Volume reduction of benign thyroid nodules 3 months after a single treatment with high-intensity focused ultrasound (HIFU)

Efficacy of HIFU for the treatment of benign thyroid nodules: a systematic review and meta-analysis

OBJECTIVE

Thyroid nodules are common and sometimes associated with cosmetic issues. Surgical treatment has several disadvantages, including visible scarring. High-intensity focused ultrasound (HIFU) is a recent noninvasive treatment for thyroid nodules. The present study aims to evaluate the effectiveness and safety of HIFU for the treatment of benign thyroid nodules.

METHODS

We searched PubMed, Embase, and Cochrane Library for studies evaluating the outcomes of HIFU for patients with benign thyroid nodules. We conducted a meta-analysis by using a random effects model and evaluated the volume reduction ratio, treatment success rate, and incidence of treatment-related complications.

RESULTS

Thirty-two studies were included in the systematic review. Only 14 studies were used in the meta-analysis because the other 18 involved data collected during overlapping periods. The average volume reduction ratios at 3, 6, and 12 months after treatment were 39.02% (95% CI: 27.57 to 50.47%, I2: 97.9%), 48.55% (95% CI: 35.53 to 61.57%, I2: 98.2%), and 55.02% (95% CI: 41.55 to 68.48%, I2: 99%), respectively. Regarding complications, the incidences of vocal cord paresis and Horner's syndrome after HIFU were 2.1% (95% CI: 0.2 to 4.1%, I2: 14.6%) and 0.7% (95% CI: 0 to 1.9%, I2: 0%), respectively.

CONCLUSIONS

HIFU is an effective and safe treatment option for patients with benign thyroid nodules. However, the effects of HIFU on nodules of large sizes and with different properties require further investigation. Additional studies, particularly randomized controlled trials involving long-term follow-up, are warranted.

CLINICAL RELEVANCE STATEMENT

Surgical treatment for thyroid nodules often results in permanent visible scars and is associated with a risk of bleeding, nerve injury, and hypothyroidism. High-intensity focused ultrasound may be an alternative for patients with benign thyroid nodules.

KEY POINTS

• The success rate of HIFU treatment for thyroid nodules is 75.8% at 6 months. Average volume reduction ratios are 48.55% and 55.02% at 6 and 12 months. • The incidence of complications such as vocal fold paresis, Horner's syndrome, recurrent laryngeal nerve palsy, hypothyroidism, and skin redness is low. • HIFU is both effective and safe as a treatment for benign thyroid nodules.

High-intensity focused ultrasound for benign thyroid nodules: Systemic review and meta-analysis

BACKGROUND

High-intensity focused ultrasound (HIFU) is a less invasive option offered for the treatment of large, compressive, benign thyroid nodules.

METHODS

Observational studies of more than five participants using HIFU in the management of benign thyroid nodules from 2000 to 2021 were identified using predefined inclusion criteria. The primary outcome was an estimate of the effectiveness of HIFU.

RESULTS

Out of 158 studies reviewed, 8 articles were included with 297 patients and 300 nodules. HIFU significantly reduced nodule volume from 1 to 24 months following therapy (weighted mean difference [WMD], 47.68, 95 % confidence interval [CI], 34.13-59.66, p < 0.0001) and achieved favorable success rates (risk ratio [RR], 1.49, 95 % CI, 1.15-1.84, p < 0.001) for 50 % volume reduction.

CONCLUSIONS

HIFU appears to be a feasible, safe, and effective treatment modality for patients with benign thyroid nodules. Future research, including randomized controlled trials, is needed to determine therapy optimization, and patient selection to identify the potential role of this new therapy.

[The Echotherapy as non-invasive treatment option for thyroid diseases]

Focused ultrasound is becoming more and more important when it comes to its application in thyroid diseases due to the development of echotherapy. This article provides insights in the application of echotherapy and the treatment process as well as clinical experiences and future perspectives. Studies have already been able to show significant volume reductions and improvement of symptoms after the treatment of benign and symptomatic thyroid nodules. Moreover, a high tolerability and a low profile in risk and side effects has been demonstrated.

Effectiveness of High-intensity Focused Ultrasound (HIFU) Therapy of Solid and Complex Benign Thyroid Nodules - A Long-term Follow up Two-center Study

PURPOSE

To investigate the effectiveness of high-intensity focused ultrasound (HIFU) of solid and complex benign thyroid nodules.

METHODS

Fifty-eight patients with benign thyroid nodules were treated with HIFU at two centers from 2014-2019. The device, EchoPulse (Teraclion, Malakoff, France), heats the nodes to 80-90 °C. Nodal volumes were measured by ultrasound at regular intervals before and up to 12 months after therapy. In a retrospective long-term two-center study, average volume reductions in relation to baseline volume were statistically analyzed by the Wilcoxon signed-rank test. Side effects were documented.

RESULTS

In solid nodules, the average percent volume reductions at the 3, 6, 9, and 12-months follow-up were 49.98%, 46.40%, 65.77%, and 63.88%, respectively. The results were significant with p<0.05 in the Wilcoxon signed-rank test at the 3, 6, and 9-months follow-up. In complex nodules, the average percent volume reduction was 35.2% at 3 months, 36.89% at 6 months, and 63.64% at twelve months follow up. The results were significant with p<0.05 in the Wilcoxon signed-rank test at the 3- and 6-months follow-up. The complication rate was 5.2%. All complications occurred in patients with solid nodules.

CONCLUSION

The study showed that HIFU is an effective treatment method for both solid and complex nodules. The complication rate is relatively high at 5.2%. No long-term complications occurred. The solid nodules responded better to HIFU than complex nodules.

The efficacy and safety of high-intensity focused ultrasound in the treatment of benign thyroid nodules: A systematic review and meta-analysis from 1990 to 2021

INTRODUCTION

To date, there have only been 2 systematic reviews, and 1 systematic review and meta-analysis on high-intensity focused ultrasound (HIFU) for benign thyroid nodules. The present systematic review and meta-analysis seeks to evaluate the efficacy and safety of HIFU in the treatment of benign thyroid nodules.

METHODS

Pubmed, Embase and Cochrane databases were searched for relevant studies from 1990 to 2021. Nine studies were included in the systematic review and 6 in the meta-analysis. Pooled volume reduction rates (VRRs) at 3, 6 and 24 months after HIFU were assessed.

