Utility and Clinical Outcomes of Perioperative Inferior Vena Cava Filter Prophylaxis in Spine Surgery Patients

STUDY DESIGN

Single-center retrospective chart review study.

OBJECTIVE

This study aimed to assess the clinical outcomes of prophylactic inferior vena cava (IVC) filter use for pulmonary embolism (PE) prevention in spine surgery patients.

SUMMARY OF BACKGROUND DATA

IVC filters can serve an important prophylactic role in preventing PE, though research involving spine surgery patients is sparse.

MATERIALS AND METHODS

This Institutional Review Board-approved single-center retrospective study assessed the characteristics and outcomes of patients who underwent spine surgery and received perioperative IVC filters for PE prophylaxis from January 2007 until December 2021. Clinical outcomes centered primarily on the occurrence of venous thromboembolism (VTE) as well as complications related to filter placement and retrieval. Thrombi that may have been entrapped by the filters were recorded incidentally on computed tomography or during the filter retrieval procedure.

RESULTS

This cohort included 380 spine surgery patients (female 51%/male 49%; median age, 61) who had received perioperative prophylactic IVC filters. The mean dwell time was 6.7 months (1-39 mo), with an overall 62% retrieval rate. Retrievals were further categorized by retrieval complexity, with 92% classified as routine and 8% as involving advanced removal techniques, while complications involved 1% (four retrievals) and were all minor. Regarding VTE event occurrence, deep vein thrombi (DVT) were experienced by 11% of patients in the postplacement period, with 1% (n=4) experiencing a PE. There were 11 incidences of thrombi that were found within or near the filters (2.9%). A multivariate analysis further assessed patient characteristics that correlated with the occurrence of PE, DVT, entrapped filter thrombi, advanced technique filter removal, and removal complications.

CONCLUSIONS

IVC filters in this high-risk spine surgery cohort achieved a relatively low rate of DVT and PE as well as a low complication rate, whereas several patient characteristics were identified that correlated with VTE events and filter retrieval outcomes.

Liver-Directed Locoregional Therapies for Neuroendocrine Liver Metastases: Recent Advances and Management

Neuroendocrine tumors (NETs) are a heterogeneous class of cancers, predominately occurring in the gastroenteropancreatic system, which pose a growing health concern with a significant rise in incidence over the past four decades. Emerging from neuroendocrine cells, these tumors often elicit paraneoplastic syndromes such as carcinoid syndrome, which can manifest as a constellation of symptoms significantly impacting patients' quality of life. The prognosis of NETs is influenced by their tendency for metastasis, especially in cases involving the liver, where the estimated 5-year survival is between 20 and 40%. Although surgical resection remains the preferred curative option, challenges emerge in cases of neuroendocrine tumors with liver metastasis (NELM) with multifocal lobar involvement, and many patients may not meet the criteria for surgery. Thus, minimally invasive and non-surgical treatments, such as locoregional therapies, have surfaced. Overall, these approaches aim to prioritize symptom relief and aid in overall tumor control. This review examines locoregional therapies, encompassing catheter-driven procedures, ablative techniques, and radioembolization therapies. These interventions play a pivotal role in enhancing progression-free survival and managing hormonal symptoms, contributing to the dynamic landscape of evolving NELM treatment. This review meticulously explores each modality, presenting the current state of the literature on their utilization and efficacy in addressing NELM.

Understanding ChatGPT for evidence-based utilization in interventional radiology

Advancement in artificial intelligence (AI) has the potential to improve the efficiency and accuracy of medical care. New techniques used in machine learning have enhanced the functionality of software to perform advanced tasks with human-like capabilities. ChatGPT is the most utilized large language model and provides a diverse range of communication tasks. Interventional Radiology (IR) may benefit from the implementation of ChatGPT for specific tasks. This review summarizes the design principles of ChatGPT relevant to healthcare and highlights activities with the greatest potential for ChatGPT utilization in the practice of IR. These tasks involve patient-directed and physician-directed communications to convey medical information efficiently and act as a medical decision support tool. ChatGPT exemplifies the evolving landscape of new AI tools for advancing patient care and how physicians and patients may benefit with strategic execution.

Locoregional Therapies for Hepatobiliary Tumors: Contemporary Strategies and Novel Applications

A large majority of primary hepatobiliary tumors are hepatocellular carcinomas (HCC), with the remainer being cholangiocarcinoma. While surgical resection remains the gold standard treatment for hepatobiliary tumors, relatively few patients are operative candidates, and systemic treatments have limited effectiveness. Locoregional therapies offer significant promise in the management of HCC. Ablation and radioembolization may offer similar outcomes to surgery for early-stage hepatocellular carcinoma while radioembolization and chemoembolization are valuable in the management of advanced disease. There is significantly less evidence for the role of locoregional therapy in the treatment of cholangiocarcinoma, although it appears to be well tolerated.

Moral Injury Among Interventional Radiologists

RATIONALE AND OBJECTIVES

To evaluate moral injury (MI) among interventional radiologists using validated assessment tools.

MATERIALS AND METHODS

An anonymous 29-question online survey was distributed to interventional radiologists using the Society of Interventional Radiology Connect Open Forum website, Twitter, Facebook, LinkedIn, and electronic mail. The survey consisted of demographic and practice environment questions, a global quality of life (QoL) scale (scored 1-100), the MI Symptom Scale‑Healthcare Professional (MISS-HP) (scored 1-100), and two open-ended questions. A MISS-HP score ≥ 36 was indicative of experiencing MI. P < .05 was considered statistically significant for all two-sided tests.

RESULTS

Beginning on March 30, 2023, 365 surveys were completed over 5 days. Of the respondents, 299 (81.9%) were male, 65 (17.8%) were female, and one preferred not to disclose gender. The respondents included practicing interventional radiologists (299; 81.9%) and interventional radiologists-in-training (66; 18.1%). Practice settings included academic (146; 40.0%), community (121; 33.2%), hybrid (84; 23.0%), or other (14; 3.8%) centers. Mean QoL was 71.1 ± 17.0 (range: 0-100) suggestive of "good" QoL. Mean QoL in the MI subgroup was significantly different from that for the rest of the group (67.6 ± 17.0 vs. 76.6 ± 16.0; P < 0.05). 223 (61.1%) respondents scored ≥ 36 on the MISS-HP, and thus were categorized as having profession-related MI. Mean MISS-HP was 39.9 ± 12.6 (range: 10-83). Mean MISS-HP in the MI subgroup was significantly different from that for the rest of the group (47.4 ± 9.6 vs. 28.0 ± 5.7; P < 0.05). There was a negative correlation between MI and QoL (r = -0.4; P < 0.001). Most common themes for greatest contribution to MI were ineffective leadership, barriers to patient care, corporatization of medicine, non-physician administration, performing futile procedures, turf battles, and reduced resources. Most common themes for ways to reduce MI were more autonomy, less bureaucracy, more administrative support, physician-directed leadership, adequate staffing, changes to the medical system, physician unionization, transparency with insurance companies, more time off, and leaving medicine/retirement.

