A Qualitative Systematic Review of Endovascular Management of Renal Artery Aneurysms.

PURPOSE: To perform a qualitative systematic review of endovascular management of renal artery aneurysms (RAAs). MATERIALS AND METHODS: A comprehensive electronic search of PubMed, MEDLINE, Embase, Google Scholar, and Cochrane databases from 2000 to 2022 was performed using the search terms "renal artery," "aneurysm," and "endovascular." Means of outcome measures were calculated with a primary end point focused on RAA-related mortality and rupture. Secondary end points included reintervention rate and renal infarction. RESULTS: Twenty-six, single-center, retrospective, observational studies were included. There were 454 RAAs treated in 427 patients using endovascular techniques. Mean age was 53.8 years, with a female predominance (62%). A variety of endovascular treatments of RAA were used with excellent technical success (96%), renal parenchymal preservation, and a low rate of moderate/severe adverse events (AEs). Primary coil embolization was the most commonly used technique (44.7%). There was an overall AE rate of 22.9%, of which 6.7% were moderate/severe and there was 0% periprocedural mortality. The most common AE was renal infarction (49 patients, 11.5%); however, renal function was preserved in 84% of patients. Nephrectomy rate was 0.4%. Computed tomography (CT) angiography was the most common imaging follow-up modality used in 72% of studies. Only 9 studies (34%) reported anticoagulant use. Although the risk of delayed aneurysm reperfusion warrants clinical and imaging surveillance, relatively few patients (3%) required reintervention in this cohort. CONCLUSIONS: Endovascular management of RAA is a technically feasible treatment option with low rates of AEs and reintervention. The present study highlights the techniques available for interventional radiologists, a need for standardization of AE reporting, anticoagulation therapy, and follow-up imaging.

Radioembolization for Treatment of Hepatocellular Carcinoma: Current Evidence and Patterns of Utilization.

Primary liver malignancy, of which hepatocellular carcinoma (HCC) is the most common type, is the second most common cause of death due to cancer worldwide. Given the historically poor prognosis of liver cancer, there has been major research on its treatment options, with significant advancements over the last decade. Transarterial radioembolization (TARE) is a locoregional treatment option for HCC that involves transarterial delivery of the ß-emitter yttrium-90 via resin or glass microspheres to arterialized tumor vasculature, delivering a tumoricidal dose to the tumor. The recent 2022 update of the Barcelona Clinic Liver Cancer (BCLC) treatment algorithm features a more prominent role for locoregional treatment, including the incorporation of radioembolization for very-early-stage (BCLC-0) and early-stage (BCLC-A) diseases. This review provides a contemporary summary of the evolving role of TARE in treatment of HCC in light of recent and upcoming trials.

Tranexamic acid as a novel adjunct in the management of vessel perforation complicating Endovascular Clot Retrieval.

AIM: To assess the safety and utility of tranexamic acid (TXA) as an adjunct salvage therapy in iatrogenic vessel perforation complicating endovascular clot retrieval. Iatrogenic vessel perforation and extravasation are known and potentially fatal complications of endovascular clot retrieval (ECR). Various methods of establishing haemostasis post perforation have been reported. TXA is widely utilised intraoperatively to reduce bleeding in various surgical specialities. The use of TXA in endovascular procedures has not been previously described in the literature. METHODS: Retrospective case control study of all cases that underwent ECR. Cases where arterial rupture occurred were identified. Details of management and functional status at 3 months were recorded. Modified Rankin score (mRS) 0-2 was considered a good functional outcome. Comparison of proportions analysis was performed. RESULTS: Of 1378 cases of ECR, rupture complicated 36 (2.6%). TXA was administered in addition to standard care in 11 cases (31%). At 3 months, 4 of 11 cases (36%) where TXA was administered had a good functional outcome compared to 3 of 22 (12%) in the standard care group (P=0.09). Mortality at 3 months occurred in 4 of 11 cases (41.7%) where TXA was administered compared to 16 of 25 (64%) where it was not (P=0.13). CONCLUSION: Tranexamic acid administration in iatrogenic vessel rupture was associated with a lower mortality rate and a larger proportion of patients achieving a good functional outcome at 3 months. This effect trended towards but was not statistically significant. TXA administration was not associated with adverse effects.

