Comprehensive validation of cardiovascular magnetic resonance techniques for the assessment of myocardial extracellular volume.
01 May 2013-Circulation-cardiovascular Imaging (LIPPINCOTT WILLIAMS & WILKINS)-Vol. 6, Iss: 3, pp 373-383
TL;DR: DynEq-CMR–derived ECV shows a good correlation with histological collagen volume fraction throughout the whole heart, and varied significantly according to contrast dose, myocardial region, and sex.
Abstract: Background— Extracellular matrix expansion is a key element of ventricular remodeling and a potential therapeutic target. Cardiovascular magnetic resonance (CMR) T1-mapping techniques are increasingly used to evaluate myocardial extracellular volume (ECV); however, the most widely applied methods are without histological validation. Our aim was to perform comprehensive validation of (1) dynamic-equilibrium CMR (DynEq-CMR), where ECV is quantified using hematocrit-adjusted myocardial and blood T1 values measured before and after gadolinium bolus; and (2) isolated measurement of myocardial T1, used as an ECV surrogate.
Methods and Results— Whole-heart histological validation was performed using 96 tissue samples, analyzed for picrosirius red collagen volume fraction, obtained from each of 16 segments of the explanted hearts of 6 patients undergoing heart transplantation who had prospectively undergone CMR before transplantation (median interval between CMR and transplantation, 29 days). DynEq-CMR–derived ECV was calculated from T1 measurements made using a modified Look-Locker inversion recovery sequence before and 10 and 15 minutes post contrast. In addition, ECV was measured 2 to 20 minutes post contrast in 30 healthy volunteers. There was a strong linear relationship between DynEq-CMR–derived ECV and histological collagen volume fraction ( P <0.001; within-subject: r =0.745; P <0.001; r 2=0.555 and between-subject: r =0.945; P <0.01; r 2=0.893; for ECV calculated using 15-minute postcontrast T1). Correlation was maintained throughout the entire heart. Isolated postcontrast T1 measurement showed significant within-subject correlation with histological collagen volume fraction ( r =−0.741; P <0.001; r 2=0.550 for 15-minute postcontrast T1), but between-subject correlations were not significant. DynEq-CMR–derived ECV varied significantly according to contrast dose, myocardial region, and sex.
Conclusions— DynEq-CMR–derived ECV shows a good correlation with histological collagen volume fraction throughout the whole heart. Isolated postcontrast T1 measurement is insufficient for ECV assessment.
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Charité1, University College London2, University of Oxford3, University of Toronto4, St George's, University of London5, National Institutes of Health6, Beth Israel Deaconess Medical Center7, University of Virginia Health System8, University of Pittsburgh9, Baker IDI Heart and Diabetes Institute10, University of Alberta11, Karolinska University Hospital12, University of Lausanne13
TL;DR: This document provides a summary of the existing evidence for the clinical value of parametric mapping in the heart as of mid 2017, and gives recommendations for practical use in different clinical scenarios for scientists, clinicians, and CMR manufacturers.
Abstract: Parametric mapping techniques provide a non-invasive tool for quantifying tissue alterations in myocardial disease in those eligible for cardiovascular magnetic resonance (CMR). Parametric mapping with CMR now permits the routine spatial visualization and quantification of changes in myocardial composition based on changes in T1, T2, and T2*(star) relaxation times and extracellular volume (ECV). These changes include specific disease pathways related to mainly intracellular disturbances of the cardiomyocyte (e.g., iron overload, or glycosphingolipid accumulation in Anderson-Fabry disease); extracellular disturbances in the myocardial interstitium (e.g., myocardial fibrosis or cardiac amyloidosis from accumulation of collagen or amyloid proteins, respectively); or both (myocardial edema with increased intracellular and/or extracellular water). Parametric mapping promises improvements in patient care through advances in quantitative diagnostics, inter- and intra-patient comparability, and relatedly improvements in treatment. There is a multitude of technical approaches and potential applications. This document provides a summary of the existing evidence for the clinical value of parametric mapping in the heart as of mid 2017, and gives recommendations for practical use in different clinical scenarios for scientists, clinicians, and CMR manufacturers.
996 citations
TL;DR: The "2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure" as discussed by the authors provides patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with heart failure.
955 citations
TL;DR: This document provides recommendations for clinical and research T1 and ECV measurement, based on published evidence when available and expert consensus when not, and addresses controversies in the field.
Abstract: Rapid innovations in cardiovascular magnetic resonance (CMR) now permit the routine acquisition of quantitative measures of myocardial and blood T1 which are key tissue characteristics. These capabilities introduce a new frontier in cardiology, enabling the practitioner/investigator to quantify biologically important myocardial properties that otherwise can be difficult to ascertain clinically. CMR may be able to track biologically important changes in the myocardium by: a) native T1 that reflects myocardial disease involving the myocyte and interstitium without use of gadolinium based contrast agents (GBCA), or b) the extracellular volume fraction (ECV)–a direct GBCA-based measurement of the size of the extracellular space, reflecting interstitial disease. The latter technique attempts to dichotomize the myocardium into its cellular and interstitial components with estimates expressed as volume fractions. This document provides recommendations for clinical and research T1 and ECV measurement, based on published evidence when available and expert consensus when not. We address site preparation, scan type, scan planning and acquisition, quality control, visualisation and analysis, technical development. We also address controversies in the field. While ECV and native T1 mapping appear destined to affect clinical decision making, they lack multi-centre application and face significant challenges, which demand a community-wide approach among stakeholders. At present, ECV and native T1 mapping appear sufficiently robust for many diseases; yet more research is required before a large-scale application for clinical decision-making can be recommended.
