Influence of maximum diameter on fine-needle aspiration biopsy outcomes in ACR TI-RADS 5 thyroid nodules.

Introduction: Fine needle aspiration (FNA) biopsy is a widely accepted method for diagnosing thyroid nodules. However, the influence of maximum diameter (MD) of ACR TIRADS 5 (TR5) thyroid nodules on the FNA outcomes remains debated. This study examined the influence of MD on the FNA outcomes and investigated the optimal MD threshold for FNA in TR5 nodules. Methods: We conducted a retrospective analysis of 280 TR5 thyroid nodules from 226 patients who underwent FNA from January to June 2022 in our department. Probably malignant (PM) group was defined as Bethesda V in cytopathology with confirmed BRAF V600E mutation or Bethesda VI, the other cytopathology outcomes were defined as probably benign (PB) group. We examined factors influencing malignant cytopathology outcomes and determined the optimal MD threshold for FNA in TR5 nodules using logistic regression and restricted cubic spline (RCS) analysis. Results: Among these nodules, 58.2% (163/280) had PM outcomes. The PM group had a significantly larger MD than the PB group [6.5mm (range 5.0-8.4) vs. 5.3mm (range 4.0-7.0), p < 0.001]. In multivariate logistic regression fully adjusted for confounders, MD was significantly associated with PM outcomes [odds ratio 1.16, 95%CI 1.05-1.31; p = 0.042]. The highest quartile of MD had a greater likelihood of PM outcomes compared to the lowest quartile [odds ratio 4.71, 95% CI 1.97-11.69, p = 0.001]. The RCS analysis identified 6.2 mm as the optimal MD threshold for FNA in TR5 nodules. Conclusion: MD significantly affects the probability of malignant outcomes in FNA of TR5 thyroid nodules. A MD threshold of ≥6.2mm is suggested for FNA in these nodules.

Microwave Ablation versus Surgical Resection for US-detected Multifocal T1N0M0 Papillary Thyroid Carcinoma: A 10-Center Study.

Background Microwave ablation (MWA) is currently under preliminary investigation for the treatment of multifocal papillary thyroid carcinoma (PTC) and has shown promising treatment efficacy. Compared with surgical resection (SR), MWA is minimally invasive and could preserve thyroid function. However, a comparative analysis between MWA and SR is warranted to draw definitive conclusions. Purpose To compare MWA and SR for preoperative US-detected T1N0M0 multifocal PTC in terms of overall and 1-, 3-, and 5-year progression-free survival rates and complication rates. Materials and Methods In this retrospective study, 775 patients with preoperative US-detected T1N0M0 multifocal PTC treated with MWA or SR across 10 centers between May 2015 and December 2021 were included. Propensity score matching (PSM) was performed for patients in the MWA and SR groups, followed by comparisons between the two groups. The primary outcomes were overall and 1-, 3-, and 5-year progression-free survival (PFS) rates and complication rates. Results After PSM, 229 patients (median age, 44 years [IQR 36.5-50.5 years]; 179 female) in the MWA group and 453 patients (median age, 45 years [IQR 37-53 years]; 367 female) in the SR group were observed for a median of 20 months (range, 12-74 months) and 26 months (range, 12-64 months), respectively. MWA resulted in less blood loss, shorter incision length, and shorter procedure and hospitalization durations (all P < .001). There was no evidence of differences in overall and 1-, 3-, or 5-year PFS rates (all P > .05) between MWA and SR (5-year rate, 77.2% vs 83.1%; P = .36) groups. Permanent hoarseness (2.2%, P = .05) and hypoparathyroidism (4.0%, P = .005) were encountered only in the SR group. Conclusion There was no evidence of a significant difference in PFS rates between MWA and SR for US-detected multifocal T1N0M0 PTC, and MWA resulted in fewer complications. Therefore, MWA is a feasible option for selected patients with multifocal T1N0M0 PTC. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Georgiades in this issue.

Complications of microwave ablation in patients with persistent/recurrent hyperparathyroidism after surgical or ablative treatment.