Chronic lymphocytic infiltration with pontine perivascular enhancement responsive to steroids (CLIPPERS) and its association with Epstein-Barr Virus (EBV)-related lymphomatoid granulomatosis: a case report.

BACKGROUND: Chronic lymphocytic infiltration with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a neuro-inflammatory syndrome first described in 2010. It has a relationship with lymphoproliferative disorders that has not been fully elucidated. This case represents an unusual progression of CLIPPERS to Epstein-Barr Virus (EBV)-related lymphomatoid granulomatosis (LYG). The exact connection between CLIPPERS and LYG remains poorly understood. CASE PRESENTATION: We present a case of a 75-year-old man who was diagnosed with CLIPPERS with initial response to immunosuppression but later progressed to EBV-related LYG. EBV polymerase chain reaction (PCR) was detected in his cerebrospinal fluid (CSF), and repeat imaging revealed findings that were uncharacteristic for CLIPPERS; thereby prompting a brain biopsy which led to a diagnosis of EBV-related LYG. This case highlights the following learning points: 1) CLIPPERS cases are often part of a spectrum of lymphomatous disease, 2) CLIPPERS can be associated with EBV-related lymphoproliferative disorders such as LYG, and 3) EBV detection in CSF should prompt earlier consideration for brain biopsy in patients. CONCLUSIONS: Our case highlights the difficulty in distinguishing CLIPPERS from other steroid-responsive conditions such as neoplastic and granulomatous diseases. Given the association of CLIPPERS with EBV-related LYG as demonstrated in this case, we recommend testing for EBV in CSF for all patients with suspected CLIPPERS. An early referral for brain biopsy and treatment with rituximab should be considered for patients with suspected CLIPPERS who test positive for EBV in their CSF.

Contemporary Treatment of Intracranial Blood Blister Aneurysms - A Systematic Review.

INTRODUCTION: Blood blister aneurysms (BBAs) are rare aneurysms affecting non-branched points of intracerebral arteries. Due to their small size and fragility, BBAs are prone to rupture, and can be challenging to diagnose and treat. Several treatment options have been suggested yet there is no consensus regarding the best modality to reduce morbidity and mortality. MATERIALS AND METHODS: A systematic review of the literature was conducted searching for articles discussing the treatment of BBAs. Inclusion criteria included: articles published between January 2010 and August 2020, English language, with each paper including at least 15 patients. Studies included required detailed reporting of patient demographics, treatment, and patient outcomes (including complications, recurrence, neurologic functional status, and mortality). RESULTS AND DISCUSSION: A total of 25 studies with 883 patients were included. Most were female (n = 594, 67.3%) and aneurysms were overwhelmingly located in the supraclinoid internal carotid artery (99%). Aneurysms were variable in size and mostly presented with subarachnoid haemorrhage. Endovascular treatment (n = 518, 58.7%) was more common than microsurgery (n = 365, 41.1%) while only 2 patients were managed conservatively. Complications were more common in patients treated microsurgically. Microsurgical procedures had an unfavorable outcome (mRS 4-6, GOS 1-3) rate of 27.8% (n = 100/360) while that of endovascular procedures was 14.7% (n = 70/477). Endovascular procedures had a lower mortality rate than microsurgical interventions (8.4% vs 11%). CONCLUSION: This review demonstrates that endovascular treatment of blood blister aneurysm has reduced morbidity and mortality when compared with microsurgical treatment. Small sample sizes and substantial study heterogeneity makes strong conclusions difficult.

Endovascular thrombectomy for tandem acute ischemic stroke associated with cervical artery dissection: a systematic review and meta-analysis.

