Publications by authors named "Gilles Soulez"

175 Publications

Management of Pancreatico-duodenal arterio-venous malformation.

CVIR Endovasc 2022 Jan 3;5(1). Epub 2022 Jan 3.

CHUM Université de Montréal, Montreal, Québec, Canada.

Purpose: To describe the interventional management and clinical outcome of pancreatico-duodenal arterio-venous malformations (PDAVMs).

Material And Methods: Seven patients presenting a PDAVM (6 women, 1 male; mean age: 61) were retrospectively reviewed. Technical, clinical success and complications of embolization and surgical management of symptomatic PDAVMs were assessed. Technical success was defined as a complete occlusion of the PDAVM and clinical success as no clinical symptom or recurrence during follow-up. Patients with asymptomatic PDAVMs were followed clinically, by Doppler ultrasound and CT-angiography.

Results: Mean follow-up time was 69 months (15-180). Five symptomatic patients presented with upper gastrointestinal bleeding (n=3), ascites (n=1), and abdominal pain (n=1). Two patients were asymptomatic. The PDAVMs were classified as follow: Yakes I (1), IIIa (2), IIIb (3) and IV (1). Five symptomatic patients were treated with 9 embolization sessions with arterial approach (onyx®, glue, coils) in 7 and venous approach in 2 (plugs, coils, covered stents, STS foam and onyx®). Technical success of embolization was 60% (3/5). Devascularization was incomplete for 2 Yakes IIIB patients. Clinical success of embolization was estimated at 80% (4/5) as one patient required additional surgery (Whipple) because of persistent bleeding. One splenic vein thrombosis was treated successfully by mechanical thrombectomy and heparin. No recurrence occurred during follow-up. No progression was documented in asymptomatic patients.

Conclusion: Embolization of symptomatic PDAVMs is effective and surgery should be performed in second intention. Complete devascularization is more difficult to obtain in Yakes III PDAVM.
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http://dx.doi.org/10.1186/s42155-021-00269-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8724485PMC
January 2022

Impact of calcification modeling to improve image fusion accuracy for endovascular aortic aneurysm repair.

Int J Numer Method Biomed Eng 2021 Dec 2:e3556. Epub 2021 Dec 2.

Department of Radiology Radiation-Oncology and Nuclear Medicine, Université de Montréal, Montréal, Quebec, Canada.

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 preoperative simulation and intraoperative image fusion techniques. However, the impact of calcification (Ca) presence on the guidance accuracy of such techniques is yet to be considered. 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. 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 = .753, p < .005). Our results suggest that considering Ca presence in patient-specific EVAR simulations increases the reliability of EVAR image guidance techniques that utilize numerical simulation, especially for patients with severe aortic Ca presence.
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http://dx.doi.org/10.1002/cnm.3556DOI Listing
December 2021

Navigation of Microrobots by MRI: Impact of Gravitational, Friction and Thrust Forces on Steering Success.

Ann Biomed Eng 2021 Dec 7;49(12):3724-3736. Epub 2021 Oct 7.

Centre de recherche du Centre hospitalier de l, Université de Montréal (CRCHUM), 900 Rue Saint-Denis, Montreal, QC, H2X 0A9, Canada.

Introduction: 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.

Method: 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 [Formula: see text]) were released into the main branch through a 5F catheter. The phantom was tilted horizontally from - 10° to +25° to evaluate the MRN performance.

Results: 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 [Formula: see text]). It was possible, in 15° elevated vascular branches, to steer 87% of injected aggregates if two MRI gradients are simultaneously activated ([Formula: see text] = +26.5 mT/m, [Formula: see text]= +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.

Conclusion: Our experimental model can determine the maximum elevation angle MRN can perform in a single-bifurcation phantom simulating in vivo conditions.
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http://dx.doi.org/10.1007/s10439-021-02865-1DOI Listing
December 2021

Systemic, local, and sclerotherapy drugs: What do we know about drug prescribing in vascular anomalies?

Pediatr Blood Cancer 2021 Dec 1;68(12):e29364. Epub 2021 Oct 1.

Department of Pharmacology and Physiology, Université de Montréal, Montréal, Quebec, Canada.

Off-label drug prescribing, frequent in the treatment of vascular anomalies (VA), relies on the quality of the literature reporting drug efficacy and safety. Our objective is to review the level of evidence (LOE) surrounding drug use in VA, which is more prevalent in pediatric care. A list of drugs used in VA was created with a literature review in July 2020. For each drug listed, the article displaying the highest LOE was determined and then compared between efficacy/safety data, routes of administration, pharmacological categories and a subset of VA. The influence of research quality on study results was also explored. The median LOE for the 74 drugs identified poor methodological quality, with a predominance of retrospective studies or case reports. Drug safety is currently inadequately reported. This is alarming as many treatments display significant safety concerns. Also, current literature displays major publication bias that probably leads to overestimation of drug efficacy in VA.
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http://dx.doi.org/10.1002/pbc.29364DOI Listing
December 2021

Future Advances in Diagnosis and Drug Delivery in Interventional Radiology Using MR Imaging-Steered Theranostic Iron Oxide Nanoparticles.

J Vasc Interv Radiol 2021 09;32(9):1292-1295.e1

Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada; Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada. Electronic address:

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http://dx.doi.org/10.1016/j.jvir.2021.05.027DOI Listing
September 2021

Prevalence and Characterization of Subclinical Coronary Atherosclerotic Plaque with CT among Individuals with HIV: Results from the Canadian HIV and Aging Cohort Study.

Radiology 2021 06 20;299(3):571-580. Epub 2021 Apr 20.

From the Departments of Radiology (I.B., M.S., G.S., A.S.C., C.C.L.), Cardiology (S.M.), Family Medicine (J.G.B., B.T.), Microbiology (C.T.) and Internal Medicine (M.D.), University of Montreal Hospital (CHUM), 1051 Sanguinet St, Montréal, QC, Canada H2X 0C1; and Department of Radiology, Providence Health Care, Vancouver, Canada (J.L.). Members of the Canadian HIV and Aging Cohort Study Group are listed in the acknowledgments.