OBJECTIVE: To evaluate the complications associated with microwave ablation (MWA) in treating persistent/recurrent hyperparathyroidism (HPT) post-surgical or ablative treatments. MATERIALS AND METHODS: From January 2015 to December 2022, 87 persistent/recurrent HPT patients (primary HPT [PHPT]: secondary HPT [SHPT] = 13:74) who underwent MWA after surgical or ablative treatment were studied. Grouping was based on ablation order (initial vs. re-MWA), prior treatment (parathyroidectomy [PTX] vs. MWA), and etiology (PHPT vs. SHPT). The study focused on documenting and comparing treatment complications and analyzing major complication risk factors. RESULT: Among the 87 patients, the overall complication rate was 17.6% (15/87), with major complications at 13.8% (12/87) and minor complications at 3.4% (3/87). Major complications included recurrent laryngeal nerve (RLN) palsy (12.6%) and Horner syndrome (1.1%), while minor complications were limited to hematoma (3.4%). Severe hypocalcemia noted in 21.6% of SHPT patients. No significant differences in major complication rates were observed between initial and re-MWA groups (10.7% vs. 13.8%, p = 0.455), PTX and MWA groups (12.5% vs. 15.4%, p = 0.770), or PHPT and SHPT groups (15.4% vs. 13.5%, p > 0.999). Risk factors for RLN palsy included ablation of superior and large parathyroid glands (>1.7 cm). All patients recovered spontaneously except for one with permanent RLN palsy in the PTX group (2.1%). CONCLUSION: Complication rates for MWA post-surgical or ablative treatments were comparable to initial MWA rates. Most complications were transient, indicating MWA as a viable and safe treatment option for persistent/recurrent HPT patients.

A Preliminary Study on the Microwave Ablation of Multifocal Papillary Thyroid Microcarcinoma.

RATIONALE AND OBJECTIVES: To evaluate the feasibility, efficiency, and safety of microwave ablation (MWA) for multifocal papillary thyroid microcarcinoma (PTMC). METHODS: This was a retrospective study, and the data of patients who underwent MWA for multifocal PTMC from October 2016 to December 2021 were reviewed. After ablation, the changes in tumor size and volume, as well as the rates of technical success, tumor disappearance, disease progression, and complications, were assessed. According to the tumor location, the cases were further divided into a unilateral multifocal disease (UMD) subgroup and a bilateral multifocal disease (BMD) subgroup. Further analyses were carried out. RESULTS: There was a total of 94 cases enrolled in the present study, which included 24 males and 70 females. The median age was 40 years (22-66 years); the median follow-up time was 14 months (6-48 months). Complete ablation was achieved in all enrolled cases. Therefore, the technical success rate was 100%. Due to expanding ablation, the MD and volume of the ablation zone increased at the 1st and 3rd months after ablation and decreased from the 12th month after ablation (p < 0.05 for all). The total complete tumor disappearance rates were 45/94 (47.87%) overall, 40.625% (13/32) in the UMD subgroup and 51.61% (32/62) in the BMD subgroup (p = 0.312). The total disease progression rates were 4.26% (4/94) overall, 6.25% (2/32) in the UMD subgroup and 3.23% (2/62) in the BMD subgroup (p = 0.881). The overall complication rate was 4.26% (4/94). CONCLUSION: This preliminary study indicates that MWA is a safe and effective treatment for multifocal PTMC.

Ultrasound-guided microwave ablation versus surgery for solitary T1bN0M0 papillary thyroid carcinoma: a prospective multicenter study.

OBJECTIVE: Microwave ablation (MWA) has emerged as a minimally invasive technology for papillary thyroid microcarcinoma (PTMC), but it has not been widely applied to treat T1bN0M0 PTC with high-level evidence. This study was designed to compare the real-world efficacy and safety of MWA or surgery for treating T1bN0M0 PTC. METHODS: From December 2019 to April 2021, 123 continuous unifocal T1bN0M0 PTC patients without lymph node metastasis (LNM) or distant metastasis (DM) were included from 10 hospitals. Patients were allocated into the MWA or surgery group based on their willingness. The main outcomes were local tumour progression (LTP), new thyroid cancer, LNM, and DM. The secondary outcomes included changes in tumour size and volume, complications, and cosmetic results. Subgroup analyses were conducted to identify influencing factors. RESULTS: Fifty-two patients chose MWA, and 71 patients chose surgery. Patients had similar demographic information and tumour characteristics in the two groups. The follow-up durations after MWA and surgery were 10.6 ± 4.2 and 10.4 ± 3.4 months, respectively. The LNM rate was 5.8% in the MWA group and 1.4% in the surgery group (p = 0.177). No LTP, new thyroid cancer, or distant metastasis (DM) occurred in either group. Five (9.6%) of the 52 patients in the MWA group and 8 (11.3%) of the 71 patients in the surgery group had complications (p = 0.27). Better cosmetic results were found in the MWA group (p < 0.01). CONCLUSION: MWA achieved comparable short-term treatment efficacy with surgery. MWA might be an optional choice for surgery for low-risk T1bN0M0 PTC but concerns about LNM need to be studied further. CLINICAL RELEVANCE STATEMENT: MWA achieved comparable short-time treatment efficacy with surgery. MWA might be an optional choice for surgery for low-risk T1bN0M0 PTC. KEY POINTS: • MWA achieved comparable short-term treatment efficacy with surgery. MWA might be an optional choice for surgery for low-risk T1bN0M0 PTC but concerns about LNM need to be studied further. • The complication rate in the surgery group was higher than that in the MWA group without a significant difference. • There was no statistically significant difference in the LNM rate between the MWA and surgery groups.

