Anna Zavodni

Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada

Are you Anna Zavodni?

Claim your profile

Publications (12)39.97 Total impact

  • [Show abstract] [Hide abstract]
    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. © RSNA, 2014.
    Radiology 02/2014; · 6.34 Impact Factor
  • [Show abstract] [Hide abstract]
    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.
    Canadian Association of Radiologists Journal 01/2014; · 0.43 Impact Factor
  • [Show abstract] [Hide abstract]
    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.
    Journal of Magnetic Resonance Imaging 10/2013; · 2.57 Impact Factor
  • [Show abstract] [Hide abstract]
    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.
    The international journal of cardiovascular imaging 04/2013; · 2.15 Impact Factor
  • [Show abstract] [Hide abstract]
    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.
    Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 03/2013; · 2.98 Impact Factor
  • Source
    Journal of Cardiovascular Magnetic Resonance 01/2013; 15(1). · 4.44 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    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.
    Journal of the American Heart Association. 01/2013; 2(2):e000087.
  • Source
    [Show abstract] [Hide abstract]
    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.
    Radiology 07/2012; 264(3):876-83. · 6.34 Impact Factor
  • [Show abstract] [Hide abstract]
    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.
    Atherosclerosis 05/2012; 223(1):160-5. · 3.71 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    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.
    Journal of Cardiovascular Magnetic Resonance 05/2012; 14:27. · 4.44 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Myocardial T1 relaxation time (T1 time) and extracellular volume fraction (ECV) are altered in patients with diffuse myocardial fibrosis. The purpose of this study was to perform an intra-individual assessment of normal T1 time and ECV for two different contrast agents. A modified Look-Locker Inversion Recovery (MOLLI) sequence was acquired at 3 T in 24 healthy subjects (8 men; 28 ± 6 years) at mid-ventricular short axis pre-contrast and every 5 min between 5-45 min after injection of a bolus of 0.15 mmol/kg gadopentetate dimeglumine (Gd-DTPA; Magnevist®) (exam 1) and 0.1 mmol/kg gadobenate dimeglumine (Gd-BOPTA; Multihance®) (exam 2) during two separate scanning sessions. T1 times were measured in myocardium and blood on generated T1 maps. ECVs were calculated as ΔR1 myocardium/ΔR1 blood*1-hematocrit. Mean pre-contrast T1 relaxation times for myocardium and blood were similar for both the first and second CMR exam (p > 0.5). Overall mean post-contrast myocardial T1 time was 15 ± 2 ms (2.5 ± 0.7%) shorter for Gd-DTPA at 0.15 mmol/kg compared to Gd-BOPTA at 0.1 mmol/kg (p < 0.01) while there was no significant difference for T1 time of blood pool (p > 0.05). Between 5 and 45 minutes after contrast injection, mean ECV values increased linearly with time for both contrast agents from 0.27 ± 0.03 to 0.30 ± 0.03 (p < 0.0001). Mean ECV values were slightly higher (by 0.01, p < 0.05) for Gd-DTPA compared to Gd-BOPTA. Inter-individual variation of ECV was higher (CV 8.7% [exam 1, Gd-DTPA] and 9.4% [exam 2, Gd-BOPTA], respectively) compared to variation of pre-contrast myocardial T1 relaxation time (CV 4.5% [exam 1] and 3.0% [exam 2], respectively). ECV with Gd-DTPA was highly correlated to ECV by Gd-BOPTA (r = 0.803; p < 0.0001). In comparison to pre-contrast myocardial T1 relaxation time, variation in ECV values of normal subjects is larger. However, absolute differences in ECV between Gd-DTPA and Gd-BOPTA were small and rank correlation was high. There is a small and linear increase in ECV over time, therefore ideally images should be acquired at the same delay after contrast injection.
    Journal of Cardiovascular Magnetic Resonance 04/2012; 14:26. · 4.44 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: All cardiac magnetic resonance (CMR) techniques aim to create still depictions of a dynamic and ever-adapting organ. Most CMR methods rely on cardiac gating to capture information during fleeting periods of relative cardiac quiescence, at end diastole or end systole, or to acquire partial images throughout the cardiac cycle and average these signals over several heart beats. Since the inception of clinical CMR in the early 1980s, priority has been given to improving methods for image gating. The aim of this work is to provide a basic understanding of the ECG acquisition, demonstrate common ECG-related artifacts and to provide practical methods for overcoming these issues. Meticulous ECG preparation is essential for optimal CMR acquisition and these techniques must be adaptable to the individual patient.
    The international journal of cardiovascular imaging 10/2011; 28(6):1465-75. · 2.15 Impact Factor

Publication Stats

77 Citations
39.97 Total Impact Points

Institutions

  • 2013–2014
    • Sunnybrook Health Sciences Centre
      • Division of Cardiology
      Toronto, Ontario, Canada
    • University of Toronto
      • Department of Medical Imaging
      Toronto, Ontario, Canada
  • 2011–2012
    • National Institutes of Health
      • Radiology and Imaging Sciences Department
      Bethesda, MD, United States