Radiofrequency ablation (RFA) is a minimally invasive treatment modality used as an alternative to surgery in patients with benign thyroid nodules, recurrent thyroid cancers (RTCs), and primary thyroid microcarcinomas. The Korean Society of Thyroid Radiology (KSThR) initially developed recommendations for the optimal use of RFA for thyroid tumors in 2009 and revised them in 2012 and 2017. As new meaningful evidence has accumulated since 2017 and in response to a growing global interest in the use of RFA for treating malignant thyroid lesions, the task force committee members of the KSThR decided to update the guidelines on the use of RFA for the management of RTCs based on a comprehensive analysis of current literature and expert consensus.

BACKGROUND:This study aimed to evaluate the safety, efficacy, and oncologic outcomes of thermal ablation techniques, including radiofrequency, laser, and microwave ablation, in treating primary thyroid cancer compared with surgical resection. METHOD:We conducted a systematic review and network meta-analysis, which included 21 comparative studies and 40 noncomparative studies. RESULTS:The three thermal ablation techniques showed significant superiority over surgical resection in terms of operative time, pain, cost, quality of life, and complications. Three years after the procedure, the tumor volume reduction and complete disappearance rates for the three thermal ablation techniques were similar, at approximately 99% and 93%-95%, respectively. The recurrence rate remained comparable (approximately 2%-3%) among the three thermal ablation techniques and surgical resection during a follow-up period exceeding 3 years. CONCLUSIONS:The safety, efficacy, and oncologic outcomes of thermal ablation techniques may be acceptable and comparable to surgical resection for selected cases of primary thyroid cancer.

BackgroundThis study was conducted to evaluate the feasibility and surgical outcomes of minimally invasive video-assisted thyroidectomy (MIVAT) and three remote-access approaches, namely the robotic bilateral axillo-breast approach (BABA-R), endoscopic breast-chest approach (BCA-E), and robotic gasless transaxillary approach (GTAA-R) in lateral neck dissection for papillary thyroid carcinoma, compared with conventional transcervical approach (CTA).MethodsThe literature search was conducted in the PubMed, EMBASE, and Cochrane Library databases, covering the period January 2000 to February 2024. A systematic review and network meta-analysis were performed to compare surgical feasibility, safety, and oncologic outcomes between approaches.ResultsFourteen articles on lateral neck dissection in patients with papillary thyroid carcinoma were included after systematic screening. The number of removed and metastatic lateral lymph nodes, the extent of lateral neck dissection, the rate of transient recurrent laryngeal nerve palsy and hypoparathyroidism, serum-stimulated thyroglobulin levels, and recurrence were not significantly different between the MIVAT and three remote-access approaches. Additionally, these were comparable to those of the CTA. However, the MIVAT and remote-access approaches took a longer operative time but provided superior cosmetic outcomes compared to the CTA.ConclusionLateral neck dissection using the MIVAT and three remote-access approaches was feasible and comparable to CTA in the number of lymph nodes removed, complications, stimulated thyroglobulin level, and recurrence. The MIVAT and remote-access approaches lasted longer but provided significantly superior cosmetic outcomes compared to the CTA.

BACKGROUND:The oncologic safety and surgical completeness of remote-access thyroidectomies are not yet clearly established. This study evaluates the oncologic outcomes and surgical completeness of three prevalent remote-access thyroidectomies: the gasless transaxillary approach (GTAA), bilateral axillo-breast approach (BABA), and transoral approach (TOA), in comparison with conventional transcervical thyroidectomy (CTT).METHODS:Literature searches were conducted in PubMed, EMBASE, and the Cochrane Library databases, covering the period from 2000 to 2023. Network meta-analyses were performed on selected studies, focusing on recurrence and surgical completeness. Surgical completeness was assessed using stimulated serum thyroglobulin levels and the count of retrieved lymph nodes.RESULTS:The review included 48 studies, encompassing a total of 16,356 patients. The number of retrieved lymph nodes was comparable among BABA, TOA, and CTT, while GTAA might be less effective. Stimulated serum thyroglobulin levels showed no significant differences across the four groups. However, the proportion of patients with stimulated thyroglobulin levels below 1.0 ng/mL was significantly lower in GTAA compared to the other groups. The overall recurrence rates were 1.31% for CTT, 0.89% for GTAA, 0.62% for BABA, and 0% for TOA, with no significant differences in recurrence rates when adjusted for follow-up duration.CONCLUSIONS:This study demonstrated that the oncologic outcomes of GTAA, BABA, and TOA are comparable to those of CTT, based on recurrence rates. In terms of surgical completeness, BABA and TOA showed equivalence to CTT, whereas GTAA might be inferior to the other techniques.

