Anna Zavodni

University of Toronto, Toronto, Ontario, Canada

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Publications (27)84.79 Total impact

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    ABSTRACT: Blunt and penetrating cardiovascular (CV) injuries are associated with a high morbidity and mortality. Rapid detection of these injuries in trauma is critical for patient survival. The advent of multi-detector computed tomography (MDCT) has led to increased detection of CV injuries during rapid comprehensive scanning of stabilized major trauma patients. MDCT has the ability to acquire images with a higher temporal and spatial resolution, as well as the capability to create multiplanar reformats. This pictorial review illustrates several common and life-threatening traumatic CV injuries from a regional trauma center.
    Full-text · Article · Oct 2015 · Journal of Clinical Imaging Science

  • No preview · Article · Oct 2015 · The Canadian journal of cardiology
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    ABSTRACT: Atherosclerosis is the ubiquitous underling pathological process that manifests in heart attack and stroke, cumulating in the death of one in three North American adults. High-resolution magnetic resonance imaging (MRI) is able to delineate atherosclerotic plaque components and total plaque burden within the carotid arteries. Using dedicated hardware, high resolution images can be obtained. Combining pre- and post-contrast T1, T2, proton-density, and magnetization-prepared rapid acquisition gradient echo weighted fat-saturation imaging, plaque components can be defined. Post-processing software allows for semi- and fully automated quantitative analysis. Imaging correlation with surgical specimens suggests that this technique accurately differentiates plaque features. Total plaque burden and specific plaque components such as a thin fibrous cap, large fatty or necrotic core and intraplaque hemorrhage are accepted markers of neuroischemic events. Given the systemic nature of atherosclerosis, emerging science suggests that the presence of carotid plaque is also an indicator of coronary artery plaque burden, although the preliminary data primarily involves patients with stable coronary disease. While the availability and cost-effectiveness of MRI will ultimately be important determinants of whether carotid MRI is adopted clinically in cardiovascular risk assessment, the high accuracy and reliability of this technique suggests that it has potential as an imaging biomarker of future risk.
    Full-text · Article · Aug 2015 · The international journal of cardiovascular imaging

  • No preview · Article · Oct 2014 · The Canadian journal of cardiology
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    ABSTRACT: Background: Patients with chronic granulomatous disease (CGD) experience immunodeficiency because of defects in the phagocyte NADPH oxidase and the concomitant reduction in reactive oxygen intermediates. This may result in a reduction in atherosclerotic injury. Methods and results: We prospectively assessed the prevalence of cardiovascular risk factors, biomarkers of inflammation and neutrophil activation, and the presence of magnetic resonance imaging and computed tomography quantified subclinical atherosclerosis in the carotid and coronary arteries of 41 patients with CGD and 25 healthy controls in the same age range. Univariable and multivariable associations among risk factors, inflammatory markers, and atherosclerosis burden were assessed. Patients with CGD had significant elevations in traditional risk factors and inflammatory markers compared with control subjects, including hypertension, high-sensitivity C-reactive protein, oxidized low-density lipoprotein, and low high-density lipoprotein. Despite this, patients with CGD had a 22% lower internal carotid artery wall volume compared with control subjects (361.3±76.4 mm(3) versus 463.5±104.7 mm(3); P<0.001). This difference was comparable in p47(phox)- and gp91(phox)-deficient subtypes of CGD and independent of risk factors in multivariate regression analysis. In contrast, the prevalence of coronary arterial calcification was similar between patients with CGD and control subjects (14.6%, CGD; 6.3%, controls; P=0.39). Conclusions: The observation by magnetic resonance imaging and computerized tomography of reduced carotid but not coronary artery atherosclerosis in patients with CGD despite the high prevalence of traditional risk factors raises questions about the role of NADPH oxidase in the pathogenesis of clinically significant atherosclerosis. Additional high-resolution studies in multiple vascular beds are required to address the therapeutic potential of NADPH oxidase inhibition in cardiovascular diseases. Clinical trial registration url: http://www.clinicaltrials.gov. Unique identifier: NCT01063309.
