriate sensitivity for the detection of malignant tumors in small (1-2 cm) thyroid nodules. The goal of these recommendations is to provide the optimal scientific evidence and expert opinion consensus regarding US-based diagnosis and management of thyroid nodules.

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.

Different sonographic features of peripheral thyroid nodule calcification and risk of malignancy: a prospective observational study

Purpose

To investigate the association of peripheral calcification, as well as its sonographic features, with thyroid nodule malignancy.

Material and methods

This study was prospectively conducted during 2015-2020 on patients diagnosed with thyroid nodule undergoing ultrasound-guided fine-needle aspiration in Shahid Beheshti teaching hospital or private offices in Babol, northern Iran. The ultrasonographic characteristics of the nodules, as well as the cytological findings, were recorded. Regression analysis was used to assess the relationship between sonographic results and malignancy. We also used receiver operator characteristics (ROC) analysis to estimate the ability of ultrasound to predict the characteristic features of malignancy, as estimated by the area under the curve (AUC).

Results

A total of 1857 thyroid nodules were finally included, of which 84 were peripherally calcified nodules. There was a significant positive association between the nodule malignancy and peripheral calcification (OR = 2.23, 95% CI: 1.13-4.35). In the nodules with peripheral calcification, significant positive associations were seen between malignancy and lobulated margin (OR = 3.85, 95% CI: 1.02-14.54) and solid composition (OR = 4.05, 95% CI: 0.99-16.53). The ROC analysis indicated that AUC for lobulated margin and solid composition was 63.8% and 66.5%, respectively, in predicting malignant thyroid nodules.

Conclusion

The findings showed that peripheral calcification on sonography can be a potential indicator of malignant thyroid nodules. Also, the presence of lobulated margin and/or solid composition, besides peripheral calcification, can be helpful in better distinguishing malignant from benign 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.

Diagnostic Value of Sonographic Features in Distinguishing Malignant Partially Cystic Thyroid Nodules: A Systematic Review and Meta-Analysis

Ultrasonography (US) is one of the most important methods for the management of thyroid nodules, which can be classified as solid, partially cystic, or cystic by composition. The various Thyroid Imaging Reporting and Data System classifications pay more attention to solid nodules and have reported pertinent US features associated with malignancy. However, the likelihood of malignancy of partially cystic thyroid nodules (PCTNs) is 3.3-17.6%, and few studies have systematically discussed the value of US in differentiating such entities. Therefore, we deemed it necessary to perform a systematic evaluation of US features in recognizing malignant PCTNs. Our systematic review and meta-analysis aimed to assess the value of US features in predicting malignant PCTNs. We searched the PubMed/MEDLINE, Web of Science, and Cochrane Library databases to find studies that researched US features of PCTNs and that were published before June 2020. Review Manager 5.3 was used to summarize suspicious US features and calculate the sensitivity, specificity, and likelihood ratios. MetaDiSc 1.4 was used to estimate receiver operating characteristic curves and calculate areas under the curves (AUCs). Our review included eight studies with a total of 2,004 PCTNs. Seven features were considered to be associated with malignancy. High specificity (>0.9) was found in nodules with a taller-than-wide shape, those that were spiculated/microlobulated or with an ill-defined margin, those with microcalcification, and a non-smooth rim. Among US features, eccentric configuration, microcalcification, and marked or mild hypoechogenicity were more reliable in predicting malignancy (AUC: 0.9592, 0.8504, and 0.8092, respectively). After meta-analysis, we recommend combining PCTN US features including an eccentric internal solid portion, marked or mild hypoechogenicity, and presence of microcalcification to better identify malignant nodules. More studies are needed to explore and improve the diagnostic value of US in PCTNs.

Diagnostic performance of the modified Korean Thyroid Imaging Reporting and Data System for thyroid malignancy according to nodule size: a comparison with five society guidelines

Purpose

The aim of this study was to evaluate the diagnostic performance of the modified Korean Thyroid Imaging Reporting and Data System (K-TIRADS) compared with five society risk stratification systems (RSSs) according to nodule size.

Methods

In total, 3,826 consecutive thyroid nodules (≥1 cm) with final diagnoses in 3,088 patients were classified according to five RSSs. The K-TIRADS was modified by raising the biopsy size threshold for low-suspicion nodules and subcategorizing intermediate-suspicion nodules. We assessed the performance of the RSSs as triage tests and their diagnostic accuracy according to nodule size (with a threshold of 2 cm).

Results

Of all nodules, 3,277 (85.7%) were benign and 549 (14.3%) were malignant. In small thyroid nodules (≤2 cm), the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) had the highest reduction rate of unnecessary biopsies (76.3%) and the lowest sensitivity (76.1%). The modified K-TIRADS had the second highest reduction rate of unnecessary biopsies (67.6%) and sensitivity (86.6%). The modified K-TIRADS and ACR TI-RADS had the highest diagnostic odds ratios (P=0.165) and the highest areas under the curve (P=0.315). In large nodules (>2 cm), the sensitivity of the ACR TI-RADS for malignancy was significantly lower (88.8%) than the sensitivities of the modified K-TIRADS and other RSSs, which were very high (98.7%-99.3%) (P<0.001).

Conclusion

The modified K-TIRADS allows a large proportion of unnecessary biopsies to be avoided, while maintaining high sensitivity and diagnostic accuracy for small malignant tumors and very high sensitivity for large malignant tumors.

Imaging, biopsy and non-surgical treatment of thyroid lesions: where are we at?

KEY POINTS

• Ultrasound is the prevalent modality for assessment of the thyroid and biopsy guidance of lesions. • The various TI-RADS classifications provide scoring systems which help indicate the likelihood of malignancy. • Ongoing research helps to improve the characterisation of nodules, biopsy techniques and non-surgical treatment methods.