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, = 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 ( = 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; = .45), as were CAC score (odds ratio [OR], 1.06; 95% CI: 0.58, 1.94; = .85) and overall plaque prevalence (prevalence ratio, 1.07; 95% CI: 0.86, 1.32; = .55) after adjustment for cardiovascular risk. Noncalcified plaque prevalence (prevalence ratio, 2.5; 95% CI: 1.07, 5.67; = .03) and volume (OR, 2.8; 95% CI: 1.05, 7.40; = .04) were higher in PLWH. Calcified plaque frequency was reduced in PLWH (OR, 0.6; 95% CI: 0.40, 0.91; = .02). Treatment with protease inhibitors was associated with higher volume of overall (OR, 1.8; 95% CI: 1.09, 2.85; = .02) and mixed plaque (OR, 1.6; 95% CI: 1.04, 2.45; = .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 . See also the editorial by Lai in this issue.
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http://dx.doi.org/10.1148/radiol.2021203297DOI Listing
June 2021

Off-Label Use and Safety of Drug Use in Vascular Anomalies.

Dermatology 2021 6;237(4):649-657. Epub 2021 Apr 6.

Vascular Anomaly Team, CHU Sainte-Justine, Université de Montréal, Montreal, Québec, Canada.

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.
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http://dx.doi.org/10.1159/000515980DOI Listing
December 2021

Safety and Efficacy of Paclitaxel-Eluting Balloon Angioplasty for Dysfunctional Hemodialysis Access: A randomized trial Comparing with Angioplasty Alone.

J Vasc Interv Radiol 2021 03 19;32(3):350-359.e2. Epub 2021 Jan 19.

Department of Radiology, Centre Hospitalier de l'Université de Montréal, Montreal, Canada; Centre de recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Canada.

Purpose: To assess whether angioplasty of hemodialysis access (HA) stenosis with a drug-coated balloon (DCB) would prevent restenosis in comparison with plain-balloon percutaneous transluminal angioplasty (PTA).

Materials And Methods: This prospective randomized clinical trial enrolled 120 patients with dysfunctional arteriovenous fistulae (n = 109) and grafts (n = 11), due to a ≥50% stenosis between March 2014 and April 2018. All patients underwent high-pressure balloon angioplasty and were then randomized to either DCB (n = 60) or PTA (n = 60). Patients were followed-up for 1 year, and angiography was performed 6 months after angioplasty. The primary endpoint was the late lumen loss (LLL) at 6 months. Secondary endpoints included other angiographic parameters at 6 months and HA failures, adverse event, and mortality at 12 months. Continuous variables were compared with a Student t-test, and Kaplan-Meier curves were used for freedom from HA failure and for mortality.

Results: LLL in the DCB and in the PTA group were 0.64 mm ± 1.20 and 1.13 mm ± 1.51, respectively (P = .082, adjusted P = .0498). DCB was associated with lower percentage stenosis (54.2% ± 19.3 vs 61.7% ± 18.2; P = .047) and binary restenosis ≥50% (56.5% vs 81.1%; P = .009) than PTA. The number of HA failures after 12 months was lower for DCB than for PTA (45% vs 66.7%; P = .017). Mortality at 12 months was 10% and 8.3% in the DCB and PTA groups, respectively (P = .75).

Conclusions: Despite LLL improvement that failed to reach statistical significance, this study demonstrated decreased incidence and severity of restenosis with DCB compared with PTA to treat dysfunctional HA.
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http://dx.doi.org/10.1016/j.jvir.2020.10.030DOI Listing
March 2021

Combination of Alcohol and EVOH as a New Embolic Agent: Midterm Tissue and Inflammatory Effects in a Swine Model.

Radiol Res Pract 2020 23;2020:8831060. Epub 2020 Oct 23.

Diagnostic and Interventional Radiology Section, Department of Medical Imaging, University Hospital Timone APHM, 278 Rue Saint-Pierre, Marseille 13005, France.

Objective: To evaluate the vascular occlusion and midterm tissue toxicity properties of a combination of ethylene-vinyl alcohol (EVOH) (Squid 18®) (75%) and alcohol (25%)-Alco-Squid 18-in a swine model.

Materials And Methods: Alco-Squid 18 (75% Squid 18® mixed with 25% alcohol) (AS18) was compared to embolization with 96% alcohol alone and to embolization with Squid 18® (S18®) alone. An arteriovenous malformation (AVM) model was created in group 1 ( = 2). Each AVM model was then embolized with AS18 or S18® alone with evaluation of a ratio between the volume of embolic agent divided by the volume of the AVM (evaluated by CT). For group 2 ( = 5), each agent was tested on three different kidneys (upper pole kidney artery). Pre- and postinterventional CTs, angiographies, blood alcohol content dosages, and histological studies (3 months postintervention) were performed.

Results: AS18 has better distal distribution than S18® alone, both in the kidneys (mean capsule-S18® distance: 3.9 mm (±0.23) and mean capsule-AS18 distance: 2.3 mm (±0.11) (=0.029) and in the AVM model. Histological exploration found a higher rate of tubular necrosis with AS18 compared with S18® alone and alcohol alone (3.78 ± 0.44 compared to 2.33 ± 1.22 ( = 0.012) and 1.22 ± 0.67 (  < 0 .0001)). The blood alcohol content was negligible in all cases.

Conclusion: AS18 can suggest a better distal sclerotic and embolic character as compared with S18® alone without systemic toxicity.
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http://dx.doi.org/10.1155/2020/8831060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7605951PMC
October 2020

Current State of Bibliometric Research on the Scholarly Activity of Academic Radiologists.

Acad Radiol 2022 Jan 3;29(1):107-118. Epub 2020 Nov 3.

