Primary Imaging Test and Appropriate Biopsy Methods for Thyroid Nodules: Guidelines by Korean Society of Radiology and National Evidence-Based Healthcare Collaborating Agency

Canadian Association of Radiologists Head and Neck Imaging Referral Guideline

The Canadian Association of Radiologists (CAR) Head and Neck Expert Panel consists of radiologists, a laryngologist and laryngeal surgeon, a patient advisor, and an epidemiologist/guideline methodologist. After developing a list of 11 clinical/diagnostic scenarios, a systematic rapid scoping review was undertaken to identify systematically produced referral guidelines that provide recommendations for one or more of these clinical/diagnostic scenarios. Recommendations from 17 guidelines and contextualization criteria in the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) for guidelines framework were used to develop 26 recommendation statements across the 11 scenarios. This guideline presents the methods of development and the referral recommendations for sinus disease, tinnitus, thyroid and parathyroid disease, neck mass of unknown origin, acute sialadenitis, chronic salivary conditions, and temporomandibular joint dysfunction.

Cancer rates and characteristics of thyroid nodules with macrocalcification

AIMS

The aim of this study was to determine the malignant potential of thyroid nodules with macrocalcifications and to evaluate the role of other sonographic findings in the diagnosis of malignancy in thyroid nodules besides macrocalcifications.

METHODS

The findings of 8250 patients who applied to our outpatient clinic and underwent thyroid ultrasonography(US) between 2008 and 2021 were retrospectively reviewed. We included a total of 296 patients with 296 macrocalcified nodules (macrocalcification group) and an age- and sex matched group of 300 patients (control group) with the cytopathologic and/or histopathologic data of fine-needle aspiration biopsy (FNAB) of thyroid nodules without calcification. Demographic characteristics of these patients, US characteristics of the nodules, and thyroid function tests were recorded. Cytopathological data of FNAB were classified according to BETHESDA.

RESULTS

The malignancy rate was 14.2% (42/296) in the macrocalcification group and 5.3% (16/300) in the control group (p < 0.001). There was no significant relationship between interrupted peripheral calcification and malignancy. Hypoechoic or markedly hypoechoic appearance, irregular border, solid structure, presence of accompanying pathological lymphadenopathy on sonographic examination and upper and middle zone localization were other sonographic features that increased the risk of malignancy of a nodule. The presence of autoimmunity was not found to be associated with the risk of malignancy. TSH and calcitonin levels of malignant nodules were higher than benign nodules. There was no significant difference between gender and malignancy. In the univariate analysis, it was found that the presence of macrocalcification increased the risk of malignancy 2.935 times. (OR:2.935, p < 0.001.95% CI for OR 1.611-5.349) In addition, being younger, being in the high TIRADS category, and being in the upper and middle zones were factors that increased the risk of malignancy. Gender, TSH level, nodule volume and structure were not associated with malignancy. However, after multivariate analysis, factors that significantly increased the risk of malignancy were younger age, higher TIRADS category, and nodule localization.

CONCLUSION

In our study, the malignancy rate was higher in the macrocalcification group than in the control group. However, no correlation was found after multivariate analysis. In the multivariate analysis, younger age, higher TIRADS category, and nodules located in the upper and middle zone were other factors associated with malignancy. There was no association between peripheral interrupted calcification and malignancy risk.

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.

A comparative analysis of core needle biopsy and repeat fine needle aspiration in patients with inconclusive initial cytology of thyroid nodules

Purpose

To assess and compare the effectiveness of ultrasound-guided core needle biopsy (CNB) in comparison to repeat fine-needle aspiration(rFNA) for thyroid nodules that yield inconclusive results following the initial fine-needle aspiration (FNA).

Methods

A cohort of 471 patients who received an inconclusive cytological diagnosis following the initial FNA were included in this study. These patients subsequently underwent either CNB (n=242) or rFNA (n=229). The inconclusive FNA results encompassed categories I, III, and IV of The Bethesda System for Reporting Thyroid Cytopathology(TBSRTC), as well as the ultrasound images indicating malignancy despite FNA results falling under TBSRTC category II. This study assessed the sampling satisfaction rate, diagnostic efficacy, and complications associated with CNB compared to rFNA. Additionally, the impact of repeat puncture time and nodule size on diagnostic efficacy was analyzed.

Results

Following repeat punctures, the satisfaction rate of the CNB sampling was found to be significantly higher than that of rFNA (83.9% vs 66.8%). The diagnostic rate in the CNB group was significantly greater compared to that of the rFNA group (70.7% vs 35.8%). In patients with nodule maximum diameters ranging from 5 mm to 20 mm, the diagnostic accuracy was significantly higher in the CNB group compared to that in the rFNA group. In patients with intervals less than 90 days, between 90 days and one year, the diagnostic rate in the CNB group was found to be higher compared to that in the rFNA group. In CNB, not immediately adjacent to the capsule was a risk factor for nodular puncture bleeding (37.0% vs 22.7%.).

Conclusion

CNB demonstrated higher rates of satisfaction and diagnosis compared to the rFNA. The diagnostic effectiveness of CNB was not influenced by the time interval or the size of the thyroid nodule. Therefore, in cases where the initial FNA diagnosis of thyroid nodules is inconclusive, CNB should be considered as a viable option for re-puncture.

[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.

Effectiveness of High-intensity Focused Ultrasound (HIFU) Therapy of Solid and Complex Benign Thyroid Nodules - A Long-term Follow up Two-center Study

PURPOSE

To investigate the effectiveness of high-intensity focused ultrasound (HIFU) of solid and complex benign thyroid nodules.

METHODS

Fifty-eight patients with benign thyroid nodules were treated with HIFU at two centers from 2014-2019. The device, EchoPulse (Teraclion, Malakoff, France), heats the nodes to 80-90 °C. Nodal volumes were measured by ultrasound at regular intervals before and up to 12 months after therapy. In a retrospective long-term two-center study, average volume reductions in relation to baseline volume were statistically analyzed by the Wilcoxon signed-rank test. Side effects were documented.

RESULTS

In solid nodules, the average percent volume reductions at the 3, 6, 9, and 12-months follow-up were 49.98%, 46.40%, 65.77%, and 63.88%, respectively. The results were significant with p<0.05 in the Wilcoxon signed-rank test at the 3, 6, and 9-months follow-up. In complex nodules, the average percent volume reduction was 35.2% at 3 months, 36.89% at 6 months, and 63.64% at twelve months follow up. The results were significant with p<0.05 in the Wilcoxon signed-rank test at the 3- and 6-months follow-up. The complication rate was 5.2%. All complications occurred in patients with solid nodules.

