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Objective: This study aimed to compare therapeutic efficacy and technical outcomes between adjustable electrode (AE) and conventional fixed electrode (FE) for radiofrequency ablation (RFA) of benign thyroid nodules., Materials and Methods: Between 2013 and 2021, RFA was performed on histologically proven benign thyroid nodules. For the AE method, AE length ≥ 1 cm with higher power and < 1 cm with lower power were utilized for ablating feeding vessels and nodules, especially those near anatomical structures, respectively. The therapeutic efficacy (volume reduction rate [VRR], complication rate, and regrowth rate) and technical outcomes (total energy delivery, ablated volume/energy, RFA time, and ablated volume/time) of FE and AE were compared. Continuous parameters were compared using a two-sample t -test or Mann-Whitney U test, and categorical parameters were compared using a chi-squared test or Fisher's exact test., Results: A total of 182 nodules (FE: 92 vs. AE: 90) in 173 patients (mean age ± standard deviation, 47.0 ± 14.7 years; female, 90.8% [157/173]; median follow-up, 726 days [interquartile range, 441-1075 days]) were analyzed. The therapeutic efficacy was comparable, whereas technical outcomes were more favorable for AE. Both electrodes demonstrated comparable overall median VRR (FE: 92.4% vs. AE: 84.9%, P = 0.240) without immediate major complications. Overall regrowth rates were comparable between the two groups (FE: 2.2% [2/90] vs. AE: 1.1% [1/90], P > 0.99). AE demonstrated a shorter median RFA time (FE: 811 vs. AE: 627 seconds, P = 0.009). Both delivered comparable median energy (FE: 42.8 vs. AE: 29.2 kJ, P = 0.069), but AE demonstrated higher median ablated volume/energy and median ablated volume/time (FE: 0.2 vs. AE: 0.3 cc/kJ, P < 0.001; and FE: 0.7 vs. AE: 1.0 cc/min, P < 0.001, respectively)., Conclusion: Therapeutic efficacy between FE and AE was comparable. AE demonstrated better technical outcomes than FE in terms of RFA time, ablated volume/energy, and ablated volume/time., Competing Interests: Jae Ho Shin who is on the editorial board of the Korean Journal of Radiology was not involved in the editorial evaluation or decision to publish this article. All remaining authors have declared no conflicts of interest., (Copyright © 2024 The Korean Society of Radiology.)

Ultrasonography (US) is a primary imaging modality for diagnosing nodular thyroid disease and has an essential role in identifying the most appropriate management strategy for patients with nodular thyroid disease. Standardized imaging techniques and reporting formats for thyroid US are necessary. For this purpose, the Korean Society of Thyroid Radiology (KSThR) organized a task force in June 2021 and developed recommendations for standardized imaging technique and reporting format, based on the 2021 KSThR consensus statement and recommendations for US-based diagnosis and management of thyroid nodules. The goal was to achieve an expert consensus applicable to clinical practice., Competing Interests: Dong Gyu Na, Ji-Hoon Kim, and Jung Hwan Baek, who is on the editorial board of the Korean Journal of Radiology was not involved in the editorial evaluation or decision to publish this article. All remaining authors have declared no conflicts of interest., (Copyright © 2023 The Korean Society of Radiology.)

