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There is a growing need for small-diameter (6 mm) off-the-shelf synthetic vascular conduits for different surgical bypass procedures, with actual synthetic conduits showing unacceptable thrombosis rates. The goal of this study was to build vascular grafts with better compliance than standard synthetic conduits and with an inner layer stimulating endothelialization while remaining antithrombogenic.Tubular vascular conduits made of a scaffold of polyurethane/polycaprolactone combined with a bioactive coating based on chondroitin sulfate (CS) were created using electrospinning and plasma polymerization. In vitro testing followed by a comparative in vivo trial in a sheep model as bilateral carotid bypasses was performed to assess the conduits' performance compared to the actual standard.In vitro, the novel small-diameter (5 mm) electrospun vascular grafts coated with chondroitin sulfate (CS) showed 10 times more compliance compared to commercial expanded polytetrafluoroethylene (ePTFE) conduits while maintaining adequate suturability, burst pressure profiles, and structural stability over time. The subsequent in vivo trial was terminated after electrospun vascular grafts coated with CS showed to be inferior compared to their expanded polytetrafluoroethylene counterparts.The inability of the experimental conduits to perform well in vivo despite promising in vitro results may be related to the low porosity of the grafts and the lack of rapid endothelialization despite the presence of the CS coating. Further research is warranted to explore ways to improve electrospun polyurethane/polycaprolactone scaffold in order to make it prone to transmural endothelialization while being resistant to strenuous conditions.

To assess the ability of four-dimensional (4D) flow MRI to measure hepatic arterial hemodynamics by determining the effects of spatial resolution and respiratory motion suppression in vitro and its applicability in vivo with comparison to two-dimensional (2D) phase-contrast MRI.A dynamic hepatic artery phantom and 20 consecutive volunteers were scanned. The accuracies of Cartesian 4D flow sequences with k-space reordering and navigator gating at four spatial resolutions (0.5- to 1-mm isotropic) and navigator acceptance windows (± 8 to ± 2 mm) and one 2D phase-contrast sequence (0.5-mm in -plane) were assessed in vitro at 3 T. Two sequences centered on gastroduodenal and hepatic artery branches were assessed in vivo for intra - and interobserver agreement and compared to 2D phase-contrast.In vitro, higher spatial resolution led to a greater decrease in error than narrower navigator window (30.5 to -4.67% vs -6.64 to -4.67% for flow). In vivo, hepatic and gastroduodenal arteries were more often visualized with the higher resolution sequence (90 vs 71%). Despite similar interobserver agreement (κ = 0.660 and 0.704), the higher resolution sequence had lower variability for area (CV = 20.04 vs 30.67%), flow (CV = 34.92 vs 51.99%), and average velocity (CV = 26.47 vs 44.76%). 4D flow had lower differences between inflow and outflow at the hepatic artery bifurcation (11.03 ± 5.05% and 15.69 ± 6.14%) than 2D phase-contrast (28.77 ± 21.01%).High-resolution 4D flow can assess hepatic artery anatomy and hemodynamics with improved accuracy, greater vessel visibility, better interobserver reliability, and internal consistency.• Motion-suppressed Cartesian four-dimensional (4D) flow MRI with higher spatial resolution provides more accurate measurements even when accepted respiratory motion exceeds voxel size. • 4D flow MRI with higher spatial resolution provides substantial interobserver agreement for visualization of hepatic artery branches. • Lower peak and average velocities and a trend toward better internal consistency were observed with 4D flow MRI as compared to 2D phase-contrast.

