Thyroid Oct 26, Thu. Thyroid 08:00-09:30 208

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1 Thyroid 377 SS 22 PD-08 :00 Ultrafast Doppler US for cranial arteries in neonates Hyun Gi Kim Ajou University Hospital, Korea. Thyroid 08:00-09: Thyroid cancer PURPOSE: Recently, Ultrafast Doppler technique has been developed. The method made possible to merge color and spectral Doppler in one feature. The objective of this study was to investigate the accuracy and usefulness of the new technique. MATERIALS AND METHODS: Thirty neonates underwent both conventional and Ultrafast Doppler ultrasound (US). With both methods, we measured peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI) of the anterior cerebral artery (ACA), the middle cerebral artery (MCA), and the posterior cerebral artery (PCA). The occurrence of technical failures and acquisition time of each method were evaluated. RESULTS: The mean corrected gestational age of neonates at the time of Doppler study was 38. ± 2.6 weeks. The measured values of ACA were comparable between the conventional and Ultrafast Doppler US: PSV, 75. cm/s and 70.3 cm/s (p = 0.05); EDV, 2.5 cm/s and 9.6 cm/s (p = 0.69); and RI, 0.72 and 0.73 (p = 0.480). The measured values of MCA (PSV, 87.6 cm/s and 84.5 cm/s [p = 0.94]; EDV, 26.3 cm/s and 24. cm/s [p = 0.44]; and RI, 0.69 and 0.72 [p = 0.054]) and PCA (PSV, 62.8 cm/s and 6.9 cm/s [p = 0.645]; EDV, 9.4 cm/s and 9.7 cm/s [p = 0.699]; and RI, 0.70 and 0.68 [p = 0.30]) were comparable between the conventional and Ultrafast Doppler US. There was no difference between the two methods in terms of technical failure. Compared to the conventional technique, the acquisition time was shorter using the Ultrafast Doppler US (3.8 ± 0.4 seconds vs. 4.3 ± 0.6 seconds, p = 0.00). CONCLUSION: Ultrafast Doppler US provides comparable values to conventional Doppler and has an advantage for shorter acquisition time when used for cranial arteries in neonates. Chairperson(s) Jung Hwan Baek University of Ulsan College of Medicine, Asan Medical Center, Korea Jung suk Sim Withsim Clinic, Korea SS 04 TH-0 08:00 Recurrent/persistent papillary thyroid carcinoma: clinical and radiological characteristics of radiologically stable disease versus progressive disease Taek Min Kim, Ji-hoon Kim, Eun Kyoung Hong, Roh-Eul Yoo, Koung Mi Kang, Tae Jin Yun, Seung Hong Choi, Chul-Ho Sohn Seoul National University Hospital, Korea. jihnkim@gmail.com PURPOSE: To assess the relative incidence and to evaluate clinical/radiological differences between the radiologically stable recurrent or persistent papillary thyroid cancer (RPTC) and progressive RPTC. MATERIALS AND METHODS: From January 2005 to October 205, 08 patients (M:F = 28:80; mean age, 53.5 years) with recurrent/persistent thyroid carcinoma who underwent at least two CT examinations prior to the re-operation were included in this retrospective study. The two CT examinations (mean interval, 28.8 months; range, 2-9 months) were reviewed to determine whether the tumor recurrence was stable (no size increase between the two CT exams) or progressive (more than 2 mm increase in size between the two CT exams). Radiological features and clinical characteristics of stable and progressive groups were compared using t-test and chi-square test, as appropriate. RESULTS: The relative incidences of stable RPTC and progressive RPTC were 55.6% (60/08) and 44.4% (48/08), respectively. Among progressive RPTC, 4.8% (6/08) patients demonstrated increase in size of tumors, and 29.6% (32/08) patients presented with newly appeared tumor between the two CT exams. There was no significant difference in size of recurrent tumor between stable and progressive group at the st CT exam (mean, 0. mm vs..0 mm). The mean growth rate of progressive group was 4.6 mm/year (range, mm). Among the various radiological and clinical factors, there were significant differences in age (48.8 years vs years, p < 0.00) and history of neck dissection at corresponding level (5.% [2/39] vs. 65.5% [9/29], p < 0.00) between radiologically stable

2 378 KCR 207 and progressive group, respectively. CONCLUSION: More than a half of the surgically confirmed RPTC, included in our study, were radiologically stable. However, the previous neck dissection at the level of the recurrent tumor was a factor that could potentially distinguish progressive RPTC from stable RPTC. SS 04 TH-02 08:0 Histogram analysis of apparent diffusion coefficient maps to differentiate follicular thyroid carcinomas from adenomas among indeterminate thyroid nodules on US-guided core needle biopsy Sae Rom Chung, Jeong Hyun Lee, Young Jun Choi, Jung Hwan Baek Asan Medical Center, Korea. jeonghlee@amc.seoul.kr PURPOSE: To evaluate the role of histogram analysis of apparent diffusion coefficient (ADC) map to differentiate follicular carcinomas from adenomas among thyroid nodules with indeterminate cytology on US-guided core needle biopsy. MATERIALS AND METHODS: This prospective protocol was approved by our local Institutional Review Board. Seventeen patients were prospectively enrolled, who were planned to undergo diagnostic lobectomy for indeterminate thyroid nodule (atypical of unknown significance/follicular lesion of undetermined significance [AUS/FLUS] or suspicious for follicular neoplasm/follicular neoplasm [SFN]) on US-guided core needle biopsy (USCNB). All patients underwent diffusion-weighted imaging (DWI) using zoomed EPI sequence on the day before surgery. Histogram parameters were derived from ADC values obtained using a hand-drawn region-of-interest of a whole tumor on the ADC map. The parameters were compared with the final diagnosis based on histopathological examination after surgery. The accuracy of the parameters in differentiating follicular carcinoma from follicular adenoma was evaluated using the receiveroperating characteristic curve (ROC) analysis. RESULTS: Twelve patients were confirmed as follicular adenoma and five patients as follicular carcinoma. Histogram-derived parameters including 0th (ADC 0th ) and 25th (ADC 25th ) percentiles, and median of ADC values were significantly lower in follicular adenoma than follicular carcinoma (p < 0.05, respectively). ROC curve analysis revealed ADC 25th achieved the highest AUC (0.867) with cutoff value of mm 2 /s. CONCLUSION: Histogram-derived parameters of ADC maps could effectively differentiate follicular carcinoma from adenoma in patients with indeterminate thyroid nodules on US-guided core needle biopsy with ADC 25th being the most promising parameter. SS 04 TH-03 08:20 Columnar cell variant of papillary thyroid carcinoma: differentiation between indolent and aggressive types Joo Yeon Cho, Jung Hee Shin, Soo Yeun Hahn, Young Lyun Oh Samsung Medical Center, Korea. porori3@naver.com PURPOSE: The columnar cell variant of papillary thyroid carcinoma (CCV-PTC) is regarded as a rare subtype of PTC that is classified into one of aggressive variants with early dissemination and short survival periods. However, the prognosis of the columnar cell variant is still controversial, as cases of CCV- PTC with indolent behavior have also been reported. MATERIALS AND METHODS: Seven cases of CCV- PTC were identified from surgical pathology at Samsung Medical Center from 994 to 206. The histological, architectural, and cytological features fulfilled the diagnostic criteria of the CCV-PTC. We reviewed the US features and clinicopathological findings of 7 cases. RESULTS: Four young female patients aged from 27 to 34 years (mean, 3.25 years) were proven as indolent clinical course, two old patients aged 55 and 70 years were presented as aggressive clinical course. The remaining one old patient was incidentally found and not followed up. All patients underwent total thyroidectomy and radioiodine therapy. Indolent group had T staging without nodal metastasis and no disease during follow-up (range, 8-7 years). While aggressive group showed greater tumor size (.8 cm and 6 cm), gross extrathyroidal extension to muscle, lymph node and distant metastasis. One male patient who recurred immediately after operation died four years after the diagnosis of thyroid cancer. At US, indolent group revealed smooth margin except for one. All two cases of aggressive group had microlobulated margin. CONCLUSION: CCV-PTC has a good prognosis in young patients with T staging. Early recognition and complete treatment prevent aggressive course of this tumor.