CONCLUSION

MI is prevalent among interventional radiologists, and it negatively correlates with QoL. Future work should investigate causative factors and mitigating solutions.

Wellness Among Interventional Radiologists: Results From a Multidimensional Survey

RATIONALE AND OBJECTIVES

To evaluate wellness among interventional radiologists using a multidimensional survey.

MATERIALS AND METHODS

An anonymous 53-item survey, including 36 Perceived Wellness Survey (PWS) prompts, was created in Qualtrics (an online survey tool) to assess wellness among interventional radiology attendings and residents. The survey was open from June to September, 2022, 2 years into the COVID-19 Pandemic. The survey was distributed via Society of Interventional Radiology Forums, social media (Twitter, LinkedIn, and Facebook), and personal correspondence. PWS scores were categorized into Wellness Composite and subscores (physical, emotional, intellectual, psychological, social, and spiritual).

RESULTS

367 surveys were completed. 300 (81.7%) respondents were male and 67 (18.3%) were female. Respondents included attending physicians (297; 81.0%) and residents (70; 19.0%). Practice settings included academic (174; 47.4%), private (114; 31.0%), private-academic hybrid (62; 16.9%), and others (17; 4.7%). Mean Wellness Composite at academic centers (14.74 ± 3.16; range: 5.42-23.50) was significantly lower than at private (15.22 ± 3.37; range: 6.13-23.51) and hybrid (16.14 ± 2.47; range: 10.20-23.50) practices (p = 0.01). Respondents < 40 years old had significantly lower emotional wellness subscores compared to those ≥ 40 years old (4.34 ± 0.86 vs. 4.60 ± 0.87; p = 0.006). There were no significant differences between geographic regions in the United States, however, International respondents had significantly lower social and intellectual wellness (INT) subscores. Physical wellness subscore (4.00 ± 0.9) was significantly lower than the other subscores (4.59 ± 0.81) (p < .001). Overall mean Wellness Composite was 15.11 ± 3.13 (range: 5.42-23.51).

CONCLUSION

Overall self-reported wellness was lower among interventional radiologists practicing at academic centers. Interventional Radiologists < 40 years old and residents had lower emotional wellness, while international respondents had lower social and INT. Overall wellness scores were lower than prior PWS studies.

Medical Malpractice and Diagnostic Radiology: Challenges and Opportunities

Medicolegal challenges in radiology are broad and impact both radiologists and patients. Radiologists may be affected directly by malpractice litigation or indirectly due to defensive imaging ordering practices. Patients also could be harmed physically, emotionally, or financially by unnecessary tests or procedures. As technology advances, the incorporation of artificial intelligence into medicine will bring with it new medicolegal challenges and opportunities. This article reviews the current and emerging direct and indirect effects of medical malpractice on radiologists and summarizes evidence-based solutions.

Interventional radiology education: Patient experience with an educational website

RATIONALE AND OBJECTIVES

The aim of this study was to examine the impact of an educational website on patient understanding of Interventional Radiology (IR).

MATERIAL AND METHODS

An informational website with descriptions and images of 12 common IR procedures was developed with the aim of educating patients. One hundred patients referred to a large, academic institution were randomly selected to participate. Anonymous 11-question, 5-point Likert-scale assessments were administered before and after engaging with the educational website. The survey evaluated patients' understanding of IR procedures and satisfaction with the website as an educational tool.

RESULTS

One hundred patients completed the pre-/post-implementation evaluations. Among matched questions, there was an increase in patient understanding of IR with mean score improvement from 2.10 to 4.57 (p < 0.001), their knowledge of common procedures from 1.74 to 4.66 (p < 0.001), and their consideration for their next procedure to be with IR from 2.24 to 4.62 (p < 0.001). Additionally, patients had an overall positive impression of the website (mean 4.80). Over 75% of patients found the descriptions and images "very helpful".

CONCLUSION

This study demonstrated that website use for patient education has the potential to be effective in increasing overall patient understanding of IR and familiarity with common interventional procedures.

Intraoperative Embolization during Inferior Vena Cava Tumor Thrombectomy for Renal Cell Carcinoma

Intraoperative tumor thrombus embolization is a potentially lethal complication during inferior vena cava (IVC) thrombectomy for renal cell carcinoma (RCC). Intraoperative embolization is uncommonly encountered because IVC thrombectomy surgical technique is focused on avoiding this complication. Nonetheless, early recognition of embolization is essential so that emergent management can be instituted. When available, cardiopulmonary bypass (CPB) and embolectomy should be considered the gold standard for the management of intraoperative embolization. Several novel endovascular techniques are also available for selective use. We present the case of a 71-year-old female with a right renal mass and level II (retrohepatic) IVC tumor thrombus. During cytoreductive nephrectomy and IVC thrombectomy, tumor embolization was diagnosed during a period of hypotension based on transesophageal echocardiographic finding of new thrombus within the right atrium. This prompted sternotomy, CPB, and pulmonary artery embolectomy. The patient survived this embolization event and has a complete response to systemic therapy 9 months postoperatively. This case serves as the framework for a discussion on management considerations surrounding intraoperative embolization during IVC thrombectomy.

Detecting and Characterizing Inferior Vena Cava Filters on Abdominal Computed Tomography with Data-Driven Computational Frameworks