RESULTS

This systematic review and meta-analysis showed that pooled VRRs at 3, 6, and 24 months after HIFU were 42.14 (95% confidence interval [CI] 28.66-55.62, I2=91%), 53.51 (95% CI 36.78-70.25, I2=97%) and 46.89 (95% CI 18.87-74.92, I2=99%), respectively. There was significant heterogeneity in the pooled VRRs at 3, 6 and 24 months after HIFU. No studies recorded complete disappearance of the nodules. Common side effects included pain, skin changes and oedema. There were no major complications except for transient vocal cord paralysis and voice hoarseness (0.014%) and transient Horner syndrome (0.5%).

CONCLUSION

HIFU may be an effective and safe alternative treatment modality for benign thyroid nodules. Larger clinical trials with longer follow-up are needed to evaluate the effectiveness of HIFU in treating benign thyroid nodules.

Effects of Regional and General Anesthesia on the Therapeutic Outcome of Benign Thyroid Nodules Treated with High Intensity Focused Ultrasound (HIFU)

BACKGROUND

The study investigated whether anesthesia performed during high-intensity-focused-ultrasound treatment (HIFU) of benign thyroid nodules influenced the therapy outcome, based on volume reduction and the amount of energy delivered.

METHODS

Thirty patients with benign thyroid nodules were treated with HIFU under general or regional anesthesia at two centers from 2014 to 2019. During HIFU, a therapeutic ultrasound probe, EchoPulse (Teraclion, Malakoff, France), heats the focus to 80-90 degrees Celsius. Nodal volumes were measured by ultrasound before and 3 months after therapy. For statistical analysis, the total population was divided into two groups according to the anesthesia performed. In a retrospective long-term multicenter study, volume reduction and the energy delivered were analyzed using the Wilcoxon signed-rank test and the Mann-Whitney test.

RESULTS

At three months follow-up, the total study population had an average volume reduction of 39.26% (range 4.03-91.16%, p < 0.001, n = 30), the general anesthesia group of 47.46% (range 13.64-91.16%, p = 0.001, n = 15) and the regional anesthesia group of 31.06% (range 4.03-68.63%, p = 0.001, n = 15). Under regional anesthesia a median energy of 3.16 kJ/cm³ (range: 0.96 - 8.2 kJ/cm³) and under general anesthesia a median energy of 0.88 kJ/cm³ (range: 0.18 - 1.63 kJ/cm³) were delivered. All results were significant with p < 0.05. The complication rate was 6.67%.

CONCLUSION

HIFU is an effective method to treat benign thyroid nodules. Comparing anesthesia methods, volume reduction is higher in patients treated under general anesthesia and less energy has to be delivered under general anesthesia.

TRIAL REGISTRATION NUMBER

2020-1728-evBO.

AGENCY

Ethik-Kommission bei der Landesäztekammer Hessen.

Radiofrequency ablation and related ultrasound-guided ablation technologies for treatment of benign and malignant thyroid disease: An international multidisciplinary consensus statement of the American Head and Neck Society Endocrine Surgery Section with the Asia Pacific Society of Thyroid Surgery, Associazione Medici Endocrinologi, British Association of Endocrine and Thyroid Surgeons, European Thyroid Association, Italian Society of Endocrine Surgery Units, Korean Society of Thyroid Radiology, Latin American Thyroid Society, and Thyroid Nodules Therapies Association

BACKGROUND

The use of ultrasound-guided ablation procedures to treat both benign and malignant thyroid conditions is gaining increasing interest. This document has been developed as an international interdisciplinary evidence-based statement with a primary focus on radiofrequency ablation and is intended to serve as a manual for best practice application of ablation technologies.

METHODS

A comprehensive literature review was conducted to guide statement development and generation of best practice recommendations. Modified Delphi method was applied to assess whether statements met consensus among the entire author panel.

RESULTS

A review of the current state of ultrasound-guided ablation procedures for the treatment of benign and malignant thyroid conditions is presented. Eighteen best practice recommendations in topic areas of preprocedural evaluation, technique, postprocedural management, efficacy, potential complications, and implementation are provided.

CONCLUSIONS

As ultrasound-guided ablation procedures are increasingly utilized in benign and malignant thyroid disease, evidence-based and thoughtful application of best practices is warranted.

Targeting the extracellular matrix for immunomodulation: applications in drug delivery and cell therapies

Host immune cells interact bi-directionally with their extracellular matrix (ECM) to receive and deposit molecular signals, which orchestrate cellular activation, proliferation, differentiation, and function to maintain healthy tissue homeostasis. In response to pathogens or damage, immune cells infiltrate diseased sites and synthesize critical ECM molecules such as glycoproteins, proteoglycans, and glycosaminoglycans to promote healing. When the immune system misidentifies pathogens or fails to survey damaged cells effectively, maladies such as chronic inflammation, autoimmune diseases, and cancer can develop. In these conditions, it is essential to restore balance to the body through modulation of the immune system and the ECM. This review details the components of dysregulated ECM implicated in pathogenic environments and therapeutic approaches to restore tissue homeostasis. We evaluate emerging strategies to overcome inflamed, immune inhibitory, and otherwise diseased microenvironments, including mechanical stimulation, targeted proteases, adoptive cell therapy, mechanomedicine, and biomaterial-based cell therapeutics. We highlight various strategies that have produced efficacious responses in both pre-clinical and human trials and identify additional opportunities to develop next-generation interventions. Significantly, we identify a need for therapies to address dense or fibrotic tissue for the treatment of organ tissue damage and various cancer subtypes. Finally, we conclude that therapeutic techniques that disrupt, evade, or specifically target the pathogenic microenvironment have a high potential for improving therapeutic outcomes and should be considered a priority for immediate exploration. A schematic showing the various methods of extracellular matrix disruption/targeting in both fibrotic and cancerous environments. a Biomaterial-based cell therapy can be used to deliver anti-inflammatory cytokines, chemotherapeutics, or other factors for localized, slow release of therapeutics. b Mechanotherapeutics can be used to inhibit the deposition of molecules such as collagen that affect stiffness. c Ablation of the ECM and target tissue can be accomplished via mechanical degradation such as focused ultrasound. d Proteases can be used to improve the distribution of therapies such as oncolytic virus. e Localization of therapeutics such as checkpoint inhibitors can be improved with the targeting of specific ECM components, reducing off-target effects and toxicity.

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.

Efficacy and safety of high-intensity focused ultrasound (HIFU) for treating benign thyroid nodules: a systematic review and meta-analysis

BACKGROUND

High-intensity focused ultrasound (HIFU) is an emerging thermal ablation technique that has been successfully applied to various benign thyroid nodules.

PURPOSE

To evaluate the efficacy and safety of HIFU for the treatment of benign thyroid nodules.