3 Thyroid 379 SS 04 TH-04 08:30 Risk of thyroid malignancy in lung cancer risk patients with incidental thyroid nodules detected on screening low dose chest CT Hyobin Seo, Kwang Nam Jin 2, Ji Sang park 3, Koung Mi Kang 4, Ji-hoon Kim 4 Korea University Anam Hospital, 2 SMG-SNU Boramae Medical Center, 3 Soonchunhyang University Bucheon Hospital, 4 Seoul National University Hospital, Korea. jihnkim@gmail.com PURPOSE: To evaluate clinical significance of incidental thyroid nodule (ITN) detected on screening low dose chest CT (LDCT) in high-risk patients for lung cancer. MATERIALS AND METHODS: From 2004 to 203, in single health-care center, 2379 consecutive subjects at high risk for lung cancer based on the National Lung Screening Trial (current or former smoker with cessation within 5 years, a history of cigarette smoking of at least 30 pack-years, and between 55 and 74 years of age) who underwent both screening LDCT and thyroid ultrasonography (US) were enrolled in this retrospective study. Clinicoradiolgical records were reviewed with focus on the presence of ITNs on LDCT, features of thyroid US, and cytopathologic results of thyroid nodules. The results were compared between the group with ITN and the group without ITN. RESULTS: In all populations, the prevalence of ITN on LDCT was 5.0% (0/202). The prevalence of the thyroid nodule on US and the thyroid nodule that met fine needle aspiration (FNA) criteria, percentage of the thyroid nodule that underwent FNA or core needle biopsy, the thyroid nodules that were cytohistologically reported as indication for surgery, and surgically proven thyroid cancer were as follows: 50.2% (05/202), 5.3% (08/202), 5.7% (6/202), 0.9% (9/202) and 0.5% (/202), respectively. Those results [94.% (95/0), 47.5% (48/0), 49.5% (50/0), 6.9% (7/0), 3.0% (3/0)] in patients with ITN were significantly higher than those (47.9% [920/920], 6.5% [60/920], 7.2% [66/920],.3% [2/920], 0.8% [7/920]) in patients without ITN (p = 0.000). All surgically proven thyroid cancers from 3 patients with ITN and from 8 patients without ITN were papillary thyroid microcarcinoma with low pathologic TNM stage (TaNa). CONCLUSION: In patients with high risk for lung cancer, ITN detected on LDCT increased the risk of the thyroid cancer. However, the risk for clinically significant thyroid cancer seems to be very low, whether there is ITN or not. SS 04 TH-05 08:40 BRAF V600E mutation from aspirates of papillary cancer: is there clinicopathological features differences compared to surgically confirmed specimen Yoonjung Choi, Shinho Kook, Seonhyeong Choi, Inyoung Yoon, Suji Kim, Doyeon Ahn Kangbuk Samsung Hospital, Korea. yoonjung99.choi@samsung.com PURPOSE: To compare the clinicopathological results and diagnostic accuracies of two different methods to obtain BRAF V600 mutation from papillary thyroid cancer (PTC): from the aspirate in pre surgical stage to BRAF mutated PTC evaluated and from the surgical gross specimen. MATERIALS AND METHODS: This retrospective study was approved by an Institutional Review Board, with waiver of informed consent for ultrasound guided fine needle aspiration (US-FNA) based cytology BRAF mutation test and surgical procedure. A total of 379 patients who underwent thyroidectomy for PTC were included; the number of patients diagnosed BRAF V600 mutation with cytology base (Group ) was 67(44.7%) and with the gross specimen (Group 2) was 762 (55.3%). Ultrasonographic examinations of the malignant thyroid nodules such as tumor size, multiplicity, bilaterality, vascular invasion (VI), lymphatic invasion (LI), extrathyroidal invasion (ETE), and lymph node metastasis (LNM) were retrospectively reviewed. The prevalence of BRAF V600 mutation in each group (Group vs. Group 2) was compared by using t-test and the difference of clinicopathological features in of BRAF V600E mutation of PTC patients between two groups was evaluated. RESULTS: Of 379 patients who underwent thyroidectomy for PTC, BRAF V600E mutation was present in 87 patients (86.%). Size, bilaterality, multifocality, LVI, BVI did not show any statistical differences between the BRAF positive and BRAF negative patients, but ETE, LNM, and other associated pathology such as Hashimoto thyroiditis and lymphocytic thyroiditis were statistically more frequent in BRAF mutated patient. 23 patients underwent BRAF test using both cytology and specimen in the same nodule. Among them, 5 patients had discordant BRAF mutation results; 4 out of 5 nodules were densely calcified nodules and the other was less than 5 mm. Group and group 2 respectively showed 83.3% (54 of 67 patients) and 88.3% (673 of 762 patients) positive for the BRAF mutation, and ETE was significantly more frequent in BRAF mutated group in both group and 2. CONCLUSION: Ultrasound features of malignant nodules should be considered when performing BRAF mutation test with aspiration, especially for the nodules with dense calcifications or with too small size.