885 citations
Cites background or methods from "Comprehensive validation of cardiov..."
...For the bolus only approach, with single timepoint postcontrast measurement, a 15 minutes minimum delay should be used for ECV measures in non-infarcted myocardium [56,63,66]....
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...clinical throughput, and is supported by the literature [56,63,66]....
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...Agreement with the collagen volume fraction appears significantly higher for ECV [24,54,63] compared to isolated post...
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...There is some evidence for this phenomenon with upward drift of ECV measures with longer measurement times post Gd or low bolus doses [56,63,72]....
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...ECV has robust histological validation as an ECM measurement which correlates with the collagen volume fraction [24,54,63]....
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TL;DR: The technical aspects of key T1-mapping methods and imaging protocols are described and their limitations including the factors that influence their accuracy, precision, and reproducibility are described.
Abstract: The longitudinal relaxation time constant (T1) of the myocardium is altered in various disease states due to increased water content or other changes to the local molecular environment. Changes in both native T1 and T1 following administration of gadolinium (Gd) based contrast agents are considered important biomarkers and multiple methods have been suggested for quantifying myocardial T1 in vivo. Characterization of the native T1 of myocardial tissue may be used to detect and assess various cardiomyopathies while measurement of T1 with extracellular Gd based contrast agents provides additional information about the extracellular volume (ECV) fraction. The latter is particularly valuable for more diffuse diseases that are more challenging to detect using conventional late gadolinium enhancement (LGE). Both T1 and ECV measures have been shown to have important prognostic significance. T1-mapping has the potential to detect and quantify diffuse fibrosis at an early stage provided that the measurements have adequate reproducibility. Inversion recovery methods such as MOLLI have excellent precision and are highly reproducible when using tightly controlled protocols. The MOLLI method is widely available and is relatively mature. The accuracy of inversion recovery techniques is affected significantly by magnetization transfer (MT). Despite this, the estimate of apparent T1 using inversion recovery is a sensitive measure, which has been demonstrated to be a useful tool in characterizing tissue and discriminating disease. Saturation recovery methods have the potential to provide a more accurate measurement of T1 that is less sensitive to MT as well as other factors. Saturation recovery techniques are, however, noisier and somewhat more artifact prone and have not demonstrated the same level of reproducibility at this point in time. This review article focuses on the technical aspects of key T1-mapping methods and imaging protocols and describes their limitations including the factors that influence their accuracy, precision, and reproducibility.
574 citations
Cites background from "Comprehensive validation of cardiov..."
...The magnitude of error in ECV measurement due to intercompartmental exchange mechanisms during Gd washout may not be significant in a clinical context [9,15,55,56]....
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TL;DR: The 2022 guideline as discussed by the authors provides patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with heart failure, with the intent to improve quality of care and align with patients' interests.
Abstract: Aim: The “2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure” replaces the “2013 ACCF/AHA Guideline for the Management of Heart Failure” and the “2017 ACC/AHA/HFSA Focused Update of the 2013 ACCF/AHA Guideline for the Management of Heart Failure.” The 2022 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with heart failure. Methods: A comprehensive literature search was conducted from May 2020 to December 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from MEDLINE (PubMed), EMBASE, the Cochrane Collaboration, the Agency for Healthcare Research and Quality, and other relevant databases. Additional relevant clinical trials and research studies, published through September 2021, were also considered. This guideline was harmonized with other American Heart Association/American College of Cardiology guidelines published through December 2021. Structure: Heart failure remains a leading cause of morbidity and mortality globally. The 2022 heart failure guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with heart failure, with the intent to improve quality of care and align with patients’ interests. Many recommendations from the earlier heart failure guidelines have been updated with new evidence, and new recommendations have been created when supported by published data. Value statements are provided for certain treatments with high-quality published economic analyses.
484 citations
References
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TL;DR: An alternative approach, based on graphical techniques and simple calculations, is described, together with the relation between this analysis and the assessment of repeatability.
43,884 citations
TL;DR: Attempts to standardize options for all cardiac imaging modalities should be based on the sound principles that have evolved from cardiac anatomy and clinical needs, and selection of standardized methods must bebased on the following criteria.
