Analyzing Radiation Use during Transjugular Intrahepatic Portosystemic Shunt Creation.

Portal vein access during transjugular intrahepatic portosystemic shunt creation was examined in 11 patients. Radiation metrics (kerma area product, reference point air kerma, and fluoroscopy times) during portal vein access were significantly greater for conventional versus intravascular US-guided transjugular intrahepatic portosystemic shunt (54.8 mGy ∙ cm2 ± 27.6 vs 8.4 mGy ∙ cm2 ± 5.0, P = .009; 210.4 mGy ± 109.1 vs 29.5 mGy ± 18.4, P = .009; 19.1 min ± 8.6 vs 8.9 min ± 4.6, P = .04). Wedged hepatic venography is a major contributor to radiation exposure. Intravascular US guidance is associated with significantly reduced radiation use.

Intranodal Lymphangiography with Thoracic Duct Embolization for Treatment of Chyle Leak after Thoracic Outlet Decompression Surgery.

From 2015 to 2019, 9 patients underwent ultrasound-guided intranodal lymphangiography for the treatment of a chyle leak following thoracic outlet decompression surgery. Chyle leaks were identified by Lipiodol (Guerbet, Roissy, France) extravasation near the left supraclavicular surgical bed in all patients. The technical success rate of thoracic duct embolization was 67% (6 of 9), including fluoroscopic transabdominal antegrade access (n = 4) and ultrasound-guided retrograde access in the left neck (n = 2). Clinical success was achieved in 89% of patients (8 of 9). The mean interval from lymphangiography to drain removal was 6.6 days (range, 4-18 d). No patients had a chyle leak recurrence during clinical follow-up (mean, 304 d).

Outcomes of Yttrium-90 Radioembolization for Unresectable Combined Biphenotypic Hepatocellular-Cholangiocarcinoma.

PURPOSE: To evaluate outcomes of yttrium-90 radioembolization in patients with combined biphenotypic hepatocellular-cholangiocarcinoma (cHCC-CC). MATERIALS AND METHODS: A retrospective review of patients with biopsy-confirmed cHCC-CC treated with yttrium-90 radioembolization between 2012 and 2018 was performed. Twenty-two patients with cHCC-CC (mean age 65.6 y, 17 men, 5 women) underwent 29 radioembolization treatments (5 resin, 24 glass microspheres). Survival data were available in 21 patients, and hepatic imaging response data were available in 20 patients. Hepatic imaging response to radioembolization was assessed on follow-up CT or MR imaging using modified Response Evaluation Criteria In Solid Tumours criteria. Univariate stepwise Cox regression analysis was used to evaluate the association between demographic and clinical factors and survival. Logistic regression evaluated associations between clinical factors and response to treatment, overall response, and disease control. RESULTS: Hepatic imaging response was as follows: 15% complete response, 40% partial response, 10% stable disease, and 35% progressive disease (55% response rate, 65% disease control rate). Two patients were downstaged or bridged to transplant, and 1 patient was downstaged to resection. Median overall survival was 9.3 mo (range, 2.5-31.0 mo) from time of radioembolization. Nonreponse to treatment, bilobar disease, presence of multiple tumors, and elevated carbohydrate antigen 19-9 before treatment were associated with reduced survival after radioembolization. CONCLUSIONS: Radioembolization is a viable option for locoregional control of cHCC-CC with good response and disease control rates.

Contrast-enhanced US for the Interventional Radiologist: Current and Emerging Applications.

US is a powerful and nearly ubiquitous tool in the practice of interventional radiology. Use of contrast-enhanced US (CEUS) has gained traction in diagnostic imaging given the recent approval by the U.S. Food and Drug Administration (FDA) of microbubble contrast agents for use in the liver, such as sulfur hexafluoride lipid-type A microspheres. Adoption of CEUS by interventional radiologists can enhance not only procedure guidance but also preprocedure patient evaluation and assessment of treatment response across a wide spectrum of oncologic, vascular, and nonvascular procedures. In addition, the unique physical properties of microbubble contrast agents make them amenable as therapeutic vehicles in themselves, which can lay a foundation for future therapeutic innovations in the field in drug delivery, thrombolysis, and vascular flow augmentation. The purpose of this article is to provide an introduction to and overview of CEUS aimed at the interventional radiologist, highlighting its role before, during, and after frequently practiced oncologic and vascular interventions such as biopsy, ablation, transarterial chemoembolization, detection and control of hemorrhage, evaluation of transjugular intrahepatic portosystemic shunts (TIPS), detection of aortic endograft endoleak, thrombus detection and evaluation, evaluation of vascular malformations, lymphangiography, and percutaneous drain placement. Basic physical principles of CEUS, injection and scanning protocols, and logistics for practice implementation are also discussed. Early adoption of CEUS by the interventional radiology community will ensure rapid innovation of the field and development of future novel procedures. Online supplemental material is available for this article. ©RSNA, 2020.

