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.

RF ablation was effective in shrinking benign thyroid nodules and in controlling nodule-related problems over a 4-year follow-up. There were no life-threatening complications or sequelae. Therefore, RF ablation can be used as a non-surgical treatment for patients with benign non-functioning thyroid nodules.

Core needle biopsy (CNB) has been suggested as a complementary diagnostic method to fine-needle aspiration in patients with thyroid nodules. Many recent CNB studies have suggested a more advanced role for CNB, but there are still no guidelines on its use. Therefore, the Task Force Committee of the Korean Society of Thyroid Radiology has developed the present consensus statement and recommendations for the role of CNB in the diagnosis of thyroid nodules. These recommendations are based on evidence from the current literature and expert consensus.

Purpose To compare the diagnostic performance of ultrasonography (US)-based fine-needle aspiration biopsy (FNAB) criteria from seven international societies in the detection of thyroid malignancy. Materials and Methods This study included a total of 2000 consecutive thyroid nodules (≥1 cm) in 1802 patients with final diagnoses from January 2010 to May 2011. US features of the thyroid nodules were retrospectively reviewed and were classified according to the categories defined by the seven international society guidelines. The diagnostic performance of US-based FNAB criteria in the detection of thyroid malignancy and unnecessary FNAB rates were calculated and compared by using a generalized estimating equation method. Results Of the 2000 thyroid nodules, 1546 (78.3%) were benign and 454 (22.7%) were malignant, with papillary carcinoma comprising 85.5% of all malignancies. The Korean Thyroid Association/Korean Society of Thyroid Radiology (KTA/KSThR) (94.5%), National Comprehensive Cancer Network (NCCN) (92.5%), and American Thyroid Association (ATA) (89.6%) guidelines were more sensitive than those of the American Association of Clinical Endocrinologists/American College of Endocrinology/Associazione Medici Endocrinologi (AACE/ACE/AME) (80.4%), American College of Radiology (ACR) (74.7%), French Society of Endocrinology (FSE) (72.7%), and Society of Radiology in Ultrasound (SRU) (70.9%) (P < .001), while the latter guidelines had higher specificity (P < .001). The rate of unnecessary FNAB was lowest with the ACR guidelines (25.3%), followed by the FSE (29.1%), AACE/ACE/AME (32.5%), SRU (45.2%), ATA (51.7%), NCCN (54.0%), and KTA/KSThR (56.9%) guidelines. Conclusion Because the diagnostic performance of US-based FNAB criteria varies according to the individual international society guidelines, clinicians should be aware of the strengths and weaknesses of US-based FNAB criteria in the management of thyroid nodules. RSNA, 2018 Online supplemental material is available for this article.