MATERIAL AND METHODS

The Ovid-MEDLINE and EMBASE databases were searched up to 9 July 2018 for studies describing the use of HIFU to treat benign thyroid nodules. We included studies that have outcomes with sufficient detail to evaluate the volume reduction rate (VRR). The pooled proportions of VRR ≥50% and pooled VRR at one, three, and six months after HIFU were assessed using random-effects modeling. Heterogeneity among studies was determined using Chi-square statistics for pooled estimates and the inconsistency index I².

RESULTS

Seven studies were included in the systematic review and four in the meta-analysis. The pooled VRR at one, three, and six months after HIFU were 17.59 (95% confidence interval [CI] 12.56-22.62), 48.93 (95% CI 42.20-55.66), and 60.43 (95% CI 51.88-68.98). The pooled proportions of VRR ≥50% at six months after HIFU were 75% (95% CI 53-89; I²=73.6%). There were no major complications of HIFU.

CONCLUSION

HIFU may be a safe and effective treatment modality for benign thyroid nodules, especially for small nodules.

Combining high-intensity focused ultrasound (HIFU) ablation with percutaneous ethanol injection (PEI) in the treatment of benign thyroid nodules

OBJECTIVE

Assessing the 6-month efficacy of combined high-intensity focused ultrasound (HIFU) ablation with percutaneous ethanol injection (PEI) in benign thyroid nodules by comparing it with HIFU ablation alone.

METHODS

One hundred and eighty-one (55.2%) patients underwent HIFU alone (group I) while 147 (44.8%) underwent concomitant HIFU and PEI treatment for solid or predominantly solid nodules (group II). Intravenous sedation and analgesia were given before the start of treatment. Extent of nodule shrinkage (by volume reduction ratio (VRR)), pain scores (by 0-10 visual analogue scale) during and after ablation, and rate of vocal cord palsy (VCP), skin burn, and nausea/vomiting were compared between the two groups.

RESULTS

The mean amount of ethanol injected in group II was 1.3 ± 0.7 ml. The 3- and 6-month VRR were significantly greater in group II (60.41 ± 20.49% vs. 50.13 ± 21.06%, p = 0.001; and 71.08 ± 21.25% vs. 61.37 ± 22.76%, p = 0.001, respectively), and "on-beam" treatment time was significantly shorter in group II (26.55 min vs. 30.26 min, p = 0.001). Group II patients reported significantly lower pain score during treatment (2.24 ± 3.07 vs. 4.97 ± 3.21, p < 0.001) and 2 h after treatment (2.23 ± 2.50 vs. 2.97 ± 4.39, p = 0.044). Rates of VCP, skin burn, and nausea or vomiting were not significantly different (p > 0.05).

CONCLUSIONS

The combined HIFU and PEI approach with improved administration of intravenous sedation and analgesia was associated with a significantly better 6-month efficacy than HIFU alone in benign thyroid nodules without compromising the safety and comfort of patients.

KEY POINTS

• Concomitant HIFU and PEI have a better treatment efficacy than HIFU alone. • Concomitant HIFU and PEI have a comparable safety profile as HIFU alone.

Single-session high-intensity focused ultrasound (HIFU) ablation for benign thyroid nodules: a systematic review

BACKGROUND

Thyroid nodules are common; the majority of them are benign and asymptomatic. Thyroidectomy might be an option; however, the frequency of post-operative complications mandates the development of alternative approaches, such as high-intensity focused ultrasound ablation (HIFU). HIFU induces thermal destruction without penetrating the skin. The present systematic review aims to synthesize all available data, evaluating studies with single-session HIFU therapy and investigating its efficacy.

MATERIALS AND METHODS

This systematic review was conducted in accordance with the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and MetaAnalyses). Eligible articles were identified by a search of Medline bibliographic database (PubMed) and Cochrane Library. Out of 39 results, 11 articles were considered to meet the inclusion criteria.

RESULTS

All eligible studies included patients with solid or predominantly solid benign thyroid nodules. All patients were treated with the same HIFU device. The success rate of the method was defined in the majority, with the volume reduction rate (VRR) over 50% from baseline. The mean or median VRR ranged from 48.7 to 70.41%, depending on the last follow-up date. No major complications were observed.

CONCLUSION

Single-session HIFU is safe and effective for the treatment of benign thyroid nodules.

Identifying predictive factors for efficacy in high intensity focused ultrasound (HIFU) ablation of benign thyroid nodules - a retrospective analysis

Objective: Since it is unclear whether clinical parameters can independently predict the subsequent treatment response following high intensity focused ultrasound (HIFU) ablation of benign thyroid nodules, we aimed to examine clinical factors that may independently predict 12-month efficacy after HIFU treatment.Methods: One hundred and forty patients who had single ablation were categorized into two groups, those with 12-month nodule shrinkage above the median (Group I, n = 70) and with shrinkage below or equal to the median (Group II, n = 70). Baseline characteristics, treatment parameters, percentage change in serum TSH, Free thyroxine (FT4) and thyroglobulin (Tg) from baseline to Day 4 and appearance of microbubbles (hyperechoic marks (HEMs)) during treatment were compared between groups. To determine independent factors, a multivariate analysis was done by logistic regression analysis.Results: Baseline characteristics and treatment parameters were comparable between groups. However, on Day-4, group I had significantly lower serum TSH (0.49mIU/L vs. 0.84mIU/L, p = 0.011) and higher FT4 (22.11 pmol/L vs. 18.47 pmol/L, p = 0.008) than group II. The percentage change in TSH, FT4 and Tg were significantly greater in group I (p = 0.002, p = 0.009 and p = 0.001 respectively). The proportion of HEMs observed during treatment was also significantly higher in group I (42.69% vs. 31.72%, p = 0.030). Among the significant factors, the percentage change in FT4 was the only independent factor for 12-month shrinkage (OR = 1.018, 95%CI =1.003-1.032, p = 0.017).Conclusions: Percentage change in serum FT4 on post-treatment Day-4 was an independent blood parameter for the subsequent nodule shrinkage at 12 months. This finding could potentially facilitate the decision for earlier retreatment of treated nodules.

