Radiofrequency ablation of benign thyroid nodules: safety and imaging follow-up in 236 patients. Eur Radiol. 2008;18:1244-1250. [PMID: 18286289 DOI: 10.1007/s00330-008-0880-6]

Treatment efficacy and safety of ultrasound-guided percutaneous bipolar radiofrequency ablation for benign thyroid nodules

OBJECTIVE

To evaluate the therapeutic efficacy and safety of ultrasound-guided percutaneous bipolar radiofrequency ablation (BRFA) of benign thyroid nodules by comparison with a matched untreated control group.

METHODS

The therapeutic efficacy and safety in 35 patients who were subjected to a single session of ultrasound-guided percutaneous BRFA (Group A) for benign thyroid nodules were compared with those in 35 untreated patients (Group B) with benign nodules. The benign nature of all the nodules was confirmed by ultrasound-guided fine-needle aspiration biopsy (FNAB), and all the patients had normal thyroid functions. BRFA was performed with a bipolar electrode (CelonProSurge 150-T20) with an output power of 20 W. Nodule volume, thyroid function and clinical symptoms of all the patients were compared before treatment and during follow-up.

RESULTS

In Group A, the BRFA procedures were completed with a mean time of 10.02 ± 3.30 min (range, 5.47-16.03 min) and with a mean total energy deposition of 10.747 ± 3704 J (range, 5510-17.770 J). The procedures were tolerated well in all the patients without causing any major complications. At the 6-month follow-up, all of the nodule volume decreased significantly (from 8.81 ± 8.66 to 1.59 ± 1.55 ml, p < 0.001) in Group A, whereas the nodule volume increased from 6.90 ± 3.77 to 7.87 ± 3.95 ml in Group B (p < 0.001). All (100%) the 35 nodules in Group A had volume reduction ratios (VRRs) of >50%, among which 3 (8.57%) had VRRs >90%. In Group A, the clinical symptoms of the patients who had symptoms before BRFA disappeared, whereas in Group B, the patients had no resolution of clinical symptoms at the 6-month follow-up.

CONCLUSION

Ultrasound-guided percutaneous BRFA seems to be an effective and safe method for the treatment of benign thyroid nodules. It may gain a wide use in clinical practice.

ADVANCES IN KNOWLEDGE

Based on the comparable efficacy and clinical symptoms between the BRFA and untreated groups, the technique of BRFA can be used as an effective and safe method for the treatment of benign thyroid nodules.

Radiofrequency versus Ethanol Ablation for Treating Predominantly Cystic Thyroid Nodules: A Randomized Clinical Trial

Objective

To compare single-session radiofrequency ablation (RFA) and ethanol ablation (EA) for treating predominantly cystic thyroid nodules (PCTNs).

Materials and Methods

This single-blind, randomized trial was approved by the Institutional Review Board of two centers and informed consent was obtained from all patients before enrollment. Fifty patients with a single PCTN (cystic portion less than 90% and greater than 50%) were randomly assigned to be treated by either RFA (25 patients) or EA (25 patients) at two hospitals. The primary outcome was the tumor volume reduction ratio (%) at the six-month follow-up and the superiority margin was set at 13% (RFA minus EA). Analysis was performed primarily in an intention-to-treat manner. The secondary outcomes were the therapeutic success rate, improvement of symptomatic and cosmetic problems, and the number of major complications.

Results

The mean volume reduction was 87.5 ± 11.5% for RFA (n = 22) and 82.4 ± 28.6% for EA (n = 24) (p = 0.710; mean difference [95% confidence interval], 5.1% [-8.0 to 18.2]), indicating no significant difference. Regarding the secondary outcomes, therapeutic success (p = 0.490), mean symptom (p = 0.205) and cosmetic scores (p = 0.710) showed no difference. There were no major complications in either group (p > 0.99).

Conclusion

The therapeutic efficacy of RFA is not superior to that of EA; therefore, EA might be preferable as the first-line treatment for PCTNs.

Radiofrequency ablation of benign symptomatic thyroid nodules: prospective safety and efficacy study

BACKGROUND

Radiofrequency ablation (RFA) is a relatively novel procedure in the management of benign nodular goiter. This study was conducted to evaluate the safety and efficacy of ultrasound (US)-guided percutaneous RFA for benign symptomatic thyroid nodules as an alternative to surgery.

METHODS

The study involved patients for whom a fine needle aspiration biopsy had proved a diagnosis of benign nodular goiter and had nodule-related symptoms such as dysphagia, cosmetic problems, sensation of foreign body in the neck, hyperthyroidism due to autonomous nodules or fear of malignancy. Percutaneous RFA was performed as an outpatient procedure under local anesthesia. The primary outcome was an evaluation of the changes in symptom scores (0-10) for pain, dysphagia and foreign body sensation at the 1st, 3rd, and 6th months after the RFA procedure. Secondary outcomes were assessing volume changes in nodules, complication rates, and changes in thyroid function status.

RESULTS

A total of 33 patients (24% female, 76% male) and a total of 65 nodules were included into the study. More than one nodule was treated in 63.6% of the patients. We found a statistically significant improvement from baseline to values at the 1st, 3rd, and 6th months, respectively, as follows: pain scores (2.9 ± 2.7, 2.3 ± 2.01, 1.8 ± 1.7, and 1.5 ± 1.2, p 0.005), dysphagia scores (3.9 ± 2.7, 2.6 ± 1.9; 1.7 ± 1.6, and 1.1 ± 0.3, p 0.032), and foreign body sensation scores 3.6 ± 3, 2.5 ± 2.2; 1.6 ± 1.5, and 1.1 ± 0.4, p 0.002).The mean pre-treatment nodule volume was 7.3 ± 8.3 mL. There was a statistically significant size reduction in the nodules at the 1st, 3rd, and 6th months after RFA (3.5 ± 3.8, 2.7 ± 3.4, and 1.2 ± 1.7 mL, p 0.002). The volume reduction was found to be 74% at 6th months following the RFA (p 0.005). 8 patients had autonomously functioning nodules in the pre-treatment period, 50% (n: 4) became euthyroid at the 6th month after RFA. There were no complaints other than pain (12%).

CONCLUSION

RFA can be an alternative treatment modality in the management of benign symptomatic thyroid nodules. The results showed that it is a safe and effective procedure.

Efficacy and Safety of Radiofrequency Ablation Versus Observation for Nonfunctioning Benign Thyroid Nodules: A Randomized Controlled International Collaborative Trial

BACKGROUND

Percutaneous radiofrequency thermal ablation (RFA) has been reported as an effective tool for the management of benign thyroid nodules (BTN). However, large, randomized controlled trials (RCTs) are lacking.

OBJECTIVE

The aims of this study were to assess the volume reduction of BTN after a single RFA performed using the moving-shot technique and to compare the volume reduction obtained in patients treated in two centers with different experience of the moving-shot technique.

METHOD

This study was an international prospective RCT. It was carried out at the Mauriziano Hospital (Turin, Italy) and the Asan Medical Center (Seoul, Korea). Eighty patients harboring solid, compressive, nonfunctioning BTN (volume 10-20 mL) were enrolled. Twenty patients in each country were treated by RFA using a 18-Gauge internally cooled electrode (group A); 20 nontreated patients in each country were followed as controls (group B).