Purpose: This study aimed to train and validate deep learning (DL) models for differentiating malignant from benign thyroid nodules on US images and compare their performance with that of radiologists., Methods: Images of thyroid nodules in patients who underwent US-guided fine-needle aspiration biopsy at our institution between January 2010 and March 2020 were retrospectively reviewed. Four radiologists independently classified the images. Images of thyroid nodules were trained using three different image classification DL models (VGG16, VGG19, and ResNet). The diagnostic performances of the DL models were calculated for the internal and external datasets and compared with the diagnoses of the four radiologists. Pairwise comparisons of the AUCs between the radiologists and DL models were made using bootstrap-based tests., Results: In total, 15,409 images from 7,321 patients (mean age, 60 ± 13 years; malignant nodules, 20.7%) were randomly grouped into training (n = 12,327) and validation (n = 3,082) sets. Independent internal (n = 432; 197 patients) and external (n = 168; 59 patients) test sets were also acquired. The DL models demonstrated a higher diagnostic performance than the radiologists in the internal test set (AUC, 0.83 - 0.86 vs. 0.71 - 0.76, P < 0.05), but not in the external test set. The VGG16 model demonstrated the highest diagnostic performance in internal (AUC, 0.86; sensitivity, 91.8%; specificity, 73.2%) and external (AUC: 0.83; sensitivity: 78.6%; specificity: 76.8%) test sets. However, no statistical differences were found in the AUCs among the DL models., Conclusions: The DL models demonstrated comparable diagnostic performance to radiologists in distinguishing benign from malignant thyroid nodules on US images and may play a potential role in augmenting radiologists' diagnosis of thyroid nodules., (Copyright © 2022 Elsevier B.V. All rights reserved.)

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., Competing Interests: Dong Gyu Na, Jung Hwan Baek, Ji-hoon Kim, Jeong Hyun Lee, Jung Hee Shin who is on the editorial board of the Korean Journal of Radiology was not involved in the editorial evaluation or decision to publish this article. All remaining authors have declared no conflicts of interest., (Copyright © 2021 The Korean Society of 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., Competing Interests: None of the members of the Guideline Committee has a financial disclosure or conflict of interest except Jung Hwan Baek. He has been a consultant of two radiofrequency companies, STARmed and RF Medical, since 2017., (Copyright © 2021 The Korean Society of Radiology.)

Objective: The purpose of this study was to evaluate the usefulness of CT for quantitative assessment of the neck structures after RFA in patients with benign thyroid nodules., Materials and Methods: This single-center, retrospective cohort study included 38 patients with benign thyroid nodules who had received RFA and had available pre- and post-treatment CT images. Changes in the tracheal anteroposterior (AP)/transverse diameter ratio, cross-sectional tracheal area, midline deviation of the trachea, and anterior neck angle after RFA were quantitatively measured using CT. Volume reduction rates (VRRs) for the thyroid gland and nodules were measured using CT and US, respectively, and the intraclass correlation coefficient (ICC) was calculated. The paired Wilcoxon signed-rank test was used to compare pre- and post-treatment CT-based measurements, and univariate linear regression analysis was performed to determine the association of VRR with the mean delivered radiofrequency energy, number of RFA sessions, and initial thyroid volume., Results: After RFA, the tracheal AP/transverse diameter ratio and midline deviation were significantly decreased while the tracheal area and anterior neck angle were significantly increased (all, p  < 0.001). The thyroid volume reduction was also significant (VRR, 42.1% ± 21.1%, p  < 0.001), with moderate consistency between the CT-based thyroid VRR and US-based nodule VRR (ICC = 0.68, 95% confidence interval = 0.38-0.83, p  < 0.001). The mean delivered radiofrequency energy ( p  = 0.565), number of RFA sessions ( p  = 0.209), and initial thyroid volume ( p  = 0.363) showed no significant association with VRR., Conclusion: CT-based quantitative assessments may be useful for evaluating improvements in the neck structures after RFA for benign thyroid nodules.

Background: To evaluate the imaging features, clinical manifestations, and prognosis of patients with thyroid nodule rupture after radiofrequency ablation (RFA)., Methods: The records of 12 patients who experienced thyroid nodule rupture after RFA at four Korean thyroid centers between March 2010 and July 2017 were retrospectively reviewed. Clinical data evaluated included baseline patient characteristics, treatment methods, initial presenting symptoms, imaging features, treatment, and prognosis., Results: The most common symptoms of post-RFA nodule rupture were sudden neck bulging and pain. Based on imaging features, the localization of nodule rupture was classified into three types: anterior, posterolateral, and medial types. The anterior type is the most often, followed by posterolateral and medial type. Eight patients recovered completely after conservative treatment. Four patients who did not improve with conservative management required invasive procedures, including incision and drainage or aspiration., Conclusion: Thyroid nodule rupture after RFA can be classified into three types based on its localization: anterior, posterolateral, and medial types. Because majority of thyroid nodule ruptures after RFA can be managed conservatively, familiarity with these imaging features is essential in avoiding unnecessary imaging workup or invasive procedures., Competing Interests: No potential conflict of interest relevant to this article was reported., (Copyright © 2019 Korean Endocrine Society.)

