The evolution of immune checkpoint inhibitor combinations in advanced hepatocellular carcinoma - A systematic review.

BACKGROUND AND OBJECTIVE: Since approval of sorafenib in 2008, systemic therapy has been established as the main treatment option for advanced hepatocellular carcinoma (HCC). Recently, immune checkpoints inhibitors (ICIs) have been extensively tested in this setting. Multiple ICI combination regimens have recently received regulatory approval and new data continues to emerge. The purpose of this review is to provide a comprehensive summary of the most up-to-date evidence on ICI combinations in advanced HCC. METHODS: A search of published and presented literature was conducted to identify phase III trials of ICI combinations in advanced HCC patients. Supplemental bibliographic search of review articles and meta-analyses was also conducted. Efficacy and safety data was summarized in text, tables, and plots. FINDINGS AND DISCUSSION: The literature search identified a total of six phase III trials assessing ICI combinations in advanced HCC. Two trials compared ICI plus anti-VEGF monoclonal antibody combinations to sorafenib, three trials compared ICI plus tyrosine kinase inhibitor (TKI) combinations to TKIs alone, and one trial compared a dual ICI regimen to sorafenib. Statistically significant survival benefits were seen with atezolizumab-bevacizumab and sintilimab-bevacizumab biosimilar as well as durvalumab-tremelimumab and camrelizumab-rivoceranib combinations. ICI combination regimens have also shown improvements in response rates and progression-free survival relative to the previous standard of care, sorafenib, and generally presented predictable and manageable safety profiles. CONCLUSION: ICI combinations represent the new standard of care for advanced HCC. Ongoing randomized trials and real-world evidence will further clarify the role of these combinations in this rapidly evolving field.

Clinical consensus statement: Establishing the roles of locoregional and systemic therapies for the treatment of intermediate-stage hepatocellular carcinoma in Canada.

BACKGROUND: Hepatocellular carcinoma (HCC) a leading cause of cancer mortality worldwide and approximately one-third of patients present with intermediate-stage disease. The treatment landscape of intermediate-stage HCC is rapidly evolving due to developments in local, locoregional and systemic therapies. Treatment recommendations focused on this heterogenous disease stage and that take into account the Canadian reality are lacking. To address this gap, a pan-Canadian group of experts in hepatology, transplant, surgery, radiation therapy, nuclear medicine, interventional radiology, and medical oncology came together to develop consensus recommendations on management of intermediate-stage HCC relevant to the Canadian context. METHODS: A modified Delphi framework was used to develop consensus statements with strengths of recommendation and supporting levels of evidence graded using the AHA/ACC classification system. Tentative consensus statements were drafted based on a systematic search and expert input in a series of iterative feedback cycles and were then circulated via online survey to assess the level of agreement. RESULTS & CONCLUSION: The pre-defined ratification threshold of 80 % agreement was reached for all statements in the areas of multidisciplinary treatment (n = 4), intra-arterial therapy (n = 14), biologics (n = 5), radiation therapy (n = 3), surgical resection and transplantation (n = 7), and percutaneous ablative therapy (n = 4). These generally reflected an expansion in treatment options due to developments in previously established or emergent techniques, introduction of new and more active therapies and increased therapeutic flexibility. These developments have allowed for greater treatment tailoring and personalization as well as a paradigm shift toward strategies with curative intent in a wider range of disease settings.

Hepatic Hilar Nerve Block for Adjunctive Analgesia during Percutaneous Thermal Ablation of Hepatic Tumors: A Retrospective Analysis.