PURPOSE:The goal of this study was to follow benign thyroid nodules confirmed by ultrasound (US)-guided core needle biopsy (CNB) after inconclusive cytology on fine-needle aspiration (FNA) biopsy.METHODS:Sixty-two thyroid nodules from 62 patients with CNB-confirmed benign histology that initially had inconclusive cytology on FNA were retrospectively included. The thyroid nodules were followed for 38.7 months (median, 27.5 months; range, 6 to 101 months), and the US findings of biopsied nodules, such as the interval change in size, US characteristics, and imaging category based on the Korean Thyroid Imaging Reporting and Data System (K-TIRADS), were evaluated. In addition, patients' clinical records were reviewed for any further management or newly diagnosed thyroid malignancy.RESULTS:Among 62 cases, three (4.8%) showed interval size growth, while 59 (95.2%) demonstrated no interval change or a decrease in size. There was no upgrade of K-TIRADS category or any newly diagnosed malignancy during the follow-up period.CONCLUSION:US-guided CNB-confirmed benign thyroid nodules with inconclusive cytology on FNA showed a stable status during follow-up, and repeated CNB could be helpful in the management of nodules with inconclusive cytology on FNA.

Immunoglobulin G4 (IgG4)-related disease is a systemic fibro-inflammatory disease characterized by pathologic findings in various organs. Imaging is critical for the diagnosis and treatment assessment of patients with IgG4-related disease. In this pictorial essay, we review the key features of multiple imaging modalities, typical pathologic findings, and differential diagnosis of IgG4-related disease. This systematic pictorial review can further our understanding of the broad-spectrum manifestations of this disease.

To provide high-quality training to residents in a rapidly changing medical environment, it is very important to improve the annual training curriculum centered on competency and ensure that training hospitals maintain an environment suitable for training. The Korean Society of Radiology (KSR) has been steadily improving the training system and has suggested the improvement of the training system by strengthening the competency-based evaluation and faculty development. Currently, KSR was selected for the second annual training curriculum systematization construction project in July 2021, and developed entrustable professional activities, core competencies, and assessment guidelines required by the construction project. Therefore, the development process and assessment guidelines will be introduced to residents and the faculty.

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.

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.

Objectives: The purpose of this study was to compare the short-term voice outcomes of transoral robotic thyroidectomy (TORT) and trans-cervical thyroidectomy. Materials and methods: The acoustic parameters and the voice handicap index (VHI)-10 scores were compared between the two groups preoperatively, and 1 week, 1 month, and 3 months postoperatively. Results: Forty-two patients in the TORT group and 47 patients in the trans-cervical group completed the VHI-10 questionnaire and acoustic analysis. The highest frequency and pitch range was higher and broader, respectively, in the TORT group than in the trans-cervical group until 3 months after surgery. They were not significantly impaired by surgery in the TORT group. The postoperative VHI-10 score was not significantly different between the two groups at any time point. Surgical approach (TORT vs. trans-cervical) and age were independent factors related to highest frequency and pitch range in multiple regression analysis. Conclusion: TORT has advantages of excellent postoperative voice outcomes compared to trans-cervical thyroidectomy in the short-term period.