Department of Radiology, Centre hospitalier de l'Université de Montréal (CHUM), 1000 St-Denis street, Montreal (QC), Canada H2 X0C1; Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), 900 rue Saint-Denis, Montreal (QC), Canada H2 X 0A9. Electronic address:

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.
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http://dx.doi.org/10.1016/j.acra.2020.10.011DOI Listing
January 2022

FairEmbo Concept for Arterial Embolizations: In Vivo Feasibility and Safety Study with Suture-Based Microparticles Compared with Microspheres.

Cardiovasc Intervent Radiol 2021 Apr 25;44(4):625-632. Epub 2020 Oct 25.

Interventional Radiololy Section, Department of Medical Imaging, University Hospital Timone, APHM, Marseille, France.

Purpose: Microspheres are effective embolic agents, especially for the management of bleeding and oncologic lesions. The first FairEmbo study reported the effectiveness of embolization using suture fragments. The effectiveness and safety of arterial embolization with suture-based microparticles (SBM) were assessed in a swine model.

Materials And Methods: In this ethical-approved animal study, a polar artery in each kidney was embolized in four swine: one side with hand-cut non-absorbable SBM (Flexocrin 2®) and the contralateral side with Embozene® 900 for comparison. Swine were followed for 3 months (M3) to evaluate the effectiveness and the safety of SBM. Follow-up protocol included clinical monitoring, computed tomography (CT) control and digital subtraction angiography (DSA), followed by histological analyses. The SBM confection parameters were evaluated by automatic microscopic sizer. RStudio software and Mann-Whitney test (significance at P < 0.05) were used for statistics.

Results: The average size of SBM was 1002 μm (SD = 258). All targets were effectively embolized by SBM with an angiogram defect estimated at 45.6% (95% CI [35.9-55.2]), compared to 40.5% (95% CI [30.6-55.5]) for Embozene® group (P = 0.342). The average duration of SBM embolization procedure was significantly increased compared to Embozene® embolization (1202 s versus 222 s, P = 0.029). There were no statistical differences in M3 DSA and CT for SBM and Embozene®, with persistence of partial arterial occlusion and atrophic embolized area. No postoperative complications were observed on clinical and CT controls.

Conclusion: This experimental study suggests that embolization with SBM is feasible, safe and effective in short- and medium-term follow-up as compared to microspheres.
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http://dx.doi.org/10.1007/s00270-020-02678-0DOI Listing
April 2021

The feasibility of degradable glass microspheres as transient embolic medical devices.

J Biomater Appl 2021 01 28;35(6):615-632. Epub 2020 Jul 28.

Department of Medicine, Dalhousie University, Halifax, Canada.

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.
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http://dx.doi.org/10.1177/0885328220944871DOI Listing
January 2021

Adrenal vein sampling: External validation of multinomial regression modelling and left adrenal vein-to-peripheral vein ratio to predict lateralization index without right adrenal vein sampling.

Clin Endocrinol (Oxf) 2020 12 7;93(6):661-671. Epub 2020 Aug 7.

Department of Radiology, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, QC, Canada.

Background: Adrenal vein sampling (AVS) failure is mainly due to right adrenal vein unavailability. Multinomial regression modelling (MRM) and left adrenal vein-to-peripheral vein ratio (LAV/PV) were proposed to predict the lateralization index without the right AVS.

Objective: To assess external validity of MRM and LAV/PV to predict lateralization index when right adrenal vein sampling is missing.

Design: Diagnostic retrospective study.

Patients: Development and validation cohorts included AVS of 174 and 122 patients, respectively, from 2 different centres.

Measurements: Development and validation cohort data were used, respectively, for calibration and for validation of MRM and LAV/PV to predict the lateralization index without the right adrenal vein sampling. Sensitivity and specificity of MRM and LAV/PV were compared between both centres at different pre-established specificity thresholds based on receiver operating characteristic curves generated from the development cohort data.

Results: At a specificity threshold of 95% set in the development cohort, specificity values exceeded 90% (range, 90.6%-98.8%) for all verified MRM and LAV/PV models in the validation cohort. Corresponding sensitivities for MRM and LAV/PV, respectively, range from 54.1% to 83.7% and 32.8% to 88.4% for the development cohort compared to 33.3%-87.5% and 2.8%-79.2% for the validation cohort. Overall, diagnostic accuracy of both methods was higher to detect right (82.8%-93.5%) than left (70.2%-80.6%) lateralization index status in both centres.

Conclusions: Minimal changes in specificity from development to validation cohorts validate the use of MRM and LAV/PV to predict the lateralization index when the right AVS is missing. Both methods had better accuracy for right than left lateralization detection.
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http://dx.doi.org/10.1111/cen.14295DOI Listing
December 2020

The Canadian Association for Interventional Radiology (CAIR) and Canadian Association of Radiologists (CAR) Guidelines for Interventional Radiology Procedures for Patients With Suspected or Confirmed COVID-19.

Can Assoc Radiol J 2020 Nov 7;71(4):514-517. Epub 2020 May 7.

Department of Radiology, CHUM, Quebec, Canada.

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.
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http://dx.doi.org/10.1177/0846537120924310DOI Listing
November 2020

Eye Lens Dosimetry in Interventional Radiology: Assessment With Dedicated Hp(3) Dosimeters.

Can Assoc Radiol J 2021 May 27;72(2):317-323. Epub 2020 Mar 27.

Department of Radiology, Centre Hospitalier de Université de Montréal, Montreal, Quebec, Canada.

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 ( = .027). Mean eye lens (left and central) and neck TLD doses were 10.87 ± 2.67 and 16.56 ± 5.67 mSv, respectively ( = .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.
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http://dx.doi.org/10.1177/0846537120911755DOI Listing
May 2021

Feasibility of shear wave sonoelastography to detect endoleak and evaluate thrombus organization after endovascular repair of abdominal aortic aneurysm.

Eur Radiol 2020 Jul 4;30(7):3879-3889. Epub 2020 Mar 4.