In this review article, we discuss the literature pertaining to the bibliometric analysis of academic radiologists' scholarly activity in order to identify current trends, knowledge gaps, and potential future directions. Current research provides cross-sectional analyses of bibliometrics on three main themes: academic ranking, gender disparity, and research funding. The most commonly used parameters are the publication and the citation counts, the h-index and the number of years in academia. The h-index correlates positively with academic ranking and, in the case of editorial board members, with the journal's impact factor. Scholars who have secured National Institutes of Health funding tend to have higher h-indexes than those who have not. Whereas gender balance has been achieved in medical school and in several medical specialties, women remain significantly fewer than men in most areas of radiology. The underrepresentation of women is particularly noticeable at higher academic ranks and in leadership positions, suggesting that significant barriers to female radiologists' career advancement exist. Scholarly productivity of radiology residents and the impact of research on academic productivity are subjects that have received less attention in the published literature. Future studies should focus on whether bibliometric parameters can be used as reliable measurements of scholarly activity to help determine appointments, promotions and grant allocations, and to assess interventions that promote gender parity.

OBJECTIVES The main objective was to assess whether a composite coronary artery bypass grafting strategy including a saphenous vein graft bridge to distribute left internal mammary artery outflow provides non-inferior patency rates compared to conventional grafting surgery with separated left internal mammary artery to left anterior descending coronary graft and aorto-coronary saphenous vein grafts to other anterolateral targets. METHODS All patients underwent isolated grafting surgery with cardiopulmonary bypass and received ≥2 grafts/patients on the anterolateral territory. The graft patency (i.e. non-occluded) was assessed using multislice spiral computed tomography at 1 year. RESULTS From 2012 to 2021, 208 patients were randomized to a bridge (n = 105) or conventional grafting strategy (n = 103). Patient characteristics were comparable between groups. The anterolateral graft patency was non-inferior in the composite bridge compared to conventional grafting strategy at 1 year [risk difference 0.7% (90% confidence interval –4.8 to 6.2%)]. The graft patency to the left anterior descending coronary was no different between groups (P = 0.175). Intraoperatively, the bridge group required shorter vein length for anterolateral targets (P < 0.001) and exhibited greater Doppler flow in the mammary artery pedicle (P = 0.004). The composite outcome of death, myocardial infarction or target vessel reintervention at 30 days was no different (P = 0.164). CONCLUSIONS Anterolateral graft patency of the composite bridge grafting strategy is non-inferior to the conventional grafting strategy at 1 year. This novel grafting strategy is safe, efficient, associated with several advantages including better mammary artery flow and shorter vein requirement, and could be a valuable alternative to conventional grafting strategies. Ten-year clinical follow-up is underway. Trial registration ClinicalTrials.gov: NCT01585285.

Magnetic resonance navigation (MRN) uses MRI gradients to steer magnetic drug-eluting beads (MDEBs) across vascular bifurcations. We aim to experimentally verify our theoretical forces balance model (gravitational, thrust, friction, buoyant and gradient steering forces) to improve the MRN targeted success rate. A single-bifurcation phantom (3 mm inner diameter) made of poly-vinyl alcohol was connected to a cardiac pump at 0.8 mL/s, 60 beats/minutes with a glycerol solution to reproduce the viscosity of blood. MDEB aggregates (25 ± 6 particles, 200 $$\mu {\text{m}}$$ ) were released into the main branch through a 5F catheter. The phantom was tilted horizontally from − 10° to +25° to evaluate the MRN performance. The gravitational force was equivalent to 71.85 mT/m in a 3T MRI. The gradient duration and amplitude had a power relationship (amplitude=78.717 $${(duration)}^{-0.525}$$ ). It was possible, in 15° elevated vascular branches, to steer 87% of injected aggregates if two MRI gradients are simultaneously activated ( $${G}_{x}$$ = +26.5 mT/m, $${G}_{y}$$ = +18 mT/m for 57% duty cycle), the flow velocity was minimized to 8 cm/s and a residual pulsatile flow to minimize the force of friction. Our experimental model can determine the maximum elevation angle MRN can perform in a single-bifurcation phantom simulating in vivo conditions.

