Browsing by Author "Friedrich, Matthias G."
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Item Open Access Comparison of long and short axis quantification of left ventricular volume parameters by cardiovascular magnetic resonance, with ex-vivo validation(BioMed Central, 2011-08-11) Childs, Helene; Ma, Lucia; Ma, Michael; Clarke, James; Cocker, Myra; Green, Jordin; Strohm, Oliver; Friedrich, Matthias G.Item Open Access Imaging reperfusion hemorrhage by cardiovascular magnetic resonance: an in vivo study with ex vivo validation(2008) Kumar, Andreas; Friedrich, Matthias G.Item Open Access Importance of Reference Muscle Selection in Quantitative Signal Intensity Analysis of T2-Weighted Images of Myocardial Edema Using a T2 Ratio Method(2015-06-21) Carbone, Iacopo; Childs, Helene; Aljizeeri, Ahmed; Merchant, Naeem; Friedrich, Matthias G.Objectives. The purpose of our study was to identify the suitability of various skeletal muscles as reference regions for calculating the T2 SI ratio for a semiautomated quantification of the extent of myocardial edema with T2-weighted images. Methods. Thirty-four patients with acute myocardial infarction (MI) were enrolled. The extent of myocardial edema was determined by T2 SI ratio map, using 4 different muscles as reference: major and minor pectoralis, serratus anterior, teres minor-infraspinatus, and subscapularis. The size of myocardial edema as visually quantified was used as the standard of truth. The control group consisted of 15 patients with chronic MI. Intra- and interobserver variability were assessed. Results. Due to poor image quality four patients were excluded from the analysis. In acute MI patients, serratus anterior muscle showed the strongest correlation with the visual analysis (; ) and low inter- and intraobserver variability, while the other muscles resulted in a significant interobserver variability. In contrast, the use of other muscles as a reference led to overestimating edema size. Conclusions. In acute MI patients, serratus anterior resulted to be the most reliable and reproducible muscle for measuring the extent of myocardial edema.Item Open Access Magnetic resonance imaging in vascular biology(2008-02-29) Voehringer, Matthias; Sechtem, Udo; Friedrich, Matthias G.Summary Symptoms are only the tip of the iceberg in atherosclerotic disease. Beneath the surface are multiple patho-physiological processes taking place in and around the vessel wall. The increasing knowledge in the field of vascular biology also reveals new imaging targets as biological markers of the disease. Promising targets particularly relate to the early detection of subjects at risk and monitoring of therapeutical efforts. Among other imaging modalities magnetic resonance imaging (MRI) is an emerging tool with strong potential and a favourable safety profile. This article summarizes the different approaches of imaging various facets of atherosclerotic disease by MRI. In particular, endothelial function, arterial stiffness, vessel remodeling, angiogenesis inside the vessel wall, vessel stenosis and plaque characterization are addressed. As such MRI is a very versatile diagnostic tool for vascular biology research with high diagnostic accuracy and reproducibility of its results. Moreover, MRI allows for comprehensive studies, applying several techniques within one exam.Item Open Access Normal sex and age-specific parameters in a multi-ethnic population: a cardiovascular magnetic resonance study of the Canadian Alliance for Healthy Hearts and Minds cohort(2022-01-03) Luu, Judy M.; Gebhard, Catherine; Ramasundarahettige, Chinthanie; Desai, Dipika; Schulze, Karleen; Marcotte, Francois; Awadalla, Philip; Broet, Philippe; Dummer, Trevor; Hicks, Jason; Larose, Eric; Moody, Alan; Smith, Eric E.; Tardif, Jean-Claude; Teixeira, Tiago; Teo, Koon K.; Vena, Jennifer; Lee, Douglas S.; Anand, Sonia S.; Friedrich, Matthias G.Abstract Background Despite the growing utility of cardiovascular magnetic resonance (CMR) for cardiac morphology and function, sex and age-specific normal reference values derived from large, multi-ethnic data sets are lacking. Furthermore, most available studies use a simplified tracing methodology. Using a large cohort of participants without history of cardiovascular disease (CVD) or risk factors from the Canadian Alliance for Healthy Heart and Minds, we sought to establish a robust set of reference values for ventricular and atrial parameters using an anatomically correct contouring method, and to determine the influence of age and sex on