4 380 KCR 207 SS 04 TH-06 08:50 US prediction of highly aggressive telomerase reverse transcriptase (TERT) promoter-mutated papillary thyroid cancer Jung han Woo, Tae Hyuk Kim, Chang-Seok Ki, Soo Yeon Hahn, Jung Hee Shin Samsung Medical Center, Korea. PURPOSE: Telomerase reverse transcriptase (TERT) promoter mutations are found in highly aggressive thyroid malignancies. Our aim was to define the ultrasonographic (US) features of TERT promoter-mutated papillary thyroid cancer (PTC) and to evaluate their predictive performances. MATERIALS AND METHODS: US findings were reviewed for 85 patients with surgically confirmed PTC between 994 and Genomic DNA to identify TERT promoter mutations was extracted from archived surgical specimens. Logistic regression analysis was performed to compare clinical factors and US findings between TERT promoter-mutated and wild-type PTCs. RESULTS: A TERT promoter mutation was detected in 8.% (5 of 85) of specimens from PTC patients with a strong trend toward increasing age. Nonparallel orientation and microlobulated margin were independent US findings for predicting TERT promoter-mutated PTC in patients over 50 years (odds ratio [OR] 5.898, 95% confidence interval [95% CI] , p = for orientation; OR 5.83, 95% CI , p = for margin). Prevalence of TERT promoter mutations increased to 50.0% in PTC patients older than 50 years with both US findings and was 0% in patients without either finding. For identifying TERT promoter-mutated PTC, US had 64.3% sensitivity, 80.8% specificity, 50.0% positive predictive value and 88.4% negative predictive value. CONCLUSION: TERT promoter-mutated PTC could be suggested by the US features of nonparallel orientation and microlobulated margin in patients older than 50 years. Prebiopsy recognition of this unique US pattern would mandate the nodule fall into a biopsy suggested category. SS 04 TH-07 09:00 Predictive findings of distant metastasis in follicular thyroid carcinoma patients Hankyul Kim, Jung Hee Shin, Soo Yeon Hahn, Young Lyun Oh, Sun Wook Kim Samsung Medical Center, Korea. helena35.shin@samsung.com PURPOSE: Follicular thyroid carcinoma (FTC) usually has a good prognosis as a well-differentiated tumor. However, its prognosis in the presence of distant metastasis is often poor. Identifying a FTC with a propensity to metastasis enables risk stratification of the patients. The aim of this study was to identify predictive findings of FTC associated with distant metastasis. MATERIALS AND METHODS: The Institutional Review Board approved this retrospective study and informed consent was waived. A review of medical records identified 406 patients who underwent surgery and were subsequently diagnosed as FTC from 994 to 206 in our institution. After review of imaging and pathologic studies, 32 patients were included in this study. Preoperative ultrasound and clinicopathologic features of FTC patients were compared between groups with and without distant metastasis. Sensitivity, specificity and the area under the receiver operating characteristic curve (AUC) were used to assess the diagnostic performance of distant metastasis for FTC. RESULTS: Distant metastasis in FTC patients was present in 37 (.5%) of 32 patients. Multivariate analysis adjusted for clinical variables revealed that independent predictors of distant metastasis for FTC were older age ( 55 years), internal multiloculation and the presence of rim calcification of thyroid nodules on ultrasound on preoperative status (p = , p = and p = , respectively) and older age ( 55 years), widely invasive pathologic type, internal multiloculation and the presence of rim calcification on ultrasound on postoperative status (p = 0.008, p = , p = , and p = , respectively). Sensitivities, specificities and AUCs for predicting distant metastasis for FTC were 86.5%, 77.5% and on preoperative status and 70.3%, 9.2% and on postoperative status, respectively. CONCLUSION: Ultrasonographic internal multiloculation, with rim calcification and older age ( 55 years), and pathologic widely invasiveness provide the predictive findings associated with distant metastasis in FTC patients.

5 Thyroid 38 SS 04 TH-08 09:0 Histogram analysis of grayscale US for the differentiation of the subtypes of follicular variant of papillary thyroid cancer Mi-ri Kwon, Jung Hee Shin, Soo Yeon Hahn, Ji young Kwak 2, Yaeji Lim 3, Eunjung Lee 4 Samsung Medical Center, 2 Yonsei University College of Medicine, 3 Department of Statistics, Pukyong National University, 4 Department of Computational Science and Engineering, Yonsei University, Korea. jhshin@skku.edu PURPOSE: To evaluate the diagnostic value of histogram analysis using ultrasound (US) for differentiating the subtypes of the follicular variant of papillary thyroid cancer (FVPTC). BACKGROUND: The prognosis of the subtypes of FVPTC is different according to the invasiveness on pathology. As noninvasive encapsulated FVPTC (EFVPTC) had highly indolent behavior and better prognosis compared to invasive EFVPTC and infiltrative FVPTC, revision of nomenclature to noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) had been proposed to reduce overtreatment. As paradigm shifts, imaging diagnosis became more important. MATERIALS AND METHODS: From January 204 to May 206, 5 patients surgically confirmed as FVPTC were included. Preoperative US features were retrospectively reviewed. For the grayscale histogram analysis, region of interest (ROI) for nodules were obtained. Pixel echogenicity values in ROI were measured with in-house software. Histogram parameters (median, maximum, minimum, standard deviation, root mean square, skewness, kurtosis, energy, entropy, and autocorrelation) were obtained for each nodule. RESULTS: The 52 nodules in 5 patients composed of 48 (3.6%) NIFTPs, 60 (39.5%) invasive EFVPTCs and 44 (28.9%) infiltrative FVPTCs. US features were significantly different between subtypes of FVPTC. The discrimination between NIFTP and infiltrative FVPTC, between invasive EFVPTC and infiltrative FVPTC by means of histogram parameters was achieved. However, parameters were not significantly different between NIFTP and invasive EFVPTC. CONCLUSION: Grayscale histogram analysis was feasible for differentiating NIFTP and infiltrative FVPTC, but not for NIFTP and invasive EFVPTC. Histogram can be used as a supplementary tool for differentiating the subtypes of FVPTC. SS 04 TH-09 