Purpose We aimed to compare the efficacy of ultrasound-guided core-needle biopsy (CNB) with repeat fine-needle aspiration (rFNA) cytology in thyroid nodules with inconclusive results in initial fine-needle aspiration cytology. Methods We studied 402 patients who required a repeat biopsy of thyroid nodules using ultrasound-guided CNB (n = 192) or rFNA (n = 210) because of inconclusive results in initial FNA, corresponding to categories I, III, and IV of the Bethesda System for Reporting Thyroid Cytopathology. If repeat biopsy results were benign (category II), suspicious malignancy (category V), or malignancy (category VI), they were defined as "diagnostic results". The diagnostic yield and performances of repeat biopsy were analyzed and compared between the rFNA and CNB groups. Results The diagnostic results were obtained significantly higher in the CNB group than in the rFNA group (72.4% vs. 52.4%; P < 0.001). In the subgroup analysis, the diagnostic results were significantly higher in the CNB group than in the rFNA group for patients of categories I and III (P < 0.001 in both) in initial FNA. However, in patients with category IV nodules, there were no significant differences in diagnostic results between the two groups (P = 0.46). Conclusion Compared to rFNA, ultrasound-guided CNB is useful and effective as a repeat biopsy option for thyroid nodules with non-diagnostic results (category I) and atypia of undetermined significance (AUS) or follicular lesion of undetermined significance (FLUS) (category III) in initial FNA.

Background Previous studies have suggested that texture analysis is a promising tool in the diagnosis, characterization, and assessment of treatment response in various cancer types. Therefore, application of texture analysis may be helpful for early prediction of pathologic response in breast cancer. Purpose To investigate whether texture analysis of features from MRI is associated with pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC) in breast cancer. Materials and Methods This retrospective study included 136 women (mean age, 47.9 years; range, 31-70 years) who underwent NAC and subsequent surgery for breast cancer between January 2012 and August 2017. Patients were monitored with 3.0-T MRI before (pretreatment) and after (midtreatment) three or four cycles of NAC. Texture analysis was performed at pre- and midtreatment T2-weighted MRI, contrast material-enhanced T1-weighted MRI, diffusion-weighted MRI, and apparent diffusion coefficient (ADC) mapping by using commercial software. A random forest method was applied to build a predictive model for classifying those with pCR with use of texture parameters. Diagnostic performance for predicting pCR was assessed and compared with that of six other machine learning classifiers (adaptive boosting, decision tree, k-nearest neighbor, linear support vector machine, naive Bayes, and linear discriminant analysis) by using the Wald test and DeLong method. Results Forty of the 136 patients (29%) achieved pCR after NAC. In the prediction of pCR, the random forest classifier showed the lowest diagnostic performance with pretreatment ADC (area under the receiver operating characteristic curve [AUC], 0.53; 95% confidence interval: 0.44, 0.61) and the highest diagnostic performance with midtreatment contrast-enhanced T1-weighted MRI (AUC, 0.82; 95% confidence interval: 0.74, 0.88) among pre- and midtreatment T2-weighted MRI, contrast-enhanced T1-weighted MRI, diffusion-weighted MRI, and ADC mapping. Conclusion Texture parameters using a random forest method of contrast-enhanced T1-weighted MRI at midtreatment of neoadjuvant chemotherapy were valuable and associated with pathologic complete response in breast cancer. © RSNA, 2019 Online supplemental material is available for this article.

Purpose To evaluate a deep learning model to predict recurrence of thyroid tumor using preoperative ultrasonography (US). Materials and Methods We included representative images from 229 US-based patients (male:female = 42:187; mean age, 49.6 years) who had been diagnosed with thyroid cancer on preoperative US and subsequently underwent thyroid surgery. After selecting each representative transverse or longitudinal US image, we created a data set from the resulting database of 898 images after augmentation. The Python 2.7.6 and Keras 2.1.5 framework for neural networks were used for deep learning with a convolutional neural network. We compared the clinical and histological features between patients with and without recurrence. The predictive performance of the deep learning model between groups was evaluated using receiver operating characteristic (ROC) analysis, and the area under the ROC curve served as a summary of the prognostic performance of the deep learning model to predict recurrent thyroid cancer. Results Tumor recurrence was noted in 49 (21.4%) among the 229 patients. Tumor size and multifocality varied significantly between the groups with and without recurrence (p < 0.05). The overall mean area under the curve (AUC) value of the deep learning model for prediction of recurrent thyroid cancer was 0.9 ± 0.06. The mean AUC value was 0.87 ± 0.03 in macrocarcinoma and 0.79 ± 0.16 in microcarcinoma. Conclusion A deep learning model for analysis of US images of thyroid cancer showed the possibility of predicting recurrence of thyroid cancer.