Factors influencing selection of an interventional radiology training program.

PURPOSE: To understand factors influencing the choice and ranking of Interventional Radiology (IR) training programs among a cohort of medical students and diagnostic radiology residents pursuing careers in IR. MATERIALS AND METHODS: An IRB approved, 34 question online survey (surveymonkey.com) evaluated the impact of twenty-two different factors and demographics on IR training program selection for medical students and residents. The factors analyzed included programmatic features, location characteristics, academic reputation, program size, benefits/financial incentives, emphasis on clinical care, and future job opportunities. Comparison of Likert scale responses between medical students and residents were performed by using unpaired two-sample t-tests. RESULTS: 181 (145 male, 35 female) individuals responded to the survey, 74 medical students (40.9%) and 107 residents (59.1%). Medical students and residents both selected variety of IR cases as the most important and highest rated factor when choosing an IR program. Medical students ranked availability of a mentor (p = .03), inpatient consultation service (p = .003), outpatient clinic experience (p = .003), and ICU rotation experience (p < .001) significantly higher. Residents rated job placement/accomplishments of prior fellows (p = .03) and opinion of spouse/significant others (p = .002) significantly higher than medical students. CONCLUSIONS: The top rated factors are similar among medical students and residents however medical students value the clinical aspects of the program (ICU experience, inpatient consultation service, outpatient clinic) more than residents. Residents placed more value on job placement opportunities in selecting an IR program.

Cryoablation of low-flow vascular malformations.

PURPOSE: We aimed to evaluate the safety and effectiveness of cryoablation in the treatment of low-flow malformations, specifically venous malformation (VM) and fibroadipose vascular anomaly (FAVA). METHODS: We conducted a retrospective review of 11 consecutive patients with low-flow malformations (14 lesions; 9 VM, 5 FAVA), median lesion volume 10.8 cm3, (range, 1.8-55.6 cm3) with a median age of 19 years (range, 10-50 years) who underwent cryoablation to achieve symptomatic control. Average follow-up was at a median of 207 days postprocedure (range, 120-886 days). Indications for treatment included focal pain and swelling. Technical success was achieved if the cryoablation ice ball covered the region of the malformation that corresponded to the patient's symptoms. Clinical success was considered complete if all symptoms resolved and partial if some symptoms persisted but did not necessitate further treatment. RESULTS: The technical success rate was 100%. At 1-month follow-up, 13 of 14 lesions (93%) had a complete response and one (7%) had a partial response. At 6-month follow-up 12 of 13 (92%) had a complete response and 1 (8%) had a partial response. A total of 6 patients underwent primary cryoablation. Out of 9 VM cases, 7 had prior sclerotherapy and 2 had primary cryoablation. Out of the 5 FAVA cases, 1 had prior sclerotherapy and the remaining 4 cases underwent primary cryoablation. There were 3 minor complications following cryoablation including 2 cases of skin blisters and 1 case of transient numbness. These complications resolved with conservative management. CONCLUSION: Cryoablation is safe and effective in the treatment of low-flow vascular malformations, either after sclerotherapy or as primary treatment.

Acute Lower Extremity Deep Venous Thrombosis: The Data, Where We Are, and How It Is Done.

The incidence of venous thromboembolism, including both deep vein thrombosis and pulmonary embolism, is estimated at 300,000-600,000 per year. Although thrombosis may occur anywhere, it is thrombosis of the deep veins of the lower extremities that is of interest as this is where thrombosis occurs most often within the venous system. This article discusses the evaluation and interventions, including endovascular catheter-direct treatments, for patients with acute deep venous thrombosis.

Intravascular access devices from an interventional radiology perspective: indications, implantation techniques, and optimizing patency.