PURPOSE: Strokes associated with cervical artery dissection have been managed primarily with antithrombotics with poor outcomes. The additive role of endovascular thrombectomy remains unclear. The objective was to perform systematic review and meta-analysis to compare endovascular thrombectomy and medical therapy for acute ischemic stroke associated with cervical artery dissection. METHODS: Studies from six electronic databases included outcomes of patient cohorts with acute ischemic stroke secondary to cervical artery dissection who underwent treatment with endovascular thrombectomy. A meta-analysis of proportions was conducted with a random effects model. Modified Rankin score at 90 days (mRS 0-2) was the primary outcome. Other outcomes included proportion of patients with thrombolysis in cerebral infarction (TICI) 2b-3 flow, 90-day mortality rate, and 90-day symptomatic intracerebral hemorrhage (sICH) rate. RESULTS: Six studies were included, comprising 193 cases that underwent thrombectomy compared with 59 cases that were managed medically. Successful recanalization with a pooled proportion of thrombolysis in cerebral infarction (TICI) 2b-3 flow in the thrombectomy group was 74%. Favorable outcome (mRS 0-2) was superior in the pooled thrombectomy group (62.9%, 95% CI 55.8-69.5%) compared with medical management (41.5%, 95% CI 29.0-55.1%, P = 0.006). The pooled rate of 90-day mortality was similar for endovascular vs medical (8.6% vs 6.3%). The pooled rate of symptomatic intracranial haemorrhage (sICH) did not significantly differ (5.9% vs 4.2%, P = 0.60). CONCLUSIONS: Current data suggest that endovascular thrombectomy may be an option in patients with acute ischemic stroke due to cervical artery dissection. This requires further confirmation in higher quality prospective studies.

Peering Into the Black Box of Artificial Intelligence: Evaluation Metrics of Machine Learning Methods.

OBJECTIVE: Machine learning (ML) and artificial intelligence (AI) are rapidly becoming the most talked about and controversial topics in radiology and medicine. Over the past few years, the numbers of ML- or AI-focused studies in the literature have increased almost exponentially, and ML has become a hot topic at academic and industry conferences. However, despite the increased awareness of ML as a tool, many medical professionals have a poor understanding of how ML works and how to critically appraise studies and tools that are presented to us. Thus, we present a brief overview of ML, explain the metrics used in ML and how to interpret them, and explain some of the technical jargon associated with the field so that readers with a medical background and basic knowledge of statistics can feel more comfortable when examining ML applications. CONCLUSION: Attention to sample size, overfitting, underfitting, cross validation, as well as a broad knowledge of the metrics of machine learning, can help those with little or no technical knowledge begin to assess machine learning studies. However, transparency in methods and sharing of algorithms is vital to allow clinicians to assess these tools themselves.

Carotid artery stenting: Current state of evidence and future directions.

Both carotid endarterectomy (CEA) and carotid artery stenting (CAS) are common treatments for carotid artery stenosis. Several randomized controlled trials (RCTs) have compared CEA to CAS in the treatment of carotid artery stenosis. These studies have suggested that CAS is more strongly associated with periprocedural stroke; however, CEA is more strongly associated with myocardial infarction. Published long-term outcomes report that CAS and CEA are similar. A reduction in complications associated with CAS has also been demonstrated over time. The symptomatic status of the patient and history of previous CEA or cervical radiotherapy are significant factors when deciding between CEA or CAS. Numerous carotid artery stents are available, varying in material, shape and design but with minimal evidence comparing stent types. The role of cerebral protection devices is unclear. Dual antiplatelet therapy is typically prescribed to prevent in-stent thrombosis, and however, evidence comparing periprocedural and postprocedural antiplatelet therapy is scarce, resulting in inconsistent guidelines. Several RCTs are underway that will aim to clarify some of these uncertainties. In this review, we summarize the development of varying techniques of CAS and studies comparing CAS to CEA as treatment options for carotid artery stenosis.

The 100 most cited articles in the endovascular treatment of thoracic and abdominal aortic aneurysms.