An Introduction to High Intensity Focused Ultrasound: Systematic Review on Principles, Devices, and Clinical Applications

Ultrasound can penetrate deep into tissues and interact with human tissue via thermal and mechanical mechanisms. The ability to focus an ultrasound beam and its energy onto millimeter-size targets was a significant milestone in the development of therapeutic applications of focused ultrasound. Focused ultrasound can be used as a non-invasive thermal ablation technique for tumor treatment and is being developed as an option to standard oncologic therapies. High-intensity focused ultrasound has now been used for clinical treatment of a variety of solid malignant tumors, including those in the pancreas, liver, kidney, bone, prostate, and breast, as well as uterine fibroids and soft-tissue sarcomas. Magnetic resonance imaging and Ultrasound imaging can be combined with high intensity focused ultrasound to provide real-time imaging during ablation. Magnetic resonance guided focused ultrasound represents a novel non-invasive method of treatment that may play an important role as an alternative to open neurosurgical procedures for treatment of a number of brain disorders. This paper briefly reviews the underlying principles of HIFU and presents current applications, outcomes, and complications after treatment. Recent applications of Focused ultrasound for tumor treatment, drug delivery, vessel occlusion, histotripsy, movement disorders, and vascular, oncologic, and psychiatric applications are reviewed, along with clinical challenges and potential future clinical applications of HIFU.

The current state and future perspectives of high intensity focused ultrasound (HIFU) ablation for benign thyroid nodules

High intensity focused ultrasound (HIFU) is a new thermoablation technique used to treat benign thyroid nodules. In this method, the ultrasound beam passes through the patient's skin and focuses very precisely on the target lesion at a distance far from the source of ultrasound generation, making HIFU the only truly non-invasive method of thermoablation developed to date. HIFU is therefore an attractive alternative to surgery and other thermoablative techniques. This review describes the principles of HIFU treatment, the selection of patients suitable for HIFU, the course and effects of treatment, and future perspectives.

Safety and efficacy of thermal ablation (radiofrequency and laser): should we treat all types of thyroid nodules? †

Background: Thermal ablation is a minimally invasive technique that is gradually acknowledged as an effective alternative to surgery to treat thyroid nodules. Two main techniques have been described: radiofrequency (RFA) and laser ablation. Objective: To evaluate the safety and efficacy of the two main techniques (RFA and laser ablation) for the treatment of benign thyroid nodules. Patients: This bicentric retrospective study included 166 consecutive patients, who received clinical, biological and ultrasound evaluations for thyroid nodules, from October 2013 to November 2017. Methods: One of the two techniques was proposed if a nodule was proven to be benign after fine needle aspiration cytology or micro-biopsy. Adverse events and outcomes (symptoms, nodule reduction) were assessed at 6 weeks and 6, 12, and 18 months after treatment. Results: One hundred and eighty-nine nodules (mean size 17.5 ± 16.9 mL, 86.1% palpable) were treated by RFA (n = 108 (57.1%)) or laser ablation (n = 81 (42.9%)) in 166 patients (80.1% women, mean age 51.7 years). Two cases of transient recurrent laryngeal nerve palsy, one hematoma, and two successfully drained abscesses (5/166 = 3%) were observed. Clinical symptoms improved significantly in the two groups (anterior cervical discomfort -83.6%, esthetic complaints -84.9% and dysphagia -86.4%). Nodule volume (mL) decreased significantly (baseline vs. 18 months) from 20.4 ± 18.6 to 5.8 ± 6.6 (-75%) in the RFA, and from 13.6 ± 13.3 to 3.4 ± 4.1 (-83.9%) in the laser ablation groups. Conclusions: Transient but potentially serious adverse events were reported in 3% of patients. A significant volumetric reduction was achieved with both techniques, regardless of nodule's characteristics, at 18 months.

Role of second high-intensity focused ultrasound (HIFU) treatment for unsatisfactory benign thyroid nodules after first treatment

BACKGROUND

We aimed to assess the efficacy and safety of second high-intensity focused ultrasound (HIFU) ablation treatment in benign thyroid nodules that had failed to shrink by > 50% 6 months after the first treatment.

METHODS

Twenty-eight patients who did not achieve 50% volume reduction at 6 months after the first HIFU treatment underwent a second HIFU treatment. Nodule volume was measured on ultrasound at baseline, 3 months and 6 months. Extent of nodule shrinkage (by volume reduction ratio) (VRR) = [Baseline volume - volume at 6 months]/[Baseline volume] * 100. Treatment success was defined as VRR > 50%. Obstructive symptom score (by 0-10 visual analogue scale, VAS) was evaluated for 6 months after treatment.

RESULTS

No complications occurred after the second treatment. The mean 6-month VRR was 21.78 ± 16.87% with a median (range) of 16.16 (1.63-54.07)%. At 6 months, only two (7.1%) patients achieved treatment success, while nine (32.1%) patients had VRR < 10%. However, relative to baseline (3.96 ± 1.04), the mean VAS significantly improved at 3 and 6 months (2.96 ± 1.43, p<0.001 and 2.58 ± 1.39, p<0.001, respectively). There was a significant correlation between VRR and improvement in VAS score at 6 months (ρ=0.438, p=0.025). Greater nodule volume before the second treatment (OR=1.169, 95% CI=1.004-1.361, p=0.045) was a significant factor for greater VRR after the second treatment.

CONCLUSIONS

Although subjective obstructive symptoms continued to improve after the second treatment, the actual extent of nodule shrinkage was small. Larger-volume nodules tended to shrink more significantly than smaller-volume nodules in the second treatment.

KEY POINTS

• Second treatment resulted in small shrinkage in unsatisfactory nodules after first treatment. • Obstructive symptoms tended to continue to improve after second treatment. • Larger-size nodules tended to respond better in the second treatment.

Comparison of high intensity focused ultrasound and radioiodine for treating toxic thyroid nodules

PURPOSE

We compared the effectiveness of high intensity focused ultrasound (HIFU) and radioiodine (RAI) to treat patients carrying toxic thyroid nodule (TTN). Normalization of serum thyrotropin (TSH) 1 year after treatment was the primary end-point; concurrent changes in nodules' volume and scintigraphic pattern were also evaluated as secondary end-points.

MATERIALS AND METHODS

Among patients ≥18 years old with TTN observed at our centre between January 1st, 2016 and December 31th, 2016 we prospectively enrolled 17 and 15 age and sex-matched patients treated with RAI and HIFU, respectively. Biochemical thyroid tests and nodules' volume were assessed before and 3, 6 and 12 months after treatments. A thyroid scintigraphy was performed before and 1 year after treatment, respectively.

RESULTS

The final series included 17 patients treated with RAI and 15 patients treated with HIFU, respectively. Neither demographic nor clinical differences were found at baseline. One year after treatment 14 of 17 RAI-treated and 4 of 15 HIFU-treated patients fulfilled criteria for response to treatment (P = .0008). Indeed, the median TSH value was 1.5 IU/mL and 0.2 IU/mL in HIFU and RAI groups, respectively (P < .0001). Finally, despite a similar decrease in nodules' volume in both groups, a scintigraphic response was achieved in 16 of 17 (94%) RAI-treated compared to 8 of 15 (53%) HIFU-treated patients (P = .024), respectively.