CONCLUSION

The study showed that HIFU is an effective treatment method for both solid and complex nodules. The complication rate is relatively high at 5.2%. No long-term complications occurred. The solid nodules responded better to HIFU than complex nodules.

High intensity focused ultrasound in the therapy of benign thyroid nodules-first German bicentric study with long-term follow-up

PURPOSE

The study evaluated high-intensity-focused ultrasound (HIFU) for benign thyroid nodules in terms of efficiency, complication rate, influence of preablative nodule size, parameters influencing the therapeutic success and hormonal-thyroid-function.

METHODS

Seventy-two patients with 75 nodules were treated with HIFU at 2 centers from 2014-2019. Median nodule volume was 4.4 ml (range 0.33-53). The therapeutic ultrasound probe (EchoPulse THC900888-H) generated 80-90 °C in the target tissue with 87.6-320.3 J per sonication. Nodal volume was measured at baseline and over 12 months after therapy in a retrospective bicentric-study with long-term follow-up. Hormonal-thyroid function (TSH, T3, T4) was measured before and after ablation. Complications were assessed.

RESULTS

Significant volume reduction (p < 0.05 Wilcoxon-signed-rank test) of thyroid nodules was 38.98% at 3 months, 37.32% at 6 months, 61.54% at 9 months and 60.66% at 12 months. Volume reduction of nodules <3 ml did not differ significantly from nodules >3 ml (p > 0.05 Mann-Whitney test). At 3 months solid nodules had a significant volume reduction of 52.08%, complex nodules of 32.57%, nodules treated under regional anesthesia of 33.07% and under general anesthesia of 49.47%. Hormonal-thyroid function was not influenced significantly by HIFU therapy (p > 0.05 Wilcoxon-signed-rank test). Complication rate was 3.8%. No long-term complications occurred.

CONCLUSION

Significant volume reduction of thyroid nodules up to 12 months after HIFU was shown. All complications were reversible. Therapy was more efficient in solid than complex nodules and in nodules treated under general anesthesia than with regional anesthesia. Hormonal-thyroid-function was not affected.

TRIAL REGISTRAFTION NUMBER

2020-1728-evBO. Date of registration: 16.06.2020. Agency: Ethik-Kommission bei der Landesäztekammer Hessen.

Anxiety and quality of life among papillary thyroid cancer patients awaiting final pathology results after surgery

PURPOSE

There is a lack of research on short-term mental health and health-related quality of life (HRQoL) in thyroid cancer patients. This study aimed to assess the short-term anxiety level and HRQoL of patients during the early postoperative period while awaiting pathology results, and to explore the important factors associated with state anxiety.

METHODS

In this single-center cross-sectional study, 349 patients with papillary thyroid cancer were included. Anxiety and HRQoL were measured using the State-Trait Anxiety Inventory (STAI) and the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC-QLQ-C30), respectively.

RESULTS

In general, papillary thyroid cancer patients reported good quality of life with a mean global quality of life score of 75.69 ± 20.66 (on a scale of 0-100, where 100 means the best). There was no significant difference in HRQoL between the two groups, except regarding social functioning (p = 0.027). The anxiety levels of the two groups were similar; however, the state anxiety score (42.17 ± 12.52) was significantly higher than the trait anxiety score (40.69 ± 11.18) among patients in the non-FNA group (p = 0.023). Dyspnea, insomnia, QL, and trait anxiety were independent factors that affected state anxiety.

CONCLUSION

Patients with papillary thyroid cancer had good postoperative HRQoL and a significantly higher than usual level of state anxiety while awaiting pathology results. Symptoms of dyspnea and insomnia, global quality of life, and trait anxiety are important factors associated with state anxiety. Preoperative FNA results may moderate the change in anxiety level. These findings may help clinicians provide psychological support.

Validation of Ultrasound Risk Stratification Systems for Cervical Lymph Node Metastasis in Patients with Thyroid Cancer

Simple Summary

Ultrasound (US) malignancy risk stratification systems (RSS) for cervical lymph nodes (LNs) have not been fully established in patients with thyroid cancer. In this study, we assessed the malignancy risks of each US feature and risk category from the Korean Society of Thyroid Radiology (KSThR) and the European Thyroid Association (ETA). Both systems effectively classified malignancy risks; however, 15.1% of LNs were unclassifiable in ETA RSS. Suspicious US features of hyperechogenicity, cystic change, echogenic foci, and abnormal vascularity were independently associated with metastasis. When the primary tumor characteristics were assessed, tumor multiplicity was associated with metastasis in the indeterminate LN group. We refined this system and proposed an RSS based on the KSThR system for cervical LNs in patients with thyroid cancer.

Abstract

A malignancy risk stratification system (RSS) for cervical lymph nodes (LNs) has not been fully established. This study aimed to validate the current RSS for the diagnosis of cervical LN metastasis in thyroid cancer. In total, 346 LNs from 282 consecutive patients between December 2006 and June 2015 were included. We determined the malignancy risk of each ultrasound (US) feature and performed univariable and multivariable logistic regression analyses. Each risk category from the Korean Society of Thyroid Radiology (KSThR) and the European Thyroid Association (ETA) was applied to calculate malignancy risks. The effects of size, number of suspicious features, and primary tumor characteristics were analyzed to refine the current RSS. Suspicious features including echogenic foci, cystic change, hyperechogenicity, and abnormal vascularity were independently predictive of malignancy (p ≤ 0.045). The malignancy risks of probably benign, indeterminate, and suspicious categories were 2.2–2.5%, 26.8–29.0%, and 85.8–87.4%, respectively, according to the KSThR and ETA criteria. According to the ETA criteria, 15.1% of LNs were unclassifiable. In indeterminate LNs, multiplicity of the primary tumor was significantly associated with malignancy (odds ratio, 6.53; p = 0.004). We refined the KSThR system and proposed a US RSS for LNs in patients with thyroid cancer.

Comparison of Core Needle Biopsy and Repeat Fine-Needle Aspiration in Avoiding Diagnostic Surgery for Thyroid Nodules Initially Diagnosed as Atypia/Follicular Lesion of Undetermined Significance

Objective

To compare core needle biopsy (CNB) and repeat fine-needle aspiration (rFNA) to reduce the rate of diagnostic surgery and prevent unnecessary surgery in nodules initially diagnosed as atypia/follicular lesions of undetermined significance (AUS/FLUS).