OBJECTIVE: Since the introduction of endovascular technology to treat thoracic and abdominal aortic aneurysms, there has been a global research effort focused on assessing the effectiveness of treatment. A bibliometric analysis is used to identify the scientific impact of an article, impactful authors, institutions, and collaborative groups. Our objective was to identify and to analyze the 100 most cited articles in the field of endovascular treatment of thoracic and abdominal aortic aneurysms. METHODS: We performed a retrospective bibliometric analysis in April 2018. Articles were searched on the Science Citation Index Expanded database using Web of Science to identify the most cited articles in endovascular therapy for thoracic and aortic aneurysms since 1945. Use of selected key terms ("AAA," "aortic aneurysm," "thoracic aneurysm," "abdominal aneurysm," "endovascular," "endoluminal," "stent," "graft," "repair," "EVAR," and "TEVAR") yielded a total of 23,354 articles. The top 100 articles were identified and analyzed to extract relevant information including year of publication, citation count, journal, authorship country of origin, and article type. RESULTS: The earliest articles were published in 1991, with the majority being published in the 2000s (n = 59). The number of citations for the top 100 articles ranged from 151 to 1142, with a median citation count of 212. All articles were cited an average of 22.4 times per year. Almost half (n = 46) of the top 100 articles were published in the Journal of Vascular Surgery. Thirty-nine authors contributed four or more articles, with two being credited on 10 papers to make the list. The majority (n = 62) of the articles arose from the United States, while the United Kingdom contributed 11 articles. There were 7 guidelines and 12 randomized controlled trials, and the majority constituted level III or level IV evidence. CONCLUSIONS: This study provides a comprehensive and informative analysis of the most cited and impactful research undertaken in the field of endovascular treatment of abdominal and thoracic aortic aneurysms. By quantitatively assessing the 100 most cited articles in the field, we recognize the contributions of key authors, institutions, and collaborative groups and develop an understanding of the strengths of past research and the requirements for future global efforts.

Techniques for Infrapopliteal Arterial Bifurcation Stenting.

BACKGROUND: Endovascular treatment of infrapopliteal peripheral arterial disease (PAD) is an established and effective treatment strategy for patients with symptomatic PAD. Increasingly, complex infrapopliteal lesions are treated with an endovascular first approach, especially in the setting of critical limb ischemia (CLI) for limb salvage, avoiding major amputations which impact on mobility and quality of life. However, many complex infrapopliteal lesions involving the bifurcation of the tibial arteries remain challenging to treat because of recoil or acute dissection after angioplasty and may require stenting using specialized techniques. METHODS AND RESULTS: We illustrated techniques for infrapopliteal arterial bifurcation stenting using case-based examples. The techniques covered include the single-stent, culottes, kissing, crush, and T-stenting techniques, and each is considered based on individual strengths and limitations. CONCLUSIONS: Infrapopliteal bifurcation stenting allows complex bifurcation lesions to be treated effectively when flow-limiting complications are encountered after angioplasty.

Combined Vertebral Augmentation and Radiofrequency Ablation in the Management of Spinal Metastases: an Update.

OPINION STATEMENT: Spinal metastases are the most commonly encountered tumour of the spine, occurring in up to 40% of patients with cancer. Each year, approximately 5% of cancer patients will develop spinal metastases. This number is expected to increase as the life expectancy of cancer patients increases. Patients with spinal metastases experience severe and frequently debilitating pain, which often decreases their remaining quality of life. With a median survival of less than 1 year, the goals of treatment in spinal metastases are reducing pain, improving or maintaining level of function and providing mechanical stability. Currently, conventional treatment strategies involve a combination of analgesics, bisphosphonates, radiotherapy and/or relatively extensive surgery. Despite these measures, pain management in patients with spinal metastases is often suboptimal. In the last two decades, minimally invasive percutaneous interventional radiology techniques such as vertebral augmentation and radiofrequency ablation (RFA) have shown progressive success in reducing pain and improving function in many patients with symptomatic spinal metastases. Both vertebral augmentation and RFA are increasingly being recognised as excellent alternative to medical and surgical management in carefully selected patients with spinal metastases, namely those with severe refractory pain limiting daily activities and stable pathological vertebral compression fractures. In addition, for more complicated lesions such as spinal metastasis with soft tissue extension, combined treatments such as vertebral augmentation in conjunction with RFA may be helpful. While combined RFA and vertebral augmentation have theoretical benefits, comparative trials have not been performed to establish superiority of combined therapy. We believe that a multidisciplinary approach as well as careful pre-procedure evaluation and imaging will be necessary for effective and safe management of spinal metastases. RFA and vertebral augmentation should be considered during early stages of the disease so as to maintain the remaining quality of life in this patient population group.