Two data-driven algorithms were developed for detecting and characterizing Inferior Vena Cava (IVC) filters on abdominal computed tomography to assist healthcare providers with the appropriate management of these devices to decrease complications: one based on 2-dimensional data and transfer learning (2D + TL) and an augmented version of the same algorithm which accounts for the 3-dimensional information leveraging recurrent convolutional neural networks (3D + RCNN). The study contains 2048 abdominal computed tomography studies obtained from 439 patients who underwent IVC filter placement during the 10-year period from January 1st, 2009, to January 1st, 2019. Among these, 399 patients had retrievable filters, and 40 had non-retrievable filter types. The reference annotations for the filter location were obtained through a custom-developed interface. The ground truth annotations for the filter types were determined based on the electronic medical record and physician review of imaging. The initial stage of the framework returns a list of locations containing metallic objects based on the density of the structure. The second stage processes the candidate locations and determines which one contains an IVC filter. The final stage of the pipeline classifies the filter types as retrievable vs. non-retrievable. The computational models are trained using Tensorflow Keras API on an Nvidia Quadro GV100 system. We utilized a fine-tuning supervised training strategy to conduct our experiments. We find that the system achieves high sensitivity on detecting the filter locations with a high confidence value. The 2D + TL model achieved a sensitivity of 0.911 and a precision of 0.804, and the 3D + RCNN model achieved a sensitivity of 0.923 and a precision of 0.853 for filter detection. The system confidence for the IVC location predictions is high: 0.993 for 2D + TL and 0.996 for 3D + RCNN. The filter type prediction component of the system achieved 0.945 sensitivity, 0.882 specificity, and 0.97 AUC score with 2D + TL and 0. 940 sensitivity, 0.927 specificity, and 0.975 AUC score with 3D + RCNN. With the intent to create tools to improve patient outcomes, this study describes the initial phase of a computational framework to support healthcare providers in detecting patients with retained IVC filters, so an individualized decision can be made to remove these devices when appropriate, to decrease complications. To our knowledge, this is the first study that curates abdominal computed tomography (CT) scans and presents an algorithm for automated detection and characterization of IVC filters.

A History and Modern Framework for Quality Improvement in Interventional Radiology

Quality improvement (QI) initiatives have benefited patients as well as the broader practice of medicine. Large-scale QI has been facilitated by multi-institutional data registries, many of which were formed out of national or international medical society initiatives. With broad participation, QI registries have provided benefits that include but are not limited to establishing treatment guidelines, facilitating research related to uncommon procedures and conditions, and demonstrating the fiscal and clinical value of procedures for both medical providers and health systems. Because of the benefits offered by these databases, Society of Interventional Radiology (SIR) and SIR Foundation have committed to the development of an interventional radiology (IR) clinical data registry known as VIRTEX. A large IR database with participation from a multitude of practice environments has the potential to have a significant positive impact on the specialty through data-driven advances in patient safety and outcomes, clinical research, and reimbursement. This article reviews the current landscape of societal QI programs, presents a vision for a large-scale IR clinical data registry supported by SIR, and discusses the anticipated results that such a framework can produce.

Informed consent for image-guided procedures: a nationwide survey of perceptions and current practices

AIM

To characterise the current landscape of informed consent practices for image-guided procedures, including location of consent, guideline availability, and utility of decision-aid resources.

MATERIALS AND METHODS

A survey of 159 interventional radiologists was conducted from April through June 2022. The survey evaluated participant demographics (gender, practice type, and level of training) and consent practices. Fifteen questions investigated discussion of benefits, risks, and alternatives, who obtained consent, location of consent conversations, how decision-making capacity is assessed, availability of formal guidance on consent discussions, and if and how decision-aids are used.

RESULTS

Most respondents (93.7%) were "extremely" or "very" comfortable discussing the benefits and risks of image-guided procedures during informed consent. Most respondents were "very" comfortable discussing alternative treatments within radiology (86.8%) while fewer felt confident regarding alternatives outside radiology (46.5%). Most respondents indicated obtaining consent in a pre-procedure area (89.9%), while 12.7% of respondents obtained consent in the procedure room. Of the respondents, 66.7% did not have formal education or documented guidance on what providers should disclose during consent. Ninety-two respondents (57.9%) reported using decision aids. The type of decision aid varied, with most reporting using illustrations or drawings (46.6%). Decision aid utility was more prevalent in non-teaching/academic (71.4%) versus academic (61%) institutions (p=0.02).

CONCLUSION

Regardless of demographics, interventionalists are confident in discussing benefits, risks, and alternative image-guided therapies, but are less confident discussing alternative treatment options outside of radiology. Formal education on informed consent is less common, and the use of decision aids varies between teaching and non-teaching institutions.

Clinical Outcomes of DEB-TACE in Hepatic Metastatic Neuroendocrine Tumors: A 5-Year Single-Institutional Experience

RATIONALE AND OBJECTIVES

To evaluate single-institution outcomes of drug-eluting bead transarterial chemoembolization (DEB-TACE) in the treatment of locally advanced neuroendocrine tumor (NET) hepatic metastases with a focus on safety and efficacy of treatment.

MATERIALS AND METHODS

A single-center retrospective cohort study of the outcomes of consecutive patients with NELM who underwent DEB-TACE between 2014 and 2019 was performed. Clinicopathologic characteristics, radiologic response (modified Response Evaluation Criteria in Solid Tumors) at 1-month follow-up, adverse events, progression-free survival (PFS), and overall survival were calculated.

RESULTS

Among 287 patients (mean age of 62 years; 39% male: 61% female), disease burden was bilobar (90.2%) with mean largest tumor diameter measuring 4.9 ± 2.8 cm. Of these patients, 14.6% had no evidence of tumor in other organs or lymph nodes. Complete response occurred in 60 (20.9%) patients while 133 (46.3%) had partial responses. Major complication occurred in 2.4%. Liver function tests including total bilirubin and AST were overall stable at the 1-month follow-up, with only a small increase in the ALT at +8.9% (p < 0.01). Overall survival was 80.1% at 1 year, 49.1% at 3 years, and 12.3% at 5 years with a mean PFS of 14.4 ± 12.5 months.

CONCLUSION

Based on this institutional experience, DEB-TACE is an acceptable locoregional therapy choice for hepatic metastases of NET due to its tolerable safety profile and relative efficacy.

Long-term Clinical Outcomes of Yttrium-90 Transarterial Radioembolization for Hepatocellular Carcinoma: A 5-Year Institutional Experience

RATIONALE AND OBJECTIVES

To examine the clinical outcomes of yttrium-90 (Y90) transarterial radioembolization (TARE) for primary hepatocellular carcinoma (HCC) through the evaluation of a 5-year institutional experience.

MATERIALS AND METHODS

This retrospective study evaluated 88 consecutive patients with primary HCC receiving Y90 TARE treatment at an academic medical center from 2017 to 2021. Disease distribution was bilobar in 60.2% of patients with an average lesion diameter of 5.0 ± 3.4 cm and Barcelona Clinic Liver Cancer stage B or C in 77% of the participants. Clinical outcomes were elucidated by examination of complications, liver function tests, biochemical response, and radiographic response. Objective response ratio (ORR) and progression-free survival (PFS) were also calculated.

RESULTS

The mean administered Y90 radiation dose was 127.8 ± 20.2 Gy. No significant complications or LFT elevations occurred post-therapy. Of the 73.9% of patients with α-fetoprotein-producing tumors, 67.8% experienced a complete or partial biochemical response 1 month post-treatment. The ORR was 83.3% on 6-month imaging and PFS was 9.6 ± 8.5 months. Functional outcomes (Eastern Cooperative Oncology Group) were maintained or improved in 79.6% and 76.1% of patients by 6 months and 1 year post-treatment, respectively. The mean survival was 14.7 ± 12.1 months. At 6 months post-treatment, 77.3% of patients were downstaged to or maintained Milan criteria, which was sustained for 74.4% and 70.0% of patients 1 year and 2 years after treatment, respectively.