09:20 US and clinicopathological features of papillary thyroid carcinomas with BRAF and telomerase reverse transcriptase (TERT) promoter mutations Soo Yeon Hahn, Tae Hyuk Kim, Jung Hee Shin, Chang Seok Ki Samsung Medical Center, Korea. jhshin@skku.edu PURPOSE: To investigate if any relationship exists between the telomerase reverse transcriptase (TERT) promoter or BRAF mutation and ultrasound (US) and clinicopathological features of papillary thyroid carcinomas (PTCs). MATERIALS AND METHODS: The Institutional Review Board approved the study protocol and the use of human thyroid tissue. The study included 50 patients with surgically confirmed PTC from October 994 to December The mean clinical and imaging follow up periods were 49.6 ± 24.6 and 43. ± 34.5 months, respectively. According to the existence of TERT promoter or BRAF mutations, we categorized patients into three groups (no mutation, BRAF mutation alone, or TERT + BRAF mutations) and analyzed the relationships between TERT promoter or BRAF mutation and US and clinicopathological features using uni- and multinomial logistic regression analysis and Cochran-Armitage trend test. The rate of recurrence or death according to mutation analysis was estimated by the Kaplan-Meier method. RESULTS: There were 35 (23.3%) cases with no mutation, 04 (69.3%) with BRAF mutation alone, and (7.3%) with TERT + BRAF mutations. According to the results of the Cochran-Armitage trend test, as the number of genetic mutations increased from no mutation to BRAF mutation alone to both BRAF and TERT mutations, the proportions of hypoechogenicity (3.4% vs. 66.4% vs. 54.5%, p = ), non-parallel orientation (25.7% vs. 49.0% vs. 72.7%, p = ), spiculated/microlobulated margin (45.7% vs. 5.9% vs. 90.9%, p = ), microcalcifications (62.9% vs. 72.% vs. 90.9%, p = ), and K-TIRADS category 5 (48.6% vs. 7.% vs. 63.6%, p = ) increased. PTCs with TERT + BRAF mutations recurred more frequently than other groups (odd ratio [OR] = 7.92 and 3.468). The intervals to recurrence and overall survival were significantly shorter in the TERT + BRAF mutation group than in the other groups (p < and p < 0.000). CONCLUSION: PTCs with no mutation, with BRAF mutation alone, and with both TERT and BRAF mutations linearly increase in the probability of displaying malignant US features. In PTCs, the coexistence of BRAF with TERT mutations is more strongly correlated with recurrence and mortality than BRAF mutation alone.

6 382 KCR 207 Thyroid 09:40 - :0 208 Thyroid elasography/core needle biopsy when compared to grayscale US alone. Adding additional imaging modalities such as elastography and Doppler to grayscale US does not improve the diagnostic performances in differentiating thyroid nodules. Chairperson(s) Jin Young Kwak Yonsei University School of Medicine, Severance Hospital, Korea Jeong Hyun Lee University of Ulsan College of Medicine, Asan Medical Center, Korea SS 09 TH-0 09:40 Direct comparison of combined strain/shear wave elastography and power Doppler/superb microvascular imaging to grayscale US in differential diagnosis of thyroid nodules Jung Hyun Yoon, Eun-Kyung Kim, Jin Young Kwak, Youngjean Park, Hee Jung Moon 2 Severance Hospital, 2 Yonsei University College of Medicine, Korea. artemis4u@yuhs.ac PURPOSE: To evaluate the role of various elastographic and Doppler parameters in the differential diagnosis of thyroid nodules when added to grayscale ultrasonography (US). MATERIALS AND METHODS: This prospective study was approved by our IRB, and informed consent was obtained from all patients. From January to February 206, 7 thyroid nodules in 69 patients (mean age, 50.3 ± 3.0 years) who were scheduled for US-guided fine needle aspiration (FNA) or surgery were included in this study. Elastography including strain and shearwave elastography images, and Doppler including power Doppler, superb microvascular imaging (SMI), and microflow imaging (MFI) were obtained from the same thyroid nodule using a single US machine. Diagnostic performances of grayscale US with/without elastography or Doppler US were calculated and compared. RESULTS: Among the 7 thyroid nodules, 63 (36.8%) were malignant and 08 (63.2%) were benign. When comparing the diagnostic performances between US combined to elastography parameters to grayscale US, specificity, PPV, and accuracy of grayscale US was significantly higher than US combined to elastographic parameters (all ps < 0.05). AUC for grayscale US was 0.877, significantly higher than US combined to elastography patterns, and SWE ratio (all ps < 0.05). AUC for grayscale US was 0.877, higher than any Doppler parameters and any combination of grayscale US and Doppler parameters. CONCLUSION: US combined to various elastographic or vascularity parameters did not have superior performances SS 09 TH-02 09:50 Diagnostic utility of real time US elastography in differentiating benign and malignant thyroid nodules Navneet Redhu Kainos Superspeciality Hospital, Rohtak, India. navneet5084@gmail.com PURPOSE: To evaluate the diagnostic utility of real time ultrasound (US) elastography in differentiating benign and malignant thyroid nodules. MATERIALS AND METHODS: This prospective observational study was conducted in the Department of Radiodiagnosis and Department of Surgical Oncology and Endocrinology over a period of months. 65 patients were examined by conventional US, and US elastography. The final diagnosis was obtained from cytological/histological findings. Tissue stiffness on US elastography was scored from (low stiffness over the entire nodule) to 5 (high stiffness over the entire nodule and surrounding tissue). RESULTS: On real-time US elastography, 29 of 5 benign nodules (56.8%) had a score of or 2, all were benign on cytological, whereas 2 of 4 malignant nodules had a score of 4 and 5, with sensitivity of 85.7%, specificity of 98%, a positive predictive value of 92.3%, and a negative predictive value of 96.%. Elastography score 3 was found in 23 thyroid nodules, out of them 2 were benign and only 2 were malignant. The predictivity of US elastographic measurement was independent of the nodule size. CONCLUSION: Real-time US elastography is a promising imaging technique that is useful in the differential diagnosis of thyroid cancer. Utilization of US elastography could reduce the rate of thyroid biopsies because of its high elasticity being highly associated with benign cytology.