A comparative study of quality of life in patients with papillary thyroid carcinoma undergoing microwave ablation vs. Total thyroidectomy.

OBJECTIVE: To compare the health-related quality of life (HRQoL) of patients with T1N0M0 papillary thyroid carcinoma (PTC) who underwent microwave ablation (MWA) and those who underwent total thyroidectomy (TT). MATERIALS AND METHODS: From February 2018 to February 2022, 180 T1N0M0 PTC patients were enrolled in present study, including 90 in the MWA group and 90 in the TT group, respectively. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) and Thyroid Cancer-Specific Quality of Life Questionnaire (THYCA-QoL) were completed by patients to evaluate their HRQoL scores. RESULTS: According to the results of the EORTC-QLQ-C30, there was a significant difference in the scores of global health, physical, emotional, etc. between the two groups, which indicated that the quality of life in these items in the MWA group was better than those in the TT group (all p < 0.05). According to the results of the THYCA-QoL, all items had significant differences between the two groups except for headache, which demonstrated the thyroid-specific quality of life was higher in the MWA group than in the TT group (all p < 0.05). CONCLUSION: Ultrasound (US)-guided MWA offers a significant advantage in HRQoL over TT in T1N0M0 PTC patients, which provides an important reference for MWA as an alternative strategy to TT.

Safety enhancement of improved hydrodissection for microwave ablation in secondary hyperparathyroidism.

OBJECTIVE: To study the safety of improved hydrodissection based on the periparathyroidal fascial space during microwave ablation (MWA) for secondary hyperparathyroidism (SHPT). MATERIALS AND METHODS: Data from 337 patients (162 males and 175 females; mean age, 50.8 ± 12.8 [range, 16-84] years) who underwent MWA for SHPT were retrospectively reviewed. Among them, 177 patients underwent traditional hydrodissection (traditional group) and 160 patients underwent improved hydrodissection based on periparathyroidal fascial spaces (improved group). Safety enhancement was analyzed by comparing the complications between the two groups. The characteristics of the hydrodissected fascial spaces, complications, and the follow-up results were recorded. The baseline data, clinical parameters, laboratory indices and characteristics of SHPT lesions were analyzed to assess the risk factors associated with hoarseness. RESULTS: Hydrodissection was successfully performed in all the enrolled patients according to the protocol. Six periparathyroid fascial spaces were hydrodissected, depending on the location of the SHPT lesions. The incidence of hoarseness due to recurrent laryngeal nerve injury, the most common complication of thermal ablation for SHPT lesions, was lower in the improved group than in the traditional group (6.9% vs. 13.0%, p = 0.044). The median hoarseness recovery time in the improved group was shorter than that in the traditional group (2 vs. 6 months, p < 0.001). There was no difference in technical efficiency between the two groups (improved group vs. traditional group: 75.0% vs. 70.6%; p > 0.05). CONCLUSIONS: Compared with traditional hydrodissection, improved hydrodissection based on periparathyroidal fascial spaces could enhance safety during MWA for SHPT.

Efficacy and safety of microwave ablation for the treatment of multifocal versus unifocal T1N0M0 papillary thyroid carcinoma: a propensity-matched multicentre retrospective study.

OBJECTIVES: Microwave ablation (MWA) has been widely used for unifocal papillary thyroid carcinoma (U-PTC) and has recently been preliminarily used in multifocal papillary thyroid carcinoma (M-PTC). However, the efficacy and safety of MWA for M-PTC have not been investigated in large samples. The aim of the present study was to evaluate the efficacy and safety of MWA for M-PTC and compare them with MWA for U-PTC. MATERIALS AND METHODS: This retrospective multicentre study enrolled 504 patients (376 females) who underwent MWA for U-PTC (340 cases) or M-PTC (164 cases) from Jan 2015 to Dec 2020. The median age of the patients was 43 years (age range, 20-80 years). Propensity score matching (PSM) was used to balance the baseline characteristics between M-PTC group and U-PTC group. The tumour progression, tumour disappearance, and complication rates were compared between the two groups. RESULTS: The complete ablation was achieved in all enrolled cases in one session. According to the statistical results, no significant differences were shown in tumour progression-free survival (p  = 0.29) or cumulative tumour progression rate (6.7% vs. 4.3%, p  = 0.33) between the M-PTC and U-PTC groups during the follow-up time. However, the tumour disappearance rate in the M-PTC group was lower in the U-PTC group (40.9% vs. 62.8%, p < 0.001), and tumour disappearance was slower in the M-PTC group (p < 0.001). The complication rate showed no significant difference (3.0% vs. 4.9%, p  = 0.571). CONCLUSIONS: MWA is an effective and safe treatment for selected patients with M-PTC, and the prognosis is similar to that of U-PTC. CLINICAL RELEVANCE STATEMENT: The present study provided evidence that compared with unifocal papillary thyroid cancer, microwave ablation could also treat multifocal T1N0M0 papillary thyroid cancer safely with similar clinical outcome, which could promote the application of minimally invasive treatment for papillary thyroid cancer. KEY RESULTS: • Microwave ablation for multifocal and unifocal T1N0M0 papillary thyroid carcinoma had similar tumour progression rates after propensity score matching (6.7% vs. 4.3%, p = 0.33). • The tumour disappearance rate in the multifocal group was lower than that in the unifocal group (40.9% vs. 62.8%, p < 0.001), and tumour disappearance was slower in the multifocal group (p < 0.001). • Tumour size, number, and location were not risk factors for tumour progression in the multifocal papillary thyroid cancer group.

