It is challenging to identify Papillary Thyroid Cancer (PTC) which shows atypia of undetermined significance (AUS) by Fine-needle Aspiration (FNA). This study aims to seek the meaningful quantitative biomarkers of the microvasculature and construct a classification model for PTC with AUS based on these new biomarkers and Thyroid Imaging Reporting and Data System (TI-RADS).

This prospective study enrolled 281 patients with 300 thyroid nodules showing AUS. These cases were divided into two groups with the largest dimension (LD) of 10 mm, A (< 10 mm) and B (≥ 10 mm). Firstly, an open-source artifact suppression algorithm, which combined a multi-scale Frangi filter and TOPHAT operation, was proposed for the segmentation of micro-vessels in Ultra Micro-Angiography (UMA) images. Then, 18 quantitative biomarkers were calculated and analyzed through Mann-Whitney test (U-test), while LASSO regression was utilized to remove collinear features. Finally, two different classification models were built using logistic regression through the selected biomarkers combined with Chinese TI-RADS (C TI-RADS) or American College of Radiology TI-RADS (ACR TI-RADS). The performances were evaluated using the mean Area Under the Curve (AUC) value and the DeLong test, through a 5-fold cross-validation experiment.

Group A comprised 58 benign nodules and 104 PTCs, while Group B consisted of 60 benign nodules and 78 PTCs. Four biomarkers were selected in Group A. The 5-fold cross-validation experiment showed that the mean Area Under Curve (AUC) improved from 0.725 with ACR TI-RADS to 0.851 (P < 0.05), while the mean AUC improved from 0.809 with C TI-RADS to 0.882 (P < 0.05). In Group B, four different biomarkers were selected, and the classification models showed improvements from 0.841 with ACR TI-RADS to 0.874 and from 0.894 with C TI-RADS to 0.936.

This study demonstrated the potential value of microvasculature in the prediction of PTC in AUS Cases and improved the performance of ultrasound examination. Moreover, the morphology of microvasculature showed different changes at different LD groups.

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.

To assess the safety and efficacy of radiofrequency ablation (RFA) for capsular-located papillary thyroid microcarcinoma (PTMC) in a large cohort and to compare its outcomes with those of noncapsular-located PTMC.

We retrospectively reviewed patients who underwent RFA for solitary capsular-located and noncapsular-located low-risk PTMC (n = 1095) from June 2014 to October 2020. To balance confounding variables between capsular and noncapsular groups, we employed the 1:1 propensity score matching approach. We evaluated and compared tumor changes, disease progression, and complications in both groups. Furthermore, we analyzed the association between capsular location and disease progression using multivariable Cox regression.

During a mean follow-up time of 29.86 ± 16.14 months and 29.73 ± 15.69 months, no substantial difference was observed between capsular and noncapsular groups in the latest volume (0.83 ± 3.66 mm3 vs. 0.85 ± 3.67 mm3, p = 0.44) and volume reduction ratio (99.29 ± 4.04% vs. 99.43 ± 3.03%, p = 0.43), and cumulative disappearance rate (87.87% vs. 86.07%, p = 0.31). In addition, no significant differences were observed in complication incidence (1.35% vs. 1.12%, p = 0.76) and progression-free survival (p = 0.53). Based on adjusted multivariate Cox proportional hazard analysis, the association between capsular location and disease progression was nonsignificant (all p > 0.05).

This study demonstrates that the short-term outcomes of RFA for capsular-located PTMCs are comparable to those of noncapsular-located PTMCs. These findings indicate that RFA may be a viable and effective alternative for eligible patients with solitary capsular-located PTMC.

Radiofrequency ablation may serve as a safe and effective alternative treatment method for eligible patients with capsular-located and noncapsular-located papillary thyroid microcarcinoma.

• The safety and efficacy of radiofrequency ablation for capsular-located and noncapsular-located papillary thyroid microcarcinomas were comparable. • Disease progression did not differ significantly between capsular-located and noncapsular-located papillary thyroid microcarcinomas. • The incidence of complications for capsular-located papillary thyroid microcarcinoma was low.

Thyroid cancer is the most common endocrine malignancy. While there has been no appreciable increase in the observed mortality of well-differentiated thyroid cancer, there has been an overall rise in its incidence worldwide over the last few decades. Patients with papillary thyroid carcinoma (PTC) and clinical evidence of central (cN1) and/or lateral lymph node metastases require total thyroidectomy plus central and/or lateral neck dissection as the initial surgical treatment. Nodal status in PTC patients plays a crucial role in the prognostic evaluation of the recurrence risk. The 2015 guidelines of the American Thyroid Association (ATA) have more accurately determined the indications for therapeutic central and lateral lymph node dissection. However, prophylactic central neck lymph node dissection (pCND) in negative lymph node (cN0) PTC patients is controversial, as the 2009 ATA guidelines recommended that CND "should be considered" routinely in patients who underwent total thyroidectomy for PTC. Although the current guidelines show clear indications for therapeutic CND, the role of pCND in cN0 patients with PTC is still debated. In small solitary papillary carcinoma (T1, T2), pCND is not recommended unless there are high-risk prediction factors for recurrence and diffuse nodal spread (extrathyroid extension, mutation in the BRAF gene). pCND can be considered in cN0 disease with advanced primary tumors (T3 or T4) or clinical lateral neck disease (cN1b) or for staging and treatment planning purposes. The role of the preoperative evaluation is fund-amental to minimizing the possible detrimental effect of overtreatment of the types of patients who are associated with low disease-related morbidity and mortality. On the other hand, it determines the choice of appropriate treatment and determines if close monitoring of patients at a higher risk is needed. Thus, pCND is currently recommended for T3 and T4 tumors but not for T1 and T2 tumors without high-risk prediction factors of recurrence.