ventricular parameters. Methods and results Participants (n = 3206, 65% females; age 55.2 ± 8.4 years for females and 55.1 ± 8.8 years for men) underwent CMR using standard methods for quantitative measurements of cardiac parameters. Normal ventricular and atrial reference values are provided: (1) for males and females, (2) stratified by four age categories, and (3) for different races/ethnicities. Values are reported as absolute, indexed to body surface area, or height. Ventricular volumes and mass were significantly larger for males than females (p < 0.001). Ventricular ejection fraction was significantly diminished in males as compared to females (p < 0.001). Indexed left ventricular (LV) end-systolic, end-diastolic volumes, mass and right ventricular (RV) parameters significantly decreased as age increased for both sexes (p < 0.001). For females, but not men, mean LV and RVEF significantly increased with age (p < 0.001). Conclusion Using anatomically correct contouring methodology, we provide accurate sex and age-specific normal reference values for CMR parameters derived from the largest, multi-ethnic population free of CVD to date. Clinical trial registration ClinicalTrials.gov, NCT02220582. Registered 20 August 2014—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02220582 .Item Open Access Oxygenation-sensitive CMR for assessing vasodilator-induced changes of myocardial oxygenation(BioMed Central, 2010-03-31) Vöhringer, Matthias; Flewitt, Jacqueline A.; Green, Jordin D.; Dharmakumar, Rohan; Wang Jr, Jiun; Tyberg, John V.; Friedrich, Matthias G.Item Open Access The impact of reporting magnetic resonance imaging incidental findings in the Canadian alliance for healthy hearts and minds cohort(2021-10-28) Luu, Judy M.; Sergeant, Anand K.; Anand, Sonia S.; Desai, Dipika; Schulze, Karleen; Knoppers, Bartha M.; Zawati, Ma’n H.; Smith, Eric E.; Moody, Alan R.; Black, Sandra E.; Larose, Eric; Marcotte, Francois; Kleiderman, Erika; Tardif, Jean-Claude; Lee, Douglas S.; Friedrich, Matthias G.Abstract Background In the Canadian Alliance for Healthy Hearts and Minds (CAHHM) cohort, participants underwent magnetic resonance imaging (MRI) of the brain, heart, and abdomen, that generated incidental findings (IFs). The approach to managing these unexpected results remain a complex issue. Our objectives were to describe the CAHHM policy for the management of IFs, to understand the impact of disclosing IFs to healthy research participants, and to reflect on the ethical obligations of researchers in future MRI studies. Methods Between 2013 and 2019, 8252 participants (mean age 58 ± 9 years, 54% women) were recruited with a follow-up questionnaire administered to 909 participants (40% response rate) at 1-year. The CAHHM policy followed a restricted approach, whereby routine feedback on IFs was not provided. Only IFs of severe structural abnormalities were reported. Results Severe structural abnormalities occurred in 8.3% (95% confidence interval 7.7–8.9%) of participants, with the highest proportions found in the brain (4.2%) and abdomen (3.1%). The majority of participants (97%) informed of an IF reported no change in quality of life, with 3% of participants reporting that the knowledge of an IF negatively impacted their quality of life. Furthermore, 50% reported increased stress in learning about an IF, and in 95%, the discovery of an IF did not adversely impact his/her life insurance policy. Most participants (90%) would enrol in the study again and perceived the MRI scan to be beneficial, regardless of whether they were informed of IFs. While the implications of a restricted approach to IF management was perceived to be mostly positive, a degree of diagnostic misconception was present amongst participants, indicating the importance of a more thorough consent process to support participant autonomy. Conclusion The management of IFs from research MRI scans remain a challenging issue, as participants may experience stress and a reduced quality of life when IFs are disclosed. The restricted approach to IF management in CAHHM demonstrated a fair fulfillment of the overarching ethical principles of respect for autonomy, concern for wellbeing, and justice. The approach outlined in the CAHHM policy may serve as a framework for future research studies. Clinical trial registration https://clinicaltrials.gov/ct2/show/NCT02220582 .Item Open Access Understanding the cardiac phenotype of endurance athletes: a cardiovascular magnetic resonance (cmr) study(2011) Cocker, Myra Sabene; Friedrich, Matthias G.