CONCLUSIONS

In our series, RAI clearly outperforms HIFU in treating patients carrying TTN and remains the first-line noninvasive treatment in such cases.

High-intensity focused ultrasound (HIFU) therapy for benign thyroid nodules without anesthesia or sedation

BACKGROUND

Thermal ablation of thyroid nodules has gained momentum due to the possibility to avoid surgery. High-intensity focused ultrasound (HIFU) allows thermal treatment by energy ultrasound beam inside the targeted zone. Aim of our study was to evaluate the effects of HIFU treatment using Beamotion mode without anesthesia.

METHODS

Since 2016, patients with normal thyroid function, benign thyroid nodules with diameter no larger than 4 cm, and presenting local discomfort and/or compressive symptoms were treated by HIFU. We performed Beamotion HIFU and did not use anesthesia. Nodule size and thyroid function were evaluated before HIFU and 6 and 12 months later. Complications to therapy and tolerability of patients were also recorded. According to local ethical committee, for this retrospective study formal consent was not required.

RESULTS

The final series included 26 nodules from 26 patients with estimated volume of 2.81 ± 2.04 mL, treated by a power of 33.3 ± 10.3 W/site and energy of 2.1 ± 1.1 kJ. Nodules volume was significantly (p < 0.0001) reduced at 6 months of follow-up (1.83 ± 1.63 mL), and further at 1 year (1.57 ± 1.47 mL). Mean percentage of reduction over time of nodules was 48%. A 73% of patients described good comfort during treatment, 100% experienced good comfort just after therapy, and tolerability was high. No complications were recorded. At one 1 year of follow-up, 85% of subjects reported a reduction of local symptoms.

CONCLUSIONS

HIFU therapy is effective in reducing size of thyroid nodules with major diameter below 4 cm and can be performed without anesthesia.

Two-year efficacy of single-session high-intensity focused ultrasound (HIFU) ablation of benign thyroid nodules

OBJECTIVES

Assessing the efficacy of single high-intensity focused ultrasound (HIFU) ablation in benign thyroid nodules beyond 12 months.

METHODS

One hundred and eight patients underwent single HIFU treatment. Extent of nodule shrinkage [by volume reduction ratio (VRR)] and obstructive symptom score [by 0-10 visual analogue scale (VAS)] were evaluated for 24 months after treatment. VRR (%) was calculated based on the formula: [baseline volume - volume at visit] / [baseline volume] × 100. Binary logistic regression was performed to evaluate factors associated with 24-month treatment success (VRR ≥ 50%).

RESULTS

After treatment, the mean (± SD) VRR at 3, 6, 12 ,18 and 24 months were 51.32 ± 20.71%, 62.99 ± 22.05%, 68.66 ± 18.48%, 69.76 ± 17.88% and 70.41 ± 17.39%, respectively, while the median (IQR) VAS at baseline, 6, 12 and 24 months was gradually lowered from 4.0 (2.0), 2.0 (1.0), 2.0 (1.0) to 1.0 (2.0), respectively. Sixty-three (58.3%) nodules had a further volume reduction (i.e. > 4.5%) from 12 to 24 months, while 22 (20.4%) nodules had a volume increase of > 4.5% from 12 to 24 months. Small pre-ablation nodule volume was a significant determinant for treatment success at 24 months (OR=1.045, 95% CI=1.021-1.092, p = 0.038).

CONCLUSIONS

A majority of nodules had further volume reduction beyond 12 months after single HIFU ablation, but since one-fifth of nodules had a notable volume increase beyond 12 months, a longer period of surveillance would be necessary. Small pre-ablation nodule volume was a significant factor determining 24-month treatment success.

KEY POINTS

• Small but significant nodule shrinkage continues beyond 12 months after single treatment. • Obstructive symptom continues to improve beyond 12 months after single treatment • Smaller-sized nodules have a greater chance of treatment success at 24 months.

Comparison of Mono- and Bipolar Radiofrequency Ablation in Benign Thyroid Disease

PURPOSE

Radiofrequency ablation (RFA) is an approved minimal invasive method for the treatment of benign thyroid nodules. Several experimental, mainly ex vivo animal studies have compared the effectiveness of different RFA procedures in liver tissue. The aim of this retrospective clinical study was to evaluate the difference between monopolar and bipolar RFA in thyroid tissue considering thyroid volume reduction, patient discomfort and ultrasound evaluation.

METHODS

Eighteen patients with symptomatic complex benign thyroid nodules were treated in a single RFA session. Nine patients were treated with monopolar RFA, and nine other patients were treated with bipolar RFA. All patients underwent assessments before therapy and at 3-month follow-up (3MFU) including a complete hormone status (T3, T4, TSH, TG, TPOAb, TgAb, TRAb) and several ultrasound (US) evaluations using B-mode and color-coded Doppler imaging. The US evaluations contained measurement of volume, US Doppler, US echogenicity and US elastography. Additionally, applied energy (kJ), power output (W), number of shots (N) and total treatment time (s) were recorded in every case.

RESULTS

Monopolar RFA resulted in a significant (p < 0.05) average thyroid volume reduction of Ø 18 ± 77 ml (25.1 ± 103%) and a nodule volume reduction of Ø 10.6 ± 22 ml (60.3 ± 62%). Bipolar RFA resulted in a significant (p < 0.05) average thyroid volume reduction of Ø 21.2 ± 54 ml (43.2 ± 84%) and a nodule volume reduction of Ø 13.8 ± 33 ml (70.8 ± 46%). Both groups showed equal results concerning volume reduction (p > 0.05). Monopolar RFA did not lead to any significant changes concerning the US scores, whereas bipolar RFA led to a significant (p < 0.05) reduction in US Doppler and nodular blood flow. No significant difference between both groups could be found concerning applied energy, treatment time, power output and number of shots (p > 0.05).

CONCLUSION

Bipolar RFA did not show any disadvantages in comparison with monopolar RFA in the treatment of benign thyroid nodules. It shows better performance in terms of volume reduction and is superior when it comes to feasibility and patient discomfort. The recent study confirms the good ex vivo results for bipolar RFA.

Image-guided chemical and thermal ablations for thyroid disease: Review of efficacy and complications

Image-guided ablation of thyroid disease is increasingly being commonly reported. Techniques including ethanol injection and thermal ablation using radio-frequency, laser, and microwave devices have been described. Minimally invasive approaches to the management of benign cystic, solid, and functional thyroid nodules as well as both primary and recurrent thyroid malignancy have been reported. The purpose of this article is to review the current evidence relating to image-guided ablation of thyroid disease with a focus on clinical outcomes and complication rates for patients treated with this minimally invasive approach.