Influence factors and nomogram for volume reduction rate in benign thyroid nodule after thermal ablation.

BACKGROUND: Thermal ablation is a minimally invasive and safe treatment for benign thyroid nodules, and the volume reduction rate (VRR) of nodule is a primary clinical efficacy indicator. PURPOSE: To screen factors influencing VRR in benign thyroid nodules after thermal ablation and establish a predictable nomogram. MATERIALS AND METHODS: This retrospective study enrolled 238 patients with benign thyroid nodules who underwent thermal ablation between January 2016 and September 2021. Clinical information and imaging characteristics in routine ultrasound (US) and contrast-enhanced ultrasound (CEUS) were evaluated. Factors influencing the VRR ≥75% were screened using multivariate logistic regression, and a predictable nomogram was established. RESULTS: At the 12-month follow-up, the VRR of nodule was 77.0 ± 20.6% (18.4-100%). Seven factors influencing the VRR ≥75.0% were identified: echogenicity, component, calcification, enhancement degree, enhancement defect, ring enhancement, and energy of ablation. A nomogram was established based on the above factors, and the predictive ability of the model was confirmed by internal validation with 1000 bootstrap repetitions. The area under the receiver-operating characteristic curve (AUC) of the model was 0.926, and the calibration curve and decision curve analysis (DCA) revealed that this model demonstrated predictive ability. CONCLUSION: Seven factors influencing VRR in benign thyroid nodules after thermal ablation were screened out in the present study and used to establish a nomogram to predict the probability of VRR ≥75% at the 12-month follow-up. It would be beneficial to make personalized medical decisions to trigger thermal ablation in patients with benign thyroid nodules.

Safety and efficacy of microwave ablation for the treatment of low-risk papillary thyroid microcarcinoma: a prospective multicenter study.

OBJECTIVES: To assess the safety and efficacy of ultrasound-guided thermal ablation for low-risk papillary thyroid microcarcinoma (PTMC) via a prospective multicenter study. METHODS: From January 2017 through June 2021, low-risk PTMC patients were screened. The management details of active surveillance (AS), surgery, and thermal ablation were discussed. Among patients who accepted thermal ablation, microwave ablation (MWA) was performed. The main outcome was disease-free survival (DFS). The secondary outcomes were tumor size and volume changes, local tumor progression (LTP), lymph node metastasis (LNM), and complication rate. RESULTS: A total of 1278 patients were included in the study. The operation time of ablation was 30.21 ± 5.14 min with local anesthesia. The mean follow-up time was 34.57 ± 28.98 months. Six patients exhibited LTP at 36 months, of whom 5 patients underwent a second ablation, and 1 patient received surgery. The central LNM rate was 0.39% at 6 months, 0.63% at 12 months, and 0.78% at 36 months. Of the 10 patients with central LNM at 36 months, 5 patients chose ablation, 3 patients chose surgery and the other 2 patients chose AS. The overall complication rate was 1.41%, and 1.10% of patients developed hoarseness of the voice. All of the patients recovered within 6 months. CONCLUSIONS: Thermal ablation of low-risk PTMC was observed to be safe and efficacious with few minor complications. This technique may help to bridge the gap between surgery and AS as treatment options for patients wishing to have their PTMC managed in a minimally invasive manner. CLINICAL RELEVANCE STATEMENT: This study proved that microwave ablation is a safe and effective treatment method for papillary thyroid microcarcinoma. KEY POINTS: Percutaneous US-guided microwave ablation of papillary thyroid microcarcinoma is a very minimally invasive treatment under local anesthesia during a short time period. The local tumor progression and complication rate of microwave ablation in the treatment of papillary thyroid microcarcinoma are very low.

