Thermal Ablation of Thyroid Nodules, From the AJR "How We Do It" Special Series.

Ablation has been shown to be an effective option for treatment of well-selected patients with thyroid nodules, particularly benign nodules, and thermal ablation is being increasingly used for this purpose. The general approach to thermal ablation of the thyroid will be familiar to interventional radiologists who perform ablation in other tissues; however, thermal ablation of the thyroid has additional unique considerations. In this review, we provide evidence-based and real-world guidance on the performance of thermal ablation for the treatment of patients with thyroid nodules, drawing on our collective experience and clinical practice. We describe patient selection, ablation modalities, equipment, general procedural approach, additional technical considerations, and postprocedural follow-up. We discuss various clinical scenarios; give tips on performing specific portions of the procedure and highlight a range of relevant anatomic, biochemical, and clinical factors, as a guide for interventional radiologists in establishing a successful thyroid ablation practice.

General Principles for the Safe Performance, Training, and Adoption of Ablation Techniques for Benign Thyroid Nodules: An American Thyroid Association Statement.

Background: The primary goal of this interdisciplinary consensus statement is to provide a framework for the safe adoption and implementation of ablation technologies for benign thyroid nodules. Summary: This consensus statement is organized around three key themes: (1) safety of ablation techniques and their implementation, (2) optimal skillset criteria for proceduralists performing ablative procedures, and (3) defining expectations of success for this treatment option given its unique risks and benefits. Ablation safety considerations in pre-procedural, peri-procedural, and post-procedural settings are discussed, including clinical factors related to patient selection and counseling, anesthetic and technical considerations to optimize patient safety, peri-procedural risk mitigation strategies, post-procedural complication management, and safe follow-up practices. Prior training, knowledge, and steps that should be considered by any physician who desires to incorporate thyroid nodule ablation into their practice are defined and discussed. Examples of successful clinical practice implementation models of this emerging technology are provided. Conclusions: Thyroid ablative procedures provide valid alternative treatment strategies to conventional surgical management for a subset of patients with symptomatic benign thyroid nodules. Careful patient and nodule selection are critical to the success of these procedures as is extensive pre-procedural patient counseling. Although these emerging technologies hold great promise, they are not without risk and require the development of a unique skillset and environment for optimal, safe performance and consistent outcomes.

Double-Barrel Nitinol Stent Placement for Iliocaval Reconstruction: The Effect of Deployment Sequence and Direction on Final Configuration.

Double-barrel stent placement across the iliocaval confluence is commonly used for the treatment of chronic bilateral iliocaval occlusion. The difference in the deployment outcomes of synchronous parallel stent deployment versus asynchronous or antiparallel deployment and the underlying stent interactions are poorly understood. In this study, 3 strategies of double-barrel nitinol self-expanding stent deployment across the iliocaval confluence (synchronous parallel, asynchronous parallel, and synchronous antiparallel) were contrasted in vivo in 3 swine followed by assessment of the explanted stent construct. Synchronous parallel stent deployment achieved a desired double-barrel configuration. The asynchronous parallel and antiparallel deployment strategies both resulted in a crushed stent despite subsequent simultaneous balloon angioplasty. These animal model results suggested that in patients who undergo double-barrel iliocaval reconstruction, synchronous parallel stent deployment may provide the desired stent conformation and increase the chance for clinical success.

Uterine Fibroid Embolization or Myomectomy: How Much Marketing Is Enough? Comparative Analysis of Public Search Trends in Google and Medical Publications in PubMed.

To compare public popularity and volume of scientific publications regarding uterine fibroid embolization (UFE) and myomectomy. Google Trends and PubMed data were queried to assess temporal variations in online public search volumes and number of research publications for UFE and myomectomy. Time series analysis was used to identify meaningful temporal trends and forecast a future trend. Compared with UFE, myomectomy had significantly higher volumes of public online search and research publications, with an increasing trend over time (P < .0001). The forecasting models predicted a continuing increase in both public search volumes and number of research publications for myomectomy and static future trends in these metrics for UFE. This study signals significantly lower public popularity and research efforts for UFE compared with myomectomy for uterine fibroids. More effective marketing strategies and further research support will be needed to fill this gap.

Radiofrequency Ablation for Benign Thyroid Nodules: Radiology In Training.

Two patients, one with benign nonfunctioning nodules and one with functioning thyroid nodules, both of whom underwent radiofrequency ablation, are presented. Preprocedural evaluation, procedural considerations, and follow-up care of thyroid radiofrequency ablation, as well as published evidence on the topic, are discussed.