CONCLUSION

Y90-TARE is a safe and effective therapy for primary HCC. Enduring outcomes further act as a realistic bridge to liver transplantation, with a majority of patients maintaining Milan criteria and preserving their functional status long term.

Pretreatment findings on magnetic resonance imaging in primary central nervous system lymphoma may predict overall survival duration

BACKGROUND

and purpose: Primary central nervous system lymphoma (PCNSL) lesions often show avid contrast enhancement on T1-weighted contrast-enhanced MRI sequences. However, several case reports and a clinical study have described PCNSL in patients with no contrast enhancement on MRI. We assessed whether overall survival (OS) time was related to any tumor characteristics (lesion location, volume, and number; contrast enhancement; necrosis; proximity to the subarachnoid space; and edema) on MRI in patients with PCNSL.

MATERIALS AND METHODS

We retrospectively reviewed records (MRI features, pathology, and survival data) of all patients at our institution with PCNSL who had been seen from, 2007 through 2017, and had undergone pretreatment MRI.

RESULTS

We identified 79 patients (42 men, 37 women) with a mean age at diagnosis of 61.7 ± 10.4 years. The mean OS duration was 44.6 ± 41.7 months. The most common pathological diagnosis (74 patients) was diffuse large B-cell lymphoma. No associations were found between OS time and lesion location, volume, and number; contrast enhancement; necrosis; proximity to the subarachnoid space; or edema. However, a sole patient with non-enhancing PCNSL on MRI was found to have low-grade disease, with prolonged survival (>83 months). Several other patients with leptomeningeal disease had a mean OS time of 80 months. Patients with hemorrhagic lesions had a mean OS of 25.5 months.

CONCLUSIONS

The survival time for patients with PCNSL may be longer than previously thought, especially for patients with leptomeningeal seeding and lesions with hemorrhagic components Also, non-enhancing tumors may be less aggressive than enhancing tumors.

Recent Advances in Image-Guided Locoregional Therapies for Primary Liver Tumors

Primary liver cancer is the leading cause of cancer-related deaths worldwide. with incidences predicted to rise over the next several decades. Locoregional therapies, such as radiofrequency or microwave ablation, are described as image-guided percutaneous procedures, which offer either a curative intent for early-stage hepatocellular carcinoma or bridging/downstaging for surgical resection or transplantation. Catheter-driven locoregional therapies, such as transarterial chemoembolization and radioembolization, induce tumor hypoxia, can be palliative, and improve survival for early-to-intermediate hepatocellular carcinoma and unresectable intrahepatic cholangiocarcinoma. Herein, we provide a comprehensive overview of the antineoplastic mechanisms underpinning locoregional therapies, different treatment approaches, and the current state of the literature for the efficacy of locoregional therapies for primary liver cancer. We also discuss emerging advancements, such as the adjuvant use of immunotherapies and molecular targeting agents with locoregional therapy, for the treatment of primary liver cancer.

Locoregional Therapy for Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) has a poor prognosis, and surgical resection (SR) offers the only potential for cure. Unfortunately, only a small proportion of patients are eligible for resection due to locally advanced or metastatic disease. Locoregional therapies (LRT) are often used in unresectable liver-only or liver-dominant ICC. This review explores the role of these therapies in the treatment of ICC, including radiofrequency ablation (RFA), microwave ablation (MWA), transarterial chemoembolization (TACE), transarterial radioembolization (TARE), external beam radiotherapy (EBRT), stereotactic body radiotherapy (SBRT), hepatic arterial infusion (HAI) of chemotherapy, irreversible electroporation (IE), and brachytherapy. A search of the current literature was performed to examine types of LRT currently used in the treatment of ICC. We examined patient selection, technique, and outcomes of each type. Overall, LRTs are well-tolerated in the treatment of ICC and are effective in improving overall survival (OS) in this patient population. Further studies are needed to reduce bias from heterogenous patient populations and small sample sizes, as well as to determine whether certain LRTs are superior to others and to examine optimal treatment selection.

Hepatocellular carcinoma: State of the art diagnostic imaging

Primary liver cancer is the fourth most common malignancy worldwide, with hepatocellular carcinoma (HCC) comprising up to 90% of cases. Imaging is a staple for surveillance and diagnostic criteria for HCC in current guidelines. Because early diagnosis can impact treatment approaches, utilizing new imaging methods and protocols to aid in differentiation and tumor grading provides a unique opportunity to drastically impact patient prognosis. Within this review manuscript, we provide an overview of imaging modalities used to screen and evaluate HCC. We also briefly discuss emerging uses of new imaging techniques that offer the potential for improving current paradigms for HCC characterization, management, and treatment monitoring.

Thermal ablation for primary and metastatic lung tumors: Single-center analysis of peri-procedural and intermediate-term clinical outcomes

PURPOSE

To evaluate the peri-procedural and intermediate-term clinical outcomes of thermal ablation of primary and metastatic lung cancer through analysis of a 5-year institutional experience.

METHODS

In this retrospective, IRB-approved study, 55 consecutive lung ablation interventions (33 cryoablation and 22 microwave ablations) performed at an academic medical center from 2017 to 2022 were evaluated. Cryoablation was performed utilizing multiple 14-guage probes using a triple freeze/thaw protocol. Microwave ablation required a single 14-guage probe, set to 60-80 watts for 5-10 min. Lung disease distribution was 58.2 % bilateral with largest lesion size of 5.5 cm. Periprocedural outcomes including technical success and complications as well as long-term outcomes including radiographic response, objective response ratio (ORR), disease control rate (DCR), progression free survival (PFS), overall survival (OS), and functional status were elucidated.

RESULTS

Technical success rate was 100 %. The most common complication was pneumothorax which occurred in 36 (65.5 %) patients, with 27 (49.1 %) requiring chest tube placement. At 6 months, 52 (98.2 %) of the patients demonstrated a complete response and 1 patient exhibited a partial response, yielding an ORR and a DCR of 100 %. The PFS was 26 ± 19 months, and the OS was 90.9 %, 83.6 %, and 74.5 % at 1, 3, and 5 years, respectively. Additionally, 92.7 % (51) of patients maintained or improved their functional status (ECOG) at 6 months.