PURPOSE: To determine whether hepatic hilar nerve block techniques reduce analgesic and sedation requirements during percutaneous image-guided thermal ablation of hepatic tumors. MATERIALS AND METHODS: A single-center retrospective cohort analysis was performed of 177 patients (median age, 67 years; range, 33-86 years) who underwent percutaneous image-guided thermal ablation of liver tumors. All patients were treated utilizing local anesthetic and moderate sedation between November 2018 and November 2021 at a tertiary level hospital, with or without the administration of a hepatic hilar nerve block. Univariable and multivariable linear regression analyses were performed to determine the relationship between the administration of the hilar nerve block and fentanyl and midazolam dosages. RESULTS: A total of 114 (64%) patients received a hilar nerve block in addition to procedural sedation, and 63 (36%) patients received procedural sedation alone. There were no significant differences in the baseline demographic and tumor characteristics between the cohorts. The procedure duration was longer in the hilar block cohort than in the unblocked cohort (median, 95 vs 82 minutes; P = .0012). The technical success rate (98% in both the cohorts, P = .93) and adverse event rate (11% vs 3%, P = .14) were not significantly different between the cohorts. After adjusting for patient and tumor characteristics, ablation modality, and procedure and ablation durations, hilar nerve blocks were associated with lower fentanyl (-18.4%, P = .0045) and midazolam (-22.7%, P = .0007) dosages. CONCLUSIONS: Hepatic hilar nerve blocks significantly decrease the fentanyl and midazolam requirements during thermal ablation of hepatic tumors, without a significant change in the technical success or adverse event rates.

Clinical consensus statement: Selective internal radiation therapy with yttrium 90 resin microspheres for hepatocellular carcinoma in Asia.

BACKGROUND: Hepatocellular carcinoma (HCC) is subject to different management approaches and guidelines according to Eastern and Western therapeutic algorithms. Use of selective internal radiation therapy (SIRT) with resin yttrium 90 microspheres for HCC has increased in Asia in recent years, without clearly defined indications for its optimal application. The objective of this systematic review and expert consensus statement is to provide guidance and perspectives on the use of SIRT among patients with HCC in Asia. MATERIALS AND METHODS: A systematic literature review identified current publications on HCC management and SIRT recommendations. A group of 10 experts, representing stakeholder specialties and countries, convened between August 2020 and March 2021 and implemented a modified Delphi consensus approach to develop guidelines and indications for use of SIRT for HCC in Asia. Final recommendations were organized and adjudicated based on the level of evidence and strength of recommendation, per approaches outlined by the American College of Cardiology/American Heart Association and Oxford Centre for Evidence-Based Medicine. RESULTS: The experts acknowledged a general lack of evidence relating to use of SIRT in Asia and identified as an unmet need the lack of phase 3 randomized trials comparing clinical outcomes and survival following SIRT versus other therapies for HCC. Through an iterative process, the expert group explored areas of clinical relevance and generated 31 guidance statements and a patient management algorithm that achieved consensus. CONCLUSION: These recommendations aim to support clinicians in their decision-making and to help them identify and treat patients with HCC using SIRT in Asia. The recommendations also highlight areas in which further clinical trials are needed to define the role of SIRT in management of HCC among Asian populations.

Hepatic Hilar Nerve Block for Hepatic Interventions: Anatomy, Technique, and Initial Clinical Experience in Thermal Ablation of Liver Tumors.