Rendezvous Technique for Advanced Pancreatic Duct Interventions.

Interventional radiology can be used to perform complex pancreatic duct (PD) interventions in cases in which PD abnormalities limit the feasibility of an endoscopic approach. A multidisciplinary approach with gastroenterology using the rendezvous technique can improve procedural success. The establishment of through-and-through access to the PD via a combined percutaneous and endoscopic approach can be used when endoscopy alone fails. In this study, 3 cases are presented in which the rendezvous technique was successfully employed to access the PD for subsequent interventions.

Image-Guided Percutaneous Ablation for Primary and Metastatic Tumors.

Image-guided percutaneous ablation methods have been further developed during the recent two decades and have transformed the minimally invasive and precision features of treatment options targeting primary and metastatic tumors. They work by percutaneously introducing applicators to precisely destroy a tumor and offer much lower risks than conventional methods. There are usually shorter recovery periods, less bleeding, and more preservation of organ parenchyma, expanding the treatment options of patients with cancer who may not be eligible for resection. Image-guided ablation techniques are currently utilized for the treatment of primary and metastatic tumors in various organs including the liver, pancreas, kidneys, thyroid and parathyroid, prostate, lung, bone, and soft tissue. This article provides a brief review of the various imaging modalities and available ablation techniques and discusses their applications and associated complications in various organs.

Multicenter assessment of augmented reality registration methods for image-guided interventions.

PURPOSE: To evaluate manual and automatic registration times and registration accuracies on HoloLens 2 for aligning a 3D CT phantom model onto a CT grid, a crucial step for intuitive 3D navigation during CT-guided interventions; to compare registration times between HoloLens 1 and 2. METHODS: Eighteen participants in various stages of clinical training across two academic centers performed registration of a 3D CT phantom model onto a CT grid using HoloLens 2. Registration times and accuracies were compared among different registration methods, clinical experience levels, and consecutive attempts. Registration times were also compared retrospectively to prior HoloLens 1 results. RESULTS: Mean aggregate manual registration times were 27.7 s, 24.3 s, and 72.8 s for one-handed gesture, two-handed gesture, and Xbox controller, respectively; mean automatic registration time was 5.3 s (ANOVA p < 0.0001). No significant difference in registration times was found among attendings, residents and fellows, and medical students (p > 0.05). Significant improvements in registration times were detected across consecutive attempts using hand gestures (p < 0.01). Compared to prior HoloLens 1 data, hand gesture registration was 81.7% faster with HoloLens 2 (p < 0.05). Registration accuracies were not significantly different across manual registration methods, measuring at 5.9 mm, 9.5 mm, and 8.6 mm with one-handed gesture, two-handed gesture, and Xbox controller, respectively (p > 0.05). CONCLUSIONS: Manual registration times decreased significantly on HoloLens 2, approaching those of automatic registration and outperforming Xbox controller registration. Fast, adaptive, and accurate registration of holographic models of cross-sectional imaging is paramount for the implementation of augmented reality-assisted 3D navigation during CT-guided interventions.

Review of the Korean Society of Interventional Radiology and European Thyroid Association Guidelines Regarding the Role of Radiofrequency Ablation for Benign and Malignant Thyroid Tumors.

While radiofrequency ablation (RFA) for the treatment of symptomatic thyroid nodules has been gaining more widespread adoption in the United States, there is limited societal guidance for its role, and safe adoption. As many of the first adopters of thyroid nodule RFA developed their practices, they looked to the Korean Society of Interventional Radiology (KSIR), and European Thyroid Association (ETA) guidelines as a framework. Currently, efforts are underway from the American Thyroid Association to create updated guidelines for US providers. International consensus guidelines are also underway. Until these guidelines are available, a thorough understanding of the current available guidelines is key for interventionalists building a thyroid nodule RFA program.

Radiofrequency Ablation of Solid Benign Thyroid Nodules.

Symptomatic solid benign thyroid nodules may present either as nonfunctioning nodules causing compressive symptoms or as hyperfunctioning nodules causing symptoms of hyperthyroidism. While surgical resection or radioiodine ablation of these nodules can be performed, percutaneous radiofrequency ablation (RFA) of benign solid thyroid nodules has been shown to be a safe and effective alternative in select patients. Preprocedural evaluation should include a history focusing on signs and symptoms of thyroid dysfunction, a physical exam, thyroid ultrasound, thyroid function tests, and discussion of key intraprocedural details with the patient such as the anesthesia plan and risks. Thyroid RFA can be safely performed as an outpatient procedure with less than 2% major and minor complication rates. This report will focus on the basic technique of performing RFA for symptomatic thyroid nodules.