Materials and Methods

This study included 231 consecutive patients (150 female and 81 male; mean age ± standard deviation, 51.9 ± 11.7 years) with 235 thyroid nodules (≥ 1 cm) initially diagnosed as AUS/FLUS, who later underwent both rFNA and CNB. The nodules that required diagnostic surgery after the biopsy were defined using three different scenarios according to the rFNA and CNB results: criterion 1, surgery for low-risk indeterminate (categories I and III); criterion 2, surgery for high-risk indeterminate (categories IV and V); and criterion 3, surgery for all indeterminate nodules (categories I, III, IV, and V). We compared the expected rates of diagnostic surgery between CNB and rFNA in all 235 nodules using the three surgical criteria. In addition, the expected rates of unnecessary surgery (i.e., surgery for benign pathology) were compared in a subgroup of 182 nodules with available final diagnoses.

Results

CNB showed significantly lower rates of nondiagnostic, AUS/FLUS, and suspicious for malignancy diagnoses (p ≤ 0.016) and higher rates of follicular neoplasm or suspicious for a follicular neoplasm (p < 0.001) and malignant diagnoses (p = 0.031). CNB showed a significantly lower expected rate of diagnostic surgery than rFNA for criterion 1 (29.8% vs. 48.1%, p < 0.001) and criterion 3 (46.4% vs. 55.3%, p = 0.029), and a significantly higher rate for criterion 2 (16.6% vs. 7.2%, p = 0.001). CNB showed a significantly lower expected rate of unnecessary surgery than rFNA for criterion 1 (18.7% vs. 29.7%, p = 0.024).

Conclusion

CNB was superior to rFNA in reducing the rates of potential diagnostic surgery and unnecessary surgery for nodules initially diagnosed as AUS/FLUS in a scenario where nodules with low-risk indeterminate results (categories I and III) would undergo surgery.

Impact of the ultrasonography assessment method on the malignancy risk and diagnostic performance of five risk stratification systems in thyroid nodules

PURPOSE

Ultrasonographic (US) assessment methods may affect the estimated malignancy risk of thyroid nodules. This study aimed to investigate the impact of retrospective and prospective US assessments on the estimated malignancy risk of US features, classified categories, and diagnostic performance of five risk stratification systems (RSSs) in thyroid nodules.

METHODS

A total of 3685 consecutive thyroid nodules (≥1 cm) with final diagnoses (retrospective dataset, n = 2180; prospective dataset, n = 1505) were included in this study. We compared the estimated malignancy risk of US features, classified categories, and diagnostic performances of the five common RSSs between retrospective (static US images without cine clips) and prospective datasets of real-time US assessment.

RESULTS

There was no significant difference in the prevalence and histological type of malignant tumours between the two datasets (p ≥ 0.216). The malignancy risk of solid composition and nonparallel orientation was higher and that of microcalcification was lower in the prospective dataset than in the retrospective dataset (p < 0.001, p = 0.018, p = 0.007, respectively). The retrospective US assessment showed slightly higher malignancy risk of intermediate- or high-risk nodules according to the RSSs. Prospective US assessment showed lower specificities and higher unnecessary biopsy rates by all RSSs compared to the retrospective US assessment (p ≤ 0.006, p ≤ 0.045, respectively).

CONCLUSIONS

The retrospective US assessment showed higher malignancy risk of microcalcification and some classified categories by RSSs, and overestimated the specificities and underestimated the unnecessary biopsy rates by all RSSs compared to prospective US assessment.

Histopathological correlation of punctate echogenic foci on ultrasonography in papillary thyroid carcinoma

PURPOSE

To investigate the pathological entities of punctate echogenic foci (PEF) by correlating PEF with histopathological features of papillary thyroid carcinoma (PTC).

METHODS

This study included 121 consecutive patients who had undergone thyroidectomy for PTC. The inclusion criterion was entire tumor resection with a 3-mm thickness for histopathological examination. We assessed the presence and number (<5 or ≥5) of PEF defined as punctate hyperechoic foci within the solid component of nodules. All surgical tumor specimens were retrospectively reviewed for the presence of microcalcifications, including the psammomatous calcification, coarse microcalcification, and micro-ossification, and inspissated colloid.

RESULTS

PEF were detected in 71 (58.7%) PTCs. Psammomatous calcifications, coarse microcalcifications, and inspissated colloids were more frequently found in PTCs with PEF than in those without (74.6%, 42.3%, and 46.5%, respectively, p ≤ 0.024). Any type of microcalcification was found in 90.1% of PTCs with PEF. Psammomatous calcifications, coarse microcalcifications, and inspissated colloids were independently associated with PEF (p ≤ 0.012). Psammomatous calcifications were found in all PTCs with a high number (≥5) of PEF.

CONCLUSION

Microcalcifications were found in most PTCs with PEF and psammomatous calcification was the main pathological entity of PEF in PTC. Our study validates reliability of PEF as a predictor of microcalcifications in PTC.

Exploring the Value of Radiomics Features Based on B-Mode and Contrast-Enhanced Ultrasound in Discriminating the Nature of Thyroid Nodules

Background

With the improvement of ultrasound imaging resolution and the application of various new technologies, the detection rate of thyroid nodules has increased greatly in recent years. However, there are still challenges in accurately diagnosing the nature of thyroid nodules. This study aimed to evaluate the clinical application value of the radiomics features extracted from B-mode ultrasound (B-US) images combined with contrast-enhanced ultrasound (CEUS) images in the differentiation of benign and malignant thyroid nodules by comparing the diagnostic performance of four logistic models.

Methods

We retrospectively collected and ultimately included B-US images and CEUS images of 123 nodules from 123 patients, and then extracted the corresponding radiomics features from these images respectively. Meanwhile, a senior radiologist combined the thyroid imaging reporting and data system (TI-RADS) and the enhancement pattern of the ultrasonography to make a graded diagnosis of the malignancy of these nodules. Next, based on these radiomics features and grades, logistic regression was used to help build the models (B-US radiomics model, CEUS radiomics model, B-US+CEUS radiomics model, and TI-RADS+CEUS model). Finally, the study assessed the diagnostic performance of these radiomics features with a comparison of the area under the curve (AUC) of the receiver operating characteristic curve of four logistic models for predicting the benignity or malignancy of thyroid nodules.

Results

The AUC in the differential diagnosis of the nature of thyroid nodules was 0.791 for the B-US radiomics model, 0.766 for the CEUS radiomics model, 0.861 for the B-US+CEUS radiomics model, and 0.785 for the TI-RADS+CEUS model. Compared to the TI-RADS+CEUS model, there was no statistical significance observed in AUC between the B-US radiomics model, CEUS radiomics model, B-US+CEUS radiomics model, and TI-RADS+CEUS model (P>0.05). However, a significant difference was observed between the single B-US radiomics model or CEUS radiomics model and B-US+CEUS radiomics model (P<0.05).