Background People living with HIV (PLWH) have a higher risk of myocardial infarction. Coronary atherosclerotic plaque CT characterization helps to predict cardiovascular risk. Purpose To measure CT characteristics of coronary plaque in PLWH without known cardiovascular disease and healthy volunteers without HIV. Materials and Methods In this prospective study, noncontrast CT (all participants, n = 265) was used for coronary artery calcium (CAC) scoring in asymptomatic PLWH and healthy volunteers without HIV, without known cardiovascular disease, from 2012 to 2019. At coronary CT angiography (n = 233), prevalence, frequency, and volume of calcified, mixed, and noncalcified plaque were measured. Poisson regressions were used with adjustment for cardiovascular risk factors. Results There were 181 PLWH (mean age, 56 years ± 7; 167 men) and 84 healthy volunteers (mean age, 57 years ± 8; 65 men) evaluated by using noncontrast CT. CT angiography was performed in 155 PLWH and 78 healthy volunteers. Median 10-year Framingham risk score was not different between PLWH and healthy volunteers (10% vs 9%, respectively; P = .45), as were CAC score (odds ratio [OR], 1.06; 95% CI: 0.58, 1.94; P = .85) and overall plaque prevalence (prevalence ratio, 1.07; 95% CI: 0.86, 1.32; P = .55) after adjustment for cardiovascular risk. Noncalcified plaque prevalence (prevalence ratio, 2.5; 95% CI: 1.07, 5.67; P = .03) and volume (OR, 2.8; 95% CI: 1.05, 7.40; P = .04) were higher in PLWH. Calcified plaque frequency was reduced in PLWH (OR, 0.6; 95% CI: 0.40, 0.91; P = .02). Treatment with protease inhibitors was associated with higher volume of overall (OR, 1.8; 95% CI: 1.09, 2.85; P = .02) and mixed plaque (OR, 1.6; 95% CI: 1.04, 2.45; P = .03). Conclusion Noncalcified coronary plaque burden at coronary CT angiography was two- to threefold higher in asymptomatic people living with HIV without known cardiovascular disease compared with healthy volunteers without HIV. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Lai in this issue.

Radiology practices characterized as small and rural are challenged to recruit and retain interventional radiologists. Lack of access to interventional radiologic services results in a failure to meet the needs of patients, hospitals, and other community stakeholders. Acknowledging this challenge, the ACR's Commission on General, Small, Emergency and/or Rural Practice and Commission on Interventional and Cardiovascular Imaging and the Society of Interventional Radiology partnered to establish a joint task force to study this issue and identify strategies the ACR and the Society of Interventional Radiology should take to improve small and rural practice recruitment and retention of interventional radiologists. This report describes the deliberations and recommendations of the task force.

Background: Off-label drug use is associated with an increased risk of adverse drug reactions. It is common in pediatrics and in rare diseases, which are two characteristics applying to vascular anomalies (VA). Objectives: The aim of this work was to quantify off-label drug use in VA and assess its safety. Methods: A review was conducted to extract a list of drugs used in VA management. A drug was considered to have significant safety concerns if a black box warning was present or if a serious adverse drug reaction (SADR) was reported in at least 1% of the patients (SADR is defined as a noxious and unintended response to a drug that occurs at any dose and results in hospitalization, prolongation of existing hospitalization, congenital malformation, persistent or significant disability or incapacity, life-threatening condition, or death). The labelling status and safety of each drug was assessed based on the product monograph, Micromedex, and the FDA data. Results: We found that 98.9% of the inventoried drugs were used off-label or unlicensed for VA management. Only the oral solution of propranolol hydrochloride (Hemangeol®) for the treatment of infantile hemangiomas is approved. Significant safety issues concerned 73% of the drugs and were more frequent among systemic than locally delivered drugs. Conclusions: Off-label drug use in VA is the rule and not the exception. Significant safety concerns are common. It is necessary to carefully weigh risk and benefits for every patient when using systemic and local treatments carrying safety concerns. Patients should be openly informed and involved in the decision-making process.