Laboratory of Clinical Imaging Processing, Centre hospitalier de l'Université de Montréal (CHUM) Research Center (CRCHUM), Montréal, Québec, Canada.

Purpose: To investigate the feasibility of shear wave sonoelastography (SWS) for endoleak detection and thrombus characterization of abdominal aortic aneurysm (AAA) after endovascular repair (EVAR).

Materials And Methods: Participants who underwent EVAR were prospectively recruited between November 2014 and March 2016 and followed until March 2019. Elasticity maps of AAA were computed using SWS and compared to computed tomography angiography (CTA) and color Doppler ultrasound (CDUS). Two readers, blinded to the CTA and CDUS results, reviewed elasticity maps and B-mode images to detect endoleaks. Three or more CTAs per participant were analyzed: pre-EVAR, baseline post-EVAR, and follow-ups. The primary endpoint was endoleak detection. Secondary endpoints included correlation between total thrombus elasticity, proportion of fresh thrombus, and aneurysm growth between baseline and reference CTAs. A 3-year follow-up was made to detect missed endoleaks, EVAR complication, and mortality. Data analyses included Cohen's kappa; sensitivity, specificity, and positive predictive value (PPV); Pearson coefficient; and Student's t tests.

Results: Seven endoleaks in 28 participants were detected by the two SWS readers (k = 0.858). Sensitivity of endoleak detection with SWS was 100%; specificity and PPV averaged 67% and 50%, respectively. CDUS sensitivity was estimated at 43%. Aneurysm growth was significantly greater in the endoleak group compared to sealed AAAs. No correlation between growth and thrombus elasticity or proportion of fresh thrombus in AAAs was found. No new endoleaks were observed in participants with SWS negative studies.

Conclusion: SWS has the potential to detect endoleaks in AAA after EVAR with comparable sensitivity to CTA and superior sensitivity to CDUS.

Key Points: • Dynamic elastography with shear wave sonoelastography (SWS) detected 100% of endoleaks in abdominal aortic aneurysm (AAA) follow-up that were identified by a combination of CT angiography (CTA) and color Doppler ultrasound (CDUS). • Based on elasticity maps, SWS differentiated endoleaks from thrombi within the aneurysm sac (p < 0.001). • After 3-year follow-up, no new endoleaks were observed in SWS negative examinations.
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http://dx.doi.org/10.1007/s00330-020-06739-3DOI Listing
July 2020

Increased carotid artery wall stiffness and plaque prevalence in HIV infected patients measured with ultrasound elastography.

Eur Radiol 2020 Jun 12;30(6):3178-3187. Epub 2020 Feb 12.

Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montréal, QC, H2X 0A9, Canada.

Objectives: Assess carotid artery strain and motion in people living with HIV as markers of premature aging using ultrasound noninvasive vascular elastography (NIVE).

Methods: Seventy-four HIV-infected and 75 age-matched control subjects were recruited from a prospective, controlled cohort study from October 2015 to October 2017 (mean age 56 years ± 8 years; 128 men). NIVE applied to longitudinal ultrasound images of common and internal carotid arteries quantified the cumulated axial strain, cumulated shear strain, cumulated axial translation, and cumulated lateral translations. The presence of plaque was also assessed. An association between elastography biomarkers and HIV status was evaluated with Mann-Whitney tests and multivariable linear regression models.

Results: A higher occurrence of carotid artery plaques was found in HIV-infected individuals (p = 0.011). Lower cumulated lateral translations were found in HIV-infected subjects on both common and internal carotid arteries (p = 0.037 and p = 0.026, respectively). These observations remained significant when considering multivariable models including common cardiovascular risk factors and clinical characteristics (p < 0.05). Lower cumulated axial strains were also observed in internal carotid arteries when considering both multivariable models (p < 0.05).

Conclusion: Lower translation and strain of the carotid artery wall in HIV-infected individuals indicates increased vessel wall stiffness. These new imaging biomarkers could be used to characterize premature atherosclerosis development.

Key Points: • Noninvasive vascular elastography (NIVE) based on ultrasound imaging quantifies translations and strains of carotid arteries. • Lower translation and strain of the carotid artery wall found in HIV-infected individuals indicate premature arterial stiffening, compared with age-matched controls. • Carotid artery plaques were more prevalent in HIV-infected individuals than in control subjects.
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http://dx.doi.org/10.1007/s00330-020-06660-9DOI Listing
June 2020

Percutaneous Thrombectomy with the JETi8 Peripheral Thrombectomy System for the Treatment of Deep Vein Thrombosis.

J Vasc Interv Radiol 2020 Mar 22;31(3):444-453.e2. Epub 2020 Jan 22.

Department of Radiology, Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada; Centre de recherche, CHUM, Pavillon R, 900 rue Saint-Denis, Montréal, Québec, Canada, H2X 0A9. Electronic address:

Purpose: This study evaluated the safety and efficacy of the JETi8 peripheral thrombectomy system in treating acute deep vein thrombosis (DVT).

Materials And Methods: A retrospective study was conducted in 18 consecutive patients (mean age, 41 years old [range, 15-74 years old]; 5 men and 13 women). There were 21 instances of DVTs (9 iliofemoral, 10 axillosubclavian, and 2 portal), which were treated using the JETi8 thrombectomy device between November 2016 and July 2018. Thrombus was laced with recombinant tissue plasminogen activator (r-TPA) (9.3 mg, on average; range, 2-12 mg) in 17 procedures (81%) prior to thrombectomy. Technical success was defined as restoration of antegrade flow using the JETi8 with or without additional treatment of an underlying obstructive lesion. Procedural success was defined as technical success with or without the addition of overnight catheter-directed thrombolysis (CDT) RESULTS: Mean procedure time was 83 minutes (range, 30-160 minutes), and mean thrombus reduction with the JETi8 alone was 92% (range, 60%-100%). Stent placement was required in 6 procedures (29%). Technical success using the JETi8 system alone was 76% (16 of 21 procedures), whereas 5 procedures (24%) required subsequent overnight CDT in the intensive care unit. Procedural success rate was 100% (20 of 20 procedures). Mean aspirated volume was 531 mL (range, 250-1,230 mL). The only adverse event was a subsegmental pulmonary embolism. Seven patients (33%) were discharged the same day. Recurrent thrombosis was observed in 5 patients (24%), of whom 3 were successfully treated with the JETi8 system.