Conclusion

In our study, the B-US radiomics model, CEUS radiomics model, and B-US+CEUS radiomics model demonstrated similar performance with the TI-RADS+CEUS model of senior radiologists in diagnosing the benignity or malignancy of thyroid nodules, while the B-US+CEUS radiomics model showed better diagnostic performance than single B-US radiomics model or CEUS radiomics model. It was proved that B-US radiomics features and CEUS radiomics features are of high clinical value as the combination of the two had better diagnostic performance.

2020 Imaging Guidelines for Thyroid Nodules and Differentiated Thyroid Cancer: Korean Society of Thyroid Radiology

Imaging plays a key role in the diagnosis and characterization of thyroid diseases, and the information provided by imaging studies is essential for management planning. A referral guideline for imaging studies may help physicians make reasonable decisions and minimize the number of unnecessary examinations. The Korean Society of Thyroid Radiology (KSThR) developed imaging guidelines for thyroid nodules and differentiated thyroid cancer using an adaptation process through a collaboration between the National Evidence-based Healthcare Collaborating Agency and the working group of KSThR, which is composed of radiologists specializing in thyroid imaging. When evidence is either insufficient or equivocal, expert opinion may supplement the available evidence for recommending imaging. Therefore, we suggest rating the appropriateness of imaging for specific clinical situations in this guideline.

Which ultrasound image plane is appropriate for evaluating the taller-than-wide sign in the risk stratification of thyroid nodules?

OBJECTIVES

This study aimed to determine the ultrasound (US) image plane appropriate for evaluating the taller-than-wide (TTW) sign in the risk stratification of thyroid nodules using the five widely used risk stratification systems (RSSs).

METHODS

A total of 1905 consecutive thyroid nodules with final diagnoses were included. The TTW sign was prospectively assessed in the transverse and longitudinal US image planes. The diagnostic performances of the TTW sign and biopsy criteria by the RSSs for malignancy were compared by sensitivity, specificity, and receiver operating characteristic curve analysis between the two criteria of TTW signs according to image planes (criterion 1, transverse plane; criterion 2, either transverse or longitudinal plane).

RESULTS

Of all 1905 nodules, 1481 (77.7%) were benign and 424 (22.3%) were malignant. The criteria 1 and 2 of TTW signs had similar sensitivities (37.5% and 38.7%) and specificities (94.8% and 94.4%) with minimal differences, and the area under the curve (AUC) of TTW signs for malignancy was not significantly different between criteria 1 and 2 (0.662 and 0.665, p = 0.158, respectively). The sensitivity, specificity, and AUC of biopsy criteria by the five RSSs were not significantly different between criteria 1 and 2 in nodules ≥ 1 cm (p ≥ 0.157, p ≥ 0.317, and p ≥ 0.198, respectively).

CONCLUSIONS

The diagnostic performances of the TTW sign and biopsy criteria of the five RSSs were similar between criteria 1 and 2. TTW signs by criterion 1 (transverse plane) may be appropriate in the risk stratification of thyroid nodules.

KEY POINTS

• The diagnostic performance of the taller-than-wide sign by ROC analysis was not significantly different between US image plane criteria (transverse plane vs. either transverse or longitudinal plane). • The diagnostic performances of biopsy criteria for malignancy by the five risk stratification systems were similar between the two taller-than-wide sign criteria. • The taller-than-wide sign using the transverse plane may be appropriate in the risk stratification of thyroid nodules.

Malignancy Risk Stratification of Thyroid Nodules with Macrocalcification and Rim Calcification Based on Ultrasound Patterns

Objective

To determine the association of macrocalcification and rim calcification with malignancy and to stratify the malignancy risk of thyroid nodules with macrocalcification and rim calcification based on ultrasound (US) patterns.

Materials and Methods

The study included a total of 3603 consecutive nodules (≥ 1 cm) with final diagnoses. The associations of macrocalcification and rim calcification with malignancy and malignancy risk of the nodules were assessed overall and in subgroups based on the US patterns of the nodules. The malignancy risk of the thyroid nodules was categorized as high (> 50%), intermediate (upper-intermediate: > 30%, ≤ 50%; lower-intermediate: > 10%, ≤ 30%), and low (≤ 10%).

Results

Macrocalcification was independently associated with malignancy in all nodules and solid hypoechoic (SH) nodules (p < 0.001). Rim calcification was not associated with malignancy in all nodules (p = 0.802); however, it was independently associated with malignancy in partially cystic or isoechoic and hyperechoic (PCIH) nodules (p = 0.010). The malignancy risks of nodules with macrocalcification were classified as upper-intermediate and high in SH nodules, and as low and lower-intermediate in PCIH nodules based on suspicious US features. The malignancy risks of nodules with rim calcification were stratified as low and lower-intermediate based on suspicious US features.

Conclusion

Macrocalcification increased the malignancy risk in all and SH nodules with or without suspicious US features, with low to high malignancy risks depending on the US patterns. Rim calcification increased the malignancy risk in PCIH nodules, with low and lower-intermediate malignancy risks based on suspicious US features. However, the role of rim calcification in risk stratification of thyroid nodules remains uncertain.

Explore the Diagnostic Efficiency of Chinese Thyroid Imaging Reporting and Data Systems by Comparing With the Other Four Systems (ACR TI-RADS, Kwak-TIRADS, KSThR-TIRADS, and EU-TIRADS): A Single-Center Study

PURPOSE

To explore the characteristics of C-TIRADS by comparing it with ACR-TIRADS, Kwak-TIRADS, KSThR-TIRADS and EU-TIRADS.

METHODS

A total of 1096 nodules were collected from 884 patients undergoing thyroidectomy in our center between May 2018 and December 2020. Divided the nodules into two groups: ">10mm" and "≤10mm". Ultrasound characteristics of each nodule were observed and recorded by 2 doctors, then classified based on ACR-TIRADS, Kwak-TIRADS, KSThR-TIRADS, EU-TIRADS, and C-TIRADS.

RESULTS

A total of 682 benign nodules cases (62.23%) and 414 malignant nodules cases (37.77%) were identified. The ICC value of each guideline was:0.937(ACR-TIRADS), 0.858(EU-IRADS), 0.811(Kwak-TIRADS), 0.835(KTA/KSThR-TIRADS) and 0.854(C-TIRADS). The nodule malignancy rates in the groups(Kwak-TIRADS 4B, C-TIRADS 4B、4C) of two sizes were significantly different (all p<0.05). There was no statistical difference in the other grades of two sizes (all p>0.05). Unnecessary biopsy rates were the lowest in C-TIRADS (49.02% p<0.001). Furthermore, Kwak-TIRADS had the highest sensitivity and NPV (89.9%, 91.0%, all p<0.05), while C-TIRADS had the highest specificity and PPV (82.3%, 69.2%, all p<0.05). C-TIRADS and Kwak-TIRADS had the highest accuracy (76.0%, 72.5%, P=0.071). The AUCs of the 5 guidelines were C-TIRADS(0.816, P<0.05), Kwak-TIRADS(0.789, P<0.05) KTA/KSThR-TIRADS and ACR-TIRADS(0.773, 0.763, P=0.305), EU-TIRADS(0.734, P<0.05). The AUCs of the five guidelines were not statistically different between "nodules>10mm" and "nodules ≤ 10mm" (all P>0.05).