7 Thyroid 383 SS 09 TH-03 0:00 False negative rate of US-guided fine-needle aspiration for thyroid nodule influence of nodule size and US pattern Su Min Ha, Hye Shin Ahn, Dong Gyu Na 2, Hyewon Choi Chung-Ang University Hospital, 2 GangNeung Asan Hospital, Korea. ach0224@naver.com PURPOSE: To retrospectively evaluate the false negative rate (FNR) of ultrasound (US)-guided fine needle aspiration (FNA) according to the nodule size and US pattern. MATERIALS AND METHODS: From January 203 to December 204, consecutive 653 thyroid nodules of 596 patients who underwent US-guided FNA for thyroid nodules ( cm). The FNA results were categorized according to the Bethesda system and the false negative result was determined in nodule with benign FNA result and finally diagnosed malignant tumor. The nodules were categorized into 3 groups according to the nodule size ( -2, 2-4, and 4 cm, respectively) and US patterns based on the Korean thyroid imaging reporting and data system (K-TIRADS), which included 3 groups of K-TIRADS 2 (benign), K-TIRADS 3/4 (low/intermediate suspicion), and K-TIRADS 5 (high suspicion) nodules, respectively. RESULTS: Of 653 thyroid nodules, 590 nodules with final diagnoses were finally included (438 benign nodules and 52 malignant nodules). Malignant nodules included 28 (84.2%) papillary thyroid carcinomas (PTC), 2 (.3%) follicular carcinomas (FC), and 22 (4.5%) other malignant tumors. The overall falsenegative rate (FNRs) was.8% (8/442) and FNRs of 3 groups according to the nodules size were.7% (5/299), 0.8% (/30), and 5.4% (2/3), respectively. FNRs of 3 groups according to the K-TIRADS were 0% (0/2),.4% (6/42), and 22.2% (2/9), respectively. The large nodule size ( 4 cm) and K-TIRADS 5 nodules were significantly associated with higher false negative rate (p = and p = 0.0, respectively). Among K-TIRADS 3/4 nodules, the FNR was significantly higher (5.4%) in large nodules ( 4 cm) than that (%) of smaller nodules (< 4 cm) (p = < 0.00). Among large nodules ( 4 cm), two cases of false negative results were found only in nodules with K-TIRADS 3/4 US pattern and the final diagnoses were follicular carcinoma and follicular variant PTC, respectively. CONCLUSION: The FNR is relatively high in nodules with high suspicion US pattern and in large ( 4 cm) nodules with low/intermediate suspicion US pattern. Repeated biopsy should be considered for these nodules although the initial FNA result was benign. SS 09 TH-04 0:0 Complications following US-guided core needle biopsy for thyroid nodules: a systematic review and meta-analysis Eun Ju Ha, Jung Hwan Baek 2, Chong Hyun Suh 3 Ajou University Hospital, 2 Asan Medical Center, 3 Namwon Medical Center, Korea. radbaek@naver.com PURPOSE: To present the various complications of ultrasound (US)-guided core needle biopsy (CNB) of thyroid lesions, using a systematic review and metaanalysis. MATERIALS AND METHODS: Ovid-MEDLINE and EMBASE databases were searched for studies on the US-guided CNB for thyroid lesions. Studies from January, 994 to December 3, 206, were included. Review of 393 potential papers, including a full-text review of 73, identified 39 eligible papers covering a total of 488 patients for meta-analysis. The pooled proportions of complications were assessed using random-effects modeling. Subgroup analysis was performed including Asia versus non-asia group, radiologist versus nonradiologist group, nodule size < 20 mm versus nodule size 20 mm, CNB only versus CNB plus FNA, and studies before 203 versus after 203, Heterogeneity among studies was determined using the χ 2 statistic for the pooled estimates and the inconsistency index I 2. RESULTS: The pooled proportion of overall complications after CNB for thyroid lesions was.% (95% confidence interval (CI): , I 2 = 87.2%). The pooled proportion of major complications (0.06% (95% CI: ), I 2 = 0.0%) was lower than that of minor complications (.08% (95% CI: %), I 2 = 93.7%). The subgroup analysis revealed that there was no significant difference between studies on Asia versus non-asia group (p = ), radiologist versus non-radiologist group (p = ), nodule size < 20 mm versus nodule size 20 mm (p = 0.59), CNB only versus CNB plus FNA (p = 0.928) and studies before 203 versus after 203 (p = 0.960). CONCLUSION: US-guided CNB of thyroid lesions was found to be a safe procedure with a low complication rate in a systematic review with meta-analysis.

8 384 KCR 207 SS 09 TH-05 0:20 Diagnostic efficacy and safety of core needle biopsy as a first-line diagnostic method in thyroid nodules: a prospective cohort study Dong Gyu Na GangNeung Asan Hospital, Korea. nndgna@gmail.com PURPOSE: To evaluate the diagnostic efficacy and safety of core needle biopsy (CNB) as a first-line diagnostic method in thyroid nodules. MATERIALS AND METHODS: This study prospectively enrolled all patients with thyroid nodules indicated for fineneedle aspiration (FNA) based on the recommendations of the Korean Society of Thyroid Radiology. From February 206 to February 207, a total of 56 consecutive nodules of 35 patients were included and one patient refused this protocol. The nodule size was 5.7 ± 9.4 mm. CNB was performed by an experienced radiologist. We compressed the biopsy site immediately after the needle was withdrawn and patients were observed with self-manual compression for min. The diagnostic efficacy of CNB was evaluated by the rate of inconclusive results (nondiagnostic or indeterminate CNB result). The safety of the CNB procedure was evaluated by major and minor complication rates. US evaluation was performed to assess any hemorrhage before and after self-manual compression of the biopsy site, and delayed complication was assessed 5-7 days after CNB. The minor complication of hematoma was defined as any symptomatic small to moderate hematoma requiring no hospitalization. RESULTS: CNB alone was performed in 80.7% and simultaneous CNB/FNA in 9.3% of nodules. The number of CNB sampling was.5 ± 0.5. The diagnostic results of CNB was nondiagnostic.3%, benign 63.5%, indeterminate 0.9%, follicular neoplasm 4.5%, suspicious malignant 2.6%, and malignancy 7.3%. There was no major complication and no delayed complication. There was one case (0.7%) of minor complication (small perithyroidal hematoma). Asymptomatic small or minimal perithyroidal hematomas were found in 3% and asymptomatic mild parenchymal hemorrhage (edema) in 0.7%. CONCLUSION: CNB is effective for reducing inconclusive results and safe for an experienced operator. CNB may be used as an alternative first-line diagnostic method for thyroid nodules. SS 09 TH-06 0:30 Diagnostic efficacy of core needle biopsy as a first-line diagnostic tool for low or intermediate suspicion thyroid nodules: comparison with fine needle aspiration using propensity score analysis Hye shin Ahn, Inyoung Youn 2, Dong Gyu Na 3, Soo Jin Kim 4, Hyewon Choi Chung-Ang University Hospital, 2 Kangbuk Samsung Hospital, 3 GangNeung Asan Hospital, 4 New Korea Hospital/Human Medical Imaging and Intervention Center, Korea. yuki0486@naver.com PURPOSE: To retrospectively compare the diagnostic efficacy of fine needle aspiration (FNA) and core-needle biopsy (CNB) as a first-line diagnostic tool for low or intermediate suspicion thyroid nodules MATERIALS AND METHODS: From January 200 to May 205, consecutive 408 thyroid nodules ( cm) with low or intermediate suspicion US patterns were selected from a database of patients who initially underwent CNB at one institution. For the comparison of CNB, another dataset of consecutive 433 thyroid nodules ( cm) were included from patients who initially underwent FNA at two institutions. Adjustments for significant differences in patients characteristics were facilitated via propensity score matching (PSM). The rate of inconclusive results including nondiagnostic or atypia/follicular lesion of undetermined significance (AUS/FLUS) was compared. Diagnostic values for malignancy and the complication rate of FNA and CNB were evaluated. RESULTS: A : matching of 299 patients via PSM yield no significant differences between two groups for any covariate. After PSM, CNB showed lower rates of nondiagnostic result (.0% vs. 7.0%, p < 0.00), AUS/ FLUS (9.7% vs. 29.4%, p < 0.00), and inconclusive result (0.7% vs. 36.5%, p < 0.00) than FNA. A total of 208 FNA and 253 CNB nodules were finally diagnosed. With the criteria of Bethesda category 4, 5, and 6, CNB showed a significantly higher sensitivity (00% vs. 48.0%, p = 0.00) for malignancy than FNA, while the specificities of those were similar (99.2% vs. 98.4%, p = 0.450). There were only several cases of mild hemorrhage in both groups. However, the complication rate showed no statistical difference (CNB:.47% vs. FNA: 0.23%, p = 0.065). CONCLUSION: CNB may be more effective for the diagnosis of malignancy than FNA as a first-line diagnostic tool in low or intermediate suspicion thyroid nodules.

