Sae Rom Chung

Thyroid Radiofrequency Ablation: Updates on Innovative Devices and Techniques

Radiofrequency ablation (RFA) is a well-known, effective, and safe method for treating benign thyroid nodules and recurrent thyroid cancers. Thyroid-dedicated devices and basic techniques for thyroid RFA were introduced by the Korean Society of Thyroid Radiology (KSThR) in 2012. Thyroid RFA has now been adopted worldwide, with subsequent advances in devices and techniques. To optimize the treatment efficacy and patient safety, understanding the basic and advanced RFA techniques and selecting the optimal treatment strategy are critical. The goal of this review is to therefore provide updates and analysis of current devices and advanced techniques for RFA treatment of benign thyroid nodules and recurrent thyroid cancers.

Safety of radiofrequency ablation of benign thyroid nodules and recurrent thyroid cancers: a systematic review and meta-analysis

Abstract Objective: We performed a systematic review and meta-analysis to evaluate the safety of radiofrequency ablation (RFA) for the treatment of benign thyroid nodules and recurrent thyroid cancers. Materials and methods: Ovid-MEDLINE, EMBASE, and Library of Cochrane databases were searched up to 12 July 2016 for studies on the safety of RFA for treating benign thyroid nodules or recurrent thyroid cancers. Pooled proportions of overall and major complications were assessed using random-effects modelling. Heterogeneity among studies was determined using the χ2 statistic for the pooled estimates and the inconsistency index I2. Results: A total of 24 eligible studies were included, giving a sample size of 2421 patients and 2786 thyroid nodules. 41 major complications and 48 minor complications of RFA were reported, giving a pooled proportion of 2.38% for overall RFA complications [95% confidence interval (CI): 1.42%–3.34%] and 1.35% for major RFA complications (95% CI: 0.89%–1.81%). There were no heterogeneities in either overall or major complications (I2 = 1.24%–21.79%). On subgroup analysis, the overall and major complication rates were significantly higher for malignant thyroid nodules than for benign thyroid nodules (p = 0.0011 and 0.0038, respectively). Conclusions: RFA was found to be safe for the treatment of benign thyroid nodules and recurrent thyroid cancers.

Tumor Vascular Permeability Pattern Is Associated With Complete Response in Immunocompetent Patients With Newly Diagnosed Primary Central Nervous System Lymphoma: Retrospective Cohort Study

AbstractA dynamic contrast-enhanced MR imaging (DCE-MRI) could provide the information about tumor drug delivery efficacy. We investigated the potential utility of the permeability pattern of DCE-MRI for predicting tumor response to high dose-methotrexate treatment and progression-free survival (PFS) in patients with primary CNS lymphoma (PCNSL). Clinical and conventional imaging parameters were assessed as potential predictors of tumor response in 48 immunocompetent PCNSL patients in a preliminary study. Fifty additional immunocompetent patients (27 men and 23 women; mean age, 60.6 years) with PCNSL underwent DCE-MRI before starting first-line treatment with high dose-methotrexate. The DCE-MRI pattern was categorized as diffuse or nondiffuse. After 4 courses of high dose methotrexate, patients underwent follow-up brain MR imaging to identify their complete response (CR). Predictors of CR and PFS were analyzed using clinical parameters, conventional MRI, and DCE-MRI. CR was noted in 20 (74.1%) of 27 patients with diffuse DCE-MRI pattern and in 4 (17.4%) of 23 patients with nondiffuse DCE-MRI pattern. The diffuse DCE-MRI pattern showed a significantly higher association with CR than the nondiffuse pattern (P < 0.001). Multivariate Cox proportional hazards model revealed that the DCE-MRI pattern (hazard ratio = 0.70; P = 0.045), age (hazard ratio = 1.47; P = 0.041), and adjuvant autologous stem-cell transplantation (hazard ratio = 6.97; P = 0.003) tended to be associated with a PFS. The pretreatment diffuse DCE-MRI pattern can be used as a potential imaging biomarker for predicting CR and a longer PFS in patients with newly diagnosed PCNSLs.

2017 Thyroid Radiofrequency Ablation Guideline: Korean Society of Thyroid Radiology

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 (KSThR) developed recommendations for the optimal use of radiofrequency ablation for thyroid tumors in 2012. As new meaningful evidences have accumulated, KSThR decided to revise the guidelines. The revised guideline is based on a comprehensive analysis of the current literature and expert consensus.