CONCLUSIONS

All five guides showed excellent interobserver agreement. C-TIRADS was slightly efficient than Kwak-IRADS, KTA/KSThR-TIRADS and ACR-TIRADS, and had greater advantages than EU-TIRADS. The diagnostic abilities of the five guidelines for "nodules ≤ 10mm" were not inferior to that of "nodules> 10mm". C-TIRADS is simple and easy to implement and can provide effective thyroid tumor risk stratification for thyroid nodule diagnosis, especially in China.

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.

Long-Term Follow-Up Results of Ultrasound-Guided Radiofrequency Ablation for Low-Risk Papillary Thyroid Microcarcinoma: More Than 5-Year Follow-Up for 84 Tumors

Background: Despite reports describing favorable short-term results for thermal ablation of thyroid cancer, there remains a need to evaluate long-term results because of its indolent characteristics. The purpose of this study was to evaluate the long-term efficacy and safety of ultrasound (US)-guided radiofrequency ablation (RFA) for low-risk papillary thyroid microcarcinoma (PTMC) over a follow-up period of more than five years. Methods: From a cohort of patients under surveillance after US-guided RFA for primary low-risk PTMC, those with a record of follow-up data of more than five years were selected for this study. Before RFA, all patients underwent US and computed tomography to evaluate the PTMC and the presence of neck metastasis. RFA was performed using thyroid-dedicated electrodes. Follow-up US was performed 6 and 12 months after initial RFA, and then every 12 months. The status of ablated tumors was evaluated according to volume reduction, local tumor progression, newly developed cancers, lymph node (LN) or distant metastasis, and delayed surgery during follow-up. Complications during the procedure and follow-up period were evaluated. Results: A total of 84 nodules from 74 patients were included in this study. All patients tolerated RFA, and the mean follow-up duration was 72 months. After RFA, complete disappearance rates of 98.8% and 100% were achieved at 24 and 60-month follow-up, respectively. Additional ablations were performed in 13 of 84 tumors. The mean number of RFA sessions was 1.2. There were four newly developed cancers in three patients, and these were also treated with RFA and completely disappeared. During the follow-up period, there was no local tumor progression, no LN or distant metastasis, and no patients underwent delayed surgery. The major complication rate was 1.4% (1/74), and there was no delayed complication or procedure-related death. Conclusions: RFA is effective for treating low-risk PTMC patients, without occurrence of local tumor progression, LN or distant metastasis, delayed complications, procedure-related death, or delayed surgery over more than five years of follow-up.

Feasibility of Adjustable Electrodes for Radiofrequency Ablation of Benign Thyroid Nodules

Objective

The purpose of this study was to evaluate a novel radiofrequency ablation (RFA) application utilizing an adjustable electrode for treatment of benign thyroid nodules.

Materials and Methods

From April 2011 to December 2018, 21 patients underwent RFA treatment on 21 thyroid nodules, utilizing an 18-gauge internally cooled electrode equipped with a size adjustable active tip. The peripheral nodule portions were ablated with the moving-shot technique and a shorter active tip, and the nodule centers were ablated with the fixed technique and a longer active tip. We assessed parameters including characteristics of the treated nodules, use of variablesized active tips, volume reduction rate, therapeutic success rate, and post-procedural complications. The therapeutic success rate was defined as a > 50% volume reduction of the initial nodule volume at the 6- or 12-month follow-up.

Results

The treated thyroid nodules were large enough to cause symptoms (mean volume, 29.6 mL). Two types of active tips per session were used for all nodules. The mean volume reduction rate at the last follow-up was 68.3 ± 4.4% and our therapeutic success rate was 90.5%. Both symptoms and cosmetic scores decreased significantly. Minor complications in three patients were recorded during and after the procedure.

Conclusion

This initial study demonstrated that an adjustable electrode for RFA of benign thyroid nodules effectively and safely resulted in volume reduction.

Thyroid Nodules with Isolated Macrocalcifications: Malignancy Risk of Isolated Macrocalcifications and Postoperative Risk Stratification of Malignant Tumors Manifesting as Isolated Macrocalcifications

Objective

To determine the malignancy risk of isolated macrocalcifications (a calcified nodule with complete posterior acoustic shadowing) detected on ultrasonography (US) and to evaluate the postoperative American Thyroid Association (ATA) risk stratification of malignant tumors manifesting as isolated macrocalcifications.

Materials and Methods

A total of 3852 thyroid nodules (≥ 1 cm) of 3061 consecutive patients who had undergone biopsy between January 2011 and June 2018 were included in this study. We assessed the prevalence, malignancy rate, and size distribution of isolated macrocalcifications and evaluated the histopathologic features and postoperative ATA risk stratification of malignant tumors manifesting as isolated macrocalcifications.

Results

Isolated macrocalcifications were found in 38 (1.2%) of the 3061 patients. Final diagnosis was established in 30 (78.9%) nodules; seven malignant tumors were diagnosed as papillary thyroid carcinomas (PTCs). The malignancy rate of the isolated macrocalcifications was 23.3% in the 30 nodules with final diagnoses and 18.4% in all nodules. Among the six surgically-treated malignant tumors, five (83.3%) had an extrathyroidal extension (ETE) (minor ETE 1, gross ETE 4), and two (33.3%) had macroscopic lymph node metastasis. Four (66.7%) malignant tumors were categorized as high-risk tumors, one as an intermediate-risk tumor, and one as a low-risk tumor using the ATA risk stratification. Histopathologically, out of the six malignant tumors, ossifications were noted in four (66.7%) and predominant calcifications in two (33.3%).

Conclusion

The US pattern of isolated macrocalcifications (≥ 1 cm) showed an intermediate malignancy risk (at least 18.4%). All malignant tumors were PTCs, and most showed an aggressive behavior and a high or intermediate postoperative ATA risk.

Unnecessary thyroid nodule biopsy rates under four ultrasound risk stratification systems: a systematic review and meta-analysis

OBJECTIVES

To summarize and compare unnecessary biopsy rates and diagnostic performance in the examination of thyroid nodules according to four representative US-based risk stratification systems.