Background Image-guided procedures for treatment of liver diseases can be painful and require heavy sedation of the patient. Local-regional nerve blocks improve pain control and reduce oversedation risks, but there are no documented liver-specific nerve blocks. Purpose To develop a safe and technically simple liver-specific nerve block. Materials and Methods Between March 2017 and October 2019, three cadavers were dissected to evaluate the hepatic hilar anatomy. The hepatic hilar nerves were targeted with transhepatic placement of a needle adjacent to the main portal vein, under US guidance, and evaluated with use of an injection of methylene blue. A hepatic nerve block, using similar technique and 0.25% bupivacaine, was offered to patients undergoing liver tumoral ablation. In a prospective pilot study, 12 patients who received the nerve block were compared with a control group regarding complications, safety, pain scores, and intraoperative opioid requirement. Student t tests were used to compare the groups' characteristics, and Mann-Whitney U tests were used for the measured outcomes. Results Cadaver results confirmed that the hepatic nerves coursing in the hepatic hilum can be targeted with US for injection of anesthetic agents, with adequate spread of injected methylene blue around the nerves in the hepatic hilar perivascular space. The 12 participants (mean age ± standard deviation, 66 years ± 13; eight men) who received a hepatic hilar block before liver thermal ablations demonstrated reduced pain compared with a control group of 12 participants (mean age, 63 years ± 15; eight men) who received only intravenous sedation. Participants who received the nerve block had a lower mean visual analog scale score for pain than the control group (3.9 ± 2.4 vs 7.0 ± 2.8, respectively; P = .01) and decreased need for intraprocedural fentanyl (mean dose, 152 µg ± 78.0 vs 235.4 µg ± 58.2, respectively; P = .01). No major complications occurred in the hepatic hilar nerve block group. Conclusion A dedicated hepatic hilar nerve block with 0.25% bupivacaine can be safely performed to provide anesthesia during liver tumoral ablation. © RSNA, 2021.

International recommendations for personalised selective internal radiation therapy of primary and metastatic liver diseases with yttrium-90 resin microspheres.

PURPOSE: A multidisciplinary expert panel convened to formulate state-of-the-art recommendations for optimisation of selective internal radiation therapy (SIRT) with yttrium-90 (90Y)-resin microspheres. METHODS: A steering committee of 23 international experts representing all participating specialties formulated recommendations for SIRT with 90Y-resin microspheres activity prescription and post-treatment dosimetry, based on literature searches and the responses to a 61-question survey that was completed by 43 leading experts (including the steering committee members). The survey was validated by the steering committee and completed anonymously. In a face-to-face meeting, the results of the survey were presented and discussed. Recommendations were derived and level of agreement defined (strong agreement ≥ 80%, moderate agreement 50%-79%, no agreement ≤ 49%). RESULTS: Forty-seven recommendations were established, including guidance such as a multidisciplinary team should define treatment strategy and therapeutic intent (strong agreement); 3D imaging with CT and an angiography with cone-beam-CT, if available, and 99mTc-MAA SPECT/CT are recommended for extrahepatic/intrahepatic deposition assessment, treatment field definition and calculation of the 90Y-resin microspheres activity needed (moderate/strong agreement). A personalised approach, using dosimetry (partition model and/or voxel-based) is recommended for activity prescription, when either whole liver or selective, non-ablative or ablative SIRT is planned (strong agreement). A mean absorbed dose to non-tumoural liver of 40 Gy or less is considered safe (strong agreement). A minimum mean target-absorbed dose to tumour of 100-120 Gy is recommended for hepatocellular carcinoma, liver metastatic colorectal cancer and cholangiocarcinoma (moderate/strong agreement). Post-SIRT imaging for treatment verification with 90Y-PET/CT is recommended (strong agreement). Post-SIRT dosimetry is also recommended (strong agreement). CONCLUSION: Practitioners are encouraged to work towards adoption of these recommendations.

Ablative Transarterial Radioembolization Improves Survival in Patients with HCC and Portal Vein Tumor Thrombus.