9 Thyroid 385 SS 09 TH-07 0:40 US-guided core needle biopsy for intermediate or low suspicion thyroid nodules: which method is effective for diagnosis? Soo Yeon Hahn, Jung Hee Shin Samsung Medical Center, Korea. PURPOSE: To retrospectively compare the diagnostic performances between two different techniques of ultrasound (US) guided core needle biopsy (CNB) for intermediate or low suspicion thyroid nodules. MATERIALS AND METHODS: One hundred and forty consecutive biopsies for the 40 intermediate or low suspicion thyroid nodules were randomly performed using two different biopsy techniques between August 205 and December 206. In the first technique, two specimens were targeted to include nodular tissue, nodular margin, and surrounding normal parenchyma (i.e., margin target). In the second technique, two specimens were obtained from two different target areas, one for margin target and another for intranodular target. Diagnostic performances of two different biopsy techniques to predict thyroid neoplasm and malignancy were compared. RESULTS: During the study period, CNB was performed for 80 intermediate or low suspicion thyroid nodules (57.%) with the first technique and 60 (42.9%) with the second technique. The accuracy of the first biopsy technique significantly higher than that of the second biopsy technique (00% vs. 93.3%, p = for predicting thyroid neoplasm; 88.8% vs. 75.0%, for predicting thyroid malignancy). The negative predictive value of the first biopsy technique for predicting thyroid malignancy was significantly higher than that of the second biopsy technique (87.5% vs. 72.2%, p = 0.035). The sensitivity, specificity, and positive predictive value were comparable between two different biopsy techniques. CONCLUSION: For intermediate or low suspicion thyroid nodules, US-guided core biopsy to obtain two specimens with marginal targets only is more effective in diagnosing thyroid neoplasm or malignancy than with marginal and intranodular target. SS 09 TH-08 0:50 Diagnostic efficacy of core needle biopsy as a first-line diagnostic tool in high suspicion thyroid nodules: comparison with fine needle aspiration using propensity score analysis Inyoung Youn, Hye shin Ahn 2, Dong Gyu Na 3, Soo Jin Kim 4 Kangbuk Samsung Hospital, 2 Chung-Ang University College of Medicine, 3 GangNeung Asan Hospital, 4 New Korea Hospital/Human Medical Imaging and Intervention Center, Korea. ach0224@gmail.com PURPOSE: To compare the diagnostic efficacy of core needle biopsy (CNB) and fine needle aspiration (FNA) as a first-line diagnostic tool in high suspicion thyroid nodules. MATERIALS AND METHODS: This study included consecutive 49 high suspicion nodules (> 5 mm) in which CNB was performed as a first-line diagnostic tool at one institution and consecutive 405 high suspicion nodules (> 5 mm) in which FNA was performed as a first-line diagnostic tool at other two institutions. With propensity score matching (PSM), we facilitated the adjustments for significant differences in patients baseline characteristics. The rate of inconclusive results and diagnostic values were compared between the results of CNB and FNA. RESULTS: Each 57 CNB and FNA group nodules were extracted using PSM analysis from a total of 824 nodules. CNB showed a lower rate of inconclusive results (8.% vs. 32.8%, p < 0.00) including nondiagnostic (.7% vs. 7.4%) and AUS/FLUS (6.4% vs. 25.4%) results compared with FNA in total nodules, and PSM analysis also showed a significantly lower rate of inconclusive results (p < 0.00). With the criteria of Bethesda category 4, 5, and 6, CNB showed significantly higher sensitivity for malignancy in total nodules (99.3% vs. 87.5%, p < 0.00) and PSM nodules (00% vs. 85.7%, p = 0.09) regardless of the nodule size. With the criteria of Bethesda category 6, CNB also showed significantly higher sensitivity for malignancy in total nodules (93.7% vs. 67.6%, p < 0.00) and PSM nodules (9.7% vs. 7.4%, p = 0.033) regardless of the nodules size. The specificity for malignancy was similarly high in both CNB and FNA group nodules (p > 0.05). CONCLUSION: CNB showed lower inconclusive results and higher sensitivity for malignancy, and CNB may be more effective than FNA as a first-line diagnostic tool in high suspicion nodules.