Systematic Review and Single-Center Experience for Endovascular Management of Visceral and Renal Artery Aneurysms.

PURPOSE: To report a systematic review of endovascular management of visceral and renal artery aneurysms (VRAA) and results at a tertiary referral center. MATERIALS AND METHODS: A literature review was performed via a comprehensive electronic search of PubMed, MEDLINE, EMBASE, and Cochrane databases, followed by retrospective analysis of all VRAAs treated at a tertiary referral center from January 1999 to December 2015. RESULTS: The systematic review included 22 studies published between 2005 and 2016 describing endovascular treatment of VRAA. In the systematic review cohort, 646 aneurysms (432 true, 151 false, 63 unclassified) were treated using endovascular methods with 93.2% technical success, 99.3% visceral preservation, 3.5% major complication (classified based on Society of Interventional Radiology criteria), 1.5% 30-day periprocedural mortality, and 4.6% reintervention rates. In the local cohort, 19 aneurysms (12 true, 7 false) were treated with 100% technical success, 94.7% visceral preservation, and 10.5% major complication rates. There was no periprocedural mortality. Over mean follow-up of 31.9 months (range, 2-170 months), there were 2 aneurysm reperfusions, which required no further treatment. Results incorporating data from the systematic review and local cohorts (665 aneurysms) showed 93.6% technical success, 99.1% visceral preservation, 3.7% major complication, 1.5% periprocedural mortality, and 4.4% reintervention rates. CONCLUSIONS: Endovascular treatment of VRAA is associated with excellent technical success and visceral preservation rates. Major complication and periprocedural mortality rates are comparatively low. A few VRAA (4.4%) required future reintervention suggesting that imaging follow-up is essential after initial treatment.

Imaging the Patient With Sacroiliac Pain.

Sacroiliac (SI) region pain is a common clinical presentation and is often due to pathology involving the SI joints, usually of inflammatory, infective, neoplastic, or post-traumatic etiology. The SI joints have a unique anatomic layout and composition and can be imaged with a variety of techniques including conventional radiographs, computed tomography, isotope bone scintigraphy, and magnetic resonance imaging. This article reviews a range of common SI joint conditions, illustrated by multimodality imaging findings. We also discuss strategies for choosing the optimal imaging modality, pearls, and pitfalls of imaging and discuss an algorithm for approaching the patient with suspected inflammatory back pain.

Out of Hours Emergency Computed Tomography Brain Studies: Comparison of Standard 3 Megapixel Diagnostic Workstation Monitors With the iPad 2.

PURPOSE: The purpose was to compare performance of diagnostic workstation monitors and the Apple iPad 2 (Cupertino, CA) in interpretation of emergency computed tomography (CT) brain studies. METHODS: Two experienced radiologists interpreted 100 random emergency CT brain studies on both on-site diagnostic workstation monitors and the iPad 2 via remote access. The radiologists were blinded to patient clinical details and to each other's interpretation and the study list was randomized between interpretations on different modalities. Interobserver agreement between radiologists and intraobserver agreement between modalities was determined and Cohen kappa coefficients calculated for each. Performance with regards to urgent and nonurgent abnormalities was assessed separately. RESULTS: There was substantial intraobserver agreement of both radiologists between the modalities with overall calculated kappa values of 0.959 and 0.940 in detecting acute abnormalities and perfect agreement with regards to hemorrhage. Intraobserver agreement kappa values were 0.939 and 0.860 for nonurgent abnormalities. Interobserver agreement between the 2 radiologists for both diagnostic monitors and the iPad 2 was also substantial ranging from 0.821-0.860. CONCLUSIONS: The iPad 2 is a reliable modality in the interpretation of CT brain studies in them emergency setting and for the detection of acute and chronic abnormalities, with comparable performance to standard diagnostic workstation monitors.

Verification of a simplified aneurysm dimensionless flow parameter to predict intracranial aneurysm rupture status.