METHODS

MEDLINE/PubMed and EMBASE databases were searched to identify original articles investigating unnecessary biopsy rates according to at least one of the following guidelines: ACR-TIRADS, ATA, EU-TIRADS, and K-TIRADS. The unnecessary biopsy rates for each risk stratification system were pooled using a random-effects model. Meta-regression analyses were performed to explore heterogeneity. Diagnostic odds ratios (DORs) for the appropriate selection of thyroid nodules for fine-needle aspiration were also pooled using a bivariate random-effects model.

RESULTS

Eight articles including 13,092 thyroid nodules met the eligibility criteria and were included. The pooled unnecessary biopsy rates of ACR-TIRADS, ATA, EU-TIRADS, and K-TIRADS were 25% (95% CI, 22-29%), 51% (95% CI, 44-58%), 38% (95% CI, 16-66%), and 55% (95% CI, 42-67%), respectively. The pooled unnecessary biopsy rate of ACR-TIRADS was significantly lower than that of ATA (p < .001) and K-TIRADS (p < .001), and also lower than that of EU-TIRADS, but not reaching statistical significance (p = .087). The pooled DORs of ACR-TIRADS, ATA, and K-TIRADS were 5.9 (95% CI, 3.6-9.6), 6.3 (95% CI, 4.5-8.8), and 4.5 (95% CI, 1.7-11.6), respectively, with the differences not being statistically significant.

CONCLUSIONS

ACR-TIRADS showed a lower unnecessary biopsy rate than the other risk stratification systems albeit DOR was comparable between ACR-TIRADS, ATA, and K-TIRADS. Future revisions of each system should be made by referring to ACR-TIRADS to reduce unnecessary biopsy rates.

KEY POINTS

• The pooled unnecessary biopsy rates of ACR-TIRADS, ATA, EU-TIRADS, and K-TIRADS were 25% (95% CI, 22-29%), 51% (95% CI, 44-58%), 38% (95% CI, 16-66%), and 55% (95% CI, 42-67%), respectively. • The pooled unnecessary biopsy rate of ACR-TIRADS was significantly lower than that of ATA (p < .001) and K-TIRADS (p < .001). • The pooled DORs of ACR-TIRADS, ATA, and K-TIRADS were 5.9 (95% CI, 3.6-9.6), 6.3 (95% CI, 4.5-8.8), and 4.5 (95% CI, 1.7-11.6), respectively, with the differences not being statistically significant.

Diagnostic Performance of Four Ultrasound Risk Stratification Systems: A Systematic Review and Meta-Analysis

Background: Several ultrasound (US)-based risk stratification systems have been increasingly used for the optimal management of thyroid nodules. However, there are considerable discrepancies across these systems. This study aimed to summarize and compare the category-based diagnostic performance in the detection of thyroid cancer of different US-based risk stratification systems from four societies: the American College of Radiology-Thyroid Imaging Reporting and Data System (ACR-TIRADS), the American Thyroid Association (ATA), the Korean Thyroid Association/Korean Society of Thyroid Radiology (KTA/KSThR; K-TIRADS), and the European Thyroid Association (EU-TIRADS). Methods: MEDLINE/PubMed and EMBASE databases were searched to identify original articles investigating the category-based diagnostic performance according to at least one of the following guidelines: ACR-TIRADS, ATA, K-TIRADS, and EU-TIRADS. Pooled sensitivity and specificity were calculated using a bivariate random-effects model. A subgroup analysis on nodules of 1 cm or larger and a meta-regression analysis to identify factors associated with the diagnostic performance were performed. Results: A total of 29 articles including 33,748 thyroid nodules met the eligibility criteria and were included in the analysis. For ACR-TIRADS, the pooled sensitivity and specificity were, respectively, 66% and 91% for category 5 and 95% and 55% for category 4 or 5. For ATA, the pooled sensitivity and specificity were, respectively, 74% and 88% for category 5 and 91% and 64% for category 4 or 5. For K-TIRADS, the pooled sensitivity and specificity were, respectively, 55% and 95% for category 5 and 89% and 64% for category 4 or 5. For EU-TIRADS, the pooled sensitivity and specificity were, respectively, 82% and 90% for category 5 and 96% and 52% for category 4 or 5. Study location, proportion of female patients and malignant nodules, and study design were associated with study heterogeneity. Conclusions: The overall diagnostic performance of the four US-based risk stratification systems was comparable.

Diagnostic Efficacy and Safety of Core Needle Biopsy as a First-Line Diagnostic Method for Thyroid Nodules: A Prospective Cohort Study

Background: The diagnostic role of ultrasonography (US)-guided core needle biopsy (CNB) as a first-line diagnostic method for thyroid nodules remains controversial. This study was performed to determine the diagnostic efficacy and safety of CNB as a first-line diagnostic method for thyroid nodules. Methods: From February 2016 to January 2018, CNB was prospectively performed by an experienced radiologist in all consecutive patients with thyroid nodules indicated for fine-needle aspiration (FNA). Three patients refused this protocol. Finally, 212 consecutive patients with 248 thyroid nodules were enrolled in this prospective study. Combined CNB/FNA was selectively performed in 43 patients. The diagnostic efficacy of CNB was evaluated by the rate of inconclusive results (nondiagnostic or indeterminate results), and its feasibility was estimated by calculating the successful biopsy rate and by measuring the procedure time from the time of the initial skin puncture to the last withdrawal of the biopsy needle from the skin. The safety of the procedure was evaluated by the major and minor complication rates. A US evaluation was performed before and after manual self-compression to assess for hemorrhage at the biopsy site, and delayed complications were assessed 5-7 days after the biopsy. Any hemorrhage that did not require hospitalization was classified as a minor complication. Results: CNB was performed once (n = 125, 50.4%), twice (n = 122, 49.2%), or three times (n = 1, 0.4%) per nodule. The diagnostic results of CNB were as follows: nondiagnostic (0.8%), benign (63.3%), indeterminate (10.1%), follicular neoplasm (3.2%), suspected malignancy (2.4%), and malignancy (20.1%); the rate of inconclusive results was 10.9%. The successful biopsy rate of CNB was 100%, and the median procedure time was 102 seconds (interquartile range 51-181 seconds). There were no major or delayed complications. There were 6 cases (2.8%) of minor complications, which included 2 cases (0.9%) with symptomatic hematomas and 4 cases (1.9%) with asymptomatic small hematomas. Conclusion: The findings confirm that CNB is effective in reducing the rate of inconclusive results and it is safe. CNB may be used as an alternative first-line diagnostic method for thyroid nodules by an experienced operator.

US-Guided Radiofrequency Ablation for Low-Risk Papillary Thyroid Microcarcinoma: Efficacy and Safety in a Large Population

OBJECTIVE

To evaluate the efficacy and safety of radiofrequency ablation (RFA) for low-risk papillary thyroid microcarcinoma (PTMC) in a large population.