Upgraded hydrodissection and its safety enhancement in microwave ablation of papillary thyroid cancer: a comparative study.

OBJECTIVES: To study the efficacy and safety of an improved hydrodissection protocol based on the perithyroidal fascial space during microwave ablation for papillary thyroid carcinoma (PTC). METHODS: The data of 341 patients (94 men and 247 women, median age 41 years old, 25%-75% interquartile range 34-53 years old, nodule maximum diameter 0.2-1.9 cm) who underwent microwave ablation for PTC were retrospectively reviewed. Among them, 185 patients underwent traditional hydrodissection and served as a control group, and 156 patients underwent improved hydrodissection based on perithyroidal fascial spaces, constituting the improved group. Improvements in safety were analyzed by comparing complications between the two groups. The characteristics of hydrodissected spaces, complications, and follow-up results were recorded. RESULTS: Hydrodissection was successfully performed in all enrolled patients according to the protocol. The incidence of hoarseness caused by recurrent laryngeal nerve injury, the most common complication in thermal ablation of thyroid nodules, was significantly lower in the improved group than in the control group (1.9% vs. 8.1%, p = 0.021). The median hoarseness recovery time in the improved group was shorter than that in the control group (2 months vs. 3 months, p = 0.032). During follow-up, no local recurrence was encountered in either group. The tumor disappearance rate was not significantly different between the two groups (69.9% vs. 75.7%, p = 0.228). CONCLUSIONS: Improved hydrodissection based on perithyroidal fascial spaces had better protective effects than traditional hydrodissection.

Microwave Ablation for Papillary Thyroid Microcarcinoma with and without US-detected Capsule Invasion: A Multicenter Prospective Cohort Study.

Background Microwave ablation (MWA) has achieved favorable results in the treatment of papillary thyroid microcarcinoma (PTMC) confined in glandular parenchyma. However, studies on the outcome of MWA for PTMC with US-detected capsular invasion remain unclarified in the literature. Purpose To compare the feasibility, effectiveness, and safety of MWA in the treatment of PTMC with and without US-detected capsular invasion. Materials and Methods Participants from 12 hospitals with a PTMC maximal diameter of 1 cm or less without US- or CT-detected lymph node metastasis (LNM) who planned to undergo MWA were enrolled in this prospective study between December 2019 and April 2021. All tumors were evaluated with preoperative US and were divided into those with and those without capsular invasion. The participants were observed until July 1, 2022. The primary end points, including technical success and disease progression, and the secondary end points, including treatment parameters, complications, and tumor shrinkage during follow-up, were compared between the two groups, and multivariable regression was performed. Results After exclusion, 461 participants (mean age, 43 years ± 11 [SD]; 337 women) were included: 83 with and 378 without capsular invasion. After one participant with capsular invasion aborted MWA because of technical failure, 82 participants with and 378 participants without capsular invasion (mean tumor volume, 0.1 mL ± 0.1 vs 0.1 mL ± 0.1; P = .07) were analyzed with a mean follow-up period of 20 months ± 4 (range, 12-25 months) and 21 months ± 4 (range, 11-26 months), respectively. In those with and those without capsular invasion, comparable technical success rates were achieved (99% [82 of 83] vs 100% [378 of 378], P = .18), with one and 11 complications, respectively (1% [one of 82] vs 3% [11 of 378], P = .38). There was no evidence of differences in disease progression (2% [one of 82] vs 1% [four of 378]; P = .82) or tumor shrinkage (mean, 97% ± 8 [SD] vs 96% ± 13; P = .58). Conclusion Microwave ablation was feasible in the treatment of papillary thyroid microcarcinoma with US-detected capsular invasion and showed comparable short-term efficacy with or without the presence of capsular invasion. © RSNA, 2023 Clinical trial registration no. NCT04197960 Supplemental material is available for this article.

Preliminary Study of Microwave Ablation for Multifocal Papillary Thyroid Microcarcinoma in Nonoperative Candidates.