Conclusions: The JETi8 system may be a safe and effective option for thrombectomy of acute DVT.
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http://dx.doi.org/10.1016/j.jvir.2019.10.022DOI Listing
March 2020

Anthropomorphic and biomechanical mockup for abdominal aortic aneurysm.

Med Eng Phys 2020 03 15;77:60-68. Epub 2020 Jan 15.

Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), 900 Rue Saint-Denis, Montréal, Québec H2X 0A9, Canada; Université de Montréal, 2900 Boulevard Edouard-Montpetit, Montréal, Québec H3T 1J4, Canada. Electronic address:

Abdominal aortic aneurysm (AAA) is an asymptomatic condition due to the dilation of abdominal aorta along with progressive wall degeneration, where rupture of AAA is life-threatening. Failures of AAA endovascular repair (EVAR) reflect our inadequate knowledge about the complex interaction between the aortic wall and medical devices. In this regard, we are presenting a hydrogel-based anthropomorphic mockup (AMM) to better understand the biomechanical constraints during EVAR. By adjusting the cryogenic treatments, we tailored the hydrogel to mimic the mechanical behavior of human AAA wall, thrombus and abdominal fat. A specific molding sequence and a pressurizing system were designed to reproduce the geometrical and diseased characteristics of AAA. A mechanically, anatomically and pathologically realistic AMM for AAA was developed for the first time, EVAR experiments were then performed with and without the surrounding fat. Substantial displacements of the aortic centerlines and vessel expansion were observed in the case without surrounding fat, revealing an essential framework created by the surrounding fat to account for the interactions with medical devices. In conclusion, the importance to consider surrounding tissue for the global deformation of AAA during EVAR was highlighted. Furthermore, potential use of this AMM for medical training was also suggested.
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http://dx.doi.org/10.1016/j.medengphy.2019.12.005DOI Listing
March 2020

Common (Cystic) Lymphatic Malformations: Current Knowledge and Management.

Tech Vasc Interv Radiol 2019 Dec 23;22(4):100631. Epub 2019 Sep 23.

Centre hospitalier universitaire de Montréal, Montreal, Canada.

The approach to treating common (cystic) lymphatic malformations (LMs) has evolved significantly over the last decade due to clinical research and recent developments in molecular biology. Surgery, sclerosing agents, and medical drugs with specific targets for biological therapy have been reported for the management of LMs. We will discuss the importance to standardize the location and imaging characterization of LMs to improve the knowledge about the outcome of the different therapeutic options. Our goal is to help the reader understand the different options for the management of LMs with the balance between risk and benefit for the patients.
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http://dx.doi.org/10.1016/j.tvir.2019.100631DOI Listing
December 2019

Interventional Management of Arteriovenous Malformations.

Tech Vasc Interv Radiol 2019 Dec 16;22(4):100633. Epub 2019 Oct 16.

Department of Radiology, Radiation-Oncology and Nuclear Medicine, Université de Montréal, Montreal, Québec, Canada; Department of Radiology, Centre Hospitalier Universitaire Ste Justine (CHU-Ste Justine), Montreal, QC.

Arteriovenous malformations (AVMs) are fast flow malformations characterized by the presence of arteriovenous shunting. These congenital lesions can be evolutive, leading to serious complications such as bleeding, skin ulceration, and cardiac failure. The interventional radiologist plays an important role in the management of these patients. He should be involved in the clinical evaluation to make the proper diagnosis, evaluate the symptoms and potential indication for endovascular treatment. This evaluation should be done in a multidisciplinary clinic with access to plastic surgeons, internal medicine and dermatologist, as well as specific specialists that might need to be implicated (ENT surgeon in the face and neck area, for example). The Schobinger clinical classification is important to assess patient evolution and indicate intervention. We recommend to treat symptomatic or evolutive AVMs. Doppler ultrasound is the first imaging examination that should be performed. Then, MR angiography or computed tomography angiography (CTA) can be proposed depending on the anatomic area involved. Embolization is currently the first line of treatment for these patients. There is currently promising research in the identification of genetic markers and molecular target(s) but there is no recognized pharmacologic treatment for AVM available yet. Digital substraction angiography (DSA) is usually performed for guidance during the embolization session but is also essential to properly classify a specific lesion, according to its anatomy. The anatomic classifications proposed by Cho and Yakes are both useful to choose the best therapeutic approach: Endovascular, direct puncture, retrograde venous approach or a combination of these techniques. Ethanol is the most efficient agent but is at higher risk of skin necrosis and nerve injury and should therefore be used with caution in dangerous territories. Glue and Onyx are liquid agents that are also well suited to occlude the nidus; they can be used in association with ethanol. On the venous side, mechanical occlusion with coils or Amplatzer plugs is mostly used. Again, they can be used in association with a liquid agent (Ethanol, glue or Onyx) to reflux in the nidus. Surgery can be indicated to resect residual AVM following embolization if residual symptoms are present and the planned surgery is feasible, with relative safety.
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http://dx.doi.org/10.1016/j.tvir.2019.100633DOI Listing
December 2019

A Cohort Longitudinal Study Identifies Morphology and Hemodynamics Predictors of Abdominal Aortic Aneurysm Growth.

Ann Biomed Eng 2020 Feb 21;48(2):606-623. Epub 2019 Oct 21.

Inria, Centre de recherche de Paris, 75012, Paris, France.