The deliberate occlusion of blood flow through transarterial embolization is currently being used to treat conditions ranging from hemorrhages to hypervascular tumors. Degradable, imageable high borate glass microspheres (BRS2) were developed and tested to improve lesion targeting and promote a temporary vascular occlusion which is sufficient for most embolization procedure. A 48 hour pilot study, in a swine renal model, was conducted to assess the embolization effectiveness and potential risks of this new embolic agent. Bilateral embolization of the caudal branch of the renal arteries using test and control particles were performed in 4 pigs. Embolization efficacy, recanalization and resulting ischemia were evaluated at different time frame (0, 24 and 48 hours). The primary outcomes for this study were the assessment of: (i) embolization effectiveness, and (ii) vessel recanalization. The test article was found to occlude vessels as effectively as the control microspheres, with the use of a smaller volume of microspheres. At the 24 hour time point, over 95% of the material was found to be completely degraded, although little to no recanalization was observed. This data suggests that BRS2 is an effective embolic agent, however further investigations into the method of delivery are required prior to clinical implementation.

The current coronavirus disease 2019 (COVID-19) pandemic is creating significant challenges to the Canadian health system, including the practice of interventional radiology (IR). Interventional radiology will continue to play an important role in patient care, during this crisis. This document serves to guide interventional and general radiologists in safely performing IR procedures on patients with suspected or confirmed COVID-19, using the best evidence, guidelines and expert recommendations available. These strategies include reviewing procedural indications, development of tactics to minimize cross contamination prior to the intervention, appropriate usage of personal protection equipment according to the type of procedure (along with defining aerosol-generating procedures in IR), along with developing the appropriate work environment during the COVID-19 pandemic. By adopting the policies described, hospitals will protect the interventional radiologists, medical radiation technologists, nurses, ancillary staff, along with patients who benefit from their care.

Purpose: To quantify eye lens dose in interventional radiology and assess whether neck dosimeter is a good surrogate to evaluate eye lens dosimetry. Methods: Radiation exposure was prospectively measured in 9 interventional radiologists between May and October 2017. Standard Hp(0,07) thermoluminescent dosimeters (TLDs) were worn at the neck outside the lead apron, and 2 dedicated eye lens Hp(3) TLDs were placed just above the eyes, one midline and another at the outer edge of the left eye. Correlations between eye lens and neck TLD doses were assessed with Pearson coefficient, and linear regression was used to predict eye lens dose from neck TLD values. Results: Eye lens dose without eye protection was 0.18 ± 0.11 (mean ± standard deviation; 0.08-0.41) mSv per workday and 35.3 ± 6.6 mSv (16.3-82.9) annually (200 workdays/year). Five (56%) radiologists exceeded the 20 mSv annual eye lens dose limit. Eye lens doses from left and central TLDs were 12.46 ± 3.02 and 9.29 ± 3.38 mSv, respectively ( P = .027). Mean eye lens (left and central) and neck TLD doses were 10.87 ± 2.67 and 16.56 ± 5.67 mSv, respectively ( P = .008). Pearson correlation coefficient between both eye lens TLD and between mean eye lens TLD and neck TLD doses were 0.91 and 0.92, respectively. Average of eye lens dose was 0.0179 + (0.5971 × neck dose). Conclusion: Full-time interventional radiologists are likely to suffer from deterministic radiation effects to the eye lens, especially on the left side. Neck TLD significantly overestimates eye lens dose. However, eye lens doses are highly correlated with neck doses and may be predicted from the neck TLD values.

Four-dimensional (4D) flow magnetic resonance imaging (MRI) is a leading-edge imaging technique and has numerous medicinal applications. In vitro 4D flow MRI can offer some advantages over in vivo ones, especially in accurately controlling flow rate (gold standard), removing patient and user-specific variations, and minimizing animal testing. Here, a complete testing method and a respiratory-motion-simulating platform are proposed for in vitro validation of 4D flow MRI. A silicon phantom based on the hepatic arteries of a living pig is made. Under the free-breathing, a human volunteer's liver motion (inferior-superior direction) is tracked using a pencil-beam MRI navigator and is extracted and converted into velocity-distance pairs to program the respiratory-motion-simulating platform. With the magnitude displacement of about 1.3 cm, the difference between the motions obtained from the volunteer and our platform is ≤ 1 mm which is within the positioning error of the MRI navigator. The influence of the platform on the MRI signal-to-noise ratio can be eliminated even if the actuator is placed in the MRI room. The 4D flow measurement errors are respectively 0.4% (stationary phantom), 9.4% (gating window = 3 mm), 27.3% (gating window = 4 mm) and 33.1% (gating window = 7 mm). The vessel resolutions decreased with the increase of the gating window. The low-cost simulation system, assembled from commercially available components, is easy to be duplicated.

