Radiofrequency Thermoablation On Ex Vivo Animal Tissues: Changes on Isolated Swine Thyroids.

The use of Radiofrequency thermoablation (RFA) for treating large thyroid nodules is limited by the modest efficiency of the available systems in terms of volume of the ablation zones (AZs). This increases the risk of incomplete ablation of the nodule. Systems employing perfused electrodes have been developed to increase the volume of the AZ. Aim of this study is to compare the size of the AZ induced by RFA systems using internally cooled perfused vs. non-perfused electrodes in swine thyroids. RFAs were performed on 40 freshly isolated swine thyroids using both systems. The perfused system was tested using 0.9% saline, 7% and 18% hypertonic saline solutions. Energy delivery to the tissue was stopped when tissue conductivity dropped (real life simulations) and after an established time of 20 seconds (controlled duration). Following RFA, thyroids were transversally and longitudinally cut. Photographs were taken for macroscopic morphometry of the ablated zones before and after formalin fixation, to evaluate tissue shrinkage. Microscopic morphometry was performed on PAS stained sections. In real life simulation experiments, gross morphometry revealed that AZs produced with electrodes perfused using 7.0% saline are larger compared to isotonic saline. Microscopically, all the conditions tested using the perfused system produced larger AZs compared to non-perfused system after 20 seconds of RFA. In conclusion, the perfusion with 7.0% NaCl solution increased the electrical conductivity of the tissue in real life simulations, resulting in larger ablated areas compared to the use of isotonic saline.

Predictor Analysis in Radiofrequency Ablation of Benign Thyroid Nodules: A Single Center Experience.

Purpose: To confirm the efficacy of ultrasound (US) guided radiofrequency ablation (RFA) in the treatment of benign thyroid nodules, we evaluated as primary outcome the technical efficacy and clinical success in a single center dataset. The secondary outcome was to find a correlation between nodules' pre-treatment features and volume reduction rate (VRR) ≥75% at 12 months after RFA and during follow-up period. Methods: This retrospective study included 119 consecutive patients (99 females, 20 males, 51.5 ± 14.4 years) with benign thyroid nodules treated in our hospital between October 2014 and December 2018 with a mean follow-up of 26.8 months (range 3-48). Clinical and US features before and after RFA were evaluated by a US examination at 1, 3, 6, 12 months and annually thereafter up to 48 months. Results: The median pre-treatment volume was 22.4 ml; after RFA we observed a statistically significant volume reduction from the first month (11.7 ml) to the last follow-up (p < 0.001 for all follow-up times). The median VRR was 47.1, 55.3, 61.2, 67.6, 72.8, 71.3, and 62.9% at 1, 3, 6, 12, 24, 36, and 48 months of follow-up respectively, showing a progressive significant improvement up to 24 months (VRRs 1 vs 3 months, 3 vs 6 months and 6 vs 12 months p < 0.001, 12 vs 24 months p = 0.05) while no differences at 24 vs 36 and 36 vs 48 months were observed. Symptoms improved significantly (complete resolution 64.35%, partial resolution 35.65%), and neck circumference was reduced as compared to pre-treatment (p < 0.001). Lower pre-treatment neck circumference (37.5 vs 36.0 cm, p = 0.01) was a positive predictor of VRR ≥75% at 12 months. Macrocystic echostructure (HR 2.48, p 0.046) and pre-treatment volume >22.4 ml (HR 0.54, p 0.036) were found to be independent positive and negative predictors of VRR ≥75% respectively. One-month post RFA VRR ≥50% represented the best positive predictor of technical success. Conclusions: This study confirmed the efficacy of RFA in the treatment of benign thyroid nodules. In particular we show that by selecting macrocystic nodules smaller than 22.4 ml better long-term response can be achieved, which is predicted by an early shrinkage of the nodule.

Radiofrequency Thermal Ablation for a Small Papillary Thyroid Carcinoma in a Patient Unfit for Surgery: A Case Report.

Ultrasound-guided radiofrequency thermal ablation has been proposed as an effective and safe procedure for treating patients who have low-risk papillary thyroid microcarcinomas and/or are unfit for surgery. We present the case of a 72-year old male patient with a small thyroid nodule diagnosed as papillary carcinoma after fine needle aspiration. Since the patient had other serious comorbidities, priority was given to other therapies and the malignant thyroid nodule was submitted to active surveillance. After detecting at a follow-up examination a slight dimensional increase of the nodule, the possibility of a radiofrequency thermal ablation was proposed to our patient, who accepted. The procedure was safely and effectively carried out. Follow-up examinations with ultrasonography (or contrast enhanced ultrasound), conducted after 1, 3, 6, and 12 months, demonstrated a progressive reduction of size and loss of vascularization in the treated area. The fine needle aspiration was repeated after 6 months: the sample revealed a very poor cellularity composed of inflammatory cells and thick colloid; no residual neoplastic cells were observed. Our experience confirmed what already demonstrated by previous reports: radiofrequency ablation can effectively eliminate small papillary carcinomas, with a very low complication rate. It may be an alternative strategy for the treatment of low-risk, indolent papillary thyroid microcarcinomas, thus avoiding the potential side-effects of surgery in patients at risk for relevant comorbidities.