RESULTS

At six months, BTN volume significantly decreased in group A (15.1±3.1 mL vs. 4.2±2.7 mL; p<0.0001), whereas it remained unchanged in group B (14.4±3.3 mL vs. 15.2±3.5 mL). The baseline volume was larger in the Italian series (16.4±2.5 mL vs. 13.9±3.3 mL, p=0.009). However, at six months, there was no significant difference between the Korean group and the Italian group (3.7±2.9 mL vs. 5.5±2.2 mL). Both cosmetic and compressive symptoms significantly improved (3.6±0.5 vs. 1.7±0.4 and 3.6±1.9 vs. 0.4±0.7, respectively; p<0.001). No side effects occurred.

CONCLUSIONS

RFA was effective in reducing the volume of BTN. The outcome was similar in centers with different experience in the moving-shot technique.

Ultrasonography-guided radiofrequency ablation of malignant musculoskeletal soft-tissue tumors using the "moving-shot" technique at a single-institution experience

The present study describes the use of the "moving-shot" technique for successful radiofrequency ablation (RFA) of malignant musculoskeletal soft-tissue tumors. Ultrasonography-guided RFA was performed in 6 malignant soft-tissue tumors in 5 patients. Short-term follow-up after RFA (8-27 weeks) showed that complete necrosis was achieved in all lesions, and 5 lesions (83%) decreased in size. Discomfort caused by the tumors decreased subjectively in all patients after ablation. Our results indicate that ultrasonography-guided RFA using the moving-shot technique can be an effective treatment option for locoregional control of malignant soft-tissue tumors. Long-term follow-up studies with a larger number of patients are necessary.

Treatment of Benign Thyroid Nodules: Comparison of Surgery with Radiofrequency Ablation

BACKGROUND AND PURPOSE

Nodular goiter is one of the most common benign lesions in thyroid nodule. The main treatment of the disease is still the traditional surgical resection, however there are many problems such as general anesthesia, surgical scar, postoperative thyroid or parathyroid function abnormalities, and high nodules recurrence rate in residual gland. The purpose of this study was to compare the efficacy, safety, and cost-effectiveness of 2 treatment methods, surgery and radiofrequency ablation, for the treatment of benign thyroid nodules.

MATERIALS AND METHODS

From May 2012 to September 2013, 200 patients with nodular goiters who underwent surgery (group A) and 200 patients treated by radiofrequency ablation (group B) were enrolled in this study. Inclusion criteria were the following: 1) cosmetic problem, 2) nodule-related symptoms, 3) hyperfunctioning nodules related to thyrotoxicosis, and 4) refusal of surgery (for group B). An internally cooled radiofrequency ablation system and an 18-ga internally cooled electrode were used. We compared the 2 groups in terms of efficacy, safety, and cost-effectiveness during a 1-year follow-up.

RESULTS

After radiofrequency ablation, the nodule volume decreased significantly from 5.4 to 0.4 mL (P = .002) at the 12-month follow-up. The incidence of complications was significantly higher from surgery than from radiofrequency ablation (6.0% versus 1.0%, P = .002). Hypothyroidism was detected in 71.5% of patients after surgery but in none following radiofrequency ablation. The rate of residual nodules (11.9% versus 2.9%, P = .004) and hospitalization days was significantly greater after surgery (6.6 versus 2.1 days, P < .001), but the cost difference was not significant.

CONCLUSIONS

Surgical resection and radiofrequency ablation are both effective treatments of nodular goiter. Compared with surgery, the advantages of radiofrequency ablation include fewer complications, preservation of thyroid function, and fewer hospitalization days. Therefore, radiofrequency ablation should be considered a first-line treatment for benign thyroid nodules.

HEALTH-RELATED QUALITY OF LIFE AFTER PERCUTANEOUS RADIOFREQUENCY ABLATION OF COLD, SOLID, BENIGN THYROID NODULES: A 2-YEAR FOLLOW-UP STUDY IN 40 PATIENTS

OBJECTIVE

We studied the impact of radiofrequency ablation (RFA) on health-related quality of life (HRQL) in patients with benign thyroid nodules (TN) in a 2-year follow-up.

METHODS

Forty patients (35 women and 5 men; age, 54.9 ± 14.3 years) with cold thyroid solitary nodules or a dominant nodule within a normofunctioning multi-nodular goiter (volume range, 6.5 to 90.0 mL) underwent RFA of thyroid nodular tissue under ultrasound real-time assistance.

RESULTS

Data are mean and standard deviation. Energy delivered was 37,154 ± 18,092 joules, with an output power of 37.4 ± 8.8 watts. Two years after RFA, nodule volume decreased from 30.0 ± 18.2 mL to 7.9 ± 9.8 mL (-80.1 ± 16.1% of initial volume; P<.0001). Thyroid-stimulating hormone, free triiodothyronine, and free thyroxine levels remained stable. Symptom score measured on a 0- to 10-cm visual analogue scale (VAS) declined from 5.6 ± 3.1 cm to 1.9 ± 1.3 cm (P<.0001). Cosmetic score (VAS 0-10 cm) declined from 5.7 ± 3.2 cm to 1.9 ± 1.5 cm (P<.0001). Two patients became anti-thyroglobulin antibody-positive. Physical Component Summary (PCS)-12 improved from 50.4 ± 8.9 to 54.5 ± 5.3, and the Mental Component Summary (MCS)-12 improved from 36.0 ± 13.3 to 50.3 ± 6.3 (P<.0001 for both score changes).

CONCLUSION

Our 2-year follow-up study confirms that RFA of benign TNs is effective in reducing nodular volume and compressive and cosmetic symptoms, without causing thyroid dysfunction or life-threatening complications. Our data indicate that the achievement of these secondary endpoints is associated with HRQL improvement, measured both as PCS and MCS.

Inter-observer variation in ultrasound measurement of the volume and diameter of thyroid nodules

Objective

Thyroid nodule measurement using ultrasonography (US) is widely performed in various clinical scenarios. The purpose of this study was to evaluate inter-observer variation in US measurement of the volume and maximum diameter of thyroid nodules.

Materials and Methods

This retrospective study included 73 consecutive patients with 85 well-defined thyroid nodules greater than 1 cm in their maximum diameter. US examinations were independently performed by using standardized measurement methods, conducted by two clinically experienced thyroid radiologists. The maximum nodule diameter and nodule volume, calculated from nodule diameters using the ellipsoid formula, were obtained by each reader. Inter-observer variations in volume and maximum diameter were determined using 95% Bland-Altman limits of agreement. The degree of inter-observer variations in volumes and the maximum diameters were compared using the Student's t test, between nodules < 2 cm in maximum diameter and those with ≥ 2 cm.

Results

The mean inter-observer difference in measuring the nodule volume was -1.6%, in terms of percentage of the nodule volume, and the 95% limit of agreement was ± 13.1%. For maximum nodule diameter, the mean inter-observer difference was -0.6%, in terms of percentage of the nodule diameter, and the 95% limit of agreement was ± 7.3%. Inter-observer variation in volume was greater in nodules of < 2 cm in maximum diameter, compared to the larger nodules (p = 0.035). However, no statistically significant difference was noted between the two groups regarding maximum nodule diameters (p = 0.511).