    Full-text · Article · Sep 2014 · Circulation
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    ABSTRACT: To characterize the evolution of right ventricular (RV) function post-myocardial infarction (MI), to describe the culprit vessel involved with RV injury and to assess the concordance between RV injury on magnetic resonance imaging (MRI) and RV infarct on electrocardiogram (EKG). Thirty-one patients underwent cardiovascular magnetic resonance (CMR) examinations at three time frames post-ST elevation MI (STEMI). Of those with an initial normal scan, RV function did not significantly change over time (60.6 ± 6.3, 57.8 ± 6.0, 55.4 ± 5.7, P > 0.05). However, in those whose RVEF (RV ejection fraction) was initially low, it significantly increased from the first scan to the third scan (46.2 ± 3.6, 50 ± 6.6, 51.3 ± 5.2, P < 0.01). Post-hoc testing revealed a significant difference between the 48-hour and the 6-month scan, and between the 48-hour and the 3-week scan; however, there was no significant difference between the 3-week and 6-month scans. Interestingly, 23% of patients with low RVEF at baseline had the left anterior descending (LAD) as the culprit vessel. Only 15% of the low RVEF at baseline group were classified as having an RVMI by EKG criteria. The optimal timepoint to assess for RV injury via CMR may be 3 weeks post-acute MI. Standard EKG criteria may underestimate RV injury when compared to CMR.J. Magn. Reson. Imaging 2013. © 2013 Wiley Periodicals, Inc.
    No preview · Article · Sep 2014 · Journal of Magnetic Resonance Imaging
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    ABSTRACT: Objet Évaluer la variabilité intra-examen et le taux d’erreur potentiel des échographies sériées dans le diagnostic de la thrombose veineuse profonde chez l’enfant. Méthodes Un examen de cohorte rétrospectif portant sur les résultats d’imagerie d’enfants ayant subi au moins trois échographies sériées d’une même région au cours d’une période de deux mois a été réalisé. L’interprétation des résultats a rendu compte 1) d’une visualisation inadéquate ou 2) de l’absence ou de la présence d’une thrombose veineuse profonde. Ces résultats ont ensuite été classifiés en fonction de l’emplacement. Enfin, les résultats des examens d’imagerie sériés ont par la suite été regroupés en fonction des constatations et des données cliniques. Résultats L’étude a englobé 64 patients et 157 segments vasculaires. Une thrombose veineuse profonde a été consignée à l’égard de 58 patients. Par ailleurs, les résultats ont été concordants chez 26 patients (40,1 %), tandis qu’ils ont fait état d’une dissolution du caillot chez 17 patients (26,6 %), d’une formation de caillot chez 12 patients (18,8 %) et affiché une discordance chez 9 patients (14 %). Enfin, au moins un segment vasculaire a été inadéquatement observé par imagerie chez 21 des 64 patients (32,8 %). Conclusions Jusqu’à 25 % des patients obtiennent des résultats incohérents dans le cadre d’échographies sériées, soulignant ainsi l’éventuelle imprécision de l’échographie en ce qui concerne l’établissement du diagnostic et le suivi de la thrombose veineuse profonde chez l’enfant. Le fait qu’au moins un segment vasculaire a été visualisé de façon inadéquate chez une grande proportion de patients rend également compte des limites de l’échographie dans le diagnostic de la thrombose veineuse profonde chez l’enfant.
    No preview · Article · Aug 2014 · Canadian Association of Radiologists Journal
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    ABSTRACT: Purpose: To determine if carotid plaque morphology and composition with magnetic resonance (MR) imaging can be used to identify asymptomatic subjects at risk for cardiovascular events. Materials and methods: Institutional review boards at each site approved the study, and all sites were Health Insurance Portability and Accountability Act (HIPAA) compliant. A total of 946 participants in the Multi-Ethnic Study of Atherosclerosis (MESA) were evaluated with MR imaging and ultrasonography (US). MR imaging was used to define carotid plaque composition and remodeling index (wall area divided by the sum of wall area and lumen area), while US was used to assess carotid wall thickness. Incident cardiovascular events, including myocardial infarction, resuscitated cardiac arrest, angina, stroke, and death, were ascertained for an average of 5.5 years. Multivariable Cox proportional hazards models, C statistics, and net reclassification improvement (NRI) for event prediction were determined. Results: Cardiovascular events occurred in 59 (6%) of participants. Carotid IMT as well as MR imaging remodeling index, lipid core, and calcium in the internal carotid artery were significant predictors of events in univariate analysis (P < .001 for all). For traditional risk factors, the C statistic for event prediction was 0.696. For MR imaging remodeling index and lipid core, the C statistic was 0.734 and the NRI was 7.4% and 15.8% for participants with and those without cardiovascular events, respectively (P = .02). The NRI for US IMT in addition to traditional risk factors was not significant. Conclusion: The identification of vulnerable plaque characteristics with MR imaging aids in cardiovascular disease prediction and improves the reclassification of baseline cardiovascular risk.