A Simplified Ultrasonographic Score for the Prediction of Cytologically Suspicious Thyroid Nodules.

PURPOSE: The major aim of ultrasound (US)-based risk stratification systems is to reduce unnecessary thyroid biopsies without losing the ability to recognize nodules with clinically significant malignancy. Each of the classic suspicious features of a thyroid nodule detected on US scan (hypoechoic pattern, microcalcifications, irregular margin, taller than wide shape, irregular vascularization) is significantly independently associated with the probability of malignancy, but none of them has good diagnostic accuracy. Thus, we evaluated the predictive value of a binary score simply based on the combination of these US features, regardless of the specific predictive value of each US feature, against the outcome of suspected malignancy at cytological diagnosis (TIR3 to TIR5 categories by SIAPEC-IAP [TIR+]). MATERIALS AND METHODS: 1009 thyroid nodules from 1081 patients were considered. The US features of suspicion of all nodules were categorized in 5 binary scores (U1 to U5), each including from 1 to 5 of those features. RESULTS: U2 (at least 2 US suspicious features) was the most balanced predictor of TIR+ (PPV 0.48, NPV 0.93, LR+ 3.05 and LR- 0.24). Weighting the predictivity of the single features did not improve the estimate. Using U2 as the criterion to send nodules to FNAC would have reduced the number of biopsies by 60 % (604 patients) and the false negatives would have only accounted for 41 cases out of 237 TIR+ (17 %) with 39 cases of TIR3 and 2 cases of TIR4, including only 6 malignant nodules on histological examination. U2 performed much better than the ATA recommendations for detecting those nodules, resulting in TIR+ at cytology. CONCLUSION: This simple and reproducible sonographic score based on 2 US features of suspicion of malignancy has quite a good performance with respect to identifying thyroid lesions categorized by cytology as medium-high risk of malignancy and could allow us to reduce cytology costs for low-risk nodules.

Retrospective analysis of the ultrasound features of resected thyroid nodules.

PURPOSE: Several ultrasound (US) risk stratification systems (US-RSSs) have been proposed to stratify the risk of malignancy (ROM) of thyroid nodules. This risk might be overestimated due to selection bias and comparison with the cytological report alone. Our study aimed to compare ROM and diagnostic performance of three guidelines (ATA, AACE/ACE/AME, EUTIRADS) and evaluate the changes in unnecessary biopsy according to the nodule size cutoff for biopsy, using histology as gold standard. METHODS: This retrospective observational study included 146 consecutive patients who underwent surgery after US and cytological characterization. We analyzed the effectiveness and accuracy of three US-RSSs. RESULTS: 46.6% of nodules were diagnosed as malignant. Applying US-RSS, the percentage of nodules that should have been analyzed by biopsy was 84.25% with ATA, 69.86% with EUTIRADS and 64.38% with AACE/ACE/AME systems. The ROM was 94.9%, 86.0%, 87.0% for high-risk category, 36.4%, 32.0%, 35.4% for intermediate-risk category and 22.9%, 0.0%, 22.9% for low-risk category by ATA, AACE/ACE/AME and EUTIRADS systems, respectively. EUTIRADS and AACE/ACE/AME systems were more accurate in differentiating malignant from benign cases. ATA score was the more sensitive US-RSS to identify malignant tumors within the high-risk category. About the unnecessary biopsies, in the intermediate-risk category, the application of the size criterion helps to increase specificity in all systems. CONCLUSIONS: The US categorization of low and high-risk thyroid nodules using current US-RSSs helps alone to determine the optimal treatment option. Nodule size remains relevant to recommend biopsy for the intermediate-risk category.

The Ablation of Thyroid Nodule's Afferent Arteries Before Radiofrequency Ablation: Preliminary Data.