Abstract: Nuclear cardiology, echocardiography, cardiovascular magnetic resonance (CMR), cardiac computed tomography (CT), positron emission computed tomography (PET), and coronary angiography are imaging modalities that have been used to measure myocardial perfusion, left ventricular function, and coronary anatomy for clinical management and research. Although there are technical differences between these modalities, all of them image the myocardium and the adjacent cavity. However, the orientation of the heart, angle selection for cardiac planes, number of segments, slice display and thickness, nomenclature for segments, and assignment of segments to coronary arterial territories have evolved independently within each field. This evolution has been based on the inherent strengths and weaknesses of the technique and the practical clinical application of these modalities as they are used for patient management. This independent evolution has resulted in a lack of standardization and has made accurate intra- and cross-modality comparisons for clinical patient management and research very difficult, if not, at times, impossible.
Attempts to standardize these options for all cardiac imaging modalities should be based on the sound principles that have evolved from cardiac anatomy and clinical needs.1–3⇓⇓ Selection of standardized methods must be based on the following criteria:
An earlier special report from the American Heart Association, American College of Cardiology, and Society of Nuclear Medicine4 defined standards for plane selection and display orientation for serial …
5,967 citations
TL;DR: A remarkable committee was convened: The American Heart Association Writing Group on Myocardial Segmentation and Registration for Cardiac Imaging came to an agreement upon all aspects of nomenclature and anatomic descriptions of the heart.
Abstract: Nuclear cardiology, echocardiography, cardiovascular magnetic resonance (CMR), cardiac computed tomography (cardiac CT), positron emission computed tomography (PET), and coronary angiography are im...
3,158 citations
TL;DR: It can be concluded that arterial hypertension together with elevated circulating aldosterone are associated with cardiac fibroblast involvement and the resultant heterogeneity in tissue structure and the stage is set to prevent pathological LVH resulting from myocardial fibrosis as well as to reverse it.
Abstract: Left ventricular hypertrophy (LVH) is the major risk factor associated with myocardial failure. An explanation for why a presumptive adaptation such as LVH would prove pathological has been elusive. Insights into the impairment in contractility of the hypertrophied myocardium have been sought in the biochemistry of cardiac myocyte contraction. Equally compelling is a consideration of abnormalities in myocardial structure that impair organ contractile function while preserving myocyte contractility. For example, in the LVH that accompanies hypertension, the extracellular space is frequently the site of an abnormal accumulation of fibrillar collagen. This reactive and progressive interstitial and perivascular fibrosis accounts for abnormal myocardial stiffness and ultimately ventricular dysfunction and is likely a result of cardiac fibroblast growth and enhanced collagen synthesis. The disproportionate involvement of this nonmyocyte cell, however, is not a uniform accompaniment to myocyte hypertrophy and LVH, suggesting that the growth of myocyte and nonmyocyte cells is independent of each other. This has now been demonstrated in in vivo studies of experimental hypertension in which the abnormal fibrous tissue response was found in the hypertensive, hypertrophied left ventricle as well as in the normotensive, nonhypertrophied right ventricle. These findings further suggest that a circulating substance that gained access to the common coronary circulation of the ventricles was involved. This hypothesis has been tested in various animal models in which plasma concentrations of angiotensin II and aldosterone were varied. Based on morphometric and morphological findings, it can be concluded that arterial hypertension (i.e., an elevation in coronary perfusion pressure) together with elevated circulating aldosterone are associated with cardiac fibroblast involvement and the resultant heterogeneity in tissue structure. Nonmyocyte cells of the cardiac interstitium represent an important determinant of pathological LVH. The mechanisms that invoke short- (e.g., collagen metabolism) and long-term (e.g., mitosis) responses of cardiac fibroblasts require further investigation and integration of in vitro with in vivo studies. The stage is set, however, to prevent pathological LVH resulting from myocardial fibrosis as well as to reverse it.
2,036 citations
TL;DR: In this article, the authors proposed a standardization of the angles for cardiac planes, number of segments, slice display and thickness, nomenclature for segments and assignment of segments to coronary arterial territories.
Abstract: Nuclear cardiology, echocardiography, cardiovascular magnetic resonance (CMR), cardiac computed tomography (CT), positron emission computed tomography (PET), and coronary angiography are imaging modalities that have been used to measure myocardial perfusion, left ventricular function, and coronary anatomy for clinical management and research. Although there are technical differences between these modalities, all of them image the myocardium and the adjacent cavity. However, the orientation of the heart, angle selection for cardiac planes, number of segments, slice display and thickness, nomenclature for segments, and assignment of segments to coronary arterial territories have evolved independently within each field. This evolution has been based on the inherent strengths and weaknesses of the technique and the practical clinical application of these modalities as they are used for patient management. This independent evolution has resulted in a lack of standardization and has made accurate intra- and cross-modality comparisons for clinical patient management and research very difficult, if not, at times, impossible.
Attempts to standardize these options for all cardiac imaging modalities should be based on the sound principles that have evolved from cardiac anatomy and clinical needs.1–3⇓⇓ Selection of standardized methods must be based on the following criteria:
An earlier special report from the American Heart Association, American College of Cardiology, and Society of Nuclear Medicine4 defined standards for plane selection and display orientation for serial …
1,645 citations