224 research outputs found

    Development and Application of Gadolinium Free Cardiac Magnetic Resonance Fibrosis Imaging for Multiscale Study of Heart Failure in Patients with End Stage Renal Disease

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    Cardiac magnetic resonance (CMR) is a powerful tool to noninvasively image ventricular fibrosis. Late gadolinium enhancement (LGE) CMR identifies focal and, with T1 mapping, diffuse fibrosis. Despite prevalent cardiac fibrosis and heart failure, patients with end stage renal disease (ESRD) are excluded from LGE. Absence of a suitable diagnostic has limited the understanding of heart failure and obstructed development of therapies in the setting of ESRD. A quantitative, gadolinium free fibrosis detection method could overcome this critical barrier, propelling the advancement of diagnostic, monitoring, and therapy options. This project describes the development of a gadolinium free CMR technique and application for cardiac fibrosis measurement in patients with ESRD. Magnetization transfer (MT) occurs during standard cine balanced steady state free precession (bSSFP) CMR, where extracellular matrix protons exchange magnetization with water molecules. Extracellular water volume expansion, concomitant with fibrosis, reduces MT and subtly elevates signal intensity. Our technique, 2-pt bSSFP, extracts endogenous contrast sensitive to tissue fibrosis by obtaining pairs of high and low MT-weighted images and calculating normalized signal differences, denoted by ΔS/So. We tested 2-pt bSSFP in patients referred for CMR and found excellent agreement spatially with LGE and quantitatively with extracellular volume fraction. Diagnostic and clinical application of 2-pt bSSFP was comparable to LGE. We applied 2-pt bSSFP to patients with ESRD for multiscale comparison with correlates of fibrosis ranging from blood biomarkers to whole organ function. Patients with ESRD displayed hypertrophy with reduced contraction, but elevated ΔS/So and fibrosis. Some biomarkers correlated with both hypertrophy and fibrosis, highlighting the need to distinguish between hypertrophic and fibrotic remodeling. We monitored fibrosis over 1 year using 2-pt bSSFP in a cohort of patients with ESRD. ΔS/So and fibrotic burden increased substantially, despite minor changes in structure and function. Collectively these studies validate and apply 2-pt bSSFP for gadolinium free fibrosis CMR in patients with ESRD. While ventricular structure and function are commensurate with progression toward heart failure, it is now possible to specifically describe global and focal patterns of cardiac fibrosis in ESRD, along with comparisons to blood biomarkers which may lead to improved diagnostics and molecular treatment targets

    T1 mapping in cardiac MRI

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    Quantitative myocardial and blood T1 have recently achieved clinical utility in numerous pathologies, as they provide non-invasive tissue characterization with the potential to replace invasive biopsy. Native T1 time (no contrast agent), changes with myocardial extracellular water (edema, focal or diffuse fibrosis), fat, iron, and amyloid protein content. After contrast, the extracellular volume fraction (ECV) estimates the size of the extracellular space and identifies interstitial disease. Spatially resolved quantification of these biomarkers (so-called T1 mapping and ECV mapping) are steadily becoming diagnostic and prognostically useful tests for several heart muscle diseases, influencing clinical decision-making with a pending second consensus statement due mid-2017. This review outlines the physics involved in estimating T1 times and summarizes the disease-specific clinical and research impacts of T1 and ECV to date. We conclude by highlighting some of the remaining challenges such as their community-wide delivery, quality control, and standardization for clinical practice

    Scar conducting channel wall thickness characterization to predict arrhythmogenicity during ventricular tachycardia ablation