PURPOSE: Patients with hepatocellular carcinoma and portal vein tumor thrombus have a poor prognosis and limited therapeutic options. We sought to compare survival, tolerability, and safety in such patients treated with conventional yttrium-90 transarterial radioembolization dosimetric techniques or ablative transarterial radioembolization. MATERIALS AND METHODS: This retrospective, single-center cohort study included patients with hepatocellular carcinoma and right, left, and/or main portal vein tumor thrombus, preserved liver function (Child-Pugh class ≤ B7), and good performance status (Eastern Cooperative Oncology Group score ≤ 1) treated with yttrium-90 microspheres from 2011 to 2018 with ablative intent transarterial radioembolization (A-TARE), or conventional technique (cTARE). Statistical models were used to compare overall survival, post-treatment survival, toxicities, and prognosticators of response. RESULTS: Fifty-seven patients were included (21 [36.8%] ablative and 36 [63.2%] conventional intent). Median overall survival was 15.7 months. Compared to conventional treatment, ablative radioembolization was associated with longer median overall survival (45.3 vs 18.2 months; P = 0.003), longer post-treatment survival (19.1 vs 4.9 months; P = 0.005), a 70% lower risk of death (hazard ratio 0.30; 95% confidence interval, 0.13-0.70; P = 0.005), and improved 4-year survival (53.9% vs 11.2%). Overall survival did not differ significantly between treatment with resin and glass microspheres (27.5 vs 22.2 months; P = 0.62). Acceptable hepatic toxicities were observed after yttrium-90 administration, without statistical differences between the groups. CONCLUSION: In patients with advanced hepatocellular carcinoma and portal vein tumor thrombus, A-TARE is associated with longer survival than cTARE. Neither modality is associated with deleterious effects on liver function.

Early clinical experience with a touchless image navigation interface for the endovascular suite.

Introduction: The inability to having comprehensive access to all pertinent imaging data related to an endovascular procedure in the sterile field is an unmet need, and its absence may have deleterious effects on decision-making, outcomes and workflow. Current image navigation solutions rely on traditional personal computing interfaces which are difficult to use in the sterile field. Innovative technological solutions are needed to address this need.Material and methods: Utilizing novel hardware and software integration, a human computer interaction (HCI) based platform has been developed through an iterative design and development process, that allows intuitive real-time access to imaging data in the sterile field. Following validation and pre-clinical testing, the platform has been introduced to the endovascular suite for clinical use.Results: Three prospective case-based observational reviews are presented that demonstrate the utility of touchless image navigation in the sterile field in facilitating decision-making and resource utilization during endovascular procedures, while avoiding the cognitive and workflow disturbances inherent in leaving the sterile field or involving non-scrubbed third persons in the image navigation process.Conclusion: Physician engagement and 'needs-based' technological innovation is needed to improve human computer interaction in the endovascular suite, in hopes of positively affecting procedural decision-making, outcomes, and workflow.

Experimental Assessment of a Novel Touchless Interface for Intraprocedural Imaging Review.

PURPOSE: To examine the feasibility of a novel technology platform that enables real-time touchless interaction with radiology images in both a simulated and an actual clinical setting. MATERIALS AND METHODS: This platform offers three different modes for image interaction. The gesture recognition mode uses a depth camera to detect the user's hand gestures which are translated to image manipulation commands. The light projection mode uses the same camera to detect finger point-and-tap movements above the icons which are projected on a surface to activate the commands. The capacitive sensing mode is enabled by a handheld, portable device, over which finger movements are detected by capacitive sensors to control the image review. Following initial feedback, light projection and capacitive sensing modes were selected for further testing by comparing with the conventional mode of image interaction in time trials for performing a series of standardized image manipulation tasks. Finally, the usability of the technology platform was examined in actual clinical procedures. RESULTS: The light projection and the capacitive sensing modes were evaluated in the time trials and exhibited 60% and 71% reduction in time, respectively, relative to the control mode (p < 0.001). Clinical feasibility for this platform was demonstrated in three actual interventional radiology cases. CONCLUSION: Accessing, navigating, and extracting relevant information from patient images intraprocedurally are cumbersome and time-consuming tasks that affect safety, efficiency, and decision-making during image-guided procedures. This study demonstrated that the novel technology addressed this issue by allowing touchless interaction with these images in the sterile field.

Y90 Radioembolization Dosimetry: Concepts for the Interventional Radiologist.