PURPOSE: To study the feasibility, safety, and effectiveness of microwave ablation (MWA) in patients with multifocal papillary thyroid microcarcinoma (PTMC). MATERIALS AND METHODS: This retrospective study included patients who underwent MWA for multifocal PTMC (number of nodules ≤3). A total of 44 patients were included, and the mean age was 43 years (SD ± 11). After ablation, progression-free survival (PFS) at 6, 12, 24, 36, and 48 months; disease progression; change in tumor size and volume; tumor disappearance rate; and adverse events (AEs) were assessed, and the feasibility, safety, and effectiveness of MWA for PTMC were evaluated on the basis of statistical analysis. RESULTS: The median follow-up period was 18 months (interquartile range, 12-33 months). The PFS rates at 6, 12, 24, 36, and 48 months were 100.0%, 96.4%, 96.4%, 70.3%, and 52.7%, respectively. The disease progression rate was 11.4% (5 of 44 patients). The maximum diameter (MD) and volume of the ablation zone were larger at the 3-month follow-up than before ablation (median MD, 13.0 vs 7.0 mm; P < .001; median volume, 503.8 vs 113.0 mm3; P < .001). Subsequently, the tumors exhibited a reduction in both size and volume after 18 months (median MD, 4.0 vs 7.0 mm; P = .04; median volume, 12.6 vs 113.0 mm3; P = .055). At the end of the follow-up period, the complete response rate was 59% (26 of 44 patients). The overall AE rate was 6.8%. CONCLUSIONS: MWA is a feasible treatment for PTMC (number of nodules ≤3), and this study preliminarily demonstrated the safety and effectiveness of this technique.

FDE-net: Frequency-domain enhancement network using dynamic-scale dilated convolution for thyroid nodule segmentation.

Thyroid nodules, a common disease of endocrine system, have a probability of nearly 10% to turn into malignant nodules and thus pose a serious threat to health. Automatic segmentation of thyroid nodules is of great importance for clinicopathological diagnosis. This work proposes FDE-Net, a combined segmental frequency domain enhancement and dynamic scale cavity convolutional network for thyroid nodule segmentation. In FDE-Net, traditional image omics method is introduced to enhance the feature image in the segmented frequency domain. Such an approach reduces the influence of noise and strengthens the detail and contour information of the image. The proposed method introduces a cascade cross-scale attention module, which addresses the insensitivity of the network to the change in target scale by fusing the features of different receptive fields and improves the ability of the network to identify multiscale target regions. It repeatedly uses the high-dimensional feature image to improve segmentation accuracy in accordance with the simple structure of thyroid nodules. In this study, 1355 ultrasound images are used for training and testing. Quantitative evaluation results showed that the Dice coefficient of FDE-Net in thyroid nodule segmentation was 83.54%, which is better than other methods. Therefore, FDE-Net can enable the accurate and rapid segmentation of thyroid nodules.

Microwave ablation vs. surgery for papillary thyroid carcinoma with minimal sonographic extrathyroid extension: a multicentre prospective study.

OBJECTIVES: Minimal extrathyroid extension (mETE) was removed from the TNM staging system. This study was designed prospectively to compare the safety and efficacy of microwave ablation (MWA) versus surgery for treating T1N0M0 papillary thyroid carcinomas (PTC) with sonographically detected mETE. METHODS: From December 2019 to April 2021, 198 patients with T1N0M0 mETE-PTCs evaluated by preoperative ultrasound from 10 hospitals were included. Ninety-two patients elected MWA, and 106 patients elected surgery for treatment. MWA was performed using extensive ablation with hydrodissection. Surgery consisted of lobectomy with ipsilateral central lymph node dissection (CLD), lobe and isthmus excision with ipsilateral CLD and total thyroidectomy with ipsilateral CLD. The rates of technical success, cost, oncologic outcomes, complications and quality of life of the two groups were assessed. RESULTS: The follow-up times for the MWA and surgery groups were 12.7 ± 4.1 and 12.6 ± 5.0 months, respectively. The technical success rate was 100% for both groups. Oncological outcomes of the two groups were similar during the follow-up (all p > 0.05). The MWA group had a shorter operation time, less blood loss and lower costs (all p < 0.001). Three complications (3.3%) were reported in the MWA group and 4 (3.8%) in the surgery group (p = 0.846). The surgery group had higher scores for scar problems and anxiety (p < 0.001 and p = 0.003, respectively). CONCLUSIONS: Microwave ablation was comparable in the short term to surgery in terms of treatment safety and efficacy in selected patients with T1N0M0 mETE-PTC detected by ultrasound. KEY POINTS: • Microwave ablation is comparable to surgery in the safety and short-term efficacy for PTCs with sonographically detected mETE. • Thermal ablation is technically feasible for mETE-PTC treatment. • Patients with mETE-PTC have similar quality of life in the two groups, except for worse scar problems and anxiety in the surgery group.

A clinical study on microwave ablation of multifocal (≤ 3) T1N0M0 papillary thyroid carcinoma.