Abdominal aortic aneurysms (AAA) are localized, commonly occurring aortic dilations. Following rupture only immediate treatment can prevent morbidity and mortality. AAA maximal diameter and growth are the current metrics to evaluate the associated risk and plan intervention. Although these criteria alone lack patient specificity, predicting their evolution would improve clinical decision. If the disease is known to be associated with altered morphology and blood flow, intraluminal thrombus deposit and clinical symptoms, the growth mechanisms are yet to be fully understood. In this retrospective longitudinal study of 138 scans, morphological analysis and blood flow simulations for 32 patients with clinically diagnosed AAAs and several follow-up CT-scans, are performed and compared to 9 control subjects. Several metrics stratify patients between healthy, low and high risk groups. Local correlations between hemodynamic metrics and AAA growth are also explored but due to their high inter-patient variability, do not explain AAA heterogeneous growth. Finally, high-risk predictors trained with successively clinical, morphological, hemodynamic and all data, and their link to the AAA evolution are built from supervise learning. Predictive performance is high for morphological, hemodynamic and all data, in contrast to clinical data. The morphology-based predictor exhibits an interesting effort-predictability tradeoff to be validated for clinical translation.
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http://dx.doi.org/10.1007/s10439-019-02375-1DOI Listing
February 2020

Magnetic Resonance Navigation for Targeted Embolization in a Two-Level Bifurcation Phantom.

Ann Biomed Eng 2019 Dec 9;47(12):2402-2415. Epub 2019 Jul 9.

Laboratory of Clinical Image Processing, Le Centre de recherche du CHUM (CRCHUM), 900 Rue Saint-Denis, Montréal, QC, H2X 0A9, Canada.

This work combines a particle injection system with our proposed magnetic resonance navigation (MRN) sequence with the intention of validating MRN in a two-bifurcation phantom for endovascular treatment of hepatocellular carcinoma (HCC). A theoretical physical model used to calculate the most appropriate size of the magnetic drug-eluting bead (MDEB, 200 μm) aggregates was proposed. The aggregates were injected into the phantom by a dedicated particle injector while a trigger signal was automatically sent to the MRI to start MRN which consists of interleaved tracking and steering sequences. When the main branch of the phantom was parallel to B, the aggregate distribution ratio in the (left-left, left-right, right-left and right-right divisions was obtained with results of 8, 68, 24 and 0% respectively at baseline (no MRN) and increased to 84%, 100, 84 and 92% (p < 0.001, p = 0.004, p < 0.001, p < 0.001) after implementing our MRN protocol. When the main branch was perpendicular to B, the right-left branch, having the smallest baseline distribution rate of 0%, reached 80% (p < 0.001) after applying MRN. Moreover, the success rate of MRN was always more than 92% at the 1st bifurcation in the experiments above.
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http://dx.doi.org/10.1007/s10439-019-02317-xDOI Listing
December 2019

Dynamic contrast-enhanced MRI to assess hepatocellular carcinoma response to Transarterial chemoembolization using LI-RADS criteria: A pilot study.

Magn Reson Imaging 2019 10 25;62:78-86. Epub 2019 Jun 25.

Department of Radiology, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, QC, Canada; Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada. Electronic address:

Purpose: To identify quantitative dynamic contrast-enhanced (DCE)-MRI perfusion parameters indicating tumor response of hepatocellular carcinoma (HCC) to transarterial chemoembolization (TACE).

Materials And Methods: This prospective pilot study was approved by our institutional review board; written and informed consent was obtained for each participant. Patients underwent DCE-MRI examinations before and after TACE. A variable flip-angle unenhanced 3D mDixon sequence was performed for T1 mapping. A dynamic 4D mDixon sequence was performed after contrast injection for assessing dynamic signal enhancement. Nonparametric analysis was conducted on the time-intensity curves. Parametric analysis was performed on the time-concentration curves using a dual-input single-compartment model. Treatment response according to Liver Reporting and Data System (LI-RADS) v2018 was used as the reference standard. The comparisons within groups (before vs. after treatment) and between groups (nonviable vs. equivocal or viable tumor) were performed using nonparametric bootstrap taking into account the clustering effect of lesions in patients.

Results: Twenty-eight patients with 52 HCCs (size: 10-104 mm) were evaluated. For nonviable tumors (n = 27), time to peak increased from 62.5 ± 18.2 s before to 83.3 ± 12.8 s after treatment (P< 0.01). For equivocal or viable tumors (n = 25), time to peak and mean transit time significantly increased (from 54.4 ± 24.1 s to 69.5 ± 18.9 s, P < 0.01 and from 14.2 ± 11.8 s to 33.9 ± 36.8 s, P= 0.01, respectively) and the transfer constant from the extracellular and extravascular space to the central vein significantly decreased from 14.8 ± 14.1 to 8.1 ± 9.1 s after treatment (P= 0.01).

Conclusion: This prospective pilot DCE-MRI study showed that time to peak significantly changed after TACE treatment for both groups (nonviable tumors and equivocal or viable tumors). In our cohort, several perfusion parameters may provide an objective marker for differentiation of treatment response after TACE in HCC patients.
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http://dx.doi.org/10.1016/j.mri.2019.06.017DOI Listing
October 2019

Interstitial imaging with multiple diffusive reflectance spectroscopy projections for blood vessels detection during brain needle biopsy procedures.

Neurophotonics 2019 Apr 23;6(2):025003. Epub 2019 Apr 23.

Polytechnique Montreal, Department of Engineering Physics, Montreal, Québec, Canada.

Blood vessel injury during image-guided brain biopsy poses a risk of hemorrhage. Approaches that reduce this risk may minimize related patient morbidity. We present here an intraoperative imaging device that has the potential to detect the brain vasculature . The device uses multiple diffuse reflectance spectra acquired in an outward-viewing geometry to detect intravascular hemoglobin, enabling the construction of an optical image in the vicinity of the biopsy needle revealing the proximity to blood vessels. This optical detection system seamlessly integrates into a commercial biopsy system without disrupting the neurosurgical clinical workflow. Using diffusive brain tissue phantoms, we show that this device can detect 0.5-mm diameter absorptive carbon rods up to from the biopsy window. We also demonstrate feasibility and practicality of the technique in a clinical environment to detect brain vasculature in an model system. brain vascular detection may add a layer of safety to image-guided biopsies and minimize patient morbidity.
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http://dx.doi.org/10.1117/1.NPh.6.2.025003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6477697PMC
April 2019

Microcirculatory Free Flap Failure With Patent Anastomosis Salvaged by In Situ Thrombolysis in Vulnerable Phase Burn.