Background/aims: Lymphocytic thyroiditis as cytology diagnosis from fine needle aspiration (FNA) is frequently detected in patients with thyroid nodules. However, the clinical outcome for upcoming hypothyroid events has been rarely clarified in euthyroid patients., Methods: We retrospectively reviewed the data of patient who had lymphocytic thyroitidis on FNA cytology of thyroid nodule from January 2005 to December 2010 at a tertiary referral hospital. In total, 109 patients with follow-up thyroid function tests (TFT) were enrolled. Final outcomes included overt and subclinical hypothyroidism with thyroid stimulating hormone (TSH) levels ≥ 10 mIU/L. Potential parameters predicting clinical hypothyroidism were analyzed by multivariate analysis., Results: Over the mean follow-up duration of 51.6 months, 14 out of 109 patients (12.8%) developed clinical hypothyroidism that required thyroid hormone replacement. The median onset time to hypothyroidism was 16 months (range, 3 to 88) and ≥ 60% of patients experienced clinical hypothyroidism within 1 year. By multivariate analysis, background thyroiditis (relative risk [RR], 9.78; p = 0.004), thyroid peroxidase antibody positivity (RR, 9.90; p = 0.003), nodule size (RR, 1.24; p < 0.001), and initial TSH (RR, 1.47; p = 0.009) were the independent risk factors for predicting hypothyroidism in euthyroid patients., Conclusion: Hypothyroidism frequently occurs during the follow-up in euthyroid patients with thyroid nodules which show lymphocytic thyroiditis on FNA cytology. Close surveillance and regular TFT are needed in high-risk patients for upcoming clinical hypothyroidism.

Minimally invasive treatment of symptomatic thyroid nodules is now commonplace. Ethanol ablation (EA) of thyroid cystic nodules has been performed since the 1990s, but there is no global consensus or guideline. Although various limitations of EA have been described, recommendations for practical application are necessary. Therefore, the Task Force Committee of the Korean Society of Thyroid Radiology initiated the present consensus statement and here we provide recommendations for the role of EA in the management of symptomatic thyroid nodules. These recommendations are based on evidence to date from the literature and expert opinion., Competing Interests: The authors have no potential conflicts of interest to disclose., (Copyright © 2019 The Korean Society of Radiology.)

Thermal ablation using radiofrequency is a new, minimally invasive modality employed as an alternative to surgery in patients with benign thyroid nodules and recurrent thyroid cancers. The Task Force Committee of the Korean Society of Thyroid Radiology (KSThR) developed recommendations for the optimal use of radiofrequency ablation for thyroid tumors in 2012. As new meaningful evidences have accumulated, KSThR decided to revise the guidelines. The revised guideline is based on a comprehensive analysis of the current literature and expert consensus.

Objective: To assess the efficacy and safety of thyroid radiofrequency (RF) ablation for benign thyroid nodules by trained radiologists according to a unified protocol in a multi-center study., Materials and Methods: From 2010 to 2011, 345 nodules from 345 patients (M:F = 43:302; mean age ± SD = 46.0 ± 12.7 years, range = 15-79) who met eligibility criteria were enrolled from five institutions. At pre-ablation, the mean volume was 14.2 ± 13.2 mL (1.1-80.8 mL). For 12 months or longer after treatment, 276 lesions, consisting of 248 solid and 28 predominantly cystic nodules, were followed. All operators performed RF ablation with a cool-tip RF system and two standard techniques (a transisthmic approach and the moving-shot technique). Volume reduction at 12 months after RF ablation (the primary outcome), therapeutic success, improvement of symptoms as well as of cosmetic problems, and complications were evaluated. Multiple linear regression analysis was applied to identify factors that were independently predictive of volume reduction., Results: The mean volume reduction at 12 months was 80.3% (n = 276) and at the 24-, 36-, 48-, and 60-month follow-ups 84.3% (n = 198), 89.2% (n = 128), 91.9% (n = 57), and 95.3% (n = 6), respectively. Our therapeutic success was 97.8%. Both mean symptom and cosmetic scores showed significant improvements ( p < 0.001). The rate of major complications was 1.0% (3/276). Solidity and applied energy were independent factors that predicted volume reduction., Conclusion: Radiofrequency ablation performed by trained radiologists from multiple institutions using a unified protocol and similar devices was effective and safe for treating benign thyroid nodules.