Objectives/HypothesisUltrasound‐guided fine‐needle aspiration cytology (US‐FNAC) is a well‐established procedure performed to establish the diagnosis of Kikuchi‐Fujimoto disease (KFD). Ultrasound‐guided core needle biopsy (US‐CNB) is an alternative diagnostic tool for KFD. However, the efficacy of US‐CNB is not well evaluated. This study aimed to evaluate the efficacy of US‐CNB and compare it with that of US‐FNAC in the diagnosis of KFD.Study DesignRetrospective cohort study.MethodsWe analyzed 170 patients who were diagnosed with KFD between January 2009 and May 2019. US‐FNAC, US‐CNB, and excisional biopsy were performed in 47, 114, and 9 patients, respectively. Diagnostic accuracies of US‐FNAC and US‐CNB were analyzed and compared.ResultsOf the 170 patients, 45 and 125 were men and women, respectively. The mean age was 26.9 ± 9.1 years. The most common symptom was cervical lymphadenopathy, followed by fever, headache, and myalgia. The diagnosis of KFD was established primarily by US‐FNAC in 21 (44.7%) of the 47 patients, by US‐CNB in 109 (95.6%) of the 114 patients, and by excisional biopsy in all 9 patients. There was no specific major complication related to US‐FNAC and US‐CNB.ConclusionUS‐CNB can be considered safe and effective and used as the primary modality for the pathological diagnosis of KFD.Level of Evidence4. Laryngoscope, 131:E1519–E1523, 2021

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.

Histiocytic sarcoma is a rare hematologic malignancy, with very few cases of primary histiocytic sarcoma of the breast described in English scientific literature. Herein, we describe a case of primary histiocytic sarcoma of the breast in a 75-year-old woman, with no clinical history of malignant tumors, who presented with a palpable solitary breast mass. Microscopically, the resected breast mass showed large pleomorphic cells, some multinucleated giant cells, and admixed inflammatory components. The pleomorphic tumor cells further showed a diffuse, noncohesive growth pattern, an abundant eosinophilic cytoplasm, and strong and diffuse immunoreactivity for cluster of differentiation (CD) 68 and CD163. Furthermore, a whole-body positron-emission tomography/computed tomography using deoxy-2-[18F]fluoro-D-glucose performed after surgery showed no other masses or lesions. After surgical excision, the patient was followed up, and no evidence of tumor recurrence or metastasis was noted.

BACKGROUND:The aim of this study was to evaluate the safety and efficacy of transoral robotic and endoscopic thyroidectomy.METHODS:We analyzed and compared the first 100 cases of transoral robotic (71 cases) and endoscopic (29 cases) thyroidectomy with 207 cases of conventional transcervical thyroidectomy.RESULTS:Transoral thyroidectomy was completed successfully in all patients, except for three who were converted to the robotic facelift or transcervical approach. The mean operative time of the transoral procedure was significantly longer than that of the conventional procedure. Perioperative complications such as hypoparathyroidism, vocal cord palsy, hematoma, and seroma did not differ between the two groups. However, there were some unusual complications such as CO2 embolism, surgical site infection, skin trauma, burn, and ecchymosis in transoral thyroidectomy. Postoperative cosmesis was significantly better in the transoral group.CONCLUSION:Transoral robotic and endoscopic thyroidectomy is feasible and comparable to conventional transcervical thyroidectomy in highly selected patients.