Conclusion

Any differences smaller than 13.1% and 7.3% in volume and maximum diameter, respectively, measured by using US for well-defined thyroid nodules of > 1 cm should not be considered as a real change in size.

Advances in nonsurgical treatment of benign thyroid nodules

Ethanol ablation has traditionally been used for treatment of cystic thyroid nodules. Laser ablation and radiofrequency ablation were introduced later and used for treatment of solid thyroid nodules. However, how to select the best treatment modality among the different techniques has, so far, not been determined and causes confusion in clinical practice. Therefore, the necessity for a proper guideline regarding the choice of the preferable treatment modality has been suggested as the use of nonsurgical treatment for benign thyroid nodules has been increasing. This article provides an up-to-date review of nonsurgical treatment of benign thyroid nodules focusing on how to select the best treatment modality according to the composition of thyroid nodules based on the clinical evidence.

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

Background

High-intensity focused ultrasound (HIFU) is a promising, non-invasive technique in treating benign thyroid nodules (TNs). The aim of this study was to evaluate the efficacy of HIFU to induce clinically meaningful shrinkage in benign predominantly solid TNs and to identify variables that influence or predict the magnitude of TN volume reduction.

Methods

For each of ten subjects, HIFU treatment was conducted on a single nodule. Nodular volume was measured sonographically at baseline and at 3 months post-procedure. Nodular function and early treatment assessment was done scintigraphically.

Results

Median nodular volume reduction was 0.7 ml absolute and 48.8% relative to pre-interventional size (p < 0.05). Absolute shrinkage was negatively correlated with the average treatment depth (τ = −0.61, p < 0.05). Absolute nodular volume was positively correlated with the scintigraphic nodular uptake reduction (τ = 0.66, p < 0.05).

Conclusions

HIFU treatment of benign predominantly solid TNs appears to be safe and effective for inducing nodular shrinkage. Despite potential for improvement, a single treatment session with HIFU is already a viable alternative to more standard methods. The feasibility of multiple HIFU treatments requires further investigation. Due to the small sample size, the findings of this analysis need conformation by larger studies.

Management of cystic or predominantly cystic thyroid nodules: role of simple aspiration of internal fluid

PURPOSE

The purpose of this study is to evaluate the efficacy of simple aspiration of cystic thyroid nodules by comparing with control groups to exclude the occurrence of spontaneous regression by the definition of current guidelines of American Thyroid Association.

MATERIALS AND METHODS

217 nodules from 210 patients with cystic thyroid nodules (cystic portion >50%) were included. Nodules were classified into three groups as follows: Group 1, observation only; Group 2, fine needle aspiration (FNA) without aspiration of internal fluid; and Group 3, FNA after aspiration of internal fluid. Significant nodule size change was defined as a difference in the largest diameter of 20%, as seen on the last follow-up ultrasound (US) compared to the initial US.

RESULTS

Demographic characteristics did not show significant differences among the three groups except for the patient age (p = 0.039). Mean nodule size significantly decreased only in group 3 (p = 0.005). Significant nodule size reductions were observed in 22.0% (13/59) in group 1, 25.7% (28/109) in group 2, and 40.8% (20/49) in group 3, respectively.

CONCLUSIONS

Aspiration of internal fluid should be considered as the first-line procedure for both the diagnosis and treatment of cystic or predominantly cystic thyroid nodules.

Radiofrequency ablation for autonomously functioning thyroid nodules: a multicenter study

BACKGROUND

The purpose of this study is to validate the generalizability of the efficacy and safety of radiofrequency (RF) ablation for treating autonomously functioning thyroid nodules (AFTN) in a large population multicenter study.

METHODS

This study included 44 patients from 5 institutions who refused or were not suitable for surgery or radioiodine therapy. Twenty-three patients were affected by a toxic nodule and 21 by a pretoxic nodule. RF ablation was performed using an 18-gauge, internally cooled electrode. Nodule volume, thyroid function, scintigraphy, symptom/cosmetic scores, and complications were evaluated before treatment and during each follow-up.

RESULTS

The mean follow-up period was 19.9±12.6 months. The mean nodule volume was initially 18.5±30.1 mL and significantly decreased after treatment at 1 month (11.8±26.9 mL, p<0.001) and the last month (4.5±9.8 mL, p<0.001). Significant improvement of triiodothyronine, free thyroxine, and thyrotropin was observed at the last follow-up. Regarding scintigraphy, 35 hot nodules became cold or were normal when scanned and 9 decreased uptake, although they remained hot nodules. The mean symptom and cosmetic scores were significantly reduced at the last follow-up. No major complications were encountered.

CONCLUSIONS

This multicenter study validated the efficacy and safety of RF ablation for treating AFTN; RF ablation can be considered an alternative to surgery or radioiodine therapy.

Radiofrequency ablation is a thyroid function-preserving treatment for patients with bilateral benign thyroid nodules

PURPOSE

To evaluate the efficacy and safety of radiofrequency (RF) ablation for treatment of bilateral thyroid nodules as well as preservation of thyroid function.

MATERIALS AND METHODS

Between January 2007 and October 2012, 18 patients (16 women and 2 men; mean age, 49.9 y; median age, 44 y; age range, 27-81 y) with bilateral thyroid nodules treated by RF ablation were included in this study. The inclusion criteria included bilateral thyroid nodules, pressure symptoms or cosmetic problems, cytologic confirmation of benignancy without atypical cells, and patient refusal of surgery. We used an RF generator (Cool-tip RF system [Covidien, Boulder, Colorado] or SSP-2000, Taewoong Medical Co, Ltd [Gyeonggi-do, Republic of Korea]) and an 18-gauge internally cooled electrode with 1-cm active tips (Cool-tip [Covidien] or Well-Point RF electrode [Taewoong Medical Co, Ltd]). RF ablation was conducted using the moving shot technique and a trans-isthmic approach. RF ablation was performed in separate sessions for nodules in each lobe. Follow-up ultrasound examinations were performed at 1-6 months, 6-12 months, and during the last month of follow-up. The diameter and volume of the nodule and clinical problems including cosmetic and symptom scores were evaluated before and after the procedure.

RESULTS

The mean initial nodule size was 4.1 cm ± 1.9, although there was a significant decrease by the time of the last follow-up examination (range, 1-48 mo; mean, 18.1 mo ± 12.8; P < .001, 2.5 cm ± 1.4). The initial nodule volume was 24.4 mL ± 32.2 and was decreased at the last follow-up (6.3 mL ± 19.0, P < .001), with a mean volume reduction of 75.9% ± 19.0. The symptom (P < .001) and cosmetic (P < .001) scores were decreased. Serum hormone levels did not differ significantly before treatment and at the last follow-up (P > .05).

CONCLUSIONS

RF ablation improves cosmetic problems and symptoms and preserves thyroid function in patients with bilateral thyroid nodules.

Moving-shot versus fixed electrode techniques for radiofrequency ablation: comparison in an ex-vivo bovine liver tissue model

Objective

To compare the ablation characteristics of the moving-shot technique (MST) and the fixed electrode technique (FET) for radiofrequency (RF) ablation in an ex-vivo bovine liver tissue model.