The rate of detection of thyroid nodules and carcinomas has increased with the widespread use of ultrasonography (US), which is the mainstay for the detection and risk stratification of thyroid nodules as well as for providing guidance for their biopsy and nonsurgical treatment. The Korean Society of Thyroid Radiology (KSThR) published their first recommendations for the US-based diagnosis and management of thyroid nodules in 2011. These recommendations have been used as the standard guidelines for the past several years in Korea. Lately, the application of US has been further emphasized for the personalized management of patients with thyroid nodules. The Task Force on Thyroid Nodules of the KSThR has revised the recommendations for the ultrasound diagnosis and imaging-based management of thyroid nodules. The review and recommendations in this report have been based on a comprehensive analysis of the current literature and the consensus of experts.

Ultrasound (US)-guided fine needle aspiration (US-FNA) has played a crucial role in managing patients with thyroid nodules, owing to its safety and accuracy. However, even with US guidance, nondiagnostic sampling and infrequent complications still occur after FNA. Accordingly, the Task Force on US-FNA of the Korean Society of Thyroid Radiology has provided consensus recommendations for the US-FNA technique and related issues to improve diagnostic yield. These detailed procedures are based on a comprehensive analysis of the current literature and from the consensus of experts.

Background: The purpose of this study is to validate the generalizability of the efficacy and safety of radiofrequency (RF) ablation for treating autonomously functioning thyroid nodules (AFTN) in a large population multicenter study., Methods: This study included 44 patients from 5 institutions who refused or were not suitable for surgery or radioiodine therapy. Twenty-three patients were affected by a toxic nodule and 21 by a pretoxic nodule. RF ablation was performed using an 18-gauge, internally cooled electrode. Nodule volume, thyroid function, scintigraphy, symptom/cosmetic scores, and complications were evaluated before treatment and during each follow-up., Results: The mean follow-up period was 19.9±12.6 months. The mean nodule volume was initially 18.5±30.1 mL and significantly decreased after treatment at 1 month (11.8±26.9 mL, p<0.001) and the last month (4.5±9.8 mL, p<0.001). Significant improvement of triiodothyronine, free thyroxine, and thyrotropin was observed at the last follow-up. Regarding scintigraphy, 35 hot nodules became cold or were normal when scanned and 9 decreased uptake, although they remained hot nodules. The mean symptom and cosmetic scores were significantly reduced at the last follow-up. No major complications were encountered., Conclusions: This multicenter study validated the efficacy and safety of RF ablation for treating AFTN; RF ablation can be considered an alternative to surgery or radioiodine therapy.

Follicular neoplasm/suspicious for follicular neoplasm (FN/SFN) can often be challenging to diagnose using core needle biopsy (CNB) specimens. We have developed the histologic criteria for the CNB diagnosis of FN and validated the usefulness of CNB. We retrospectively reviewed 184 CNBs and 224 FNACs diagnosed with FN/SFN. CNBs were histologically classified into four subgroups, based on the histologic features of follicular proliferation, fibrous capsulation, and surrounding parenchyma. Among 184 CNBs, 103 (55.9%) had previous FNAC results of non-diagnostic or indeterminate. Overall malignancy rates in FNAC (48%) and CNB (46%) were nearly identical (p > 0.05), and the neoplasm rate was higher in CNB (88%) than FNAC (74%) (p = 0.007). There was no significant difference in the malignancy rates among the four histologic subgroups. Among the 40 nodules with simultaneous CNB and FNAC, only nine had the FNAC diagnosis of FN/SFN, and others were non-diagnostic, benign, or atypia of undetermined significance. Overall, CNB improved specimen adequacy and achieved better sensitivity of the FN/SFN diagnosis in thyroid nodules that were inconclusive by FNAC. In the preoperative diagnosis of FN/SFN, CNB has no advantage over FNAC in predicting the likelihood of malignancy, but helps to reduce the need for repeat biopsy., (© 2014 APMIS. Published by John Wiley & Sons Ltd.)