Radiofrequency ablation of primary thyroid carcinoma: efficacy according to the types of thyroid carcinoma

Abstract Objective: To evaluate the efficacy of ultrasound (US)-guided radiofrequency ablation (RFA) according to the types of thyroid carcinoma, particularly in patients with a high-surgical risk. Materials and methods: Eight patients with nine tumours of pathologically proven papillary and anaplastic carcinoma were treated by US-guided RFA. Patients with primary thyroid carcinoma were divided into three groups; group (1) Anaplastic carcinoma, group (2) papillary macrocarcinoma, and group (3) papillary microcarcinoma. We evaluated changes in clinical symptoms, tumour volume and local tumour recurrence/metastasis after RFA. Patients were followed up at 1, 6 and 12 months and annually thereafter. Results: Among nine tumours, one anaplastic carcinoma was treated three times and the other anaplastic carcinoma and one papillary macrocarcinoma were treated twice. Group 3 were treated once. The initial mean tumour volume was 107.9 ± 78.6 (with neck bulging), 126.9 (with neck bulging) and 0.16 ± 0.08 mL (without cosmetic or symptomatic problems) in groups 1–3, respectively. Group 1 showed no improvement in clinical symptoms or neck bulging after RFA, whereas group 2 demonstrated a decreased tumour volume measuring 0.7 mL with improved neck bulging. In group 3, mean volume decreased measuring 0.07 ± 0.12 mL. No local tumour recurrence or metastatic lesion was detected during the mean follow-up of 19.3 months in papillary carcinomas. No major complications were encountered. Conclusions: In patients with primary thyroid carcinoma, RFA achieved excellent local tumour control for papillary macro- and microcarcinoma; however, its clinical effect on anaplastic carcinoma was questionable.

A Comparison of Ultrasound-Guided Fine Needle Aspiration versus Core Needle Biopsy for Thyroid Nodules: Pain, Tolerability, and Complications

Background To compare pain, tolerability, and complications associated with fine needle aspiration (FNA) versus core needle biopsy (CNB). Methods FNAs were performed using 23-gauge needles and CNBs were performed using 18-gauge double-action spring-activated needles in 100 patients for each procedure. Patients were asked to record a pain score using a 10-cm visual analog scale and procedure tolerability. Complications and number of biopsies were recorded. Results The median pain scores were similar for the FNA and CNB approaches during and 20 minutes after the biopsy procedures (3.7 vs. 3.6, P=0.454; 0.9 vs. 1.1, P=0.296, respectively). The procedure was tolerable in all 100 FNA patients and in 97 CNB patients (P=0.246). The mean number of biopsies was fewer in the CNB group (1.4 vs. 1.2, P=0.002). By subgroup analysis (staff vs. non-staff), no significant difference was detected in any parameter. There were no major complications in either group, but three patients who underwent CNB had minor complications (P=0.246). Conclusion FNA and CNB show no significant differences for diagnosing thyroid nodules in terms of pain, tolerability, or complications.

Diffusion-weighted imaging with reverse phase-encoding polarity: the added value to the conventional diffusion-weighted imaging in differentiating acute infarctions from hyperintense brainstem artifacts

AbstractObjectivesThe aim of our study was to assess the value of diffusion-weighted imaging with reverse phase-encoding polarity (R-DWI) in addition to conventional DWI using forward phase-encoding polarity (F-DWI) in differentiating acute brainstem infarctions from hyperintense artefacts.MethodsSeventy-six patients with 38 hyperintense brainstem artefacts and 38 acute brainstem infarctions that had undergone F-DWI and R-DWI were retrospectively selected based on the clinicoradiological diagnosis. Four radiologists independently rated their confidence in diagnosing acute infarctions and ruling out brainstem artefacts in a blind manner, and then compared the diagnostic performance and confidence between F-DWI alone and F-DWI with R-DWI.ResultsThe areas under the curve determined for F-DWI with R-DWI in diagnosing infarctions were significantly higher than F-DWI alone for all readers (resident 1, 0.908 vs 0.776; resident 2, 0.908 vs 0.789; neuroradiologist, 0.961 vs 0.868; emergency radiologist, 0.934 vs 0.855, all p < 0.05). All readers were more confident using F-DWI with R-DWI than F-DWI alone (all p < 0.05) for diagnosing acute brainstem infarction, and three readers (readers except the neuroradiologist) were more confident using F-DWI with R-DWI for ruling out brainstem artefacts (p ≤ 0.001).ConclusionThe addition of R-DWI to F-DWI is a valuable method for differentiating acute brainstem infarctions from hyperintense artefacts.Key points• Hyperintense brainstem artefacts can be confused with acute infarctions on DWI. • Additional R-DWI to F-DWI reduces inter-reader variability in diagnosing brainstem infarctions. • Additional R-DWI improves performance and confidence for discriminating infarctions from artefacts.

