Myocardial Tissue Characterization and Fibrosis by Imaging

Abstract

 Tissue composition changes such as fibrosis, edema, or infiltration are frequent features in myocardial diseases  Cardiac imaging modalities offer the ability to characterize myocardial tissue to varying extent  Cardiovascular magnetic resonance offers comprehensive myocardial tissue characterization providing various diagnostic and prognostic imaging biomarkers  Advanced cardiac imaging is expected to become an integral part in risk-stratification and personalized medicine ABSTRACT Myocardial fibrosis, either focal or diffuse, is a common feature of many cardiac diseases and is associated with a poor prognosis for major adverse cardiovascular events. While histological analysis remains the gold standard for confirming the presence of myocardial fibrosis, endomyocardial biopsy is invasive, suffers from sampling errors, and is not practical in the routine clinical setting. Cardiac imaging modalities offer non-invasive surrogate biomarkers not only for fibrosis but also for myocardial edema and infiltration to varying degrees, and have important roles in the diagnosis and management of cardiac diseases. This review summarizes important pathophysiologic features in the development of commonly-encountered cardiac diseases, and the principles, advantages and disadvantages of various cardiac imaging modalities (echocardiography, single photon emission computer tomography, positron emission tomography, multi-detector computer tomography, and cardiovascular magnetic resonance imaging) for myocardial tissue characterization, with an emphasis on imaging focal and diffuse myocardial fibrosis.

Where is the right ventricle? Accurate diagnosis with cardiovascular multimodality imaging

“…Cardiovascular MRI, while not available in most of the countries with common occurrence of EMF, is crucial in both the diagnosis and prognosis of the disease . It can add further value to diagnosis and can potentially provide an early assessment.…”

“…The key feature of cardiovascular MRI is the confirmation of the diagnosis and the differentiation of the disease from other similar presentations, such as Ebstein anomaly, tumors, or thrombus . It can also provide valuable information to help with the surgical approach, such as the accurate definition of the site and extent, the involved structures, the degree of splinting of the myocardium, viable myocardial mass, and ventricular volumes …”

“…Cardiovascular MRI, while not available in most of the countries with common occurrence of EMF, is crucial in both the diagnosis and prognosis of the disease. 1,2,6,14 It can add further value to diagnosis and can potentially provide an early assessment. The key feature of cardiovascular MRI is the confirmation of the diagnosis and the differentiation of the disease from other similar presentations, such as Ebstein anomaly, tumors, or thrombus.…”

“…2 It can also provide valuable information to help with the surgical approach, such as the accurate definition of the site and extent, the involved structures, the degree of splinting of the myocardium, viable myocardial mass, and ventricular volumes. 14,15 Computed tomography can provide direct visualization and mapping of fibrosis within the myocardial wall and shows an accurate demonstration of the morphological and dynamic properties of EMF. 1,15,16 This may be beneficial in cases involving severe heart distortion in areas where there is no MRI access.…”

Magnetic Resonance Imaging for Evaluation of Interstitial Fibrosis in Kidney Allografts

“…In this context, the use of noncontrast magnetic resonance imaging (MRI), in particular T1 mapping and diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) assessment, has gained increasing interest, and has entered a clinical routine in different areas of medicine, such as hepatology and cardiology. 14 , 15 One potential advantage of using macroscopic imaging techniques may be the possibility to obtain additional information about the extent of chronic allograft damage, with a presumably minimal degree of sampling bias and interobserver variability, owing to an objective assessment of the whole organ. In T1 mapping sequences, which are included in most imaging protocols, the tissue contrast is determined by longitudinal (T1) relaxation times.…”