CONCLUSION

Percutaneous thermal ablation techniques are evolving and promising treatments for both primary and metastatic lung tumors. Our 5-year institutional experience demonstrated their safety and efficacy with preservation of functional performance.

Single-center analysis of percutaneous ablation in the treatment of hepatocellular carcinoma: long-term outcomes of a 7-year experience

PURPOSE

The objective of this study is to examine the safety and efficacy of ablative therapy for hepatocellular carcinoma (HCC).

METHODS

A retrospective review of 419 consecutive patients diagnosed with HCC, treated with percutaneous ablation at a tertiary academic medical center from June 2015 to June 2022, was conducted. Data evaluated included demographics, disease and tumor burden scores, and functional status. Procedural outcomes included procedural course, complication rates, biochemical and radiologic response, survival, and functional status.

RESULTS

A total of 419 patients, including 313 males (74.7%) and 106 females (25.3%) with a mean age of 63.8 ± 6.64 years, made up the study cohort. 120 patients (28.6%) presented with solitary lesions and 299 patients (71.4%) had multifocal involvement, with a mean tumor size of 2.3 ± 0.92 cm. A majority of the interventions performed were microwave ablations (n = 413, 98.3%), with 6 radiofrequency ablations (1.4%). Treatment response was radiographically assessed up to 6 months post-ablation and graded as complete response (96.2%), partial response (2.6%), stable disease (0%), and progressive disease (1.2%). 97 (23.2%) of the treated patients went on to receive liver transplant. The average progression-free survival in the study population was 24 months with a survival of 85.9% (n = 360), 67.8% (n = 284), and 63.2% (n = 265) at 1 year, 3 years, and 5 years respectively. Functional outcomes, as defined by ECOG scores, were maintained or improved in 383 patients (91.4%) and 349 patients (83.3%) at 6 months and 12 months respectively.

CONCLUSIONS

This large institutional experience demonstrated safety and efficacy of ablation therapies for treatment of HCC with promising tumor response rates and enduring clinical outcomes including prolonged survival and preserved functional status.

Artificial Intelligence, Augmented Reality, and Virtual Reality Advances and Applications in Interventional Radiology

Artificial intelligence (AI) uses computer algorithms to process and interpret data as well as perform tasks, while continuously redefining itself. Machine learning, a subset of AI, is based on reverse training in which evaluation and extraction of data occur from exposure to labeled examples. AI is capable of using neural networks to extract more complex, high-level data, even from unlabeled data sets, and better emulate, or even exceed, the human brain. Advances in AI have and will continue to revolutionize medicine, especially the field of radiology. Compared to the field of interventional radiology, AI innovations in the field of diagnostic radiology are more widely understood and used, although still with significant potential and growth on the horizon. Additionally, AI is closely related and often incorporated into the technology and programming of augmented reality, virtual reality, and radiogenomic innovations which have the potential to enhance the efficiency and accuracy of radiological diagnoses and treatment planning. There are many barriers that limit the applications of artificial intelligence applications into the clinical practice and dynamic procedures of interventional radiology. Despite these barriers to implementation, artificial intelligence in IR continues to advance and the continued development of machine learning and deep learning places interventional radiology in a unique position for exponential growth. This review describes the current and possible future applications of artificial intelligence, radiogenomics, and augmented and virtual reality in interventional radiology while also describing the challenges and limitations that must be addressed before these applications can be fully implemented into common clinical practice.

Public Awareness of Interventional Radiology: Population-Based Analysis of the Current State of and Pathways for Improvement

PURPOSE

To evaluate the awareness of interventional radiology (IR) among the public and identify methods for improvement.

MATERIALS AND METHODS

Participants (N = 1,000) were anonymously surveyed using Amazon's Mechanical Turk crowdsourcing platform about medical and IR-specific knowledge, preferred methods of acquisition of medical information, and suggestions for improving awareness of IR. The survey consisted of 69 questions, including both Likert Scale and free text questions.

RESULTS

Of the participants, 92% preferred undergoing a minimally invasive procedure over surgery. However, 39.8% recognized IR as a medical specialty, and less than 50% of these participants correctly identified IR as procedurally oriented. Of those who discussed or underwent an IR procedure (n = 113), most were also offered to undergo the procedure performed by a surgeon (n = 66). Furthermore, 71% (n = 20) of those who underwent the procedure performed by a surgeon reported that lack of awareness of IR played a role in their decision. Almost half of the respondents (n = 458) were interested in learning more about IR, particularly the diseases treated and procedures performed (42% and 37%, respectively). Short (<10-minute) educational videos and increased patient education by primary care providers (PCPs) were among the most suggested ways to improve awareness. Regarding the ambiguity of the name "interventional radiology," most respondents (n = 555) reported this to be true, and "minimally invasive radiologist" was the most preferred alternative (21.18%).

CONCLUSIONS

Lack of awareness of IR may underlie underutilization. When presented with the knowledge that IR improves patient outcomes, minimally invasive procedures by an interventional radiologist are more often desired by the public than surgical options. Educational videos and patient education by PCPs may increase awareness of IR.

Salvage locoregional therapies for recurrent hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the second most common cause of cancer-related death worldwide. Despite the advent of screening efforts and algorithms to stratify patients into appropriate treatment strategies, recurrence rates remain high. In contrast to first-line treatment for HCC, which relies on several factors, including clinical staging, tumor burden, and liver function, there is no consensus or general treatment recommendations for recurrent HCC (R-HCC). Locoregional therapies include a spectrum of minimally invasive liver-directed treatments which can be used as either curative or neoadjuvant therapy for HCC. Herein, we provide a comprehensive review of recent evidence using salvage loco-regional therapies for R-HCC after failed curative-intent.

Percutaneous thrombectomy of upper extremity and thoracic central veins using Inari ClotTriever System: Experience in 14 patients

Objective

In the present report, we have described the technical and clinical outcomes of percutaneous thrombectomy in the deep veins of the upper extremity and thorax using the ClotTriever system (Inari Medical, Irvine, CA).

Methods

Fourteen patients with symptomatic deep venous occlusive disease in the upper extremity deep veins and thoracic central veins who had undergone thrombectomy using the ClotTriever system between October 2020 and January 2022 were reviewed. The technical results, adverse events, imaging follow-up data, and clinical outcomes were recorded.

Results

Fourteen patients (seven men and seven women; mean age, 53.6 ± 13.3 years) constituted the study cohort. Of the 14 patients, 9 (64.3%) had had DVT due to intravascular invasion or external compression from known malignancy, 2 (14.3%) had had infected thrombi and/or vegetation due to Staphylococcus aureus refractory to intravenous antibiotic therapy, and 3 (21.4%) had had a benign etiology for thrombus formation. The presenting symptoms included upper extremity and/or facial swelling (n = 14), upper extremity pain (n = 6), fever (n = 2), and dyspnea (n = 1). Thrombectomy with the ClotTriever system was successfully completed in all 14 patients. Seven patients (50.0%) had required additional venous stent reconstruction after thrombectomy to address the underlying stenosis. No major adverse events were noted. All the patients had experienced resolution of the presenting symptoms.