There is a need for a specific atherosclerotic risk assessment for people living with HIV (PLWH).A machine learning classification model was applied to PLWH and control subjects with low-to-intermediate cardiovascular risks to identify associative predictors of diagnosed carotid artery plaques. Associations with plaques were made using strain elastography in normal sections of the common carotid artery and traditional cardiovascular risk factors.One hundred two PLWH and 84 control subjects were recruited from the prospective Canadian HIV and Aging Cohort Study (57 ± 8 years; 159 men). Plaque presence was based on clinical ultrasound scans of left and right common carotid arteries and internal carotid arteries. A classification task for identifying subjects with plaque was defined using random forest (RF) and logistic regression models. Areas under the receiver operating characteristic curves (AUC-ROCs) were applied to select 5 among 50 combinations of 4 or less features yielding the highest AUC-ROCs.To retrospectively classify individuals with and without plaques, the 5 most discriminant combinations of features had AUC-ROCs between 0.76 and 0.79. AUC-ROCs from RF were statistically significantly higher than those obtained with logistic regressions ( P = 0.0001). The most discriminant features of RF classifications in PLWH were age, smoking status, maximum axial strain and pulse pressure (equal weights), and sex and antiretroviral therapy exposure (equal weights). When considering the whole population, the HIV status was identified as a cofactor associated with carotid artery plaques.Strain elastography adds to traditional cardiovascular risk factors for identifying individuals with carotid artery plaques.

INTRODUCTION Since the 1990s, endovascular aortic aneurysm repair (EVAR) has become a common alternative to open surgery for the treatment of abdominal aortic aneurysms (AAAs). To aid the deployment of stent-grafts, fluoroscopic image guidance can be enhanced using pre-operative simulation and intraoperative image fusion techniques. However, the impact of Ca presence on the guidance accuracy of such techniques is yet to be considered. METHODS In the present work, we introduce a guidance tool that accounts for patient-specific Ca presence. Numerical simulations of EVAR were developed for 12 elective AAA patients, both with (With-Ca) and without (No-Ca) Ca consideration. To assess the accuracy of the simulations, the image results were overlaid on corresponding intraoperative images and the overlay error was measured at selected anatomical landmarks. RESULTS With this approach we gained insight into the impact of Ca presence on image fusion accuracy. Inclusion of Ca improved mean image fusion accuracy by 8.68 ± 4.59%. In addition, a positive correlation between the relative Ca presence and the image fusion accuracy was found (R = 0.753, P

A machine learning classification model was used to discriminate subjects with and without carotid artery plaques in a population of HIV -positive and -negative individuals with low-to-intermediate cardiovascular risks. The aim was to identify associations between the presence of plaques and features consisting of traditional cardiovascular risk factors and strain elastography in normal sections of the common carotid artery. One hundred and two HIV-infected and 84 age-matched control subjects were recruited from a prospective, controlled cohort study (mean age 57 years ± 8 years; 159 men). Plaques, defined as an intima-media thickness (IMT) greater than 1 mm, were identified on ultrasound images in longitudinal views of the common and internal carotid arteries. A classification task of identifying subjects with presence of plaque was defined using a random forests model. Six strain features on normal CCA in addition to 21 clinical biomarkers and clinical ultrasound imaging features* were selected as inputs in the classification model. The 5 most discriminant combinations of features had ROC-AUCs between 0.76 and 0.80.