Materials and Methods

We performed RF ablation using FET in 110 bovine liver blocks using 11 different ablation times ranging from 5 seconds to 5 minutes (10 blocks per each time duration). Ten bovine liver blocks at each ablation time of 1- or 2-minute, were ablated with MST, which treated conceptual ablation units by moving the electrode tip. We evaluated the ablation volume obtained with FET across ablation time lengths. The results of FET and MST performed with the same ablation time lengths, i.e., 1- and 2-minute ablation time were also compared.

Results

The ablation volume achieved with FET gradually increased with increasing ablation time; however, the pair-wise statistical comparison between 2 neighboring ablation time lengths was not significant after 30 seconds. MST with either 1- or 2-minute ablation time achieved larger ablation volumes (1.1 ± 0.2 mL vs. 2.7 ± 0.3 mL, p < 0.001; and 1.4 ± 0.2 mL vs. 5.6 ± 0.4 mL, p < 0.001, respectively), longer true RF times (46.7 ± 4.6 seconds vs. 60 seconds, p < 0.001; and 64.8 ± 4.6 seconds vs. 120 seconds, p < 0.001, respectively), fewer numbers of RF cut-offs (1.6 ± 0.5 vs. 0, p < 0.001; and 5.5 ± 0.5 vs. 0, p < 0.001, respectively), and greater energy deposition (2050.16 ± 209.2 J vs. 2677.76 ± 83.68 J, p < 0.001; and 2970.64 ± 376.56 J vs. 5564.72 ± 5439.2 J, p < 0.001, respectively), than FET.

Conclusion

The MST can achieve a larger ablation volume by preventing RF cut-off, compared with the FET in an ex-vivo bovine liver model.

Local thyroid tissue ablation by high-intensity focused ultrasound: effects on thyroid function and first human feasibility study with hot and cold thyroid nodules

OBJECTIVE

The aim of this study was to assess whether high-intensity focused ultrasound (HIFU), a new and promising method for the treatment of benign hot and cold thyroid nodules using thermal ablation, has an impact on thyroid function, and to evaluate its feasibility in outpatient settings. Additionally, a possible difference in the treatment of solid and complex thyroid nodules was evaluated.

METHOD

Ten patients with one thyroid nodule each (six cold and four hot nodules) underwent HIFU in January 2014. Four nodules were solid and six nodules were complex. Serum levels of triiodothyronine (T3), thyroxine (T4), thyrotropin (TSH), thyroglobulin (hTg) and additionally antibodies against hTg (TAK), TSH receptors (TRAK) and thyroid peroxidase (TPO) were measured at enrolment and 24 h after the HIFU treatment. The pre- and post-thyroglobulin reduction was measured to evaluate the scale of ablation. In addition, patients' pain was recorded on a numeric rating scale from 0 to 10.

RESULTS

The HIFU treatment did not affect thyroid function, since hormone levels stayed stable (p < 0.05). No serious immune reaction was induced. Thyroglobulin serum levels increased significantly (p < 0.05) and were correlated to the total energy emitted by HIFU (p < 0.1). The results of complex thyroid nodules did not differ from solid thyroid nodules. Similarly, the results of hot thyroid nodules did not differ from cold thyroid nodules. All patients tolerated the whole treatment and no severe complications were observed.

CONCLUSION

HIFU is a safe and effective method to treat benign, solid, complex, hot and cold thyroid nodules preserving thyroid function. Further developments of the system are needed to gain suitability for daily use.

Early assessment of high-intensity focused ultrasound treatment of benign thyroid nodules by scintigraphic means

Background

High-intensity focused ultrasound (HIFU) allows to inflict intracorporal thermal lesions without penetrating the skin or damaging the surrounding tissue. This analysis intends to assess the magnitude of HIFU-induced ablations within benign thyroid nodules using scintigraphic imaging with ^99mTc.

Methods

Ten cold, hot, or indifferent nodules were treated using multiple pulses of HIFU to induce temperatures of around 85°C within the ablation zone. Pre- and posttreatment, uptake values of ^99mTc-pertechnetate or ^99mTc-MIBI were recorded. The pre-post reduction of nodular uptake was evaluated to assess ablation magnitude.

Results

Relative nodular uptake in relation to total thyroidal uptake decreased after one session of HIFU in all cases. Median ^99mTc-MIBI uptake reduction was 35.5% (ranging from 11% to 57%; p < 0.1), while ^99mTc-pertechnetate scintigraphy showed a median uptake reduction of 27% (range 10% to 44%; p < 0.1). No major complications were observed.

Conclusions

HIFU appears to be safe and is an easy to perform means of thermal ablation. This study shows that HIFU treatment in thyroidal nodules can be evaluated by scintigraphic means shortly after the intervention. Due to small sample size, the exact magnitude of HIFU ablation efficiency in thyroidal nodules remains a value to be assessed in a larger study.

The advent of ultrasound-guided ablation techniques in nodular thyroid disease: towards a patient-tailored approach

Surgery is the long-established therapeutic option for benign thyroid nodules, which steadily grow and become symptomatic. The cost of thyroid surgery, the risk of temporary or permanent complications, and the effect on quality of life, however, remain relevant concerns. Therefore, various minimally invasive treatments, directed towards office-based management of symptomatic nodules, without requiring general anaesthesia, and with negligible damage to the skin and cervical tissues, have been proposed during the past two decades. Today, ultrasound-guided percutaneous ethanol injection and thermal ablation with laser or radiofrequency have been thoroughly evaluated, and are accessible procedures in specialized centres. In clinical practice, relapsing thyroid cysts are effectively managed with percutaneous ethanol injection treatment, which should be considered therapy of choice. In solid non-functioning thyroid nodules that grow or become symptomatic, trained operators may safely induce, with a single session of laser ablation treatment or radiofrequency ablation, a 50% volume decrease and, in parallel, improve local symptoms. In contrast, hyperfunctioning nodules remain best treated with radioactive iodine, which results in a better control of hyperthyroidism, also in the long-term, and fewer side-effects. Currently, minimally invasive treatment is also investigated for achieving local control of small size neck recurrences of papillary thyroid carcinoma in patients who are poor candidates for repeat cervical lymph node dissection. This particular use should still be considered experimental.

Levothyroxine or minimally invasive therapies for benign thyroid nodules

BACKGROUND

Thyroid nodules (TN) are common in the adult population. Some physicians use suppressive levothyroxine (LT4) therapy to achieve a reduction in the number and volume of TN. In addition, minimally invasive treatments, such as percutaneous ethanol injection (PEI) sclerotherapy, laser photocoagulation (LP), and microwave (MW), radiofrequency (RF) and high-intensity focused ultrasound (HIFU) ablation, have been proposed, especially for pressure symptoms and cosmetic complaints, as an alternative to surgery. However, the risk to benefit ratio of all treatments for benign TN is currently unknown.

OBJECTIVES

To assess the effects of LT4 or minimally invasive therapies (PEI, LP, and RF/HIFU/MW ablation) on benign TN.