Conclusions

For the management of symptomatic deep venous occlusive disease of the upper extremity deep veins and thoracic central veins, thrombectomy using the ClotTriever system was feasible with excellent technical and clinical success.

An Artificial Intelligence Tool for Clinical Decision Support and Protocol Selection for Brain MRI

BACKGROUND AND PURPOSE

Protocolling, the process of determining the most appropriate acquisition parameters for an imaging study, is time-consuming and produces variable results depending on the performing physician. The purpose of this study was to assess the potential of an artificial intelligence-based semiautomated tool in reducing the workload and decreasing unwarranted variation in the protocolling process.

MATERIALS AND METHODS

We collected 19,721 MR imaging brain examinations at a large academic medical center. Criterion standard labels were created using physician consensus. A model based on the Long Short-Term Memory network was trained to predict the most appropriate protocol for any imaging request. The model was modified into a clinical decision support tool in which high-confidence predictions, determined by the values the model assigns to each possible choice, produced the best protocol automatically and low confidence predictions provided a shortened list of protocol choices for review.

RESULTS

The model achieved 90.5% accuracy in predicting the criterion standard labels and demonstrated higher agreement than the original protocol assignments, which achieved 85.9% accuracy (κ = 0.84 versus 0.72, P value < .001). As a clinical decision support tool, the model automatically assigned 70% of protocols with 97.3% accuracy and, for the remaining 30% of examinations, achieved 94.7% accuracy when providing the top 2 protocols.

CONCLUSIONS

Our model achieved high accuracy on a standard based on physician consensus. It showed promise as a clinical decision support tool to reduce the workload by automating the protocolling of a sizeable portion of examinations while maintaining high accuracy for the remaining examinations.

Procedural Fundamentals for Medical Students: Institutional Outcomes of a Novel Multimodal Course

RATIONALE AND OBJECTIVES

There is a gap in current medical student education pertaining to procedural skills' exposure and acquisition. The aim of this study is to evaluate the institutional experience of a novel medical student procedural course and its impact on procedural confidence.

MATERIALS AND METHODS

This is a single-center prospective study performed at a public medical school and its associated tertiary care medical center between June 2020 and January 2021. This study was deemed exempt by our Institutional Review Board and was performed with participant consent. The multimodal course developed by the radiology department consisted of four didactic lectures, four simulation sessions, and a minimum of 16 clinical rotation hours with the department's vascular access team. Primary outcomes were assessed by comparing participant pre and post course surveys including twenty-five 5-point Likert scaled questions.

RESULTS

Twenty-five self-selected students completed the course in its entirety. The curriculum and the corresponding survey analysis were stratified into sections by procedure modality. An increase in participant confidence to a moderate or greater level was observed when comparing pre and post course survey data for each procedure: vascular access (4% vs 52%, p < 0.01), thoracentesis (8% vs 48%, p < 0.01), paracentesis (8% vs 72%, p < 0.01), lumbar puncture (4% vs 44%, p < 0.01), and bone marrow biopsy (0% vs 48%, p < 0.01).

CONCLUSIONS

The creation of a medical-student-centric procedural course is feasible and fills a potential gap in undergraduate medical education. This study demonstrated that a comprehensive multimodal course, designed to include didactic, simulation and clinical experiences, increases participant exposure to, participation with, and confidence in bedside procedural performance abilities.

Emerging curative-intent minimally-invasive therapies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common cause of liver malignancy and the fourth leading cause of cancer deaths universally. Cure can be achieved for early stage HCC, which is defined as 3 or fewer lesions less than or equal to 3 cm in the setting of Child-Pugh A or B and an ECOG of 0. Patients outside of these criteria who can be down-staged with loco-regional therapies to resection or liver transplantation (LT) also achieve curative outcomes. Traditionally, surgical resection, LT, and ablation are considered curative therapies for early HCC. However, results from recently conducted LEGACY study and DOSISPHERE trial demonstrate that transarterial radio-embolization has curative outcomes for early HCC, leading to its recent incorporation into the Barcelona clinic liver criteria guidelines for early HCC. This review is based on current evidence for curative-intent loco-regional therapies including radioembolization for early-stage HCC.

Artificial intelligence: Advances and new frontiers in medical imaging

Artificial intelligence (AI) has been entwined with the field of radiology ever since digital imaging began replacing films over half a century ago. These algorithms, ranging from simplistic speech-to-text dictation programs to automated interpretation neural networks, have continuously sought to revolutionize medical imaging. With the number of imaging studies outpacing the amount of trained of readers, AI has been implemented to streamline workflow efficiency and provide quantitative, standardized interpretation. AI relies on massive amounts of data for its algorithms to function, and with the wide-spread adoption of Picture Archiving and Communication Systems (PACS), imaging data is accumulating rapidly. Current AI algorithms using machine-learning technology, or computer aided-detection, have been able to successfully pool this data for clinical use, although the scope of these algorithms remains narrow. Many systems have been developed to assist the workflow of the radiologist through PACS optimization and imaging study triage, however interpretation has generally remained a human responsibility for now. In this review article, we will summarize the current successes and limitations of AI in radiology, and explore the exciting prospects that deep-learning technology offers for the future.

Hepatocellular carcinoma locoregional therapies: Outcomes and future horizons

Hepatocellular carcinoma (HCC) is the most common primary cancer of the liver and has an overall five-year survival rate of less than twenty percent. For patients with unresectable disease, evolving liver-directed locoregional therapies provide efficacious treatment across the spectrum of disease stages and via a variety of catheter-directed and percutaneous techniques. Goals of locoregional therapies in HCC may include curative intent in early-stage disease, bridging or downstaging to surgical resection or transplantation for early or intermediate-stage disease, and local disease control and palliation in advanced-stage disease. This review explores the outcomes of chemoembolization, bland embolization, radioembolization, and percutaneous ablative therapies. Attention is also given to prognostic factors related to each of the respective techniques, as well as future directions of locoregional therapies for HCC.

Locoregional Therapies for Hepatocellular Carcinoma with Portal Vein Tumor Thrombosis

Hepatocellular carcinoma is the fourth leading cause of cancer worldwide, and the fastest increasing cause of cancer mortality in the United States. Its propensity for vascular invasion leads to the presence of portal vein tumor thrombus in up to half of patients. PVTT results in a classification of advanced disease, given the risk recurrence secondary to intravascular spread, and formal guidelines recommend systemic therapy in these patients. However, recent advances in locoregional therapies including TACE, TARE, and ablation have demonstrated the potential to drastically improve overall survival in patients with HCC complicated by PVTT.