    Preview · Article · Feb 2014 · Radiology
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    Preview · Article · Jan 2014 · Journal of Cardiovascular Magnetic Resonance
  • Emily Pang · Gregory Paul King · Simin Jeddiyan · Anna Elizabeth Helen Zavodni
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    ABSTRACT: PURPOSE The objective of this study was to evaluate the comparability of non-contrast SSFP and gadolinium enhanced MRA sequences in the quantitative and qualitative assessment of the post-operative ascending aorta. METHOD AND MATERIALS After obtaining Research Ethics Board approval, we conducted a single center retrospective review of the 59 consecutive patients sent for MRI follow-up post ascending aortic replacement surgery between 2007 and 2012. Our analysis included 51 patients (mean age 67 +/- 3 years) with both non-contrast SSFP and gadolinium enhanced MRA sequences (8 patients were excluded due to not having one or both sequences performed). The images were independently evaluated by two cardiovascular fellowship trained radiologists with at least 2 years of experience, who measured the diameter of the thoracic aorta at several points including the root, ascending aorta, arch and descending aorta, as well as assessed for qualitative abnormalities. The datasets were compared using paired T-test, Bland-Altman, and kappa coefficient analysis (statistical significance was determined using a Bonferroni correction for multiple comparisons). Intra and inter-observer variability was also determined. RESULTS There was no statistically significant difference in measurements between non-contrast SSFP and gadolinium sequences, with the exception of the aortic annulus in patients who did not have valve replacement (p < 0.001). We postulate that this finding was because the 3D gadolinium sequences allowed for measurements of the normally ovoid annulus in more than one dimension. Kappa analysis also demonstrated good agreement with regards to the quantitative observations. Inter and intra-observer variability was excellent (ICC >0.8). CONCLUSION Our results suggest that using an unenhanced SSFP MRA sequence is comparable to gadolinium enhanced MRA in the quantitative and qualitative evaluation of the post-operative ascending aorta. Adequate and accurate information is obtained from the non-contrast SSFP sequence such that intravenous gadolinium may be rendered unnecessary for surgical follow-up imaging, reducing the risk and inconvenience to the patient, as well as health care costs. CLINICAL RELEVANCE/APPLICATION Using unenhanced SSFP MRA may be sufficient in the post-operative MR imaging follow up of ascending aorta replacements, omitting the risks and costs associated with IV gadolinium administration.
    No preview · Conference Paper · Dec 2013

  • No preview · Article · Oct 2013 · The Canadian journal of cardiology
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    ABSTRACT: Intraplaque hemorrhage (IPH), a component of late-stage complicated plaque, identified within carotid endarterectomy surgical specimens has been recently demonstrated to predict cardiovascular (CV) events. MRI is able to depict carotid IPH. We investigated the ability of carotid MR-depicted IPH (MR-IPH) to identify high-risk CV patients. From January 2008 to April 2011, 216 patients (mean age, 67.5 years; range 31-100) referred for neurovascular MRI at an academic tertiary care centre, underwent 3T carotid MRI with adjunct 3D high-spatial-resolution coronal imaging to detect MR-IPH. Five experienced neuroradiologists made a binary decision on the presence or absence of MR-IPH. Patients' charts were reviewed blindly for demographic and CV outcomes data. Of the patients with and without MR-IPH, 62.5 % (15/24) and 19.8 % (38/192) had a composite CV event (defined as a past myocardial infarction, coronary intervention (i.e., angioplasty, stenting or bypass graft) and/or peripheral vascular disease), respectively. The odds ratio (OR) of a composite CV event in the MR-IPH group was 6.75 (Bivariable analysis, 95 % CI 2.75-16.6, p < 0.0001) and 3.25 (Multivariable regression analysis, 1.14-9.37, p = 0.028). MR-IPH had the highest OR of a prior CV event compared to other variables including age, sex, hypertension and stenosis. The OR of individual CV events was also significant: MI (3.35, 95 % CI 2.11-14.2, p < 0.01), coronary stenting (26.4, 95 % CI 8.80-79.4, p < 0.01), coronary angioplasty (21, 95 % CI 4.84-91.1, p < 0.01), and PVD (3.35, 95 % CI 1.09-10.3, p < 0.05). MR-IPH is independently associated with prior CV events in patients who are evaluated for neurovascular disease. Carotid MR-IPH, employed easily in routine clinical practice, is emerging as an indicator of systemic vascular disease and may potentially be a useful surrogate marker of CV risk including in those already undergoing neurovascular imaging.