SEARCH METHODS

We identified studies from computerised searches of The Cochrane Library, MEDLINE, EMBASE and LILACS (all performed up to April 2014). We also searched trial registers, examined reference lists of included randomised controlled trials (RCTs) and systematic reviews, and contacted study authors.

SELECTION CRITERIA

We included studies if they were RCTs of LT4, PEI, LP, RF, HIFU or MW therapy in participants with an established diagnosis of benign TN. We excluded trials investigating the prevention of recurrence of thyroid disease after surgery, irradiation or treatment with radioiodine.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data, assessed studies for risk of bias and evaluated overall study quality utilising the GRADE instrument. We assessed the statistical heterogeneity of included studies by visually inspecting forest plots and quantifying the diversity using the I² statistic. We synthesised data using random-effects model meta-analysis or descriptive analysis, as appropriate.

MAIN RESULTS

Thirty-one studies randomised 2952 outpatients to investigate the effects of different therapies on benign TN. Studies on LT4, PEI, LP and RF ablation therapy randomised 2083, 607, 192 and 70 participants, respectively. We found no RCTs of HIFU or MW ablation therapy in benign TN. The duration of treatment varied according to the applied therapies: up to five years for LT4 and one to three PEI ablations, one to three LP sessions and one or two RF sessions. Median follow-up was 12 months for LT4 and six months for minimally invasive therapies. Evidence was of low-to-moderate quality, and risk of performance and detection bias for subjective outcomes was high in most trials.No study evaluated all-cause mortality or health-related quality of life. Only one LT4 study provided some data on the development of thyroid cancer, reporting no abnormal cytological findings. One LP study provided limited information on costs of treatment.LT4 compared with no treatment or placebo was associated with a nodule volume reduction of 50% or more in 16% compared with 10% of participants after 6 to 24 months of follow-up (risk ratio (RR) 1.57 (95% confidence interval (CI) 1.04 to 2.38); P = 0.03; 958 participants; 10 studies; moderate-quality evidence). Pressure symptoms or cosmetic complaints were not investigated in LT4 studies. LT4 therapy was generally well tolerated: three studies provided quantitative data on signs and symptoms of hyperthyroidism, which were observed in 25% of LT4-treated versus 7% of placebo-treated participants at 12 to 18 months of follow-up (269 participants; 3 trials; low-quality evidence).PEI compared with cyst aspiration only was associated with a nodule volume reduction of 50% or more in 83% compared with 44% of participants after 1 to 24 months of follow-up (RR 1.83 (95% CI 1.32 to 2.54); P = 0.0003; 105 participants; 3 studies; low-quality evidence). Improvements in neck compression symptoms after 6 to 12 months of follow-up were seen in 78% of participants receiving PEI versus 38% of those in comparator groups. No reliable summary effect estimate could be established, RR ranged from 1.0 to 3.06 in favour of PEI (370 participants; 3 trials; low-quality evidence). In all trials, participants experienced periprocedural cervical tenderness and light-to-moderate pain usually lasting from minutes to several hours. As a result of the PEI procedure, 26% of participants reported slight-to-moderate pain compared with 12% of those receiving cyst aspiration only (RR 1.78 (95% CI 0.62 to 5.12); P = 0.28; 104 participants; 3 studies; low-quality evidence).One study comparing LP with LT4 showed a nodule volume reduction of 50% or more in favour of LP after 12 months of follow-up in 33% of LP participants versus 0% of LT4 participants, respectively (62 participants; 1 trial; low-quality evidence). A total of 82% of LP-treated versus 0% of untreated participants showed improvements in pressure symptoms after 6 to 12 months of follow-up (RR 26.65 (95% CI 5.47 to 129.72); P < 0.0001; 92 participants; 3 trials; low-quality evidence). Around 20% of LP-treated participants reported light-to-moderate cervical pain lasting 48 hours or more (97 participants; 3 trials; low-quality evidence).One trial with 40 participants, comparing RF with no treatment, resulted in a mean nodule volume reduction of 76% in the RF group compared with 0% of those in the no-treatment group at six months of follow-up (low-quality evidence). These RF-treated participants had fewer pressure symptoms and cosmetic complaints after 12 months of follow-up compared with untreated participants (a 2.8 decrease versus a 1.1 increase on a six-point scale, respectively, with higher values indicating more severe symptoms; low-quality evidence). All participants complained of pain and discomfort during RF, which disappeared when the energy was reduced or turned off (low-quality evidence).

AUTHORS' CONCLUSIONS

No study evaluated all-cause mortality, health-related quality of life or provided systematic data on the development of thyroid cancer. Longest follow-up was five years and median follow-up was 12 months. Nodule volume reductions were achieved by PEI, LP and RF, and to a lesser extent, by LT4. However, the clinical relevance of this outcome measure is doubtful. PEI, LP and RF led to improvements in pressure symptoms and cosmetic complaints. Adverse events such as light-to-moderate periprocedural pain were seen after PEI, LP and RF. Future studies should focus on patient-important outcome measures, especially health-related quality of life, and compare minimally invasive procedures with surgery. RCTs with follow-up periods of several years and good-quality observational studies are needed to provide evidence on the development of thyroid cancer, all-cause mortality and long-term adverse events.

Vascular and interventional radiology radiofrequency ablation of benign thyroid nodules and recurrent thyroid cancers: literature review

Thermal radiofrequency ablation is a relatively new, minimally invasive modality employed as an alternative to surgery in patients with benign thyroid nodules and recurrent thyroid cancers. Different recommendations are necessary for the optimal use of radiofrequency ablation for thyroid nodules. These recommendations are based on a comprehensive analysis of the current literature, the results of multicenter studies, and expert consensus.

Efficacy assessment of newly developed open-window intervention needles for the treatment of cystic thyroid nodules that cannot be aspirated

OBJECTIVE

The purpose of this study was to develop a novel open-window needle aspiration method and evaluate its efficacy in drainage and sclerotherapy of cystic thyroid nodules that cannot be aspirated with an 18-gauge needle.

METHODS

Two rectangular windows 5.0 mm in length and 1.0 mm wide were placed at the end of the percutaneous transhepatic cholangiography (PTCA) needle trocar to develop a new open-window intervention needle. The efficiency of the open-window intervention needle was compared either to a porous interventional needle or to an ordinary PTCA needle by assessing the aspiration efficiency. The efficacy of the modified open-window approach was tested by carrying out sclerotherapy and drainage on 21 thyroid cystic nodules that could not be aspirated with an 18-gauge needle and comparing it to aspiration with an 18-gauge PTCA needle of 50 cystic thyroid nodules.

RESULTS

The efficacy of aspirating coupling agents of various specifications using the new open-window intervention was superior to aspiration using the PTCA trocar needle or a porous needle (p<0.05). Ethanol ablation efficacy in the treatment of 21 cystic thyroid nodules that could not be aspirated with an 18-gauge needle and the aspiration efficacy of 50 cystic thyroid nodules with an 18-gauge PTCA needle were not significantly different (p>0.05).

CONCLUSION

The new open-window intervention needle approach was highly effective in conducting ethanol ablation of cystic thyroid nodules that could not be aspirated using conventional methodologies.