10 386 KCR 207 SS 09 TH-09 :00 Values of ASQ imaging in predicting hypothyroidism in Hashimoto s thyroiditis Ji Ye Lee, Hyun sook Hong 2, Chul-Hee Kim 2, Sun Hye Jeong Soochunhyang University Bucheon Hospital, 2 Soonchun hyang University College of Medicine, Korea. hshong@schmc.ac.kr PURPOSE: ASQ (acoustic structure quantification) can provide objective and quantitative analysis of thyroid echogenicity. Our aim is to investigate the clinical significance of ASQ imaging parameters whether it can predict progression of hypothyroidism in Hashimoto s thyroiditis (HT). MATERIALS AND METHODS: We prospectively enrolled 92 lobes in 50 patients with HT who underwent ASQ imaging with 3 year follow-up. Initial and 3 year follow-up ASQ parameters including AV mode, AV average, AV SD, AV ratio, blue mode, blue average, blue SD and clinical data including thyroid function test were collected. Clinical and ASQ parameters were analyzed as possible predictors of hypothyroidism. RESULTS: Patients who developed hypothyroidism showed lower AV mode (p = 0.003), lower AV average (p = 0.039), lower blue average (p = 0.02) and lower blue SD (p = 0.025) than patients with no change or improved thyroid function. Lower AV blue mode value (OR 0.98, p = 0.009) and larger changes in AV ratio (OR.06, p = ) were significantly associated with hypothyroidism in HT. CONCLUSION: Patients who progressed to hypothyroidism showed lower ASQ values at initial presentation. Initial ASQ parameters might be useful in stratifying the risk of hypothyroidism progression in patients with HT. Thyroid 6:00-8: Thyroid intervention/categorization system Chairperson(s) Jin Yong Sung Daerim St. Mary's Hospital, Korea Jung Hee Shin Samsung Medical Center, Sungkyunkwan University School of Medicine, Korea SS 4 TH-0 6:00 US-guided percutaneous ethanol injection for the thyroid cystic nodule: is it always successful Do hyung Lee, Young Hen Lee, Hyung Suk Seo, Sang-il Suh 2, Inseon Ryoo 2, Sung-Hye You 3 Korea University Ansan Hospital, 2 Korea University Guro Hospital, 3 Korea University Anam Hospital, Korea. younghen@empal.com PURPOSE: US-guided percutaneous ethanol injection (PEI) has been recognized as the first-line tool for the predominantly cystic thyroid nodule. However, few reports have mentioned about the outcome of this treatment in large numbers of patients. Accordingly, we described our experience for efficacy and safety of USguided PEI during the 0 years. MATERIALS AND METHODS: During the 0 years, sixty patients (M:F = 9:4, 45.3 ± 5.8 years) with predominantly cystic thyroid nodules were treated by US-guided PEI. In all cases, cytology prior to treatment, maximum cyst diameter and volume were determined. Before ethanol instillation to the cavity, as much fluid as possible was aspirated then followed by saline irrigation. The amount of ethanol injected was less than 50% of the amount of aspirated fluid. Follow-up US examination was done every 6-8 weeks; ethanol was re-injected when there was no significant reduction in the cyst volume (mean,.6 sessions). Therapeutic success was defined as more than 50% cystic volume reduction or obliteration associated with disappearance of clinical symptoms. RESULTS: Mean initial maximum cystic diameter and mean estimated cystic volume were 3.2 cm, and 2.3 ml. During the PEI treatment session, mean 5.5 ml ethanol was instilled into the cystic cavity (mean.6 sessions), and no complications occurred. During the mean 3.4 month follow-up period following PEI, therapeutic success was observed in 95.0% of patients (n = 57). Among the patients with successful therapeutic response, residual solid portion of thyroid nodule paradoxically increased in 9 patients, while still remained in 4 patients without overall volume reduction. Other three patients with multiple predominantly cystic nodules sustained cystic volume in

11 Thyroid 387 spite of PEI. CONCLUSION: US-guided PEI is a safe and effective tool to reduce cystic volume of thyroid nodule, however limited for solid portion and multiple cystic nodule. SS 4 TH-02 6:0 Initial ablation ratio: excellent predicting factor for final volume reduction ratio after radiofrequency ablation of benign thyroid nodules Jung Suk Sim, Woojin Cho Withsim Clinic, Korea. jungsuk.sim@gmail.com PURPOSE: To explore if we can expect final volume reduction ratio (VRR) after radiofrequency ablation (RFA) of symptomatic benign thyroid nodule using initial ablation ratio (IAR). MATERIALS AND METHODS: One hundred and forty three nodules - 3 predominantly cystic nodules, 28 mixed solid and cystic nodules and 02 solid nodules - were included in this study. Only one RFA was applied and all the data after 2 nd ablation was not included. Mean initial nodule volume was 9.6 ±.7 ml, mean final nodule volume was 2.5 ± 4.7 ml. Mean follow-up period was 2.7 ± 8. months and all the first followup periods were between to 3 months. IAR is a ratio indicating how many percent of the total nodule volume (Vt) has been ablated. Ablated nodule volume (Va) is seen as a hypoechoic area without vascularity on US. IAR can be calculated by the following equation. IAR = Va at procedure time / Vt at procedure time. But immediately after the RFA, there are so many edema and hemorrhage obscuring image fields, that we cannot see the exact area of ablated tissue. So, we need indirect method getting Va at procedure time. There is a third concept of nodule volume, viable nodule volume (Vv). Vv is a calculated value, Vv = Vt-Va, which means the residual untreated area of nodule, usually located in the peripheral margins. On the assumption that nodules do not grow in a short period of time, we can think of the Vv at the time of the first follow-up as the Vv of the procedure time. So, following equation can be established, Va at procedure time = Vt at procedure time-vv at first follow-up. Thus IAR = (Vt at procedure time-vv at first follow-up) / Vt at procedure time. Correlation between IAR versus final VRR was calculated by Microsoft Excel software. RESULTS: Correlation between IAR and final VRR was When IAR was lower than 70%, 50% of final VRR could be expected seldom. CONCLUSION: IAR is an excellent predicting factor for final VRR. If IAR is less than 70%, achieving 50% of final VRR is less likely, thus additional RFA should be planned promptly. SS 4 TH-03 6:20 How long does the effect of radiofrequency ablation of symptomatic benign thyroid nodules last? Jung suk Sim, Woojin Cho Withsim Clinic, Korea. jungsuk.sim@gmail.com PURPOSE: To determine the duration of the effect of radiofrequency ablation. MATERIALS AND METHODS: We studied 86 nodules that were followed up for more than 24 months after radiofrequency ablation of symptomatic benign thyroid nodules. Only one session of radiofrequency ablation