When calcification, frequently found in both benign and malignant nodules, is present in thyroid nodules, non-invasive differentiation with ultrasound becomes challenging. The goal of this study was to evaluate the utility of elastography in differentiating calcified thyroid nodules. Consecutive patients (165 patients with 196 nodules) referred for fine-needle aspiration who had undergone both ultrasound elastography and B-mode examinations were analyzed retrospectively. Calcification was present in 45 benign and 20 malignant nodules. On 65 calcified nodules, elastography had 95% sensitivity, 51.1% specificity, 46.3% positive predictive value and 95.8% negative predictive value in detecting malignancy. Twenty-three of 45 benign calcified nodules were correctly diagnosed with elastography compared with 4 of 45 by B-mode ultrasound. Although it is difficult to differentiate benign and malignant calcified thyroid nodules solely with B-mode ultrasound, elastography has the potential to reduce the number of fine-needle aspiration biopsies performed on calcified nodules., (Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Background: Patients with non-diagnostic thyroid fine needle aspiration cytology (FNAC) results undergo repeat FNAC or core needle biopsy (CNB) for definite diagnosis or surgical resection, or are followed up by clinical and ultrasound surveillance. We aimed at evaluating the risk of malignancy in patients with non-diagnostic FNACs and their clinical outcomes according to the follow-up modality., Methods: We retrospectively reviewed 1,496 (8.8 %) cases with a non-diagnostic result on a first aspiration among 17,045 thyroid FNACs performed between October 2008 and August 2012. Of the non-diagnostic FNACs, 389 patients underwent a second FNAC; 125, CNB; and 89, thyroidectomy by clinical indication. The remaining patients were clinically followed up., Results: The rate of a second non-diagnostic result was significantly higher on repeat FNAC than on CNB (33.2 vs. 2.4 %; p < 0.001). There was no significant difference in the malignancy risk among patients initially non-diagnostic, twice non-diagnostic, and thrice or more non-diagnostic, nor did this differ from the rate following CNB. No further malignancy was found in cases with ≥2 non-diagnostic CNBs. The malignancy risk was 51 % in those who underwent thyroidectomy. The sensitivity for detecting malignancy was 65 and 70 % for repeat FNACs and first CNBs, respectively, with no false positives seen in either test., Conclusions: Approximately one-third of repeat FNACs after an initial non-diagnostic aspirate are non-diagnostic on repeat examination, and the malignancy risk may not reduce following repetitively non-diagnostic FNACs. However, a single CNB may be enough to exclude malignancy risk for patients with a non-diagnostic aspirate.

Objective: The objective of this retrospective study was to develop and validate a simple diagnostic prediction model by using ultrasound (US) features of thyroid nodules obtained from multicenter retrospective data., Materials and Methods: Patient data were collected from 20 different institutions and the data included 2000 thyroid nodules from 1796 patients. For developing a diagnostic prediction model to estimate the malignant risk of thyroid nodules using suspicious malignant US features, we developed a training model in a subset of 1402 nodules from 1260 patients. Several suspicious malignant US features were evaluated to create the prediction model using a scoring tool. The scores for such US features were estimated by calculating odds ratios, and the risk score of malignancy for each thyroid nodule was defined as the sum of these individual scores. Later, we verified the usefulness of developed scoring system by applying into the remaining 598 nodules from 536 patients., Results: Among 2000 tumors, 1268 were benign and 732 were malignant. In our multiple regression analysis models, the following US features were statistically significant for malignant nodules when using the training data set: hypoechogenicity, marked hypoechogenicity, non-parallel orientation, microlobulated or spiculated margin, ill-defined margins, and microcalcifications. The malignancy rate was 7.3% in thyroid nodules that did not have suspicious-malignant features on US. Area under the receiver operating characteristic (ROC) curve was 0.867, which shows that the US risk score help predict thyroid malignancy well. In the test data set, the malignancy rates were 6.2% in thyroid nodules without malignant features on US. Area under the ROC curve of the test set was 0.872 when using the prediction model., Conclusion: The predictor model using suspicious malignant US features may be helpful in risk stratification of thyroid nodules.