Microwave ablation of benign thyroid nodules

ABSTRACT: 

Microwave ablation (MWA) has become increasingly popular as a minimally invasive treatment for benign and malignant tumors of the liver, lung and kidney. Recently, two studies have attempted to apply the technique to debulk benign thyroid nodules and gained positive results. MWA of benign nodules demonstrated significant volume reductions, while solving nodule-related clinical problems. This article reviews the basic physics, therapeutic indications, patient preparation, devices, procedures, clinical results and complications of thyroid MWA.

Diagnosis of endocrine disease: thyroid ultrasound (US) and US-assisted procedures: from the shadows into an array of applications

In patients with thyroid nodules, ultrasound (US) imaging represents an indispensable tool for assessment of the risk of malignancy. Over approximately four decades, innovative technology and successive improvements have facilitated its entry into the routine management and greatly improved its predictive value. When US features cannot reliably rule out thyroid cancer, US guidance allows a correct and safe sampling also of small or deeply located thyroid lesions. Obtained in this way, cytological or microhistological specimens may reliably define the nature of most thyroid nodules, and the information from histochemical or molecular markers shows promise in the classification of the remaining indeterminate cases. While a prompt surgical treatment can be offered in the minority of suspicious or definitely malignant cases, most individuals warrant only a follow-up. However, at initial evaluation, or over the years, a fraction of these benign lesions may grow and/or become symptomatic. Such cases may benefit from US-guided minimally invasive procedures as an alternative to surgery. Image-guided percutaneous treatments most often achieve relief of neck complaints, are inexpensive, and can be performed on an outpatient basis. The risk of major complications, after adequate training, is very low. Importantly, thyroid function is preserved. Currently, percutaneous ethanol injection for cystic lesions and thermal ablation, with laser or radiofrequency, for solid nodules are increasingly used and disseminated beyond the initial core facilities. In centres with expertise and high patient volume, their use should be considered as first-line treatment alternatives to surgery for selected patients with benign enlarging or symptomatic thyroid lesions.

Intralesional saline injection for effective ultrasound-guided aspiration of benign viscous cystic thyroid nodules

Purpose:

We aimed to evaluate the efficacy and safety of vigorous saline injection for viscous cystic thyroid nodules.

Methods:

Eighteen patients who underwent ultrasound-guided aspiration for viscous cystic thyroid nodules using a saline injection were included in our study. After failing to aspirate the cyst by the usual method, we vigorously injected saline into the cyst in multiple directions to break up and liquefy the viscous cystic contents to enable aspiration. The initial and the residual volume of the nodule were calculated, and the volume reduction rate and the time taken to perform the aspiration were recorded.

Results:

The mean volume of the cystic nodules before aspiration was 11.0 mL (range, 1.2 to 26.0 mL), while the postaspiration volume was 4.2 mL (range, 0.2 to 14.5 mL). The mean aspirated volume was 63.7% of the initial volume. The mean procedure time was 12.4 minutes (range, 5 to 26 minutes). There were no significant complications related to the procedure.

Conclusion:

A vigorous saline injection followed by aspiration can be a useful method to aspirate viscous cystic thyroid nodules as a prestep for further intervention or simple management.

Radiofrequency ablation compared to surgery for the treatment of benign thyroid nodules

Objective. Benign thyroid nodules are a common occurrence whose only remedy, in case of symptoms, has always been surgery until the advent of new techniques, such as radiofrequency ablation (RFA). This study aimed at evaluating RFA efficacy, tolerability, and costs and comparing them to hemithyroidectomy for the treatment of benign thyroid nodules. Design and Methods. 37 patients who underwent RFA were retrospectively compared to 74 patients surgically treated, either in a standard inpatient or in a short-stay surgical regimen. Efficacy, tolerability, and costs were compared. The contribution of final pathology was also taken into account. Results. RFA reduced nodular volume by 70% after 12 months and it was an effective method for treating nodule-related clinical problems, but it was not as effective as surgery for the treatment of hot nodules. RFA and surgery were both safe, although RFA had less complications and pain was rare. RFA costed €1,661.50, surgery costed €4,556.30, and short-stay surgery costed €4,139.40 per patient. RFA, however, did not allow for any pathologic analysis of the nodules, which, in 6 patients who had undergone surgery (8%), revealed that the nodules harboured malignant cells. Conclusions. RFA might transform our approach to benign thyroid nodules.

A short review of basic head and neck interventional procedures in a general radiology department

Image-guided interventional procedures provide a safe way to diagnose and treat a variety of head and neck abnormalities. The procedure time is usually short, and most procedures can be performed on an outpatient basis. Knowledge about strengths and weaknesses, efficacy, potential complications, and pitfalls of these procedures allows the best treatment to be chosen for a particular lesion type. This review discusses some of the commonly performed interventional radiology procedures in a general radiology department in the management of patients with neoplastic diseases in the head and neck region.

Combination therapy of temporary tracheal stenting and radiofrequency ablation for multinodular thyroid goiter with airway compression

We report a case of multinodular thyroid goiter in an 80-year-old man who successfully underwent tracheal stent placement for respiratory distress caused by the thyroid goiter and following two radiofrequency (RF) ablation sessions performed for thyroid volume reduction. This sequential treatment allowed elective stent removals four weeks after the second RF ablation session because the thyroid volume had been progressively reduced. Combination therapy of temporary airway stenting and RF ablation for the treatment of thyroid goiter has two advantages, i.e., immediate reliefs of dyspnea with airway stenting and reductions of the thyroid volume with RF ablation, and thus, allowing symptom reliefs even after the stent removals.

Combination therapy consisting of ethanol and radiofrequency ablation for predominantly cystic thyroid nodules

SUMMARY

Predominantly cystic thyroid nodules are often aspirated before radiofrequency ablation to enhance its efficacy; however internal bleeding during the aspiration is a problem. We evaluated the feasibility and safety of ethanol ablation to control internal bleeding that occurred during preparatory aspiration. Between September 2010 and August 2011, 11 of 40 predominantly cystic nodules bled internally during fluid aspiration before radiofrequency ablation. To control the bleeding, 99% ethanol was injected. The efficacy of ethanol in controlling bleeding, final nodule volume and complications were assessed. Control of the bleeding by ethanol ablation and subsequent radiofrequency ablation was feasible in all patients. Ninety-one percent (10/11) could be treated in 1 session. The mean nodule volume dropped from 17.1 to 4.3 mL (P < .018). There were no major complications. Ethanol ablation and radiofrequency ablation combination therapy is a feasible and safe technique for treating predominantly cystic thyroid nodules that exhibit internal bleeding during preparatory aspiration.

Single-session treatment of benign cystic thyroid nodules with ethanol versus radiofrequency ablation: a prospective randomized study

PURPOSE

To compare volume reduction of single-session ethanol ablation (EA) and radiofrequency (RF) ablation for cystic thyroid nodule treatment.