was applied and all the data after second ablation was excluded. Mean initial nodule volume was 8.3 +/- 6.3 ml. Mean follow-up period was /- 7.8 months. Nodules were classified into cystic and mixed solid and cystic group, small solid group (< 0 ml), mid-size solid group (0~20 ml) and large solid group (> 20 ml). It was concluded that the treatment effect was terminated when the volume was 50% larger than the smallest volume of the previous follow-up period. RESULTS: In the cystic and mixed solid and cystic group (n = 26), the treatment effect of radiofrequency ablation lasted for an average of /- 9.8 months. In the small solid group (n = 47), the treatment effect lasted for an average of /- 9.5 months. In the mid-size solid group (n = 0), the treatment effect lasted for an average of 3.5 +/- 9.4 months. In the large solid group (n = 3), the treatment effect lasted for an average of 9.7 +/- 4.9 months. CONCLUSION: The treatment effect of radiofrequency ablation lasts about 3 years for cystic and mixed solid and cystic nodules, small and mid-size nodules and less than year for large nodules. SS 4 TH-04 6:30 Radiofrequency ablation of primary thyroid cancer: efficacy according to the types of thyroid cancer So Yeong Jeong, Jung Hwan Baek Asan Medical Center, Korea. radbaek@naver.com PURPOSE: Surgery is the standard treatment for primary thyroid cancer patients; however, there are risk of complications can be increased in patients with high surgical risk. Ultrasound (US)-guided radiofrequency ablation (RFA) can be suggestive as alternatives to patients at high risk of surgery or those who refuse surgeries. Therefore this study evaluated the efficacy of RFA according to the types of thyroid cancers especially for patients with high surgical risk. MATERIALS AND METHODS: A total of 7 patients

12 388 KCR 207 (two men and five women; age range, years; mean, 69 ± 5 years) with 8 nodules of pathologically proven papillary carcinoma (five patients) and anaplastic carcinoma (two patients) were treated by US-guided RFA. Primary thyroid cancers were divided into 3 groups; ) group : Anaplastic carcinoma, 2) group 2: Papillary macrocarcinoma, and 3) group 3: Papillary microcarcinoma. We evaluated the change of clinical symptoms, tumor volume and local tumor recurrence or metastasis after RFA. Patients were followed at, 6, and 2 months and every one year thereafter. RESULTS: All patients were tolerable to RFA. Among 8 tumors, 3 tumors (2 anaplastic and papillary macrocarcinoma) were treated 2 times. In group, the initial mean volume of was 07.9 ± 78.6 ml with neck bulging. In group 2, initial mean volume was 26.9 ml with neck bulging. In group 3, initial mean volume of was 0.6 ± 0. ml without cosmetic or symptomatic problems. In group, there was no improvement of clinical symptoms or neck bulging after RFA. In group 2, treated tumor showed size reduction (26.9 ml vs. 0.8 ml) and disappearance of color Doppler signal with improvement of neck bulging. The volume reduction ratio was 99.3%. In group 3, mean volume also decreased to 0.09 ± 0. ml and volume reduction ratio was 4.7%. No local tumor recurrence or metastatic lesion was detected during follow-up periods. No major complications were encountered. CONCLUSION: In primary thyroid cancers, RFA achieved an excellent local tumor control effect for papillary macroand microcarcinoma; however the clinical effect for anaplastic carcinoma is questionable. nonparallel shape, or evidence of lymph node metastasis on ultrasonography (US), 4) normal serum levels of thyroid hormone and thyrotropin, and 5) follow-up periods of more than 6 months. RF ablation was performed with using a RF generator and an 8-gauge internally cooled electrode. Changes in nodules on follow-up US and complication during and after RF ablation were evaluated. RESULTS: The mean follow-up period was 36.9 ± 2.7 (range, 6-69) months. At last follow-up, the longest nodule diameter and volume significantly decreased (3.7 ±. cm vs..4 ± 0.9 cm and 4.6 ± 3.3 ml vs..7 ± 4.4 ml, respectively; p < 0.05). Both cosmetic and compressive symptoms significantly improved (3.8 ±.0 vs..4 ± 0.4 and 3.4 ±.0 vs. 0. ± 0.4, respectively; p < 0.05). Mean number of ablation sessions was 2. ±.2. There was no major complication during and after RF ablation. CONCLUSION: RF ablation could be a safe and effective treatment modality for nonfunctioning benign thyroid nodules in children and adolescents. SS 4 TH-06 6:50 High suspicion US pattern on the ATA guidelines not cytologic diagnosis may be a predicting marker of lymph node metastasis in patients with conventional papillary thyroid carcinoma Eun Cho, Eun-Kyung Kim 2, Hee Jung Moon 2, Jung Hyun Yoon 2, Youngjean Park 2, Jin Young Kwak 2 Dong-A University Hospital, 2 Severance Hospital, Korea. docjin@yuhs.ac SS 4 TH-05 6:40 Radiofrequency ablation for non-functioning benign thyroid nodules in children and adolescents Jin Yong Sung Daerim St. Mary's Hospital, Korea. jysrad68@gmail.com PURPOSE: To retrospectively evaluate efficacy and safety of radiofrequency (RF) ablation for non-functioning benign thyroid nodules in children and adolescents. MATERIALS AND METHODS: We evaluated 4 pediatric patients (M:F ratio = 4:0, mean age, 5.7 ± 2.3 [range, 2-9]) with nonfunctioning benign thyroid nodules (mean longest diameter, 3.7 ±. cm [range, cm]) who were treated with RF ablation between 2005 and 205. The inclusion criteria for RF ablation therapy were ) benign cytological confirmation in at least two separate fine needle aspiration and/or core needle biopsy, 2) reports of pressure symptoms or cosmetic problems caused by thyroid nodules, 3) without spiculated/microlobulated margin, microcalcification, PURPOSE: To evaluate the utility of ultrasound (US) patterns based on the 205 American Thyroid Association (ATA) guidelines and cytologic diagnosis of the Bethesda System for Reporting Thyroid Cytopathology as predicting markers for lymph node metastasis (LNM) in conventional papillary thyroid carcinoma (PTC). MATERIALS AND METHODS: A retrospective analysis of 657 patients with conventional PTC who underwent US-guided fine-needle aspiration (US-FNA) and surgery were included in this study. The US features of the conventional PTCs were categorized according to the 205 ATA guidelines. The cytologic diagnosis was interpreted according to the Bethesda System for Reporting Thyroid Cytopathology. Univariate and multivariate logistic regression analyses were used to investigate the association between clinical parameters and LNM in patients with conventional PTC. RESULTS: Of the 657 patients, conventional PTCs with high, intermediate, low, very low suspicion for malignancy according to the ATA guidelines were 90.3% (593 of 657), 6.8% (45 of 657), 2.4% (6 of 657), and 0.5% (3