Transarterial radioembolization (TARE) with beta particle emitting microspheres via Yttrium-90 decay has become a fundamental component of the contemporary Interventional Oncology practice. TARE continues to advance as a result of increased utilization, clinical study, technological improvements, and evolving applications. To maximize TARE safety and efficacy, a core understanding of dosimetry is essential. The intent of this overview is to provide the reader with a general survey of radiation physics and biology, device differentiation, patient selection, anatomic assessment, activity administration models, and procedural techniques involved with TARE dosimetry.

Radiation Segmentectomy and Radiation Lobectomy: A Practical Review of Techniques.

The radiation segmentectomy technique may be defined as the administration of transarterial radioembolization delivered to 1 or 2 hepatic segments with the intention of segmental tissue ablation. Since first being described in 2011, radiation segmentectomy has quickly gained acceptance as a safe, effective, and potentially curative outpatient treatment for selected lower stage hepatocellular carcinomas. We describe our recommended techniques for radiation segmentectomy with glass or resin radiomicrospheres, including patient selection, dosimetry, microcatheter techniques, and clinical and imaging follow-up, accompanied by a brief review of the radiation segmentectomy literature. Radiation lobectomy, defined as the ablation of an entire hepatic lobe via transarterial radioembolization, is an area of growing interest in many centers. We also review the existing radiation lobectomy literature and suggest which patient and tumor factors may be associated with higher likelihood of successful treatment.

Successes and Struggles with Computational Reproducibility: Lessons from the Fragile Families Challenge.

Reproducibility is fundamental to science, and an important component of reproducibility is computational reproducibility: the ability of a researcher to recreate the results of a published study using the original author's raw data and code. Although most people agree that computational reproducibility is important, it is still difficult to achieve in practice. In this article, the authors describe their approach to enabling computational reproducibility for the 12 articles in this special issue of Socius about the Fragile Families Challenge. The approach draws on two tools commonly used by professional software engineers but not widely used by academic researchers: software containers (e.g., Docker) and cloud computing (e.g., Amazon Web Services). These tools made it possible to standardize the computing environment around each submission, which will ease computational reproducibility both today and in the future. Drawing on their successes and struggles, the authors conclude with recommendations to researchers and journals.

Beyond the Knife: The Evolving Nonsurgical Management of Oligometastatic Colorectal Cancer.

In patients with liver-limited oligometastatic disease, the goal of treatment can be curative intent. Historically, this was accomplished in patients presenting with upfront resectable disease. The availability of increasingly efficacious chemotherapy and biologic combinations with encouraging response rates led to the potential to convert unresectable disease to resectability. Beyond the backbone of surgery, we now have a portfolio of locoregional strategies to consider.From an interventional radiology perspective, the use of portal vein embolization can facilitate hypertrophy of the liver in anticipation of resection, thus converting unresectable disease to one amenable to a surgical approach with curative intent. Technological advances in liver-directed ablative therapies have afforded the possibility of eliminate radiographically evident disease with the hope for long-term disease control. Advanced radiotherapy techniques are further increasing the therapeutic options for patients with metastatic colorectal cancer. Improvements in external-beam radiotherapy over the past 2 decades include image-guided radiotherapy, intensity-modulated radiotherapy, stereotactic body radiotherapy, and proton-beam therapy. Finally, selective internal radiation therapy (SIRT) with microspheres labeled with the ß-emitter 90Y enable targeted delivery of radiation to hepatic tumors. A coordinated multidisciplinary approach is required to integrate these nonsurgical adjuncts in an evidence-based manner to optimize outcomes for patients with potentially resectable metastatic disease. In this article, we summarize recent developments in systemic therapy, radiotherapy, and interventional liver-directed therapies that have changed the treatment landscape for patients with oligometastatic colorectal cancer.

90Y Radioembolization for Hepatic Malignancy in Patients with Previous Biliary Intervention: Multicenter Analysis of Hepatobiliary Infections.