J Burn Care Res 2019 08;40(5):718-722

Plastic Surgery Department, CHUM, Université de Montréal, Canada.

Free flap reconstruction in acute burns has high failure rates, relating mainly to a systemic inflammatory state. The "vulnerable phase" can last for 6 weeks after burn and can cause thrombosis of the flap microcirculation with patent arterial and venous anastomoses. Revision surgery alone may be unsuccessful, but thrombolysis can lead to flap salvage. We describe a case of successful flap salvage with thrombolysis after unsuccessful revision surgery by permeable arterial and venous anastomoses in a patient in the acute burn phase suffering from microcirculatory thrombosis. Thrombolysis in these cases has not been described to date, but it could contribute to salvaging flaps by radiological intervention alone. A 23-year-old man was admitted with a 38% TBSA burn, including loss of all eyelid skin. The right eye was reconstructed in a satisfactory manner, but the left eye required urgent corneal coverage on day 32 with a dorsalis pedis fasciocutaneous free flap. The flap was hypo-perfused postoperatively, but anastomoses were found to be permeable on exploration. Angiography performed postoperatively after revision confirmed anastomotic patency, but failed to demonstrate small vessel beds within the flap. Thus, r-tPa was given at the anastomosis site and immediately the flap recovered completely. However, a total of 10 packed red blood cell transfusions were needed over the next 9 days. Thrombolysis in the context of free flap microvascular compromise may improve the overall success rates, especially in acute-phase burn patients where this etiology may be found, due to a vulnerable inflammatory period.
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http://dx.doi.org/10.1093/jbcr/irz075DOI Listing
August 2019

Inflammation and Hypervascularization in a Large Animal Model of Knee Osteoarthritis: Imaging with Pathohistologic Correlation.

J Vasc Interv Radiol 2019 Jul 29;30(7):1116-1127. Epub 2019 Mar 29.

Department of Radiology, Centre hospitalier de l'Université de Montréal, Research Centre (CRCHUM), 900 rue Saint-Denis, Montreal H2X 0A9, Canada; Clinical Image Processing Laboratory, Centre hospitalier de l'Université de Montréal, Research Centre (CRCHUM), 900 rue Saint-Denis, Montreal H2X 0A9, Canada. Electronic address:

Purpose: To evaluate if synovial inflammation and hypervascularization are present in a dog model of knee osteoarthritis and can be detected on conventional magnetic resonance imaging (MRI), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), contrast-enhanced magnetic resonance imaging (CE-MRI), and quantitative digital subtraction angiography (Q-DSA) imaging.

Materials And Methods: Six dogs underwent MRI and angiography of both knees before and 12 weeks after right knee anterior cruciate ligament injury. Synovial vascularity was evaluated on CE-MRI, DCE-MRI, and Q-DSA by 2 independent observers. Synovial inflammation and vascularity were histologically scored independently. Cartilage lesions and osteophytes were analyzed macroscopically, and cartilage volumetry was analyzed by MRI. Vascularity and osteoarthritis markers on imaging were compared before and after osteoarthritis generation, and between the osteoarthritis model and the control knee, using linear mixed models accounting for within-dog correlation.

Results: In all knees, baseline imaging showed no abnormalities. Control knees did not develop significant osteoarthritis changes, synovial inflammation, or hypervascularization. In osteoarthritis knees, mean synovial enhancement score on CE-MR imaging increased by 13.1 ± 0.59 (P < .0001); mean synovial inflammation variable increased from 47.33 ± 18.61 to 407.97 ± 18.61 on DCE-MR imaging (P < .0001); and area under the curve on Q-DSA increased by 1058.58 ± 199.08 (P = .0043). Synovial inflammation, hypervascularization, and osteophyte formations were present in all osteoarthritis knees. Histology scores showed strong correlation with CE-MR imaging findings (Spearman correlation coefficient [SCC] = 0.742; P = .0002) and Q-DSA findings (SCC = 0.763; P < .0001) and weak correlation with DCE-MR imaging (SCC = -0.345; P = .329). Moderate correlation was found between CE-MR imaging and DSA findings (SCC = 0.536; P = .0004).

Conclusions: In this early-stage knee osteoarthritis dog model, synovial inflammation and hypervascularization were found on imaging and confirmed by histology.
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http://dx.doi.org/10.1016/j.jvir.2018.09.031DOI Listing
July 2019

Clinical Validation of a Semi-Automated Software for Maximal Diameter Measurements for Endovascular Repair Follow-up.

J Vasc Interv Radiol 2019 Apr;30(4):523-530

Department of Radiology, Radio-Oncology and Nuclear Medicine, University of Montreal, 2900 Édouard-Montpetit, Montreal, Quebec, Canada H3T 1J4; Institute of Biomedical Engineering, University of Montreal, 2900 Édouard-Montpetit, Montreal, Quebec, Canada H3T 1J4; Laboratoire Central du Traitement de l'Image, Research Imaging Platform, University of Montreal Hospital Research Center, Montreal, Canada; Department of Radiology, University of Montreal Hospital (CHUM), Montreal, Canada. Electronic address:

Purpose: To compare automated measurements of maximal diameter (D) of abdominal aortic aneurysm (AAA) orthogonal to luminal or outer wall envelope centerline for endovascular repair (EVAR) follow-up.