OBJECTIVE: To evaluate the feasibility, efficiency, and safety of microwave ablation (MWA) for T1N0M0 multifocal (≤ 3) papillary thyroid carcinoma (PTC). METHODS: This was a retrospective study, and patients who underwent MWA for multifocal (≤ 3) PTC were reviewed between October 2016 and December 2020. After ablation, the changes in tumor size and volume, as well as the rate of technical success, tumor disappearance, disease progression, and complications were assessed. RESULTS: There were a total of 57 cases enrolled in the present study, which included 18 males and 39 females. The mean age was 44 ± 11 years (22-66 years); the mean follow-up time was 18 ± 11 months (6-48 months). Complete ablation was achieved in all enrolled cases. Therefore, the technical success rate was 100%. Due to expanding ablation, the MD and volume of the ablation zone, as well as the VRR, increased at the 1st and 3rd months after ablation and decreased at 12 and 18 months after ablation (p < 0.05 for all). The total complete tumor disappearance rate was 43.9% (25/57), including 54% (24/44) in the T1a subgroup vs. 7.7% (1/13) in the T1b subgroup (p = 0.003). The total disease progression rate was 7% (4/57), including 9.1% (4/44) in the T1a subgroup vs. 0% (0/13) in the T1b subgroup (p = 0.142). The overall complication rate was 5.3% (3/57), including 6.8% (4/44) in the T1a subgroup vs. 0% (0/13) in the T1b subgroup (p = 0.206). CONCLUSION: This preliminary study indicates that MWA is a safe and effective treatment for T1N0M0 multifocal (≤ 3) PTC. KEY POINTS: • MWA is a promising alternative method for T1N0M0 multifocal (≤ 3) PTC.

Changes in Thyroid Antibodies after Microwave Ablation of Thyroid Nodules.

Purpose: Microwave ablation (MWA) is a minimally invasive method for the thermal ablation of benign thyroid nodules and papillary thyroid cancer (PTC) and has shown promising results. The aim of this study was to investigate the impact of MWA on thyroid antibodies and associated influencing factors. Materials and Methods: A total of 119 patients, including 69 with benign thyroid nodules and 50 with PTC, underwent MWA between June 2019 and June 2021. The serum levels of (free) triiodothyronine, (free) thyroxine, thyrotropin, and antibodies against Tg (TGAb), thyrotropin receptors (TRAb), and thyroid peroxidase (TPOAb) were measured during the follow up. Results: One month after ablation, three patients (4.3%) in the benign group had hypothyroidism, and one (1.4%) had hyperthyroidism. Four patients (5.8%) had subclinical hypothyroidism, and two (2.9%) had subclinical hyperthyroidism. Among the PTC patients, two (4%) had hypothyroidism, and one (2%) had hyperthyroidism. Two patients (4%) had subclinical hypothyroidism, and one (2%) had subclinical hyperthyroidism. In the benign group, among patients with normal preablation antibodies, the postablation TGAb abnormal rate was 12.7%, the TPOAb level was 4.8%, and the TRAb level was 0%. Among PTC patients, the postablation TGAb abnormal rate was 11.4%, the TPOAb level was 8.7%, and the TRAb level was 4.0%. The cutoff value of preablation TGAb for predicting postoperative antibody abnormalities was 19.0 IU/mL, while that of TPOAb was 11.4 IU/mL. Conclusions: MWA of thyroid nodules had little influence on thyroid function and antibodies. Elevations in TGAb, TPOAb, and TRAb beyond the normal ranges after MWA may be related to high preablation levels of TGAb and TPOAb.

Predicting ultrasound-guided thermal ablation benefit in primary hyperparathyroidism.

OBJECTIVES: Ultrasound (US)-guided thermal ablation for primary hyperparathyroidism (PHPT) is a relatively novel minimally invasive treatment. The recurrence rate after ablation is between 10 and 15%. The characteristics of patients who can benefit from thermal ablation therapy are not clear yet. The aim of this research was to investigate the validity of a parathyroid hormone (PTH)-based classifier for stratifying patients with PHPT. METHODS: A total of 171 patients were screened, 148 (86.5%) of whom were eligible and were divided into development (n = 104) and external validation (n = 44) cohorts. The potential relationship between the PTH-based classifier and the cure rate of patients was initially assessed in the primary cohort and then validated in the external validation cohort. The nomogram was computed from the logistic regression model. RESULTS: A cut-off of PTH < 269.1 pg/mL or ≥ 269.1 pg/mL as the optimal prognostic threshold in the training cohort was generated to stratify the patients into low-risk and high-risk groups. Patients with PTH levels < 269.1 pg/mL in the training cohort had a higher cure rate than patients with PTH levels ≥ 269.1 pg/mL (p < 0.001). The PTH level remained the strongest predictor of the cure rate in all cohorts. Furthermore, a nomogram based on the PTH level was developed to predict the cure rate in the training cohort and it performed well in the external validation cohort (AUC: 0.816, 95%CI 0.703 to 0.930; AUC: 0.816, 95%CI 0.677 to 0.956). CONCLUSIONS: The PTH-based classifier may help with individualised treatment planning for selecting patients who may benefit from thermal ablation. KEY POINTS: • This is the first analysis of predictors affecting the outcome of US-guided thermal ablation of primary hyperparathyroidism and the findings can be used to identify the potential beneficiary population of thermal ablation of primary hyperparathyroidism. • Parathyroid hormone (PTH) was confirmed as an independent prognostic factor, as it not only showed good accuracy in stratifying patients into high- and low-risk groups in the training and validation cohorts but also outperformed the clinical model. • This study developed and validated a model to predict the treatment success of thermal ablation of primary hyperparathyroidism.