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    Treballs Finals de Grau d'Enginyeria Biomèdica. Facultat de Medicina i Ciències de la Salut. Universitat de Barcelona. Curs: 2020-2021. Tutora: Paz Garre Anguera de Sojo.The obtention of cardiac images before the surgery ablation of ventricular tachycardia is widely used to obtain more and better information from the patient than the information obtained during the procedure. This technique is commonly performed using cardiac magnetic resonance since it allows to study and characterise the tissue, which is crucial to detect quantify scarred tissue and the particular region that triggers the tachycardia. In this project, the arrhythmogenicity of different conducting channels from patients subjected to ventricular tachycardia ablation has been studied along with their wall thickness in order to assess a correlation using late gadolinium enhancement cardiac magnetic resonance imaging. In addition, the correlation between the left ventricle wall thickness of the conducting channels and the outcome of the cardiac catheter ablation performed from the endocardial region of the heart has also been studied. This project emerges from a previous study performed in the Hospital Clínic de Barcelona that characterized several features of the main conducting channel that triggers the ventricular tachycardia. To perform this study, the images used and the information regarding the arrhythmogenic conducting channel of every patient were obtained from the previous research, using 26 patients for the main objective of this project and using 10 of them for the study of the outcome of the ventricular tachycardia ablation The study of the wall thickness and the visualization of the conducting channels were performed using ADAS 3D software. Results showed that there was not a significative difference between the wall thickness from arrhythmogenic conducting channels and from the non-arrhythmogenic conducting channels within the patients studied but it is important to highlight that the p-value obtained was too large, which might have been caused by the lack of patients to include to this study. However, an interesting distribution of the arrhythmogenic conducting channel was noticed in the inferior-septum region of the heart, which is interesting to study further in the future using more patients and, hence, more conducting channels to study. To conclude, it is important to highlight the role of technology and biomedical engineering in this field to achieve better image acquisition to improve therapeutical techniques for the patient and this project has contributed to the awareness and the comprehension of the role of a biomedical engineer in a clinical environment

    Review of Journal of Cardiovascular Magnetic Resonance 2015

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    There were 116 articles published in the Journal of Cardiovascular Magnetic Resonance (JCMR) in 2015, which is a 14 % increase on the 102 articles published in 2014. The quality of the submissions continues to increase. The 2015 JCMR Impact Factor (which is published in June 2016) rose to 5.75 from 4.72 for 2014 (as published in June 2015), which is the highest impact factor ever recorded for JCMR. The 2015 impact factor means that the JCMR papers that were published in 2013 and 2014 were cited on average 5.75 times in 2015. The impact factor undergoes natural variation according to citation rates of papers in the 2 years following publication, and is significantly influenced by highly cited papers such as official reports. However, the progress of the journal's impact over the last 5 years has been impressive. Our acceptance rate is <25 % and has been falling because the number of articles being submitted has been increasing. In accordance with Open-Access publishing, the JCMR articles go on-line as they are accepted with no collating of the articles into sections or special thematic issues. For this reason, the Editors have felt that it is useful once per calendar year to summarize the papers for the readership into broad areas of interest or theme, so that areas of interest can be reviewed in a single article in relation to each other and other recent JCMR articles. The papers are presented in broad themes and set in context with related literature and previously published JCMR papers to guide continuity of thought in the journal. We hope that you find the open-access system increases wider reading and citation of your papers, and that you will continue to send your quality papers to JCMR for publication

    Cardiac Magnetic Resonance as Risk Stratification Tool in Non-Ischemic Dilated Cardiomyopathy Referred for Implantable Cardioverter Defibrillator Therapy—State of Art and Perspectives

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    Non-ischemic dilated cardiomyopathy (DCM) is a disease characterized by left ventricular dilation and systolic dysfunction. Patients with DCM are at higher risk for ventricular arrhythmias and sudden cardiac death (SCD). According to current international guidelines, left ventricular ejection fraction (LVEF) <= 35% represents the main indication for prophylactic implantable cardioverter defibrillator (ICD) implantation in patients with DCM. However, LVEF lacks sensitivity and specificity as a risk marker for SCD. It has been seen that the majority of patients with DCM do not actually benefit from the ICD implantation and, on the contrary, that many patients at risk of SCD are not identified as they have preserved or mildly depressed LVEF. Therefore, the use of LVEF as unique decision parameter does not maximize the benefit of ICD therapy. Multiple risk factors used in combination could likely predict SCD risk better than any single risk parameter. Several predictors have been proposed including genetic variants, electric indexes, and volumetric parameters of LV. Cardiac magnetic resonance (CMR) can improve risk stratification thanks to tissue characterization sequences such as LGE sequence, parametric mapping, and feature tracking. This review evaluates the role of CMR as a risk stratification tool in DCM patients referred for ICD