Interventional radiology of the thyroid gland: critical review and state of the art

Thyroid nodules are a common incidental finding during a routinely ultrasound (US) exam unrelated to the thyroid gland in the healthy adult population with a prevalence of 20-76%. As treated before with surgery, in the last years new minimally invasive techniques have been developed as an alternative to surgery. The aim of this review, based on newly revised guidelines, is to provide some information regarding the basic principles, indications, materials, techniques, and results of mini-invasive procedures or treatments for thyroid nodules. We performed a narrative review including both newest and representative papers and guidelines based on the different procedures of ablation techniques developed in the last years for the diagnosis and the treatment of thyroid nodules. All examined papers referred very good results in term of volume nodule reduction, improvement in related symptoms and cosmetic problems, with a very low rate of complications and side effects for all the minimally invasive technique analyzed. Obviously, some differents between technique based on different kind of thyroid nodules and different indication were found. In conclusion, many thyroid nodules nowadays could be treated thanks to the advent of new mini-invasive technique that are less expensive and present a lower risk of major complications and side effects compared to surgery.

Treatment of benign thyroid nodules by high intensity focused ultrasound (HIFU) at different acoustic powers: a study on in-silico phantom

BACKGROUND

The non-surgical therapies of benign thyroid nodules are gaining momentum due to the possibility to reduce the nodule's volume and avoid surgery. As the last technique introduced, high intensity focused ultrasound allows the thermal tissue treatment by directing energy inside the targeted nodule with no invasive instruments. In the present study we applied the Food and Drug Administration high intensity focused ultrasound simulator to in-silico phantom to evaluate the effects obtained by different acoustic powers.

METHODS

The simulated layers were water and thyroid tissue. The source was a spherically curved circular transducer with radius r   = 2.3 cm generating a continuous wave beam at a frequency of 3 MHz. The focal distance was 6.5 cm. The sequence included a pulse (8 s) with acoustic power at different value from 5 to 50 W, and a cooling-off interval (32 s).

RESULTS

The use of acoustic power of 5 W allowed to achieve the threshold of temperature for coagulative necrosis (55 °C) at 1 s. The simulation with 50 W showed that temperature was significantly higher (above 300 °C) at 1 s and is maintained at high levels for a long interval.

CONCLUSION

Since 2016, we treated patients according to the present experience, and a significant reduction of nodule's volume was observed with good patent's comfort and no complications (unpublished data). Also, no anesthesia was practiced. We feel that the present data could contribute to develop a high intensity focused ultrasound therapy of benign thyroid nodules free from potential complications.

Update on the role of ultrasound guided radiofrequency ablation for thyroid nodule treatment

Thyroid nodules can be frequently detected in general population, most of them are benign, however malignant cases are rising in the past decades. Ultrasound (US) is the most common imaging modality to assess thyroid nodular lesions, plan patient work-up and guide minimally invasive treatment. The present review paper has been researched to evaluate the current status of radiofrequency ablation (RFA) treatment in order to evaluate indications, techniques, complications, limitations and outcome assessment in benign solid, partially cystic nodules and recurrent malignant nodules. RFA comparison with other ablation techniques has been provided as well. US guided Radiofrequency ablation has been proved to be effective and safe in cases of benign thyroid nodules and a promising treatment method alternative to surgery for patients with recurrent papillary thyroid cancer. It's major role lies in significant reduction of thyroid nodule mean volume and improvement of the patient symptoms. However, future multicenter studies are warranted to better clarify the multi-parametric patient selection criteria and evaluate RFA technique efficacy, advantages and limitations in the variety of thyroid nodular disease.

Statement and Recommendations on Interventional Ultrasound as a Thyroid Diagnostic and Treatment Procedure

The recently published guidelines of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) on interventional ultrasound (INVUS)-guided procedures summarize the intended interdisciplinary and multiprofessional approach. Herewith, we report on recommendations for interventional procedures for diagnosis and treatment of the thyroid gland.

Further Investigation on High-intensity Focused Ultrasound (HIFU) Treatment for Thyroid Nodules: Effectiveness Related to Baseline Volumes

RATIONALE AND OBJECTIVES

Several minimally invasive thermal techniques have been developed for the treatment of benign thyroid nodules. A new technique for this indication is high-intensity focused ultrasound (HIFU). The aim of this study was to assess effectiveness in varying preablative nodule volumes and whether outcome patterns that were reported during studies with other thermal ablative procedures for thyroid nodule ablation would also apply to HIFU.

MATERIALS AND METHODS

Over the last 2 years, 19 nodules in 15 patients (12 women) whose average age was 58.7 years (36-80) were treated with HIFU in an ambulatory setting. Patients with more than one nodule were treated in multiple sessions on the same day. The mean nodule volume was 2.56 mL (range 0.13-7.67 mL). The therapeutic ultrasound probe (Echopulse THC900888-H) used in this series functions with a frequency of 3 MHz, reaching temperatures of approximately 80°C-90°C and delivering an energy ranging from 87.6 to 320.3 J per sonication. To assess the effectiveness of thermal ablation, nodular volume was measured at baseline and at 3-month follow-up. The end point of the study was the volume reduction assessment after 3 months' follow-up. Therapeutic success was defined as volume reduction of more than 50% compared to baseline. This study was retrospectively analyzed using the Wilcoxon signed rank test and Kendall tau.

RESULTS

The median percentage volume reduction of all 19 nodules after 3 months was 58%. An inverse correlation between preablative nodular volume and percentage volume shrinking was found (tau = -0.46, P < .05). Therapeutic success was achieved in 10 out of 19 patients (53%).

CONCLUSIONS

HIFU of benign thyroid nodules can be carried out as an alternative therapy for nodules ≤3 mL if patients are refusing surgery or radioiodine therapy.

The efficacy and safety of high-intensity focused ultrasound ablation of benign thyroid nodules

High-intensity focused ultrasound (HIFU) is a promising form of thermal ablation of benign thyroid nodules, but evidence supporting its use is scarce. The present review evaluated the efficacy and safety of single-session HIFU treatment of benign thyroid nodules. As reported in the literature, the extent of nodule shrinkage following treatment ranged from 48.8% to 68.8%. Like other forms of ablation, the shrinkage rate was greatest in the first 3-6 months, and the best responders were patients with small (≤10 mL) nodules. Complications were uncommon, but temporary vocal cord palsy occurred in 3%-4% of patients, and was related to the distance between the HIFU beam and the recurrent laryngeal nerve. Despite being safe and efficacious, a larger-scale prospective trial is required.