MATERIALS AND METHODS

All patients gave written informed consent to participate in this prospective institutional review board-approved study. From May 6, 2010, to August 8, 2011, in this single-institutional, noninferiority trial, 50 patients, each with a single cystic thyroid nodule, were randomly assigned to EA (25 patients; mean age for women, 45.7 years, and for men, 37.5 years) or RF ablation (25 patients; mean age for women, 45.1 years, and for men, 43.7 years) treatment. Internal fluid was aspirated prior to EA or RF ablation. Primary end point was the volume reduction ratio (percentage) at 6-month follow-up; the noninferiority margin was chosen as -8% (EA minus RF ablation). Secondary end points included therapeutic success rate, improvement of symptoms and cosmetic problems, and number of major complications. Analysis was performed primarily in intention-to-treat manner. A one-sided 95% confidence interval (CI) for the mean difference in volume reduction ratio 6 months after treatment was calculated to test for noninferiority. Subsequent superiority comparison of EA with RF ablation on a condition of establishment of the noninferiority of EA to RF ablation was preplanned and used two-sided 95% CI of the outcome difference.

RESULTS

The mean volume reduction was 96.9% in EA and 93.3% in RF ablation (n = 21 for each) (difference, 3.6%; lower bound of the one-sided 95% CI of the difference, 1.2%), thus demonstrating the noninferiority of EA to RF ablation. Two-sided 95% CI of the outcome difference was 0.7% to 6.5%, demonstrating significant superiority of EA to RF ablation. All patients demonstrated therapeutic success (P > .99). Mean symptom and cosmetic scores showed no significant difference in either group (P = .806 and P = .682, respectively). There were no major complications (P > .99).

CONCLUSION

EA may be the first-line treatment modality for cystic thyroid nodules, which has comparable therapeutic efficacy to, but is less expensive than, RF ablation.

Radiofrequency ablation of benign thyroid nodules does not affect thyroid function in patients with previous lobectomy

BACKGROUND

Surgical management of symptomatic benign thyroid nodules in patients with previous lobectomy poses a dilemma for physicians. Radiofrequency (RF) ablation may provide a treatment option that avoids surgery and preserves thyroid function. We evaluated whether RF ablation of benign thyroid nodules affects thyroid function in patients with previous lobectomy.

METHODS

A total of 11 patients with 14 thyroid nodules were enrolled using the following criteria: (i) having a predominantly solid nodule; (ii) reporting pressure symptoms or cosmetic problems; (iii) cytological confirmation of benignancy; (iv) no malignant features detected using ultrasound; (v) serum thyroid hormone and thyrotropin (TSH) levels within normal limits; and (vi) refusal of or ineligibility for surgery. Thyroid function, nodule volumes, and clinical concerns were evaluated before RF ablation and during follow-up after RF ablation.

RESULTS

The mean follow-up duration after RF ablation was 43.7±30.7 months (range=7-92 months). The mean nodule volume was 9.7 mL (0.9-57.6 mL) before the procedure, and was significantly decreased at the last follow-up (p<0.001) with a mean volume reduction rate of 87.2%. The mean symptom score (p=0.003) and cosmetic score (p=0.003) were both significantly decreased at the last follow-up. Levels of TSH, free thyroxine, and triiodothyronine were not significantly different prior to treatment and at the last follow-up (p>0.05), and remained normal in all patients.

CONCLUSIONS

In patients with previous lobectomy, RF ablation should be considered as a first-line treatment for symptomatic benign thyroid nodules to preserve thyroid function.

Use of radiofrequency ablation in benign thyroid nodules: a literature review and updates

Successful thermal ablation using radiofrequency has been reported in various tumors including liver or kidney tumors. Nonsurgical minimally invasive ablative therapy such as radiofrequency ablation (RFA) has been reported to be a safe and efficient treatment option in managing symptomatic cold thyroid nodules or hyperfunctioning thyroid nodules. Pressure and cosmetic symptoms have been shown to be significantly improved both in the short and long terms after RFA. For hyperfunctioning thyroid nodules, RFA is indicated for whom surgery or radioiodine are not indicated or ineffective or for those who refuse surgery or radio-iodine. Improvement of thyroid function with decreased need for antithyroid medications has been reported. Complication rate is relatively low. By reviewing the current literature, we reported its efficacy and complications and compared the efficacy of RFA relative to other ablative options such as ethanol ablation and laser ablation.

Thyroid nodules treated with percutaneous radiofrequency thermal ablation: a comparative study

PURPOSE

Percutaneous radiofrequency thermal ablation (RTA) was reported as an effective tool for the management of thyroid nodules (TNs). The aim of this study was to investigate the effects of RTA and to establish whether they were treatment-related by comparison with a matched, untreated control group.

PATIENTS AND METHODS

The study population included 40 patients with compressive TNs: 22 had nontoxic TNs, and 18 had toxic TNs and were treated with methimazole. In all patients, a fine-needle aspiration cytology was performed to exclude a thyroid malignancy.

STUDY DESIGN

Twenty patients were treated with RTA (group A), and 20 others did not receive any treatment (group B). At baseline, age, gender, and TN features did not differ significantly between groups. All patients were clinically, biochemically, and morphologically evaluated at baseline and after 1, 3, 6, and 12 months.

RESULTS

TN volume significantly decreased in group A (1.8 ± 0.3 ml at 12 months vs. 13.3 ± 1.8 ml at baseline; P < 0.0001) and remained stable in group B [11.7 ± 1.5 ml at 12 months vs. 11.2 ± 1.5 ml at baseline; P = not significant (NS)]. At 3-, 6-, and 12-month evaluations, TN volume was significantly lower in group A than in group B (P < 0.005). At the end of the follow-up, pressure symptoms were improved in all patients in group A but persisted unchanged in group B. In group A, hyperthyroidism completely recovered in 40% and improved in 40% of patients with toxic TNs, whereas it persisted in all patients with toxic TNs in group B. RTA was safe and well tolerated in all patients.

CONCLUSIONS

RTA induced a marked TN volume shrinkage resulting in parallel improvement of pressure symptoms. In most patients with toxic TNs, hyperthyroidism significantly improved as well. RTA may represent a valid therapeutic approach in patients with TNs not receiving conventional treatments.

Radiofrequency ablation of benign non-functioning thyroid nodules: 4-year follow-up results for 111 patients

OBJECTIVES

To evaluate the clinical outcomes and safety of radiofrequency (RF) ablation for benign non-functioning thyroid nodules over a 4-year follow-up.

METHODS

We evaluated 126 benign non-functioning thyroid nodules of 111 patients treated with RF ablation and followed-up more than 3 years. RF ablation was performed using the Cool-Tip RF system and an internally cooled electrode. Nodule volume and cosmetic and symptom scores were evaluated before treatment and during follow-up. Complications and factors related to efficacy were evaluated.

RESULTS

The mean follow-up duration was 49.4 ± 13.6 months. Thyroid nodule volume decreased significantly, from 9.8 ± 8.5 ml before ablation to 0.9 ± 3.3 ml (P < 0.001) at final evaluation: a mean volume reduction of 93.4 ± 11.7 %. The mean cosmetic (P < 0.001) and symptom scores (P < 0.001) improved significantly. Factors related to efficacy were initial solidity and volume. The overall recurrence rate was 5.6 % (7/126). The overall complication rate was 3.6 % (4/111).

CONCLUSIONS

RF ablation was effective in shrinking benign thyroid nodules and in controlling nodule-related problems over a 4-year follow-up. There were no life-threatening complications or sequelae. Therefore, RF ablation can be used as a non-surgical treatment for patients with benign non-functioning thyroid nodules.