OBJECTIVES: Aneurysm number (An) is a novel prediction tool utilizing parameters of pulsatility index (PI) and aneurysm geometry. An has been shown to have the potential to differentiate intracranial aneurysm (IA) rupture status. The objective of this study is to investigate the feasibility and accuracy of An for IA rupture status prediction using Australian based clinical data. METHODS: A retrospective study was conducted across three tertiary referral hospitals between November 2017 and November 2020 and all saccular IAs with known rupture status were included. Two sets of An values were calculated based on two sets of PI values previously reported in the literature. RESULTS: Five hundred and four IA cases were included in this study. The results demonstrated no significant difference between ruptured and unruptured status when using An ≥1 as the discriminator. Further analysis showed no strong correlation between An and IA subtypes. The area under the curve (AUC) indicated poor performance in predicting rupture status (AUC1 = 0.55 and AUC2 = 0.56). CONCLUSIONS: This study does not support An ≥1 as a reliable parameter to predict the rupture status of IAs based on a retrospective cohort. Although the concept of An is supported by hemodynamic aneurysm theory, further research is needed before it can be applied in the clinical setting. ADVANCES IN KNOWLEDGE: This study demonstrates that the novel prediction tool, An, proposed in 2020 is not reliable and that further research of this hemodynamic model is needed before it can be incorporated into the prediction of IA rupture status.

Incidental cardiac findings on thoracic imaging.

The cardiac structures are well seen on nongated thoracic computed tomography studies in the investigation and follow-up of cardiopulmonary disease. A wide variety of findings can be incidentally picked up on careful evaluation of the pericardium, cardiac chambers, valves, and great vessels. Some of these findings may represent benign variants, whereas others may have more profound clinical importance. Furthermore, the expansion of interventional and surgical practice has led to the development and placement of new cardiac stents, implantable pacemaker devices, and prosthetic valves with which the practicing radiologist should be familiar. We present a collection of common incidental cardiac findings that can be readily identified on thoracic computed tomography studies and briefly discuss their clinical relevance.

Correlation between subcutaneous knee fat thickness and chondromalacia patellae on magnetic resonance imaging of the knee.

PURPOSE: Chondromalacia patellae is a common cause of anterior knee pain in young patients and can be detected noninvasively with magnetic resonance imaging (MRI). The purpose of our study was to evaluate the correlation between subcutaneous fat thickness around the knee joint on axial MRIs as a surrogate marker of obesity, with the presence or absence of chondromalacia patellae. METHODS: A retrospective review was conducted of knee MRIs in 170 patients who satisfied the inclusion criteria. Imaging was performed over a 12-month period on a 1.5T MRI system with a dedicated extremity coil. Two radiologists experienced in musculoskeletal imaging assessed each examination in consensus for the presence or absence of chondromalacia patellae and graded positive studies from 0 (absent) to 3 (full cartilage thickness defect). Measurement of subcutaneous knee fat thickness was obtained on the medial aspect of the knee. RESULTS: MRI findings of chondromalacia patellae were present in 33 patients (19.4%), of which, there were 11 grade 1 lesions (33.3%), 9 grade 2 lesions (27.3%), and 13 grade 3 lesions (39.4%). The mean subcutaneous knee fat thickness was significantly higher in the chondromalacia patellae group for all grades compared with the normal group (P < .001), and there was a significant correlation between subcutaneous knee fat thickness and grades of chondromalacia patellae (R = 0.48 [95% confidence interval, 0.38-0.68]; P < .001). Female patients had thicker subcutaneous knee fat and more severe grades of chondromalacia patellae. CONCLUSION: Subcutaneous knee fat thickness as a surrogate marker of obesity was positively associated with the presence and severity of chondromalacia patellae on MRI.

Endovascular repair of a giant common hepatic aneurysm.

Hepatic artery aneurysms are a rare phenomenon but their diagnosis and prompt treatment are imperative due to a high risk of mortality and complications. Appropriate management depends on patient characteristics, anatomical location of the aneurysm, operative risk and collateral arterial supply. Management options include surgical and endovascular approaches. The endovascular approach has gained popularity over recent years as it is an effective and less invasive alternative to surgical management. In this case report, we present a giant common hepatic artery aneurysm and its successful endovascular management. The patient had a complete resolution of symptoms after the procedure and remained well 8 months postprocedure.