Thermal ablation of thyroid nodules: are radiofrequency ablation, microwave ablation and high intensity focused ultrasound equally safe and effective methods?

OBJECTIVES

This study compares volume reduction of benign thyroid nodules three months after Radiofrequency Ablation (RFA), Microwave Ablation (MWA) or High Intensity Focused Ultrasound (HIFU) to evaluate which of these methods is the most effective and safe alternative to thyroidectomy or radioiodine therapy.

MATERIAL AND METHODS

Ninety-four patients (39 male, 55 female) with a total of 118 benign, symptomatic thyroid nodules were divided into three subgroups. HIFU was applied to 14 patients with small nodules. The other 80 patients were divided up into two groups of 40 patients each for RFA and MWA in the assumption that both methods are comparable effective. The pre-ablative and post-ablative volume was measured by ultrasound.

RESULTS

RFA showed a significant volume reduction of nodules of 50 % (p<0.05), MWA of 44 % (p<0.05) and HIFU of 48 % (p<0.05) three months after ablation. None of the examined ablation techniques caused serious or permanent complications.

CONCLUSION

RFA, MWA and HIFU showed comparable results considering volume reduction. All methods are safe and effective treatments of benign thyroid nodules.

KEY POINTS

• Thermal Ablation can be used to treat benign thyroid nodules • Thermal Ablation can be an alternative to thyroidectomy or radioiodine therapy • Radiofrequency Ablation, Microwave Ablation, High Intensity Focused Ultrasound are safe and effective.

Single-Session High-Intensity Focused Ultrasound Treatment for Persistent or Relapsed Graves Disease: Preliminary Experience in a Prospective Study

Purpose To evaluate the safety and efficacy of ultrasonography (US)-guided high-intensity focused ultrasound (HIFU) ablation as a treatment for medically refractory Graves disease (GD). Materials and Methods After ethics approval, a prospective trial (NCT02685514) was performed from November 2015 to February 2016. Thirty patients underwent ablation of the entire right and left thyroid lobes, with areas near the tracheal-esophageal groove and common carotid artery left unablated. Serum thyroid-stimulating hormone (TSH), free T4 (FT4), antithyroid autoantibodies, and TSH receptor (TSHR) antibody levels were evaluated afterward, and US color Doppler, US volumetry, and eye assessment were performed. The primary outcome was the 12-month relapse rate. Relapse referred to hyperthyroidism (FT4 > 23 pmol/L) afterward. Variables associated with relapse were analyzed by using binary logistic regression. Results The technical success rate was 96.7%. The cohort comprised entirely women, with a median age of 38.2 years (interquartile range, 29.5-49.0 years). After 12 months, eight patients (26.7%; 95% confidence interval [CI]: 14.19%, 44.95%) experienced relapse. One patient (3.3%; 95% CI: 0.59%, 16.67%) experienced vocal cord palsy, while two patients (6.7%; 95% CI: 1.85%, 21.33%) experienced Horner syndrome, but none of these conditions were permanent. No changes in gland volume, antithyroid autoantibody levels, and ophthalmic parameters were found at 12-month follow-up. Baseline TSHR was found to have decreased significantly at 6- and 12-month follow-up (P < .001 for both). TSHR antibody (odds ratio [OR] = 1.414; 95% CI: 1.018, 1.965; P = .039) and gland volume (OR = 0.557; 95% CI: 0.353, 0.880; P = .012) were associated with 12-month relapse, with higher antibody levels conferring a higher likelihood and smaller gland volumes conferring a lower likelihood. Conclusion US-guided HIFU of the thyroid may be a safe and efficacious treatment in patients with persistent or relapsed GD. However, further study is warranted before it can become mainstream for this indication. ^© RSNA, 2017 Online supplemental material is available for this article.

High intensity focused ultrasound (HIFU) ablation of benign thyroid nodules - a systematic review

Background

With an increasing number of imaging studies being done nowadays, the number of incidentally discovered thyroid nodules is expected to rise. Although many of these nodules are small and benign in nature, some do grow and may cause pressure and/or thyrotoxic symptoms. Surgical resection has traditionally been recommended for symptomatic nodules but is associated with risk of hypothyroidism, bleeding, infection, and nerve damage. High intensity focused ultrasound (HIFU) is one of the non-surgical thermal ablation techniques that may serve as an alternative in the treatment of benign thyroid nodules. The present review is to systematically evaluate the efficacy and safety of HIFU ablation.

Methods

We comprehensively searched all studies that evaluated the use of HIFU ablation as a treatment of benign thyroid nodules from Medline (PubMed) and Cochrane Library electronic databases using specific keywords. All titles identified by the search strategy were independently screened by two authors. Case reports, animal studies, editorials, expert opinions, reviews without original data and studies on pediatric population were excluded. Multiple reports of the same dataset were assessed and the most representative and updated report of a study was included.

Results

Five original studies were found. All treated thyroid nodules were confirmed to be benign cytologically and either appeared solid or predominantly (>70%) solid on ultrasonography. Only one type of commercially available US-guided device with an extracorporeal probe (3 MHz) was used in all the reported treatments. No major complications including recurrent laryngeal nerve injury, skin burn or haematoma were reported in all of the studies. The overall nodule volume reduction after single session of HIFU ablation ranged between 45 and 68%, depending on nodule size and length of follow-up.

Conclusions

Despite the few number of studies, our review appeared to suggest that HIFU is a safe and efficacious method of treating symptomatic benign thyroid nodules. However, larger-scale, prospective trials with longer follow-up period are indeed required to confirm this. In terms of the ablation itself, relative to other ablation techniques, there are still much room for improvements in shortening treatment duration and expanding the range of treatable nodules.

Single-Session High-Intensity Focused Ultrasound Treatment in Large-Sized Benign Thyroid Nodules

BACKGROUND

High-intensity focused ultrasound (HIFU) is a new promising thermal ablation technique for treating benign thyroid nodules, but its effectiveness in larger-sized nodules has been less well described. The present study aimed to evaluate the treatment efficacy (i.e., extent of shrinkage at six months) of large-sized benign thyroid nodules by ultrasound (USG)-guided HIFU ablation.

MATERIALS AND METHODS

After ethics approval, all consecutive patients who underwent HIFU ablation of a symptomatic benign thyroid nodule with six or more months of follow-up were analyzed. Treated nodules were categorized according to their pre-ablation volume (group I: <10 mL; groups II: 10-30 mL; group III: >30 mL). After treatment, the nodule volume was measured by USG at one week, one month, three months, and six months. Total energy delivered to each nodule (in kJ) and the time taken (in minutes) for that delivery were automatically recorded. The primary outcome was a change in nodule volume after six months, where percentage nodule volume change was calculated as (baseline volume - volume at six months)/(baseline volume) × 100. Ablation success was defined as >50% volume reduction.