MATERIALS AND METHODS

Cases of 152 biopsy-proven PTMCs from 133 patients who had undergone RFA for PTMC between May 2008 and January 2017 were included in this study. All patients were either of high surgical risk or refused to undergo surgery. They were followed up for at least 6 months after initial RFA. Ultrasonography (US) and computed tomography were performed to evaluate the PTMC and the presence of neck metastasis before treatment. RFA was conducted using an internally cooled thyroid-dedicated electrode system. Follow-up US was performed at 1 week, and 2, 6, and 12 months, after the initial RFA, and then at every 6-12 months. We evaluated serial changes of ablated tumors, newly developed cancers, lymph node (LN) or distant metastasis and complications.

RESULTS

Complete disappearance was found in 91.4% (139/152) of ablated tumors. Among the 13 tumors in patients who did not show complete disappearance, no tumor displayed any regrowth of the residual ablated lesion during the follow-up period. The mean follow-up period was 39 months. During the follow-up period, there were no local recurrence, no LN or distant metastasis, and no newly developed thyroid cancers. No patients were referred to surgery. The overall complication rate was 3% (4/133) of patients, including one voice change. There were no life-threatening complications or procedure-related deaths.

CONCLUSION

Our results suggest that RFA is an effective and safe option for treating low-risk PTMC patients who are of high surgical risk or refuse surgery.

European Thyroid Association Survey on Use of Minimally Invasive Techniques for Thyroid Nodules

OBJECTIVE

Image-guided interventional ultrasound (US) techniques represent diagnostic and therapeutic tools for non-surgical management of thyroid nodular disease. We sought to investigate the attitude of European Thyroid Association (ETA) members towards the use of minimally invasive techniques (MIT) in diagnosis/therapy of symptomatic nodular goitre.

METHODS

ETA members were invited to participate in an online survey investigating the use of MIT in benign and malignant thyroid nodular disease. Of 865 invited members, 221 (25.5%) completed the survey. The respondents were from 40 countries; 139 (74.7%) were from European countries.

RESULTS

Respondents personally performed thyroid US (91.6%), Fine needle aspiration (FNA; 75.3%), ethanol ablation (EA; 22.1%), core needle biopsy (CNB; 11%) and thermal treatments (4.8%). When skills and/or technology were unavailable, only 13.4% referred patients "often" or "always" to other centres with specific expertise in this field. Surgery was the preferred first option in patients with recurrent cysts, 4.0 cm benign nodules, local (radioiodine-avid or non-avid) lymph node metastases, or papillary cancers <1.0 cm. For autonomously functioning nodules radioactive iodine treatment was the preferred choice, followed by surgery. Thermal ablation (TA) was the preferred option only for a 4 cm benign nodule in old patients with comorbidities.

CONCLUSIONS

US, US-guided FNA and surgery were available to nearly all respondents, while MIT was not. CNB and EA were employed only by about 1/3 of the respondents and TA procedures were available and personally performed only by a minority. For most thyroid lesions, surgery was the preferred option versus thermal therapies. The ETA needs to develop guidelines and establish teaching to overcome geographic inequality and promote the use of MIT as a valid therapy option in appropriate cases.

Clinical practice guidelines for radiofrequency ablation of benign thyroid nodules: a systematic review

Purpose

Thermal ablation is a novel treatment alternative for benign thyroid nodules, and one of the most promising thermal ablation techniques is radiofrequency ablation (RFA). Considering the increasing use of thyroid RFA, some scientific societies have proposed clinical practice guidelines. We systemically reviewed and compared these guidelines for thyroid RFA to identify a standard treatment strategy that represents the positions of most societies.

Methods

We searched the MEDLINE and EMBASE databases for studies with human participants that were published in English between January 1, 2000 and August 2, 2019. Studies containing clinical practice guidelines for the RFA of benign thyroid nodules were included. We extracted data regarding indications, pre- and post-procedural evaluations, treatment techniques, and the need to obtain informed consent.

Results

Of the 83 studies found, four studies were included, and one study was added after searching the bibliographies of those articles. The five included studies were guidelines developed by the Korean Society of Thyroid Radiology, a group of experts from Italian scientific societies, the Italian Working Group on Minimally Invasive Treatments of the Thyroid, the United Kingdom’s National Institute for Health and Clinical Excellence, and a group of four professional Austrian thyroid associations. Indications, pre- and post-procedural evaluations, and techniques were similar across studies; however, differences in each of these categories were found.

Conclusion

While the reviewed guidelines are similar with regard to major categories, international guidelines for the RFA of benign thyroid nodules should be established in the future.

Long-Term Results of Thermal Ablation of Benign Thyroid Nodules: A Systematic Review and Meta-Analysis

BACKGROUND

Ultrasound-guided thermal ablations have become one of the main options for treating benign thyroid nodules. To determine efficacy of thermal ablation of benign thyroid nodules, we performed a meta-analysis of studies with long-term follow-up of more than 3 years.

METHODS

Databases were searched for studies published up to August 25, 2019, reporting patients with benign thyroid nodules treated with thermal ablation and with follow-up data of more than 3 years. Data extraction and quality assessment were performed according to PRISMA guidelines. The analysis yielded serial volume reduction rates (VRRs) of ablated nodules for up to 3 years or more, and adverse effect of ablation during follow-up. Radiofrequency ablation (RFA) and laser ablation (LA) were compared in a subgroup analysis.

RESULTS

The pooled VRRs for ablated nodules showed rapid volume reduction before 12 months, a plateau from 12 to 36 months, and more volume reduction appearing after 36 months, demonstrating long-term maintenance of treatment efficacy. Thermal ablation had an acceptable complication rate of 3.8%. Moreover, patients undergoing nodule ablation showed no unexpected delayed complications during the follow-up period. In the subgroup analysis, RFA was shown to be superior to LA in terms of the pooled VRR and the number of patients who underwent delayed surgery.

CONCLUSION

Thermal ablations are safe and effective methods for treating benign thyroid nodules, as shown by a long follow-up analysis of more than 3 years. In addition, RFA showed superior VRRs compared with LA for the treatment of benign thyroid nodules, with less regrowth and less delayed surgery.