Thermal ablation using radiofrequency is a new, minimally invasive modality employed as an alternative to surgery in patients with benign thyroid nodules and recurrent thyroid cancers. The Task Force Committee of the Korean Society of Thyroid Radiology has developed recommendations for the optimal use of radiofrequency ablation for thyroid nodules. These recommendations are based on a comprehensive analysis of the current literature, the results of multicenter studies, and expert consensus.

Purpose: To evaluate clinical aspects and imaging features of complications encountered in the treatment of benign thyroid nodules with radiofrequency (RF) ablation., Materials and Methods: Institutional review board approval was obtained for this retrospective study, and informed consent was waived. From June 2002 to September 2009, 1459 patients underwent RF ablation of 1543 thyroid nodules with an RF system with internally cooled electrodes at 13 thyroid centers, which were members of Korean Society of Thyroid Radiology. Numbers and types of major and minor complications were assessed., Results: The authors observed 48 complications (3.3%), 20 major and 28 minor. The major complications were voice changes (n = 15), brachial plexus injury (n = 1), tumor rupture (n = 3), and permanent hypothyroidism (n = 1). The minor complications were hematoma (n = 15), skin burn (n = 4), and vomiting (n = 9). All patients recovered spontaneously except for one with permanent hypothyroidism and one who underwent surgery., Conclusion: Although the complication rate of RF ablation is low, various complications may occur; comprehension of complications and suggested technical tips may prevent complications or properly manage those that occur., (© RSNA, 2011.)

The detection of thyroid nodules has become more common with the widespread use of ultrasonography (US). US is the mainstay for detecting and making the differential diagnosis of thyroid nodules as well as for providing guidance for a biopsy. The Task Force on Thyroid Nodules of the Korean Society of Thyroid Radiology has developed recommendations for the US diagnosis and US-based management of thyroid nodules. The review and recommendations in this report have been based on a comprehensive analysis of the current literature, the results of multicenter studies and from the consensus of experts.

Objective: Inter- and intraobserver variabilities in the description and diagnostic categorization of sonographic (US) features of thyroid nodules were evaluated., Methods: The current study was conducted on 72 malignant nodules and 61 benign nodules. The US findings for each thyroid nodule were analyzed twice at a 6-week interval by five radiologists. The analyses were in accordance with the guidelines proposed by the Thyroid Study Group of the Korean Society of Neuroradiology and Head and Neck Radiology (TSGKSNRHNR). Inter- and intraobserver variabilities were calculated using Cohen's kappa statistics. The sensitivity, specificity, positive-predictive value, and negative-predictive value in the assessment of the diagnostic accuracy using these guidelines were calculated., Result: The interobserver agreement was fair to substantial for US features and categorization. Of the US features of the thyroid nodules, internal content (solid versus cystic) showed substantial agreement (k = 0.64). There was moderate agreement with regard to shape, echogenicity, calcification, and diagnostic categories (k = 0.42, 0.57, 0.55, and 0.55, respectively). There was fair agreement for margin, echotexture, and capsule invasion (k = 0.34, 0.26, and 0.32, respectively). With regard to intraobserver agreement, there was moderate to substantial agreement for all US features except for echotexture and capsule invasion, which showed fair agreement. In particular, there was moderate to almost perfect agreement for the diagnostic category. The sensitivity, specificity, positive-predictive value, and negative-predictive value were 65.3%-81.9%, 60.7%-68.9%, 69.7%-73.8%, and 66.6%-75.5%, respectively., Conclusion: There were high degrees of inter- and intraobserver agreement using the "Guidelines for diagnostic thyroid ultrasonography," of the TSGKSNRHNR in the description and categorization of thyroid nodules.