RESULTS

Seventy-three nodules were treated successfully and followed for ≥6 months. The overall median six-month volume reduction was 68.3% (range 22.77-96.50%). At six months, group III had a significantly less volume shrinkage than group I (48.1% vs. 77.6%; p < 0.001) and group II (48.1% vs. 67.9%; p = 0.002). Also, the proportion of ablation success at six months in group III was significantly less than in the other two groups (p < 0.001). Pre-ablation nodule volume >30 mL (odds ratio = 7.813 [confidence interval 1.908-32.258]; p = 0.004) and lower total energy per nodule volume (odds ratio = 3.313 [confidence interval 1.113-9.688]; p = 0.029) were significant factors for less ablation success.

CONCLUSIONS

Single-session HIFU ablation was highly effective in causing shrinkage of benign thyroid nodules at six months, but the extent of shrinkage for larger-sized nodules (>30 mL) was noticeably less than that of smaller-sized nodules. Both pre-ablation nodule volume and total energy per nodule volume were significant determinants of ablation success. For larger-sized nodules, additional HIFU treatment three to six months after initial treatment might be preferred over sequential treatment within the same session.

High-Intensity Focused Ultrasound for Treatment of Symptomatic Benign Thyroid Nodules: A Prospective Study

Purpose To evaluate first-year efficacy and changes in pressure symptoms and health-related quality of life (HRQOL) after ultrasonographically (US) guided high-intensity focused ultrasound (HIFU) ablation of symptomatic benign thyroid nodules. Materials and Methods After ethics approval and informed consent were obtained, a prospective trial was conducted. Patients with a symptomatic benign thyroid nodule were given a choice of HIFU treatment or active surveillance. Clinical and US examinations, pressure symptom scores (visual analog scale), and HRQOL questionnaires (short form-12 survey) were evaluated at baseline and at 3, 6, and 12 months. The primary outcome was change in nodule volume after 12 months. The percentage of change in nodule volume was defined as the baseline volume minus the volume at 12 months divided by the baseline volume times 100. Ablation success was defined as a reduction in volume of greater than 50%. Nodule volume was compared by using the paired t test. Continuous variables were compared by using the Mann-Whitney U test, and categorical variables were compared by using χ² tests. Results Twenty-two patients underwent HIFU and 22 underwent active surveillance. Mean age was 53.11 years (range, 28-76 years) and 55.19 years (range, 41-70 years), respectively. The ratio of men to women was 2:20 and 1:21, respectively. The 12-month mean volume reduction ± standard deviation in the HIFU group was significant (68.87% ± 15.27 [range, 47.35%-94.89%], P < .001) but not in the surveillance group (-2.11% ± 6.29 [range, -15.64% to 12.70%], P > .05). Preablation nodule volume was the only determinant of ablation success (odds ratio, 1.877; 95% confidence interval [CI]: 1.085, 3.249; P = .024). At 12 months, patients in the HIFU group had less swelling (P < .001), lower pressure symptom scores (P < .001), and higher physical composite scores (P = .006). Physical composite scores significantly correlated with 6-month reduction in nodule size (r = 0.768; 95% CI: 0.660, 0.930; P < .001) and 12-month reduction in nodule size (r = 0.704; 95% CI: 0.680, 940; P < .001). Conclusion HIFU ablation of symptomatic benign thyroid nodules not only induced significant shrinkage but also improved pressure symptom scores and HRQOL throughout a 12-month period. ^© RSNA, 2017.

Image-guided thermal ablation of benign thyroid nodules

Benign thyroid nodules are a common disease in the general population. Most often, they are completely asymptomatic and discovered occasionally during routine ultrasound examinations, and do not require any treatment. When thyroid nodules become symptomatic, surgical excision is still considered standard treatment. In the last few years, several experiences in the treatment of benign thyroid nodules through image-guided percutaneous thermal ablation have been reported with encouraging results, so that currently, these treatments are often proposed as first-choice options for patients with symptomatic benign thyroid nodules. In this paper, we discuss the present literature on the topic, focusing on different techniques available for image-guided percutaneous ablation, particularly radiofrequency (RFA), laser (LA), microwave (MWA), and high-intensity-focus ultrasound (HIFU). Little evidence about the efficacy of MWA and HIFU is now available. According to the literature, good results have been obtained with RFA and LA. Regarding RFA, volume reduction after ablative treatment has been found to range from 47 to 84 % at 3-6 months, and from 62 to 93 % at 1 year; LA also seems to be effective in achieving shrinkage of thyroid nodules, with volume reduction from 37 to 81 % at 3-6 months, and from 13 to 82 % at 1-year follow-up. Moreover, applications of advanced image-guidance modality, such as contrast-enhanced ultrasound and virtual navigation with fusion imaging, are discussed.

Bipolar radiofrequency ablation of benign thyroid nodules using a multiple overlapping shot technique in a 3-month follow-up

Purpose The aim of this study was to evaluate the decrease of benign thyroid nodules after bipolar radiofrequency ablation (RFA) in a 3-month follow-up using a multiple overlapping shot technique ('MOST'). Methods A total of 18 patients with 20 symptomatic benign thyroid nodules (17 cold nodules, 3 hyperfunctioning nodules) were treated in one single session by bipolar RFA. Bipolar ablation was performed using MOST. The nodule volumes were measured prior to ablation and 3 months after the procedure using ultrasound. The population consisted of either solid (>80% solid tissue within the volume of interest), complex, or cystic nodules (<20% solid tissue within the volume of interest). Results Bipolar RFA resulted in a highly significant (p < 0.0001) decrease of nodule volume (ΔV), median 5.3 mL (range 0.13-43.1 mL), corresponding to a relative reduction in mean of 56 ± 17.9%. Median initial volume was 8 mL (range 0.48-62 mL); 3 months after ablation a median volume of 2.3 mL (range 0.3-32 mL) was measured. Nodule growth ≥50% occurred in 70% (14 nodules). At the follow-up no complications such as infections, persisting pain, nerve injuries or immunogen stimulation occurred. Patients with cold nodules (15) remained euthyroid, with hyperfunctioning nodules either euthyroid (2) or latent hypofunctional (1). Conclusion The use of bipolar RFA is an effective, safe and suitable thermoablative technique to treat benign thyroid nodules. Combined with the multiple overlapping shot technique it allows sufficient ablation.