Percutaneous Therapies for Hepatocellular Carcinoma: Evolution of Liver Directed Therapies.

Percutaneous ablation is a mainstay of treatment for early stage, unresectable hepatocellular carcinoma (HCC). Recent advances in technology have created multiple ablative modalities for treatment of this common malignancy. The purpose of this review is to familiarize readers with the technical and clinical aspects of both existing and emerging percutaneous treatment options for HCC.

Analysis of Costs and Payments for Inferior Vena Cava Filter Retrieval in the Medicare Population.

Over the past decade, inferior vena cava (IVC) filter retrieval has been increasing, in part due to Food and Drug Administration recommendations and legal pressure. The costs and margin of IVC filter removal are poorly understood. Medicare claims data from 2016 for the 103 highest volume centers for IVC filter retrieval were examined. Pooled mean charges, costs, payments, and margin were calculated by institution. Mean ± SD charges, costs, and payments were $14,138.00 ± $8,400.48, $3,693.28 ± $2,294.27, and $1,949.82 ± $702.91, respectively. Average (range) margin was -$1,706.18 (-$7,509.93 to $362.77). The margin was negative in 99 of the 103 (96%) institutions evaluated. The most significant contributors to the total procedure cost were operating room, supplies, and recovery (44.5%, 23.5%, and 10.4%, respectively). While IVC filter retrieval is often medically indicated, it is typically associated with a financial loss under current reimbursement structure.

Social distancing and testing as optimal strategies against the spread of COVID-19 in the Rio Grande Valley of Texas.

At the beginning of August 2020, the Rio Grande Valley (RGV) of Texas experienced a rapid increase of coronavirus disease 2019 (abbreviated as COVID-19) cases and deaths. This study aims to determine the optimal levels of effective social distancing and testing to slow the virus spread at the outset of the pandemic. We use an age-stratified eight compartment epidemiological model to depict COVID-19 transmission in the community and within households. With a simulated 120-day outbreak period data we obtain a post 180-days period optimal control strategy solution. Our results show that easing social distancing between adults by the end of the 180-day period requires very strict testing a month later and then daily testing rates of 5% followed by isolation of positive cases. Relaxing social distancing rates in adults from 50% to 25% requires both children and seniors to maintain social distancing rates of 50% for nearly the entire period while maintaining maximum testing rates of children and seniors for 150 of the 180 days considered in this model. Children have higher contact rates which leads to transmission based on our model, emphasizing the need for caution when considering school reopenings.

Relationship of Antenna Work and Ablation Cavity Volume Following Percutaneous Microwave Ablation of Hepatic Tumors.

PURPOSE: To formulate a statistical model relating ablation time, power, and work with posttreatment cavity volume following percutaneous microwave ablation of hepatic tumors in vivo. MATERIALS AND METHODS: A retrospective review (October 2015 to October 2018) yielded 122 hepatic tumors treated with microwave ablation. Ablation cavity dimensions were measured at 1-month follow-up examination and calculated using an ellipsoid volume formula. The antenna manufacturer (Neuwave Medical, Madison, Wisconsin) provided the activation time and energy used to calculate the antenna work. Generalized estimating equations with ordinary least-squares regression models were obtained to relate tumor volume with cumulative antenna work. Coefficient of determination (R2) and mean square error were used as statistical measures of model prediction performance. RESULTS: There is a logarithmic relationship between postablation cavity volume (cm3) and cumulative work (kJ), represented by the formula: log10 cm3 = -0.4583 + 0.9887 × cumulative work (log10 kJ) (R2 = 0.41, mean square error, 0.102). Ablation volumes were predicted as a function of antenna work, calculated using an antilog transformation. When a single antenna was used, ablation cavity volume was predicted using a generalized estimating equation ordinary least-squares regression model of power and time: log10cm3= -0.0546 + 0.0485 × total time (min) + 0.0107 × power (W) (R2 = 0.30; mean square error, 0.106). Using this model, a nomogram was developed to predict the postablation cavity volume based on total activation time and target power. CONCLUSION: There is a logarithmic relationship between the ablation work and posttreatment ablation cavity volume, which can be expressed in a nomogram when using a single probe.