Purpose To determine the frequency of hepatobiliary infections after transarterial radioembolization (TARE) with yttrium 90 (90Y) in patients with liver malignancy and a history of biliary intervention. Materials and Methods For this retrospective study, records of all consecutive patients with liver malignancy and history of biliary intervention treated with TARE at 14 centers between 2005 and 2015 were reviewed. Data regarding liver function, 90Y dosimetry, antibiotic prophylaxis, and bowel preparation prophylaxis were collected. Primary outcome was development of hepatobiliary infection. Results One hundred twenty-six patients (84 men, 42 women; mean age, 68.8 years) with primary (n = 39) or metastatic (n = 87) liver malignancy and history of biliary intervention underwent 180 procedures with glass (92 procedures) or resin (88 procedures) microspheres. Hepatobiliary infections (liver abscesses in nine patients, cholangitis in five patients) developed in 10 of the 126 patients (7.9%) after 11 of the 180 procedures (6.1%; nine of those procedures were performed with glass microspheres). All patients required hospitalization (median stay, 12 days; range, 2-113 days). Ten patients required percutaneous abscess drainage, three patients underwent endoscopic stent placement and stone removal, and one patient needed insertion of percutaneous biliary drains. Infections resolved in five patients, four patients died (two from infection and two from cancer progression while infection was being treated), and one patient continued to receive suppressive antibiotics. Use of glass microspheres (P = .02), previous liver resection or ablation (P = .02), and younger age (P = .003) were independently predictive of higher infection risk. Conclusion Infectious complications such as liver abscess and cholangitis are uncommon but serious complications of transarterial radioembolization with 90Y in patients with liver malignancy and a history of biliary intervention.

Intraprocedural Parenchymal Blood Volume Is a Predictor of Treatment Response for Chemoembolization in Hepatocellular Carcinoma: Results of a Prospective Study.

PURPOSE: To evaluate cone-beam parenchymal blood volume (PBV) before and after embolization as a predictor of radiographic response to transarterial chemoembolization in unresectable hepatocellular carcinoma (HCC). MATERIALS AND METHODS: A phase IIa prospective clinical trial was conducted in patients with HCCs > 1.5 cm undergoing chemoembolization; 52 tumors in 40 patients with Barcelona Clinic Liver Criteria stage B disease met inclusion criteria. Pre- and postembolization PBV analysis was performed with a semiquantitative best-fit methodology for index tumors, with a predefined primary endpoint of radiographic response at 3 months. Analyses were conducted with Wilcoxon signed-rank tests and one-way analysis of variance on ranks. RESULTS: Mean tumoral PBV measurements before and after embolization were 170 mL/1,000 mL ± 120 and 0 mL/100 mL ± 130, respectively. Per modified Response Evaluation Criteria In Solid Tumors, 25 tumors (48%) exhibited complete response (CR), 13 (25%) partial response (PR), 3 (6%) stable disease (SD), and 11 (21%) progressive disease (PD). Statistically significant changes in median PBV (ΔPBV) were identified in the CR (P = .001) and PR (P = .003) groups, with no significant difference observed in SD (P = .30) and PD groups (P = .06). A statistically significant correlation between ΔPBV and tumor response was established by one-way analysis of variance on ranks (P = .036; CR, 200 mL/100 mL ± 99; PR, 240 mL/100 mL ± 370; SD, 64 mL/100 mL ± 99; PD, 88 mL/100 mL ± 129). CONCLUSIONS: Intraprocedural PBV can be used as a predictor of response in index HCC tumors of > 1.5 cm.

Advances in Degradable Embolic Microspheres: A State of the Art Review.