Potential Bias in Image-Guided Procedure Research: A Retrospective Analysis of Disclosed Conflicts of Interest and Open Payment Records

PURPOSE

To assess the prevalence of positive conflict of interest (COI) disclosures in U.S.-based interventional radiology (IR) research as well as the level of agreement between disclosed financial relationships and open payment data for top-cited image-guided procedure research.

MATERIALS AND METHODS

All publications in volume 30 (2019) of the Journal of Vascular and Interventional Radiology (JVIR) were reviewed to estimate the prevalence of COI disclosures in IR research. Publications were categorized as primary research, systematic review, or other. Prevalence was then compared across JVIR publication subtype, categories, and whether they were device-focused with chi-squared tests. Additionally, the Web of Science database was searched for the top 10 cited studies of 10 common image-guided procedures with available U.S. physician payment data. Payments were categorized as historical (>1 year prior to publication) or active (<1 year prior to publication) and compared to disclosed financial COIs with one-way ANOVA.

RESULTS

Positive COI disclosures were present in 29% (114 of 397) of publications in JVIR volume 30. Positive COI disclosures were most prevalent in Standards of Practice (50%, p = 0.01) and more prevalent in device-focused publications (54% vs 23%, p < 0.01). Among the 396 authors of 100 U.S.-based top-cited image-guided procedure publications, 383 (97%) failed to disclose at least one active financial relationship, with an average of $57,937 in undisclosed payments per publication.

CONCLUSION

Conflicts of interest are prevalent in IR, like other areas of healthcare research, and conflicts of interest in top-cited image-guided procedure research are often underreported.

Early phase clinical studies of AR-42, a histone deacetylase inhibitor, for neurofibromatosis type 2-associated vestibular schwannomas and meningiomas

OBJECTIVES

Two pilot studies of AR-42, a pan-histone deacetylase inhibitor, in human neurofibromatosis type 2 (NF2), vestibular schwannomas (VS), and meningiomas are presented. Primary endpoints included safety, and intra-tumoral pharmacokinetics (PK) and pharmacodynamics (PD).

METHODS

Pilot 1 is a subset analysis of a phase 1 study of AR-42 in solid tumors, which included NF2 or sporadic meningiomas. Tumor volumes and treatment-related adverse events (TRAEs) are reported (NCT01129193).Pilot 2 is a phase 0 surgical study of AR-42 assessing intra-tumoral PK and PD. AR-42 was administered for 3 weeks pre-operatively. Plasma and tumor drug concentrations and p-AKT expression were measured (NCT02282917).

RESULTS

Pilot 1: Five patients with NF2 and two with sporadic meningiomas experienced a similar incidence of TRAEs to the overall phase I trial. The six evaluable patients had 15 tumors (8 VS, 7 meningiomas). On AR-42, tumor volume increased in six, remained stable in eight, and decreased in one tumor. The annual percent growth rate decreased in eight, remained stable in three, and increased in four tumors. Pilot 2: Four patients with sporadic VS and one patient with meningioma experienced no grade 3/4 toxicities. Expression of p-AKT decreased in three of four VS. All tumors had higher AR-42 concentrations than plasma.

CONCLUSIONS

AR-42 is safe. Tumor volumes showed a mixed response, but most slowed growth. On a 40-mg regimen, drug concentrated in tumors and growth pathways were suppressed in most tumors, suggesting this may be a well-tolerated and effective dose. A phase 2 study of AR-42 for NF2-associated tumors appears warranted.

LEVEL OF EVIDENCE

1b, 4.

Metastatic disease to the liver: Locoregional therapy strategies and outcomes

Secondary cancers of the liver are more than twenty times more common than primary tumors and are incurable in most cases. While surgical resection and systemic chemotherapy are often the first-line therapy for metastatic liver disease, a majority of patients present with bilobar disease not amenable to curative local resection. Furthermore, by the time metastasis to the liver has developed, many tumors demonstrate a degree of resistance to systemic chemotherapy. Fortunately, catheter-directed and percutaneous locoregional approaches have evolved as major treatment modalities for unresectable metastatic disease. These novel techniques can be used for diverse applications ranging from curative intent for small localized tumors, downstaging of large tumors for resection, or locoregional control and palliation of advanced disease. Their use has been associated with increased tumor response, increased disease-free and overall survival, and decreased morbidity and mortality in a broad range of metastatic disease. This review explores recent advances in liver-directed therapies for metastatic liver disease from primary colorectal, neuroendocrine, breast, and lung cancer, as well as uveal melanoma, cholangiocarcinoma, and sarcoma. Therapies discussed include bland transarterial embolization, chemoembolization, radioembolization, and ablative therapies, with a focus on current treatment approaches, outcomes of locoregional therapy, and future directions in each type of metastatic disease.

Interventional Radiology in the Coronavirus Disease 2019 Pandemic: Impact on Practices and Wellbeing

PURPOSE

To report the impact of the coronavirus disease 2019 (COVID-19) pandemic on interventional radiology (IR).

MATERIALS AND METHODS

A 78-question survey was distributed to practicing interventional radiologists and IR trainees. The survey consisted of demographic and practice environment queries. Anxiety symptoms were evaluated using the Generalized Anxiety Disorder-7 (GAD-7) screener, and coping strategies were assessed using the Brief-Coping Orientation to Problems Experienced (Brief-COPE) questionnaire.

RESULTS

There were 422 respondents including 333 (78.9%) attending interventional radiologists and 89 (21.1%) interventional radiologists-in-training from 15 counties. Most respondents were from academic medical centers (n = 218; 51.7%). A large majority (n = 391; 92.7%) performed a procedure on a patient with confirmed COVID-19 infection. An N95 mask was the most common (n = 366; 93.6%) safety measure employed. Cancellation or limitation of elective procedures were reported by 276 (65.4%) respondents. Many respondents (n = 177; 41.9%) had self-reported anxiety (GAD-7 score >5) with an overall mean GAD-7 score of 4.64 ± 4.63 (range: 0-21). Factors associated with reporting anxiety included female gender (p = 0.045), increased call coverage (p = 0.048), lack of adequate departmental adjustments (p <0.0001), and lack of adjustments in a timely manner (p <0.0001). The most utilized coping strategy was acceptance (mean of 5.49 ± 1.88), while the most employed dysfunctional coping strategy was self-distraction (mean of 4.16 ± 1.67). The odds of reporting anxiety increased by >125% with adoption of dysfunctional strategies.