Central venous access has become invaluable in the treatment of patients with a wide array of acute and chronic disease entities. Central venous catheters provide durable, short-term and long-term access solutions while saving the patient from repeated peripheral needle sticks. Central venous catheters include: non-tunneled central venous catheters, tunneled central venous catheters, and port catheters. Typically, the placement of a central venous catheter is performed by Vascular and Interventional Radiologists. The purpose of this article is to familiarize the reader with the role of Interventional Radiology in the placement and management of intravascular or implantable access devices, with a focus on discussing indications for central venous catheter placement, implantation techniques, potential complications, and management of catheter dysfunction.

Renal Embolization: Current Recommendations and Rationale for Clinical Practice.

PURPOSE OF REVIEW: Renal embolization (RE) is a minimally invasive endovascular procedure performed primarily by interventional radiology that can be used to treat a variety of urologic conditions including malignant renal tumors, angiomyolipomas, renal trauma, and complications following biopsy. The following review examines renal embolization indications, technique, and potential complications. RECENT FINDINGS: Renal embolization is a versatile therapeutic and adjunctive tool for many acute and chronic urologic conditions. RE has become a first-line therapy for renal trauma in lower grade injuries and increasing in prevalence for higher grade injuries. Additionally, the safety and efficacy of chemoembolization for primary treatment of renal cell carcinoma is under evaluation. A multidisciplinary approach between urology and interventional radiology should be pursued for all patients undergoing renal embolization regardless of indication. Preprocedural planning and careful monitoring of complications should be performed to optimize clinical outcomes.

Modified Balloon-Occluded Retrograde Transvenous Obliteration (BRTO) Techniques for the Treatment of Gastric Varices: Vascular Plug-Assisted Retrograde Transvenous Obliteration (PARTO)/Coil-Assisted Retrograde Transvenous Obliteration (CARTO)/Balloon-Occluded Antegrade Transvenous Obliteration (BATO).

Gastric varices in the setting of portal hypertension occur less frequently than esophageal varices but occur at lower portal pressures and are associated with more massive bleeding events and higher mortality rate. Balloon-occluded retrograde transvenous obliteration (BRTO) of gastric varices has been well documented as an effective therapy for portal hypertensive gastric varices. However, BRTO requires lengthy, higher-level post-procedural monitoring and can have complications related to balloon rupture and adverse effects of sclerosing agents. Several modified BRTO techniques have been developed including vascular plug-assisted retrograde transvenous obliteration, coil-assisted retrograde transvenous obliteration, and balloon-occluded antegrade transvenous obliteration. This article provides an overview of various modified BRTO techniques.

Denali, Tulip, and Option Inferior Vena Cava Filter Retrieval: A Single Center Experience.

PURPOSE: To compare the technical success of filter retrieval in Denali, Tulip, and Option inferior vena cava filters. MATERIALS AND METHODS: A retrospective analysis of Denali, Gunther Tulip, and Option IVC filters was conducted. Retrieval failure rates, fluoroscopy time, sedation time, use of advanced retrieval techniques, and filter-related complications that led to retrieval failure were recorded. RESULTS: There were 107 Denali, 43 Option, and 39 Tulip filters deployed and removed with average dwell times of 93.5, 86.0, and 131 days, respectively. Retrieval failure rates were 0.9% for Denali, 11.6% for Option, and 5.1% for Tulip filters (Denali vs. Option p = 0.018; Denali vs. Tulip p = 0.159; Tulip vs. Option p = 0.045). Median fluoroscopy time for filter retrieval was 3.2 min for the Denali filter, 6.75 min for the Option filter, and 4.95 min for the Tulip filter (Denali vs. Option p < 0.01; Denali vs. Tulip p < 0.01; Tulip vs. Option p = 0.67). Advanced retrieval techniques were used in 0.9% of Denali filters, 21.1% in Option filters, and 10.8% in Tulip filters (Denali vs. Option p < 0.01; Denali vs. Tulip p < 0.01; Tulip vs. Option p < 0.01). DISCUSSION: Filter retrieval failure rates were significantly higher for the Option filter when compared to both the Denali and Tulip filters. Retrieval of the Denali filter required significantly less amount of fluoroscopy time and use of advanced retrieval techniques when compared to both the Option and Tulip filters. The findings of this study indicate easier retrieval of the Denali and Tulip IVC filters when compared to the Option filter.

Interventional approaches to deep venous thrombosis.