    Full-text · Article · Apr 2013 · The international journal of cardiovascular imaging
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    ABSTRACT: Background: Carotid and coronary atherosclerosis are associated with each other in imaging and autopsy studies. The aim of this study was to evaluate whether carotid artery plaque seen on carotid ultrasound can predict incident coronary artery calcification (CAC). Methods: Agatston calcium score measurements were repeated in 5,445 participants of the Multi-Ethnic Study of Atherosclerosis (MESA; mean age, 57.9 years; 62.9% women). Internal carotid artery lesions were graded as 0%, 1% to 24%, or >25% diameter narrowing, and intima-media thickness (IMT) was measured. Plaque was present for any stenosis >0%. CAC progression was evaluated with multivariate relative risk regression for CAC scores of 0 at baseline and with multivariate linear regression for CAC score > 0, adjusting for cardiovascular risk factors, body mass index, ethnicity, and common carotid IMT. Results: CAC was positive at baseline in 2,708 of 5,445 participants (49.7%) and became positive in 458 of 2,837 (16.1%) at a mean interval of 2.4 years between repeat examinations. Plaque and internal carotid artery IMT were both strongly associated with the presence of CAC. After statistical adjustment, the presence of carotid artery plaque significantly predicted incident CAC with a relative risk of 1.37 (95% confidence interval, 1.12-1.67). Incident CAC was associated with internal carotid artery IMT, with a relative risk of 1.13 (95% confidence interval, 1.03-1.25) for each 1-mm increase. Progression of CAC was also significantly associated (P < .001) with plaque and internal carotid artery IMT. Conclusions: In individuals free of cardiovascular disease, subjective and quantitative measures of carotid artery plaques by ultrasound imaging are associated with CAC incidence and progression.
    No preview · Article · Mar 2013 · Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography
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    ABSTRACT: Carotid artery plaques are associated with coronary artery atherosclerotic lesions. We evaluated various ultrasound definitions of carotid artery plaque as predictors of future cardiovascular disease (CVD) and coronary heart disease (CHD) events. We studied the risk factors and ultrasound measurements of the carotid arteries at baseline of 6562 members (mean age 61.1 years; 52.6% women) of the Multi-Ethnic Study of Atherosclerosis (MESA). ICA lesions were defined subjectively as >0% or ≥25% diameter narrowing, as continuous intima-media thickness (IMT) measurements (maximum IMT or the mean of the maximum IMT of 6 images) and using a 1.5-mm IMT cut point. Multivariable Cox proportional hazards models were used to estimate hazard ratios for incident CVD, CHD, and stroke. Harrell's C-statistics, Net Reclassification Improvement, and Integrated Discrimination Improvement were used to evaluate the incremental predictive value of plaque metrics. At 7.8-year mean follow-up, all plaque metrics significantly predicted CVD events (n=515) when added to Framingham risk factors. All except 1 metric improved the prediction of CHD (by C-statistic, Net Reclassification Improvement, and Integrated Discrimination Improvement. Mean of the maximum IMT had the highest NRI (7.0%; P=0.0003) with risk ratio of 1.43/mm; 95% CI 1.26-1.63) followed by maximum IMT with an NRI of 6.8% and risk ratio of 1.27 (95% CI 1.18-1.38). Ultrasound-derived plaque metrics independently predict cardiovascular events in our cohort and improve risk prediction for CHD events when added to Framingham risk factors.
    Full-text · Article · Feb 2013 · Journal of the American Heart Association
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    Full-text · Article · Jan 2013 · Journal of Cardiovascular Magnetic Resonance
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    Full-text · Article · Jan 2013 · The International Journal of Cardiovascular Imaging

  • No preview · Article · Sep 2012 · The Canadian journal of cardiology
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    ABSTRACT: To develop a cardiac computed tomographic (CT) method with which to determine extracellular volume (ECV) fraction, with cardiac magnetic resonance (MR) imaging as the reference standard. Study participants provided written informed consent to participate in this institutional review board-approved study. ECV was measured in healthy subjects and patients with heart failure by using cardiac CT and cardiac MR imaging. Paired Student t test, linear regression analysis, and Pearson correlation analysis were used to determine the relationship between cardiac CT and MR imaging ECV values and clinical parameters. Twenty-four subjects were studied. There was good correlation between myocardial ECV measured at cardiac MR imaging and that measured at cardiac CT (r = 0.82, P < .001). As expected, ECV was higher in patients with heart failure than in healthy control subjects for both cardiac CT and cardiac MR imaging (P = .03, respectively). For both cardiac MR imaging and cardiac CT, ECV was positively associated with end diastolic and end systolic volume and inversely related to ejection fraction (P < .05 for all). Mean radiation dose was 1.98 mSv ± 0.16 (standard deviation) for each cardiac CT acquisition. ECV at cardiac CT and that at cardiac MR imaging showed good correlation, suggesting the potential for myocardial tissue characterization with cardiac CT.