Ethanol Ablation of Ranulas: Short-Term Follow-Up Results and Clinicoradiologic Factors for Successful Outcome

BACKGROUND AND PURPOSE: Surgical excision of an affected sublingual gland for treatment of a ranula can carry a potential of a nerve damage or postoperative complications. However, there have been little studies about effective minimally invasive therapeutic method, yet. Our aim was to evaluate the efficacy and safety of ethanol ablation of ranulas and the clinicoradiologic factors that can predict outcome. MATERIALS AND METHODS: This retrospective study evaluated 23 patients with ranulas treated by percutaneous ethanol ablation. Treatment outcome was assessed in 20 patients followed for at least 6 months. The duration of symptoms before ethanol ablation, pretreatment volume, and parapharyngeal extension on sonography and/or CT were correlated with the outcome. The Mann-Whitney U test and Fisher exact test were used for comparison of the factors according to the outcome. RESULTS: The study evaluated 14 males and 9 females with a median age of 26 years (range, 3–41 years). Among 20 patients who were followed for at least 6 months (median, 20 months; range, 6–73 months), 9 patients (45%) demonstrated complete disappearance of the ranulas and 11 (55%) showed an incomplete response. When the patients were divided according to the duration of symptoms before ethanol ablation, the complete response rate was significantly higher in patients with ≤12 months of symptoms (73%, 8/11) than that in others (11%, 1/9) (P = .010). Pretreatment volume and parapharyngeal extension were not significantly different between the 2 groups. CONCLUSIONS: Ethanol ablation is a safe and noninvasive treatment technique for ranulas with a significantly better outcome in patients with ≤12 months of symptoms. Therefore, it could be considered an alternative nonsurgical approach for ranulas with recent onset of symptoms.

Deep Learning–Based Computer-Aided Diagnosis System for Localization and Diagnosis of Metastatic Lymph Nodes on Ultrasound: A Pilot Study

BACKGROUND The presence of metastatic lymph nodes is a prognostic indicator for patients with thyroid carcinomas and is an important determinant of clinical decision making. However, evaluating neck lymph nodes requires experience and is labor- and time-intensive. Therefore, the development of a computer-aided diagnosis (CAD) system to identify and differentiate metastatic lymph nodes may be useful. METHODS From January 2008 to December 2016, we retrieved clinical records for 804 consecutive patients with 812 lymph nodes. The status of all lymph nodes was confirmed by fine-needle aspiration. The datasets were split into training (263 benign and 286 metastatic lymph nodes), validation (30 benign and 33 metastatic lymph nodes), and test (100 benign and 100 metastatic lymph nodes). Using the VGG-Class Activation Map model, we developed a CAD system to localize and differentiate the metastatic lymph nodes. We then evaluated the diagnostic performance of this CAD system in our test set. RESULTS In the test set, the accuracy, sensitivity, and specificity of our model for predicting lymph node malignancy were 83.0%, 79.5%, and 87.5%, respectively. The CAD system clearly detected the locations of the lymph nodes, which not only provided identifying data, but also demonstrated the basis of decisions. CONCLUSION We developed a deep learning-based CAD system for the localization and differentiation of metastatic lymph nodes from thyroid cancer on ultrasound. This CAD system is highly sensitive and may be used as a screening tool; however, as it is relatively less specific, the screening results should be validated by experienced physicians.

Ex vivo comparison between thyroid-dedicated bipolar and monopolar radiofrequency electrodes

Abstract Purpose: This study evaluated the characteristics of a thyroid-dedicated bipolar RF electrode (BRFE) and compared its ablation performance with that of monopolar RF electrodes (MRFEs) in normal bovine liver blocks. Methods: BRFE was tested on 60 bovine liver blocks with six different time–power combinations, applying 20, 30 and 40 W for 60 and 120 s. Subsequently, BRFE and MRFEs with 0.5-, 0.7- and 1-cm active tips were applied on 160 bovine liver blocks, creating 16 time–electrode combinations (10, 30, 60 and 120 s). The ablation characteristics, RF efficacy and true RF efficacy of each electrode group were then evaluated and compared. True RF efficacy was defined as the total ablation volume created within the total time during which valid RF current was generated. Results: The true RF efficacy of BRFE with 30 W at 60 s was significantly higher than that of BRFE with 20 W and 40 W during the preliminary experiment (p = 0.011). BRFE showed larger vertical and transverse diameters (DT1, DT2) than MRFE with a 0.5-cm active tip (all p values < 0.001, except 10 s). By contrast, MRFE with a 0.7-cm active tip created a larger DT1, DT2, volume, efficacy and true efficacy than BRFE (maximum p value = 0.011). The shape ratio of BRFE was significantly higher than that of MRFEs with 0.5-cm and 0.7-cm tips (all p < 0.001). Conclusions: Application of BRFE with 30 W could achieve a median ablation volumes and efficacy between that of MRFEs with 0.5-cm and 0.7-cm active tips and created a more ellipsoid-shaped ablation zone.