PURPOSE OF REVIEW: Catheter-directed therapy in deep vein thrombosis (DVT) is a beneficial adjunct treatment when anticoagulation alone does not provide an adequate therapeutic response. This review aims to deliver an up-to-date discussion behind the rationale, safety profile, and clinical outcomes in endovascular management of DVT. RECENT FINDINGS: Early studies have shown that the use of catheter-directed thrombolysis (CDT) to be successful in rapid thrombus removal, carry a lower incidence of postthrombotic syndrome (PTS), and improved quality of life. To date, the most robust study evaluating the use of CDT is the Catheter-Directed Venous Thrombolysis in Acute Iliofemoral Vein Thrombosis trial published in 2012, which demonstrated a relative risk reduction in PTS of 26% in the patients who received CDT at 2-year follow-up. The 5-year follow-up results from the trial has recently been published, which revealed persistent clinical benefit of CDT. Since, additional small randomized trials confer the efficacy and safety profile of CDT. Short-term results from pharmacomechanical catheter-directed thrombolysis are promising; however, the long-term efficacy has yet to be established. The recently completed Acute Venous Thrombosis: Thrombus Removal with Adjunctive Catheter-Directed Thrombolysis trial will be a pivotal study in defining the future role of pharmacomechanical catheter-directed thrombolysis in prevention of PTS. SUMMARY: CDT is a reasonable and well tolerated treatment option in selected patients with acute proximal DVT.

Alterations in 3-Hydroxyisobutyrate and FGF21 Metabolism Are Associated With Protein Ingestion-Induced Insulin Resistance.

Systemic hyperaminoacidemia, induced by either intravenous amino acid infusion or protein ingestion, reduces insulin-stimulated glucose disposal. Studies of mice suggest that the valine metabolite 3-hydroxyisobutyrate (3-HIB), fibroblast growth factor 21 (FGF21), adiponectin, and nonesterified fatty acids (NEFAs) may be involved in amino acid-mediated insulin resistance. We therefore measured in 30 women the rate of glucose disposal, and plasma 3-HIB, FGF21, adiponectin, and NEFA concentrations, under basal conditions and during a hyperinsulinemic-euglycemic clamp procedure (HECP), with and without concomitant ingestion of protein (n = 15) or an amount of leucine that matched the amount of protein (n = 15). We found that during the HECP without protein or leucine ingestion, the grand mean ± SEM plasma 3-HIB concentration decreased (from 35 ± 2 to 14 ± 1 µmol/L) and the grand median [quartiles] FGF21 concentration increased (from 178 [116, 217] to 509 [340, 648] pg/mL). Ingestion of protein, but not leucine, decreased insulin-stimulated glucose disposal (P < 0.05) and prevented both the HECP-mediated decrease in 3-HIB and increase in FGF21 concentration in plasma. Neither protein nor leucine ingestion altered plasma adiponectin or NEFA concentrations. These findings suggest that 3-HIB and FGF21 might be involved in protein-mediated insulin resistance in humans.

Management of Cavoatrial Deep Venous Thrombosis: Incorporating New Strategies.

Cavoatrial deep venous thrombosis (DVT) is diagnosed with increasing prevalence. It can be managed medically with anticoagulation or with directed interventions aimed to efficiently reduce the thrombus burden within the target venous segment. The type of management chosen depends greatly on the etiology and chronicity of the thrombosis, existing patient comorbidities, and the patient's tolerance to anticoagulants and thrombolytic agents. In addition to traditional percutaneous catheter-based pharmacomechanical thrombolysis, other catheter-based suction thrombectomy techniques have emerged in recent years. Each therapeutic modality requires operator expertise and a coordinated care paradigm to facilitate successful outcomes. Open surgical thrombectomy is alternatively reserved for specific patient conditions, including intolerance of anticoagulation, failed catheter-based interventions, or acute emergencies.

US-Guided, Direct Puncture Retrograde Thoracic Duct Access, Lymphangiography, and Embolization: Feasibility and Efficacy.

PURPOSE: To describe technical details, success rate, and advantages of direct puncture of the thoracic duct (TD) under direct ultrasound (US) guidance at venous insertion in the left neck. MATERIALS AND METHODS: All patients who underwent attempted thoracic duct embolization (TDE) via US-guided retrograde TD access in the left neck were retrospectively reviewed. Indications for lymphangiography were iatrogenic chyle leak, pulmonary lymphangiectasia, and plastic bronchitis. Ten patients with mean age 41.4 years (range, 21 d to 72 y) underwent US-guided TD access via the left neck. Technical details, procedural times, and clinical outcomes were evaluated. TD access time was defined as time from start of procedure to successful access of TD, and total procedural time was defined from start of procedure until TDE. RESULTS: All attempts at TD access via the neck were successful. Technical and clinical success of TDE was 60%. There were no complications. Mean TD access time was 17 minutes (range, 2-47 min), and mean total procedure time was 49 minutes (range, 25-69 min). Mean follow-up time was 5.4 months (range, 3-10 months). CONCLUSIONS: TDE via US-guided access in the left neck is technically feasible and safe with a potential decrease in procedure time and elimination of oil-based contrast material.