    Full-text · Article · Jul 2012 · Radiology
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    ABSTRACT: Carotid stenosis and plaque stability are critical determinants of risk for ischemic stroke. The aim of this study is to elucidate the association of CAC with carotid stenosis and plaque characteristics. We examined data from the Multi-Ethnic Study of Atherosclerosis (MESA), a prospective cohort study of subclinical cardiovascular disease in multiethnic participants (N = 6814). The association between CAC measured by computed tomography and carotid ultrasonography of carotid plaque was examined using multiple logistic linear models adjusting for traditional vascular risk factors including ethnicity. We also developed ethnic specific models to compare the relationship between CAC and carotid disease across the four ethnicities. Significant carotid stenosis was associated with the presence of CAC (OR 1.73; 95% CI, 1.20-2.49) and log-transformed Agatston score (OR per 1 point increase, 1.18; 95% CI 1.04-1.35). Overt carotid stenosis was also associated with the presence of CAC (OR, 2.34; 95% CI, 1.93-2.83) and log-transformed Agatston score (OR per 1 point increase, 1.53; 95% CI 1.38-1.69). Irregular plaque surface was associated with the presence of CAC (OR, 1.87; 95% CI 1.50-2.32) and the log-transformed Agatston score (OR per 1 point 1 increase, 1.31; 95% CI 1.16-1.48). Associations between CAC and stenosis/stability were not different across ethnicities. Both the presence of CAC and log-transferred Agatston score are independently associated with significant/overt carotid stenosis and carotid plaque surface irregularity regardless of ethnicity. The subjects with a positive or increased CAC score are more likely to have carotid disease potentially increasing their risk for future ischemic stroke.
    No preview · Article · May 2012 · Atherosclerosis
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    ABSTRACT: Myocardial T1 relaxation time (T1 time) and extracellular volume fraction (ECV) are altered in the presence of myocardial fibrosis. The purpose of this study was to evaluate acquisition factors that may result in variation of measured T1 time and ECV including magnetic field strength, cardiac phase and myocardial region. 31 study subjects were enrolled and underwent one cardiovascular MR exam at 1.5 T and two exams at 3 T, each on separate days. A Modified Look-Locker Inversion Recovery (MOLLI) sequence was acquired before and 5, 10, 12, 20, 25 and 30 min after administration of 0.15 mmol/kg gadopentetate dimeglumine (Gd-DTPA; Magnevist) at 1.5 T (exam 1). For exam 2, MOLLI sequences were acquired at 3 T both during diastole and systole, before and after administration of Gd-DTPA (0.15 mmol/kg Magnevist).Exam 3 was identical to exam 2 except gadobenate dimeglumine was administered (Gd-BOPTA; 0.1 mmol/kg Multihance). T1 times were measured in myocardium and blood. ECV was calculated by (ΔR1myocardium/ΔR1blood)*(1-hematocrit). Before gadolinium, T1 times of myocardium and blood were significantly greater at 3 T versus 1.5 T (28% and 31% greater, respectively, p < 0.001); after gadolinium, 3 T values remained greater than those at 1.5 T (14% and 12% greater for myocardium and blood at 3 T with Gd-DTPA, respectively, p < 0.0001 and 18% and 15% greater at 3 T with Gd-BOPTA, respectively, p < 0.0001). However, ECV did not vary significantly with field strength when using the same contrast agent at equimolar dose (p = 0.2). Myocardial T1 time was 1% shorter at systole compared to diastole pre-contrast and 2% shorter at diastole compared to systole post-contrast (p < 0.01). ECV values were greater during diastole compared to systole on average by 0.01 (p < 0.01 to p < 0.0001). ECV was significantly higher for the septum compared to the non-septal myocardium for all three exams (p < 0.0001-0.01) with mean absolute differences of 0.01, 0.004, and 0.07, respectively, for exams 1, 2 and 3. ECV is similar at field strengths of 1.5 T and 3 T. Due to minor variations in T1 time and ECV during the cardiac cycle and in different myocardial regions, T1 measurements should be obtained at the same cardiac phase and myocardial region in order to obtain consistent results.
    Full-text · Article · May 2012 · Journal of Cardiovascular Magnetic Resonance