Induced radiofrequency thermal ablation is the cytoreductive treatment of symptomatic benign thyroid nodules, metastatic and recurrent thyroid tumors and papillary thyroid microcarcinomas. It is a safe and effective alternative to surgery and it allows to obtain satisfactory results in terms of volumetric reduction of the nodule with significant improvement in the quality of life. The trans-isthmic approach and the moving shot technique are the two basic techniques; however, an advanced technique, artery-first feeding radiofrequency ablation, has been developed and validated. We have prospectively included 29 consecutive patients who have undergone radiofrequency ablation (Group A) or artery- first vRFA (Group B). All included patients had a diagnosis of benign nodular goiter and they underwent a single session of radiofrequency ablation. All patients followed a follow-up program at 1 month, 3 months, and 6 months. Continuous variables (age, TSH value, basal volume of nodule, used Joule, time in second of the procedure, nodules' volume at 1-, 3-, and 6- months of follow-up and percentage of volume reduction at 1-, 3-, and 6- months of follow-up) were described as mean, standard deviation and range, while categorical variables (gender, nodule structure and nodule vascularization) were described as number of cases and percentage. Independent samples t-test were performed to compare the continuous variables. A Test of Proportions was applied to the categorical variables. The Fisher's exact test was used to analyze the gender. Statistical significance was considered in case of p-value <0.05. Solid structure and spongiform structure showed statistic differences with p-values of 0.022 and 0.023 respectively between two groups. The percentage of reduction at 1 month did not show a significant difference between two groups; instead, the percentage of volume reduction was decreased mostly in the Group B at 3 months and 6 months of follow-up with a p-value of 0.003 and 0.013, respectively. The Joules/energy used showed a statistically significant difference (p-value=0.05), more energy must be used in vascular radiofrequency ablation. These data allow us to hypothesize that vRFA may improve the effectiveness of the procedure, allowing for a reduction in volume more quickly. They were preliminary but promising results, clearly a larger series of cases and prolonged follow-up are needed to clarify and confirm our observations.

Role of Nuclear Medicine in the Diagnosis of Benign Thyroid Diseases.

A deep understanding of thyroid pathophysiology is the basis for diagnosing and treating benign thyroid diseases with radioactive materials, known as radiopharmaceuticals, which are introduced into the body by injection or orally. After the radiotracer administration, the patient becomes the emitting source, and several devices have been studied to detect and capture these emissions (gamma or beta-negative) and transform them into photons, parametric images, numbers and molecular information. Thyroid scintigraphy is the only technique that allows the assessment of thyroid regional function and, therefore, the detection of areas of autonomously functioning thyroid nodules. Scintigraphy visualizes the distribution of active thyroid tissue and displays the differential accumulation of radionuclides in the investigated cells, thus providing a functional map. Moreover, this technique is a fundamental tool in the clinical and surgical management of thyroid diseases, including: single thyroid nodules with a suppressed thyroid-stimulating hormone level, for which fine-needle aspiration biopsy (FNAB) is used to identify hot nodules; multinodular goiters, especially larger ones, to identify cold or indeterminate areas requiring FNAB and hot areas that do not need cytologic evaluation, and to evaluate mediastinal extension; the diagnosis of ectopic thyroid tissue; subclinical hyperthyroidism to identify occult hyperfunctioning tissue; follicular lesions to identify a functioning cellular adenoma that could be benign, although such nodules are mostly cold on scintigraphy; to distinguish low-uptake from high-uptake thyrotoxicosis, and to determine eligibility for radioiodine therapy.

Columnar cell lesions associated with breast calcifications on vacuum-assisted core biopsies: clinical, radiographic, and histological correlations.

Columnar cell lesions of the breast are increasingly recognized at mammography for their tendency to calcify. We studied 392 vacuum-assisted core biopsies performed solely for calcifications to evaluate the frequency of columnar cell lesions, their relationship with radiological risk, appearance of calcifications, and clinical data. Management and follow-up of columnar cell lesions without and with atypia (flat epithelial atypia) was analyzed. Cases with architectural atypia (cribriform spaces and/or micropapillae) were excluded from flat epithelial atypia. Calcifications were within the lumen of acini affected by columnar cell lesions in 137 out of 156 biopsies diagnosed with some columnar cell lesions. These represented 37% of vacuum-assisted core biopsies and 62% of low radiological risk (BI-RADS3) calcifications. High-risk (BI-RADS5) calcifications were never associated with columnar cell lesions. Age and menopausal status were comparable in columnar and in not-columnar cell lesions. Atypia was associated with long-term hormone replacement therapy in both lesions. Surgical biopsy was recommended for all cases with atypia. Flat epithelial atypia, as the only histological findings on vacuum-assisted core biopsies, was never associated with malignancy at surgery. In conclusion, we suggest that surgical excision is not mandatory when flat epithelial atypia is found as the most advanced lesion on vacuum-assisted core biopsy performed for low radiological risk calcifications, and that women should be advised of the possible hormone dependency of this entity.