Material And Methods: Eighty-three consecutive patients with AAA treated by EVAR who had at least 1 computed tomography (CT) scan before and 2 CT scans after EVAR with at least 5 months' interval were included. Three-dimensional reconstruction of the AAA was achieved with dedicated segmentation software. Performances of automated calculation algorithms of D perpendicular to lumen or outer wall envelope centerlines were then compared to manual measurement of D on double-oblique multiplanar reconstruction (gold standard). Accuracy of automated D measurements at baseline, follow-up, and progression over time was evaluated by calculation of mean error, Bland-Altman plot, and regression models.

Results: Disagreement in D measurements between outer wall envelope algorithm and manual method was insignificant (mean error: baseline, -0.07 ± 1.66 mm, P = .7; first follow-up, 0.24 ± 1.69 mm, P = .2; last follow-up, -0.41 ± 2.74 mm, P = .17); whereas significant discrepancies were found between the luminal algorithm and the manual method (mean error: baseline, -1.24 ± 2.01 mm, P < .01; first follow-up, -1.49 ± 3.30 mm, P < .01; last follow-up, -1.78 ± 3.60 mm, P < .01). D progression results were more accurate with AAA outer wall envelope algorithm compared to luminal method (P = .2).

Conclusions: AAA outer wall envelope segmentation is recommended to enable automated calculation of D perpendicular to its centerline during EVAR follow-up.
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http://dx.doi.org/10.1016/j.jvir.2018.11.006DOI Listing
April 2019

The value of non-invasive vascular elastography (NIVE) in detecting early vascular changes in overweight and obese children.

Eur Radiol 2019 Jul 7;29(7):3854-3861. Epub 2019 Mar 7.

Department of Radiology, Sainte Justine Hospital, University of Montreal, 3175 Cote-Sainte-Catherine Road, Montreal, Quebec, H3T 1C5, Canada.

Objectives: Evaluate non-invasive vascular elastography (NIVE) in detecting vascular changes associated with obese children.

Methods: Case-control study to evaluate NIVE in 120 children, 60 with elevated body mass index (BMI) (≥ 85th percentile for age and sex). Participants were randomly selected from a longitudinal cohort, evaluating consequences of obesity in healthy children with one obese parent. Radiofrequency ultrasound videos of the common carotid artery were obtained. The carotid wall was segmented and NIVE applied to measure cumulated axial strain (CAS), cumulated axial translation (CAT), cumulated lateral translation (CLT), maximal shear strain (Max |SSE|), and intima-media thickness (IMT). Multivariate analyses were used controlling for age, sex, Tanner stage, blood pressure, and low-density lipoprotein. Statistical significance was set to 0.05-0.008. Participants were 10-13 years old (mean 11.4 and 12.0, for normal and elevated BMI groups, p < 0.001), 58% and 63% boys, respectively. Groups differed in age, Tanner stage, and blood pressure. In the normal BMI group, there was weak correlation between systolic blood pressure and Max |SSE| (r = 0.316, p = 0.01) and weak correlation between pulse pressure and Max |SSE| (r = 0.259, p = 0.045). After Bonferroni correction, CAT was significantly higher in the elevated BMI group (0.68 ± 0.24 mm vs. 0.52 ± 0.18 mm), p < 0.001. CAS/CAT was significantly lower in the elevated BMI group (9.54 ± 4.8 vs. 13.34 ± 6.46), p = 0.001. IMT was significantly higher in the elevated BMI group (0.36 ± 0.05 mm vs. 0.32 ± 0.05 mm) before Bonferroni correction, p = 0.013.

Conclusions: NIVE detected differences in CAT and CAS/CAT in elevated BMI children. NIVE is a promising technique to monitor radiological markers of subclinical atherosclerosis.

Key Points: • NIVE is a non-invasive technique based on measurement of subsegmental focal deformation of vascular wall to detect subclinical changes in arterial wall compliance. • Children with elevated BMI showed increased carotid artery wall movement during systole, as compared to normal BMI children (mean 0.68 ± 0.24 mm vs. 0.52 ± 0.18 mm; p < 0.001) and a lower ratio of vascular wall strain to wall movement during systole (mean 9.54 ± 4.8 vs. 13.34 ± 6.46; p = 0.001). • The detection of these subclinical changes helps physicians in the stratification of children at risk of atherosclerosis and guides in the implementation of preventive measures.
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http://dx.doi.org/10.1007/s00330-019-06051-9DOI Listing
July 2019

MRI-Compatible Injection System for Magnetic Microparticle Embolization.

IEEE Trans Biomed Eng 2019 08 20;66(8):2331-2340. Epub 2018 Dec 20.

Objective: Dipole field navigation and magnetic resonance navigation exploit B magnetic fields and imaging gradients for targeted intra-arterial therapies by using magnetic drug-eluting beads (MDEBs). The strong magnetic strength (1.5 or 3 T) of clinical magnetic resonance imaging (MRI) scanners is the main challenge preventing the formation and controlled injection of specific-sized particle aggregates. Here, an MRI-compatible injector is proposed to solve the above problem.

Methods: The injector consists of two peristaltic pumps, an optical counter, and a magnetic trap. The magnetic property of microparticles, the magnetic compatibility of different parts within the injector, and the field distribution of the MRI system were studied to determine the optimal design and setup of the injector. The performance was investigated through 30.4-emu/g biocompatible magnetic microparticles (230 ± 35 μm in diameter) corresponding to the specifications needed for trans-arterial chemoembolization in human adults.

Results: The system can form aggregates containing 20 to 60 microparticles with a precision of six particles. The corresponding aggregate lengths range from 1.6 to 3.2 mm. Based on the injections of 50 MRI-visible boluses into a phantom which mimics realistic physiological conditions, 82% of the aggregates successfully reached subbranches.

Conclusion And Significance: This system has the capability to operate within the strong magnetic field of a clinical 3-T MRI, to form proper particle aggregates and to automatically inject these aggregates into the MRI bore. Moreover, the versatility of the proposed injector renders it suitable for selective injections of MDEBs during MR-guided embolization procedures.
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http://dx.doi.org/10.1109/TBME.2018.2889000DOI Listing
August 2019
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