Considerable efforts have been placed on the development of degradable microspheres for use in transarterial embolization indications. Using the guidance of the U.S. Food and Drug Administration (FDA) special controls document for the preclinical evaluation of vascular embolization devices, this review consolidates all relevant data pertaining to novel degradable microsphere technologies for bland embolization into a single reference. This review emphasizes intended use, chemical composition, degradative mechanisms, and pre-clinical safety, efficacy, and performance, while summarizing the key advantages and disadvantages for each degradable technology that is currently under development for transarterial embolization. This review is intended to provide an inclusive reference for clinicians that may facilitate an understanding of clinical and technical concepts related to this field of interventional radiology. For materials scientists, this review highlights innovative devices and current evaluation methodologies (i.e., preclinical models), and is designed to be instructive in the development of innovative/new technologies and evaluation methodologies.

State of the ablation nation: a review of ablative therapies for cure in the treatment of hepatocellular carcinoma.

Primary liver cancer, mainly hepatocellular carcinoma, is one of the most common malignancies worldwide. Surgical management, either resection or transplantation, is considered definitive treatment, however, less than 20% of patients are ultimately candidates. Thermal ablation modalities such as radiofrequency ablation and microwave ablation have evolved such that these modalities have been applied with curative intent. Moreover, thermal ablation has demonstrated efficacy in treating early-stage tumors and can be offered as first-line treatment in patients with uncomplicated disease. Attributing to refinements in technology and techniques, recent studies evaluating stereotactic ablative body radiotherapy have shown promising results, while irreversible electroporation, an emerging modality, may further expand the role of ablative therapy in treating potentially resectable hepatocellular carcinoma.

Transradial Access for Interventional Radiology: Single-Centre Procedural and Clinical Outcome Analysis.

PURPOSE: The study sought to describe a single centre's technical approach to transradial intervention and report on clinical outcomes and safety. METHODS: A total of 749 transradial access (TRA) procedures were performed at a single hospital in 562 patients (174 women and 388 men). Procedures included 445 bland embolizations or chemoembolizations of the liver, 88 uterine artery embolizations, and 148 procedures for Selective Internal Radiation Therapy (Y90), which included mapping and administration. The mean age of the patients was 62 years (range 27-96 years). RESULTS: Four cases (0.5%) required crossover to transfemoral (tortuous anatomy, inability to secure a stable position for embolization, vessel spasm and base catheter not being of a sufficient length). A single asymptomatic, short-segment radial artery occlusion occurred (0.3%), 3 patients (0.4%) developed small hematomas postprocedurally, and 2 patients (0.7%) had transient neurological pain, which was resolved within a week without treatment. It was found that 98% of patients who had a previous femoral access procedure would choose radial access for subsequent procedures. CONCLUSIONS: Transradial access is a safe, effective technique, with a learning curve; however, this procedure has the potential to significantly improve departmental workflow and cost savings for the department and patient experience.

Use of blood pool agents with steady-state MRI to assess the vascular system.

Over the past two decades there have been significant advances in the use of magnetic resonance imaging (MRI) to assess the vascular system. New imaging sequences and improvements in magnet design have enabled the creation of higher spatial resolution images. MRI is now a viable alternative imaging modality when compared to both invasive angiography and computed tomographic angiography. The use of blood pool agents has further facilitated the use of MR angiography (MRA); their high molecular weight allows for lower doses of contrast medium administration while their prolonged presence in the blood stream allows for repeated high-quality volumetric imaging of both the arterial and venous circulation. As such, MRA is now no longer constrained by the tight windows for first-pass arterial and venous enhancement, which has resulted in the ability to assess and diagnose a large range of vascular pathologies in both arterial and venous systems. The intent of this review is to highlight MRI findings in common vascular pathologies including peripheral arterial disease (PAD), abnormalities of the abdominal aortic branches, postendovascular aortic aneurysm repair (EVAR) endoleak assessment, popliteal artery entrapment syndrome (PAES), deep venous thrombosis (DVT), vascular thoracic outlet syndrome (TOS), and vascular malformations. In addition, the latest MRI techniques currently used to optimally assess each of these pathologies will be discussed. LEVEL OF EVIDENCE: 5 Technical Efficacy: Stage 3 J. MAGN. RESON. IMAGING 2017;45:1559-1572.