CONCLUSION

The COVID-19 pandemic induced practice alterations and high rates of self-reported anxiety in IR. Female gender, increased call coverage, and lack of adequate or timely departmental adjustments were associated with increased anxiety levels.

Computational evaluation of inferior vena cava filters through computational fluid dynamics methods

Numerical simulation is growing in its importance toward the design, testing and evaluation of medical devices. Computational fluid dynamics and finite element analysis allow improved calculation of stress, heat transfer, and flow to better understand the medical device environment. Current research focuses not only on improving medical devices, but also on improving the computational tools themselves. As methods and computer technology allow for faster simulation times, iterations and trials can be performed faster to collect more data. Given the adverse events associated with long-term inferior vena cava (IVC) filter placement, IVC filter design and device evaluation are of paramount importance. This work reviews computational methods used to develop, test, and improve IVC filters to ultimately serve the needs of the patient.

Intraoperative 3 T MRI is more correlative to residual disease extent than early postoperative MRI

PURPOSE

Extent of resection of low grade glioma (LGG) is an important prognostic variable, and may influence decisions regarding adjuvant therapy in certain patient populations. Immediate postoperative magnetic resonance image (MRI) is the mainstay for assessing residual tumor. However, previous studies have suggested that early postoperative MRI fluid-attenuated inversion recovery (FLAIR) (within 48 h) may overestimate residual tumor volume in LGG. Intraoperative magnetic resonance imaging (iMRI) without subsequent resection may more accurately assess residual tumor. Consistency in MRI techniques and utilization of higher magnet strengths may further improve both comparisons between MRI studies performed at different time points as well as the specificity of MRI findings to identify residual tumor. To evaluate the utility of 3 T iMRI in the imaging of LGG, we volumetrically analyzed intraoperative, early, and late (~ 3 months after surgery) postoperative MRIs after resection of LGG.

METHODS

A total of 32 patients with LGG were assessed retrospectively. Residual tumor was defined as hyperintense T2 signal on FLAIR. Volumetric assessment was performed with intraoperative, early, and late postoperative FLAIR via TeraRecon iNtuition.

RESULTS

Perilesional FLAIR parenchymal abnormality volumes were significantly different comparing intraoperative and early postoperative MRI (2.17 ± 0.45 cm³ vs. 5.47 ± 1.07 cm³, respectively (p = 0.0002)). A significant difference of perilesional FLAIR parenchymal abnormality volumes was also found comparing early and late postoperative MRI (5.47 ± 1.07 cm³ vs. 3.22 ± 0.64 cm³, respectively (p = 0.0001)). There was no significant difference between intraoperative and late postoperative Perilesional FLAIR parenchymal abnormality volumes.

CONCLUSIONS

Intraoperative 3 T MRI without further resection appears to better reflect the volume of residual tumor in LGG compared with early postoperative 3 T MRI. Early postoperative MRI may overestimate residual tumor. As such, intraoperative MRI performed after completion of tumor resection may be more useful for making decisions regarding adjuvant therapy.

Nationwide Trends in Catheter-Directed Therapy Utilization for the Treatment of Lower Extremity Deep Vein Thrombosis in Medicare Beneficiaries

PURPOSE

To determine overall and provider specialty trends in the use of catheter-directed therapy for lower extremity deep vein thrombosis (DVT) treatment in the Medicare population.

MATERIALS AND METHODS

Using data obtained from 2007-2017 Centers for Medicare & Medicaid Services 5% research identifiable files, all claims associated with acute and chronic lower extremity DVT were identified. The annual volume of 2 services-venous percutaneous transluminal thrombectomy (current procedural terminology [CPT] code 37187) and venous infusion for thrombolysis (CPT code 37201 from 2007 to 2012 and CPT code 37212 from 2013 to 2017)-was examined for trends in DVT intervention. Utilization rates based on region and the place of service were calculated. The results were further categorized based on primary operator type (radiology, cardiology, surgery, and other).

RESULTS

The total number of DVT interventions increased over time, with 4.27 service counts per 100,000 beneficiaries in 2007 increasing to 13.4 by 2017, a growth rate of 12.09%. Radiologists performed the majority of interventions each year, except in 2013, in which they performed 46.6% of interventions, whereas surgeons and cardiologists combined performed the other 53.4%. In 2017, radiologists performed 7.56 services per 100,000 beneficiaries, which was 56.8% of the total count, more than those performed by surgeons, cardiologists, and unspecified providers combined.

CONCLUSIONS

Catheter-directed therapy is increasingly being used for the treatment of DVT, with its use undergoing a nearly 12-fold increase from 2007 to 2017 in the Medicare population. Radiologists remained the dominant provider of these services throughout the majority of study period, with a relative reduction in market share from 72% in 2007 to 57% in 2017.

Tine-Based Leadless Pacemaker: Strategies for Safe Implantation in Unconventional Clinical Scenarios

Leadless pacemakers (LPs) have emerged as a meaningful alternative to transvenous pacemakers for single-ventricular pacing. LPs eliminate many of lead- and pocket-associated complications observed with transvenous pacemakers. Owing to the lack of atrioventricular synchronous pacing until recently, the use of LP was generally reserved for those patients who either required minimal ventricular pacing or had permanent atrial fibrillation. The only commercially available LP is the Micra transcatheter pacing system (Micra-TPS, Medtronic Inc. Fridley, Minnesota), which requires insertion of a 27-F (outer diameter) introducer sheath in the femoral vein. The LP is delivered to the right ventricle using a 23-F delivery catheter. Owing to the need for a large-bore sheath, the pivotal studies for the Micra transcatheter pacing system excluded patients with indwelling inferior vena cava filters and included only a few patients with bioprosthetic or repaired tricuspid valve. Subsequent real-world experience has demonstrated the overall safety and feasibility of LP placement, and use in various unconventional clinical settings has been validated, albeit with specific precautions. Additionally, incorporation of adjunctive techniques and strategies can improve the safety of the procedure in routine clinical settings as well. The objective of this state-of-the-art review is to highlight the key procedural elements to facilitate safe and efficient implantation of LP in routine as well as in unique clinical settings.

Ethics in Interventional Radiology: A Case-Based Primer

As the field of interventional radiology assumes a larger role in patient care, the specialty has a growing responsibility to recognize and understand ethical dilemmas within the field. We present a case-based primer on common ethical issues in IR, including requests for potentially inappropriate procedures, surrogate decision making, informed consent, and managing conflicts of interest and procedural complications. This primer is intended to be used as a guide for discussion-based training in ethics in IR while inspiring further research in applied ethics in IR.