The Value of T1 Mapping Techniques in the Assessment of Myocardial Interstitial Fibrosis.

Cardiac fibrosis, characterized by net accumulation of extracellular matrix in the myocardium, is a common final pathway of heart failure. This myocardial fibrosis (MF) is not necessarily the primary cause of dysfunction; it often results from a reparative process activated in response to cardiomyocyte injury. In light of currently available treatments, late-identified MF could be definitive or irreversible, associated with worsening ventricular systolic function, abnormal cardiac remodeling, and increased ventricular stiffness and arrhythmia. T1 mapping should be used to detect incipient changes leading to myocardial damage in several clinical conditions and also in subclinical disease. This article reviews available techniques for MF detection, focusing on noninvasive quantification of diffuse fibrosis and clinical applications.

3D left ventricular extracellular volume fraction by low-radiation dose cardiac CT: assessment of interstitial myocardial fibrosis.

BACKGROUND: Myocardial fibrosis leads to impaired cardiac function and events. Extracellular volume fraction (ECV) assessed with an iodinated contrast agent and measured by cardiac CT may be a useful noninvasive marker of fibrosis. OBJECTIVE: The purpose of this study was to develop and evaluate a 3-dimensional (3D) ECV calculation toolkit (ECVTK) for ECV determination by cardiac CT. METHODS: Twenty-four subjects (10 systolic heart failure, age, 60 ± 17 years; 5 diastolic failure, age 56 ± 20 years; 9 matched healthy subjects, age 59 ± 7 years) were evaluated. Cardiac CT examinations were done on a 320-multidetector CT scanner before and after 130 mL of iopamidol (Isovue-370; Bracco Diagnostics, Plainsboro, NJ, USA) was administered. A calcium score type sequence was performed before and 7 minutes after contrast with single gantry rotation during 1 breath hold and single cardiac phase acquisition. ECV was calculated as (ΔHUmyocardium/ΔHUblood) × (1 - Hct) where Hct is the hematocrit, and ΔHU is the change in Hounsfield unit attenuation = HUafter iodine - HUbefore iodine. Cardiac magnetic resonance imaging was performed to assess myocardial structure and function. RESULTS: Mean 3D ECV values were significantly higher in the subjects with systolic heart failure than in healthy subjects and subjects with diastolic heart failure (mean, 41% ± 6%, 33% ± 2%, and 35% ± 5%, respectively; P = 0.02). Interobserver and intraobserver agreements were excellent for myocardial, blood pool, and ECV (intraclass correlation coefficient, >0.90 for all). Higher 3D ECV by cardiac CT was associated with reduced systolic circumferential strain, greater end-diastolic and -systolic volumes, and lower ejection fraction (r = 0.70, r = 0.60, r = 0.73, and r = -0.68, respectively; all P < 0.001). CONCLUSION: 3D ECV by cardiac CT can be performed with ECVTK. We demonstrated increased ECV in subjects with systolic heart failure compared with healthy subjects. Cardiac CT results also showed good correlation with important functional heart biomarkers, suggesting the potential for myocardial tissue characterization with the use of 3D ECV by cardiac CT. This trial is registered at www.ClinicalTrials.gov as NCT01160471.

Ressonância magnética cardíaca na cardiomiopatia dilatada: atualidades / Cardiac magnetic resonance in dilated cardiomyopathy: an update

JUSTIFICATIVA E OBJETIVOS: A cardiomiopatia dilatada(CMD) é a mais comum das cardiomiopatias, compreendendo mais de 90% de todos os casos. O seu diagnóstico é feito, sobretudo,com a utilização da ecocardiografia, a qual apresenta algumas limitações quanto à identificação da etiologia. A ressonância magnética cardíaca (RMC) tem se destacado como exame coadjuvante, permitindo melhor caracterização morfofuncional e tecidual do músculo cardíaco. O objetivo deste estudo foi descrevero papel da RMC no diagnóstico e avaliação das diversas causas de CMD.CONTEÚDO: A RMC apresentou bons resultados na aplicaçã oclínica em diversas causas de CMD, não possuindo capacidade de diferenciar todos os seus tipos, porém, contribuindo para a presunção diagnóstica.CONCLUSÃO: Com o avanço tecnológico da RMC, múltiplas indicações clínicas têm surgido em algumas ocasiões, com um aspecto complementar a determinados exames, em outras, como solução de dilemas diagnósticos. Tudo isso com acurácia superior aos demais métodos de imagem, poucas contraindicações e mínimos riscos de efeitos adversos.(AU)

BACKGROUND AND OBJECTIVES: Dilated cardiomyopathy (DCM) is the most common cause of cardiomyopathies,including more than 90% of all cases. Its diagnostic is done using, especially, echocardiography; which presents some limitations regarding the etiology's identification. Cardiac magnetic resonance (CMR) has been very useful as a more precise study, allowing better characterization of myocardium tissue and morphology. The objective of this article was to describe the role of the CMR in the diagnosis and evaluation of the diverse causes of DCM.CONTENTS : The CMR presented good results in the clinical applicationin diverse causes of DCM, not having capacity to differentiate all their types; however, better contributing to the diagnostic and patients follow up.CONCLUSION: With the technological development of CMR, several clinical indications have been created, in a few occasions with a complementing aspect to certain exams, in others with solutions of diagnostic dilemmas. All with higher accuracy in comparison to others image modalities, few contraindications and minimum adverse risks effects.(AU)