    Value of a short non-contrast CMR protocol in MINOCA

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    ObjectivesTo evaluate the diagnostic performance of a short non-contrast CMR (ShtCMR) protocol relative to a matched standard comprehensive CMR (StdCMR) protocol in patients with myocardial infarction with non-obstructive coronary arteries (MINOCA).MethodsThis multicenter retrospective study included patients with a working diagnosis of MINOCA who underwent a StdCMR between January 2019 and December 2020. An expert and a non-expert reader performed a blinded reading with the ShtCMR (long-axis cine images, T2w-STIR, T1- and T2-mapping). A consensus reading of the StdCMR (reference standard) was performed at least 3 months after the ShtCMR reading session. Readers were asked to report the following: (1) diagnosis; (2) level of confidence in their diagnosis with the ShtCMR; (3) number of myocardial segments involved, and (4) functional parameters.ResultsA total of 179 patients were enrolled. The ShtCMR lasted 21 &amp; PLUSMN; 9 min and the StdCMR 45 &amp; PLUSMN; 11 min (p &lt; 0.0001). ShtCMR allowed reaching the same diagnosis as StdCMR in 85% of patients when interpreted by expert readers (rising from 66% for poor confidence to 99% for good, p = 0.0001) and in 73% (p = 0.01) by non-expert ones (60% for poor vs 89% for good confidence, p = 0.0001). Overall, the ShtCMR overestimated the ejection fraction, underestimated cardiac volumes (p &lt; 0.01), and underestimated the number of segments involved by pathology (p = 0.0008) when compared with the StdCMR.ConclusionThe ShtCMR was found to be a debatable alternative to the StdCMR in patients with MINOCA. Nevertheless, when an experienced reader reaches a good or very good diagnostic confidence using the ShtCMR, the reader may choose to stop the examination, reducing the length of the CMR without affecting the patient's diagnosis

    Cardiovascular magnetic resonance (CMR) in restrictive cardiomyopathies

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    The restrictive cardiomyopathies constitute a heterogeneous group of myocardial diseases with a different pathogenesis and overlapping clinical presentations. Diagnosing them frequently poses a challenge. Echocardiography, electrocardiograms and laboratory tests may show non-specific changes. In this context, cardiac magnetic resonance (CMR) may play a crucial role in defining the diagnosis and guiding treatments, by offering a robust myocardial characterization based on the inherent magnetic properties of abnormal tissues, thus limiting the use of endomyocardial biopsy. In this review article, we explore the role of CMR in the assessment of a wide range of myocardial diseases causing restrictive patterns, from iron overload to cardiac amyloidosis, endomyocardial fibrosis or radiation-induced heart disease. Here, we emphasize the incremental value of novel relaxometric techniques such as T1 and T2 mapping, which may recognize different storage diseases based on the intrinsic magnetic properties of the accumulating metabolites, with or without the use of gadolinium-based contrast agents. We illustrate the importance of these CMR techniques and their great support when contrast media administration is contraindicated. Finally, we describe the useful role of cardiac computed tomography for diagnosis and management of restrictive cardiomyopathies when CMR is contraindicated

    T1 Mapping Basic Techniques and Clinical Applications

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    AbstractIn cardiac magnetic resonance (CMR) imaging, the T1 relaxation time for the 1H magnetization in myocardial tissue may represent a valuable biomarker for a variety of pathological conditions. This possibility has driven the growing interest in quantifying T1, rather than just relying on its effect on image contrast. The techniques have advanced to where pixel-level myocardial T1 mapping has become a routine component of CMR examinations. Combined with the use of contrast agents, T1 mapping has led an expansive investigation of interstitial remodeling in ischemic and nonischemic heart disease. The purpose of this review was to introduce the reader to the physical principles of T1 mapping, the imaging techniques developed for T1 mapping, the pathophysiological markers accessible by T1 mapping, and its clinical uses
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