Sonography-guided ethanol ablation of a remnant solid component after radio-frequency ablation of benign solid thyroid nodules: a preliminary study

BACKGROUND AND PURPOSE

No study has previously examined the feasibility of using EA to remove any peripherally located, solid components remaining after treatment of benign solid thyroid nodules by RFA. The aim of this study was to assess the efficacy of EA in removing remnant solid components following the incomplete ablation of benign solid thyroid nodules by RFA.

MATERIALS AND METHODS

During a 1-year period, RFA was performed in 18 benign solid thyroid nodules in 17 patients. EA was subsequently performed on 8 of these nodules. The success rate of EA, size and vascularity of the remaining solid components, amount of injected ethanol, degree of intranodular echo staining just after ethanol injection, and number of EA sessions were assessed.

RESULTS

Of 18 post-RFA nodules, 8 nodules were subsequently treated with EA because of incomplete ablation, as defined by the presence of peripherally located vascularized solid components. On follow-up US, 2 nodules showed marked hypoechogenicity and no vascularity of the remaining solid components, while 3 nodules showed considerably decreased echogenicity and vascularity of the remaining solid components. Three nodules showed no significant decrease or mild decrease in the echogenicity and vascularity of the remaining solid components. No serious complications were observed during or after RFA or EA, with the exception of 1 patient who experienced diffuse glandular hemorrhage during these procedures.

CONCLUSIONS

EA was effectively used to remove incompletely ablated components of benign solid thyroid nodules remaining after RFA.

Ultrasound-guided percutaneous microwave ablation of benign thyroid nodules: experimental and clinical studies

PURPOSE

To obtain the treatment parameters of internally cooled microwave antenna and to evaluate the feasibility of ultrasound-guided percutaneous microwave ablation (MWA) for benign thyroid nodules.

MATERIALS AND METHODS

MWAs were performed by microwave antenna (16G) in ex vivo porcine liver. The lesion diameters achieved in different groups (20, 25, and 30 W for 3, 5, 7, 10, and 12 min) were compared. The clinical study was approved by the ethics committee. Written informed consent was obtained from all patients. MWA was performed in 11 patients (male to female ratio=1:10; mean age, 50±7 years) with 11 benign thyroid nodules. Ultrasound scan, laboratory data, and clinical symptoms were evaluated before and 1 day and 1, 3, 6, 9, and 12 months after the procedure.

RESULTS

In ex vivo study, the ablation lesion at 30 W 12 min tended to have appropriate scope and spherical shape. In clinical study, the follow-up periods ranged from 1 to 9 months. At the last follow-up, the largest diameter decreased from 2.9±1.0 (range, 1.6-4.1) to 1.9±0.7 (range, 0.4-3.0) cm (P<0.01), and the volume decreased from 5.30±4.88 (range, 0.89-14.81) to 2.40±2.06 (range, 0.02-6.35) ml (P<0.01). The volume reduction ratio was 45.99±29.90 (range, 10.56-98.15) %. The cosmetic grading score was reduced from 3.20±0.79 to 2.30±0.95 (P<0.05). One patient experienced temporary nerve palsy and was recovered within 2 months after treatment.

CONCLUSION

The internally cooled microwave antenna can yield ideal ablation lesions, and ultrasound-guided percutaneous MWA is a feasible technique for benign thyroid nodules.

Sonographically guided radiofrequency ablation with and without a superficial saline injection to prevent skin burns in a rabbit model

OBJECTIVES

Our aim was to determine whether sonographically guided radiofrequency ablation with superficial saline injection can minimize thermal injury of the skin without an influence on therapeutic efficacy.

METHODS

Institutional Animal Care Committee approval was obtained. Twelve percutaneous radiofrequency ablation procedures were performed in the thighs of 6 rabbits (control, n = 6, right thigh; experimental, n = 6, left thigh). The ablation with local anesthesia was performed in the most superficial area of the thigh muscle. In the experimental group, 1 mL of saline was injected before the ablation at the tissue layer between the skin and ablated muscle. The duration and energy of the ablation were the same in the control and experimental groups. Rabbits were compared for their gross skin state and histopathologic findings after the ablation.

RESULTS

The degree of thermal coagulation of the muscle was similar in both groups at pathologic examination. Grossly, skin redness was mild in the experimental group but moderate in the control group. Of the 6 rabbits, 5 tended to show more frequent histopathologic changes, including an inflammatory reaction, interruption of collagen fibers, injury of the skin adnexa, and fibrosis, in the control group when compared with the experimental group. However, there was no statistically significant difference (all P> .05). One rabbit that underwent ablation at higher energy had a partially dissected epidermis in the control group only.

CONCLUSIONS

Sonographically guided radiofrequency ablation with a saline injection superficial to a tumor might prevent skin burns and provide equivalent therapeutic efficacy for ablating superficial lesions.

Symptomatic benign thyroid nodules: efficacy of additional radiofrequency ablation treatment session--prospective randomized study

PURPOSE

To prospectively evaluate the efficacy of additional radiofrequency (RF) ablation by comparing the results of one and two sessions.

MATERIALS AND METHODS

All patients gave written informed consent to participate in this institutional review board-approved prospective study. From September 2007 to February 2008, 30 patients with benign predominantly solid thyroid nodules causing pressure symptoms and/or cosmetic problems were randomly assigned to undergo single-session (group 1, n = 15) or two-session (group 2, n = 15) RF ablation. RF ablation was performed by using an 18-gauge internally cooled electrode with ultrasonographic guidance. Nodule volume and cosmetic and symptom scores were evaluated before ablation and at 1, 3, and 6 months after initial ablation, and quantitative comparisons of these were performed by using the Mann-Whitney and Wilcoxon signed rank tests; the Spearman rank test was used for correlation between nodule volume reduction and applied energy.

RESULTS

At 6-month follow-up, there was significant nodule volume reduction, from 13.3 mL ± 12.9 (standard deviation) to 3.8 mL ± 4.4 in group 1 (P = .001), and from 13.0 mL ± 6.8 to 3.0 mL ± 2.2 in group 2 (P = .001). Each group showed significant improvement in cosmetic (P < .0001) and symptom (P = .001) scores. However, there was no significant difference in volume reduction, cosmetic score, and symptom score between two groups (P = .078, P > .99, and P = .259, respectively). In group 1, three of four patients who had a pretreatment nodule volume larger than 20 mL underwent additional RF ablation because of unresolved clinical problems after the first session.

CONCLUSION

Single-session RF ablation showed significant volume reduction and satisfactory clinical response in most patients. Therefore, additional RF ablation should be limited to patients with a large nodule (>20 mL) or unresolved clinical problems.

Radiofrequency ablation of benign thyroid nodules and recurrent thyroid cancers: consensus statement and recommendations

Thermal ablation using radiofrequency is a new, minimally invasive modality employed as an alternative to surgery in patients with benign thyroid nodules and recurrent thyroid cancers. The Task Force Committee of the Korean Society of Thyroid Radiology has developed recommendations for the optimal use of radiofrequency ablation for thyroid nodules. These recommendations are based on a comprehensive analysis of the current literature, the results of multicenter studies, and expert consensus.