2019 Practice guidelines for thyroid core needle biopsy: a report of the Clinical Practice Guidelines Development Committee of the Korean Thyroid Association

Ultrasound-guided core needle biopsy (CNB) has been increasingly used for the pre-operative diagnosis of thyroid nodules. Since the Korean Society of the Thyroid Radiology published the ‘Consensus Statement and Recommendations for Thyroid CNB’ in 2017 and the Korean Endocrine Pathology Thyroid CNB Study Group published ‘Pathology Reporting of Thyroid Core Needle Biopsy’ in 2015, advances have occurred rapidly not only in the management guidelines for thyroid nodules but also in the diagnostic terminology and classification schemes. The Clinical Practice Guidelines Development Committee of the Korean Thyroid Association (KTA) reviewed publications on thyroid CNB from 1995 to September 2019 and updated the recommendations and statements for the diagnosis and management of thyroid nodules using CNB. Recommendations for the resolution of clinical controversies regarding the use of CNB were based on expert opinion. These practical guidelines include recommendations and statements regarding indications for CNB, patient preparation, CNB technique, biopsy-related complications, biopsy specimen preparation and processing, and pathology interpretation and reporting of thyroid CNB.

Thyroid Radiology Practice: Diagnosis and Interventional Treatment of Patients with Thyroid Nodules

갑상선 영상의학 진료란 갑상선 질환 환자를 영상의학적 방법을 활용하여 질병 진단과 중재적 치료를 하는 의료 행위로 정의될 수 있으며 주요 진료 대상은 갑상선 결절 질환 환자들이다. 갑상선 결절의 진단은 일차적으로 초음파 영상진단과 생검에 의해서 이루어지고 결절의 치료는 비수술적 중재적 치료와 갑상선절제술이다. 갑상선 낭종 혹은 낭성우세 양성 결절에서는 에탄올절제술이 일차적 치료법이고 고주파절제술은 고형 혹은 고형우세 양성 결절과 갑상선 재발암 치료에 적용되고 있다. 갑상선 영상의학 진료는 갑상선 결절 질환 환자의 진단 및 비수술적 치료의 대부분을 담당하는 중요한 임상적 역할을 가지고 있으며, 적절한 환자 진료를 위해서는 표준적 진료 지침에 근거하여 진료가 수행되어야 한다. 환자에게 최적의 갑상선 영상의학 진료를 제공하기 위해서는 영상의학과 외래에서 환자를 진료하는 것이 바람직하며 외래 중심의 갑상선 영상의학 진료를 확대하도록 함께 노력해야 할 시점이다.

CT features of thyroid nodules with isolated macrocalcifications detected by ultrasonography

Purpose

A thyroid nodule with an isolated macrocalcification is visualized as a calcified nodule with complete posterior shadowing on ultrasonography (US). This study aimed to determine the computed tomography (CT) features of isolated macrocalcifications detected using US.

Methods

This study included 20 patients who had thyroid nodules with isolated macroalcifications and underwent neck CT or chest CT. The patients were enrolled from a sample of 82 patients with isolated macrocalcifications detected by US drawn from 7,142 consecutive patients who underwent thyroid biopsy at two institutions. We evaluated the CT features of nodules with isolated macrocalcifications and categorized them as central or rim calcifications. We assessed the nodule size and the frequency of nondiagnostic fine-needle aspiration (FNA) results and malignant tumors according to the CT features of isolated macrocalcifications.

Results

CT scans showed central calcifications in 18 (90.0%) and rim calcifications in two (10.0%) of the 20 nodules with isolated macrocalcifications. Among the 18 nodules with central isolated macrocalcifications, complete compact calcification was found in six nodules and partial coarse calcification in 12 nodules. In 18 nodules with central isolated macrocalcifications, the nondiagnostic FNA rate and frequency of malignant tumors were not significantly different between complete and partial central calcifications (P=0.620 and P=0.999, respectively). Malignant tumors were only found in nodules with central isolated macrocalcifications.

Conclusion

The majority of nodules with isolated macrocalcifications showed central calcifications on CT. Thyroid nodules with isolated macrocalcifications detected by US should not be classified as having a type of rim or peripheral calcification.

High-intensity focused ultrasound (HIFU) for benign thyroid nodules: 2-year follow-up results

BACKGROUND

High-intensity focused ultrasound (HIFU) is the last introduced thermal treatment of thyroid nodules. Here we evaluated the results at 24 months after HIFU.

METHODS

Since 2016, HIFU was considered as a therapeutic option at our institute in patients with benign thyroid nodules presenting local symptoms. We searched in our database all patients who had undergone thyroid HIFU and selected for the study only cases followed-up for at least 24 months after the treatment. Volume reduction rate (VRR) was evaluated. A reduction above 50% defined the success of HIFU.

RESULTS

Thirty-one nodules of 31 patients (24 females and 7 males, median age 67 years) with median major diameter from 17 to 34 mm and estimated nodule volume of 5.48 mL were included. HIFU was performed with median power of 42 W/site (interquartile range 25-45) and median energy of 263 J/site (interquartile range 225-273). Median duration of the procedure was 6 min (interquartile range 5-7). At 2 years after HIFU, nodule volume was significantly (p < 0.0001) lower (i.e., 3.40 mL) with VRR of 43.3%, and 26 (83.9%) lesions were reduced. A reduction by at least 50% was observed at 6, 12, and 24 months in 2 (6.4%), 5 (16.1%), and 7 (22.5%) nodules, respectively. Visual analog score showed a significant improvement (p < 0.0001). No complications were recorded.

CONCLUSIONS

A reduction of benign thyroid nodule by more than 40% could be reached within 1 year by HIFU. Given the non-significant size increase of some lesions later, a larger study with a longer follow-up is necessary.

Clinical practice guidelines on ultrasound-guided fine needle aspiration biopsy of thyroid nodules: a critical appraisal using AGREE II

PURPOSE

To appraise the quality of current guidelines on fine needle aspiration biopsy (FNAB) of thyroid nodules for adults using the AGREE II quality assessment tool.

METHODS

We conducted an online search for guidelines on FNAB of thyroid nodules published between 2013 and October 2018. They were evaluated by four independent reviewers previously trained to apply the AGREE II instrument, which is organized into items and domains. A fifth independent reviewer calculated scores for each domain and guideline as well as inter-appraiser agreement.

RESULTS

Six sets of guidelines were included, respectively, provided by the American Thyroid Association (ATA), the American Association of Clinical Endocrinologists/American College of Endocrinology/Associazione Medici Endocrinologi (AACE/ACE/AME), the Korean Society of Thyroid Radiology (KSThR), the European Thyroid Association (ETA), the American College of Radiology (ACR) and the Korean Society of Radiology and National Evidence-Based Healthcare Collaborating Agency (KSR/NECA). Five out of the six guidelines (ATA, AACE/ACE/AME, ETA, ACR and KSR/NECA) reached a high level of overall quality, having at least five domain scores >60%. An average level of overall quality was achieved in one case (KSThR recommendations). Inter-appraiser agreement ranged from moderate to excellent.

CONCLUSIONS

Overall, the quality of guidelines on FNAB of thyroid nodules is satisfactory when evaluated using the AGREE II instrument.