Arterial Embolization for the Treatment of Renal Masses and Traumatic Renal Injuries.

Renal artery embolization (RAE) for a variety of indications has been performed for several decades. RAE techniques have been refined over time for clinical efficacy and a more favorable safety profile. Owing to improved catheters, embolic agents for precise delivery, and clinical experience, RAE is increasingly used as an adjunct to, or as the preferred alternative to surgical interventions. The indications for RAE are expanding for many urologic and medical conditions. In this article, we focus on the role and technical aspects of RAE in the treatment of renal masses and traumatic renal injuries.

Control of massive hemoptysis via a "back-door" approach through the pulmonary artery.

Bronchial artery embolization is an effective nonsurgical therapy for massive hemoptysis. Routine selection of the bronchial arteries from the aorta usually enables the interventionalist full interrogation and embolization of the culprit vascular abnormality. In problematic cases where bronchial artery access is difficult, a systemic-to-pulmonary arterial shunt can be exploited as a retrograde means of vascular intervention. A case is presented where inaccessibility of a tortuous left bronchial artery was circumvented by accessing the left pulmonary artery, leading to successful embolization and control of hemoptysis.

Routine repeat head CT may not be indicated in patients on anticoagulant/antiplatelet therapy following mild traumatic brain injury.

INTRODUCTION: Evaluation recommendations for patients on anticoagulant and antiplatelet (ACAP) therapy that present after mild traumatic brain injury (TBI) are controversial. At our institution, an initial noncontrast head computed tomography (HCT) is performed, with a subsequent HCT performed six hours later to exclude delayed intracranial hemorrhage (ICH). This study was performed to evaluate the yield and advisability of this approach. METHODS: We performed a retrospective review of subjects undergoing evaluation for ICH after mild TBI in patients on ACAP therapy between January of 2012 and April of 2013. We assessed for the frequency of ICH on both the initial noncontrast HCT and on the routine six-hour follow-up HCT. Additionally, chart review was performed to evaluate the clinical implications of ICH, when present, and to interrogate whether pertinent clinical and laboratory data may predict the presence of ICH prior to imaging. We used multivariate generalized linear models to assess whether presenting Glasgow Coma Score (GCS), loss of consciousness (LOC), neurological or physical examination findings, international normalized ratio, prothrombin time, partial thromboplastin time, platelet count, or specific ACAP regimen predicted ICH. RESULTS: 144 patients satisfied inclusion criteria. Ten patients demonstrated initial HCT positive for ICH, with only one demonstrating delayed ICH on the six-hour follow-up HCT. This patient was discharged without any intervention required or functional impairment. Presenting GCS deviation (p<0.001), LOC (p=0.04), neurological examination findings (p<0.001), clopidogrel (p=0.003), aspirin (p=0.03) or combination regimen (p=0.004) use were more commonly seen in patients with ICH. CONCLUSION: Routine six-hour follow-up HCT is likely not indicated in patients on ACAP therapy, as our study suggests clinically significant delayed ICH does not occur. Additionally, presenting GCS deviation, LOC, neurological examination findings, clopidogrel, aspirin or combination regimen use may predict ICH, and, in the absence of these findings, HCT may potentially be forgone altogether.

Role of interventional radiology in the management of acute gastrointestinal bleeding.

Acute gastrointestinal bleeding (GIB) can lead to significant morbidity and mortality without appropriate treatment. There are numerous causes of acute GIB including but not limited to infection, vascular anomalies, inflammatory diseases, trauma, and malignancy. The diagnostic and therapeutic approach of GIB depends on its location, severity, and etiology. The role of interventional radiology becomes vital in patients whose GIB remains resistant to medical and endoscopic treatment. Radiology offers diagnostic imaging studies and endovascular therapeutic interventions that can be performed promptly and effectively with successful outcomes. Computed tomography angiography and nuclear scintigraphy can localize the source of bleeding and provide essential information for the interventional radiologist to guide therapeutic management with endovascular angiography and transcatheter embolization. This review article provides insight into the essential role of Interventional Radiology in the management of acute GIB.