Purpose: To retrospectively evaluate the diagnostic accuracy of ultrasonographic (US) criteria for the depiction of benign and malignant thyroid nodules by using tissue diagnosis as the reference standard., Materials and Methods: This study had institutional review board approval, and informed consent was waived. From January 2003 through June 2003, 8024 consecutive patients had undergone thyroid US at nine affiliated hospitals. A total of 831 patients (716 women, 115 men; mean age, 49.5 years +/- 13.8 [standard deviation]) with 849 nodules (360 malignant, 489 benign) that were diagnosed at surgery or biopsy were included in this study. Three radiologists retrospectively evaluated the following characteristics on US images: nodule size, presence of spongiform appearance, shape, margin, echotexture, echogenicity, and presence of microcalcification, macrocalcification, or rim calcification. A chi(2) test and multiple regression analysis were performed. Sensitivity, specificity, and positive and negative predictive values were obtained., Results: Statistically significant (P < .05) findings of malignancy were a taller-than-wide shape (sensitivity, 40.0%; specificity, 91.4%), a spiculated margin (sensitivity, 48.3%; specificity, 91.8%), marked hypoechogenicity (sensitivity, 41.4%; specificity, 92.2%), microcalcification (sensitivity, 44.2%; specificity, 90.8%), and macrocalcification (sensitivity, 9.7%; specificity, 96.1%). The US findings for benign nodules were isoechogenicity (sensitivity, 56.6%; specificity, 88.1%; P < .001) and a spongiform appearance (sensitivity, 10.4%; specificity, 99.7%; P < .001). The presence of at least one malignant US finding had a sensitivity of 83.3%, a specificity of 74.0%, and a diagnostic accuracy of 78.0%. For thyroid nodules with a diameter of 1 cm or less, the sensitivity of microcalcifications was lower than that in larger nodules (36.6% vs 51.4%, P < .05)., Conclusion: Shape, margin, echogenicity, and presence of calcification are helpful criteria for the discrimination of malignant from benign nodules; the diagnostic accuracy of US criteria is dependent on tumor size., ((c) RSNA, 2008.)

The role of ultrasound-guided core-needle biopsy (CNB) for the diagnosis of follicular neoplasm (FN) in the screening of thyroid nodules is controversial. We developed a diagnostic system for FN in CNB specimens and aimed to validate the clinical usefulness of the method compared with fine-needle aspiration cytology (FNAC). We reviewed 5993 FNACs and 1303 CNBs from the pathology database at Seoul St. Mary's Hospital between August 2012 and December 2014. The diagnostic rate of FN was significantly higher in CNB than in FNAC (15.7% vs. 2.4%, respectively; P < 0.001). A total of 289 cases (117 FNACs and 172 CNBs) were confirmed histologically after surgical resection. NRAS mutation testing was performed with pyrosequencing. Comparing the FNAC and CNB groups, there were no differences in the positive predictive values for neoplasm (84.6% vs. 89.0%, respectively; P = 0.200) and malignancy (48.7% vs. 43.0%, respectively; P = 0.340). When we excluded the noninvasive encapsulated follicular variant of papillary carcinoma from the malignancy group, there was also no significant difference in the malignancy risk between the two groups (22.7% and 27.4% in the CNB and FNAC groups, respectively; P = 0.365). The NRAS mutation rate was 26.5% (57/215) in all FNs and occurred with similar frequency in both groups. The sensitivity, specificity, positive predictive value, and negative predictive value of a NRAS testing to predict malignancy were 40.6%, 84.9%, 68.4%, and 63.9%. In conclusion, FN was more frequently diagnosed in the CNB group than in the FNAC group, but the rates of malignancy, neoplasm, and NRAS mutation were equivalent in both groups. Therefore, CNB is a good method for the diagnosis of FN in thyroid nodule screening. [ABSTRACT FROM AUTHOR]