Microwave Ablation versus Surgical Resection for Solitary T1N0M0 Papillary Thyroid Carcinoma.

Background Microwave ablation (MWA) has attracted interest as a minimally invasive treatment for papillary thyroid carcinoma (PTC). However, comparisons between MWA and surgical resection (SR) in the management of T1N0M0 PTC are rare. Purpose To compare the technical effectiveness, disease progression, and complications of MWA and SR for solitary T1N0M0 PTC. Materials and Methods This retrospective study was conducted in a single center. A total of 1029 patients with T1N0M0 PTC treated with either MWA or SR from January 2015 to May 2021 were studied and divided into two groups according to treatment modality. Propensity score matching and inverse probability of treatment weighting were used to control for confounding factors. Disease progression was analyzed in T1N0M0 PTCs as well as T1a and T1b subgroups by using Kaplan-Meier curves and Cox proportional hazards regression models. Results A total of 404 patients (mean age, 43 years ± 12 [SD]; 289 women; 337 with T1a PTC) underwent MWA, and 625 (mean age, 46 years ± 12; 495 women; 521 with T1a PTC) underwent SR. During the follow-up (median, 25 months; IQR, 7-61 months), there was no evidence of differences regarding disease progression in T1N0M0 (4.0% vs 4.0%; P = .97), T1a (3.4% vs 3.8%; P = .89), or T1b PTCs (6.8% vs 5.0%; P = .72). Compared with SR, MWA resulted in less blood loss (2 mL vs 10 mL) and a shorter procedure time (23 minutes vs 72 minutes) (both P < .001). The rate of major complications was 5.4% (19 of 350 patients) in the MWA group and 6.3% (22 of 350 patients) in the SR group (P = .75). Permanent hoarseness only occurred in the SR group (1.7%; P = .03). Conclusion For T1a and T1b solitary T1N0M0 papillary thyroid carcinomas, there was no evidence of differences regarding disease progression and major complications between microwave ablation and surgical resection. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by vanSonnenberg and Simeone in this issue.

Ultrasound-guided microwave and radiofrequency ablation for primary hyperparathyroidism: a prospective, multicenter study.

OBJECTIVES: To prospectively investigate the efficacy and safety of ultrasound (US)-guided microwave ablation (MWA) and radiofrequency ablation (RFA) for primary hyperparathyroidism (PHPT). METHODS: We performed a prospective multicenter study of MWA and RFA for PHPT between August 2017 and October 2020 at five centers. Laboratory testing was performed pre- and post-ablation and followed for at least 6 months. The primary outcome was the cure rate. Secondary outcomes were complications and dynamic changes in serum levels of PTH, calcium, phosphorus, and ALP after ablation. RESULTS: A total of 132 participants (mean age, 57.33 ± 13.90 years), with 141 parathyroid nodules (median maximal diameter, 1.55 cm) undergoing either MWA or RFA, were enrolled in the study. The technique success rate was 99.29% (140/141). The follow-up period was 6-36 months (median, 12 months). The cure rate was 80.30% (106/132). Pre-ablation PTH level was the independent factor associated with cure rate (Odds ratio (OR), 0.22; 95% CI, 0.07-0.69; p = 0.0090). There was no difference in cure rate between the MWA group and the RFA group (80.22% vs. 80.49%, p = 0.971). The only main complication was hoarseness (5.30%). CONCLUSIONS: US-guided MWA and RFA for PHPT is an effective and safe procedure in the treatment of PHPT. Pre-ablation PTH level is the key factor affecting the cure rate after MWA and RFA. KEY POINTS: • To our knowledge, this is the first prospective multicenter clinical trial with ultrasound-guided MWA and RFA for primary hyperparathyroidism. • There was no difference in cure rate between the MWA and RFA groups for primary hyperparathyroidism. The overall cure rate was 80.30%. • Pre-ablation PTH level was the independent factor associated with cure rate (odds ratio (OR), 0.22; 95% CI, 0.07-0.69; p = 0.0090).