CMR Parametric Mapping as a Tool for Myocardial Tissue Characterization

Abstract

Cardiovascular magnetic resonance (CMR) is the current gold standard for imaging cardiac anatomy, function, and advanced myocardial tissue characterization. After cine, late gadolinium enhancement (LGE), and perfusion imaging, parametric mapping is widely regarded as the 4th era of myocardial CMR development. In contrast to conventional CMR tissue characterization techniques, which rely on relative variations in image intensities to highlight abnormal tissues, parametric mapping provides direct visualization of tissue MR properties such as T1, T2 and T2* in absolute denominations (e.g. in milliseconds). Presentation as pixel-wise parametric maps adds spatial information for a more complete assessment of the myocardium. Advantages of parametric mapping include direct, quantitative comparisons inter-and within-individuals, as well as detection of diffuse disease not evident on conventional CMR imaging, without the need for contrast agents. CMR parametric mapping methods have matured over the past decade into clinical tools, demonstrating not only clinical utility but added value in a wide range of cardiac diseases. They are particularly useful for the evaluation of acute myocardial injury, suspected infiltration and heart failure of unclear etiology. This review discusses the background of parametric mapping, particularly T1-, T2-and ECV-mapping, general magnetic resonance physics principles, clinical applications (including imaging protocols, image analysis and reporting guidelines), current challenges and future directions. CMR parametric mapping is increasingly available on routine clinical scanners, and promises to deliver advanced myocardial tissue characterization beyond conventional CMR techniques, ultimately helping clinicians to benefit patients in their clinical management.

Fast myocardial T1ρ mapping in mice using k-space weighted image contrast and a Bloch simulation-optimized radial sampling pattern

“…In addition to informative morphological and functional investigations, cMRI offers the possibility of enhanced tissue characterization to investigate tissue defects like edema, inflammation or fibrosis [1][2][3]. There are several methods facilitating magnetic resonance imaging to enable tissue characterization, such as late gadolinium enhancement (LGE), T 1 -and T 2 mapping, and the quantification of the extracellular volume [4][5][6][7][8]. However, some of these methods require the administration of gadolinium contrast agent, which is contraindicated in certain patients, especially those with reduced renal function.…”

Cardiovascular Magnetic Resonance for the Differentiation of Left Ventricular Hypertrophy

“…Novel parametric mapping techniques, such as T1 and T2 mapping, allow advanced tissue characterisation via directly quantitative pixel-wise maps [13]. Detailed review of the technical aspects and MR physics principles of parametric mapping may be found elsewhere [14••].…”

“…As clinical evidence behind MR tissue characterisation increases, it is expected that they will eventually become part of routine clinical practice, particularly in the assessment of LVH and other cardiomyopathies. Some, like parametric mapping (widely regarded as the fourth era of myocardial CMR development) [13], have already made this transition to clinical practice, with promise to provide functional and tissue characterisation without the need for contrast agents.…”

Incremental Values of T1 Mapping in the Prediction of Sudden Cardiac Death Risk in Hypertrophic Cardiomyopathy: A Comparison With Two Guidelines

“…Native T1 mapping and extracellular volume fraction (ECV) derived from native and contrast-enhanced T1 values are quantitative methods that enable the detection of myocardial tissue characterization (17). These intrinsic quantitative parameters can reflect the states of focal and diffuse interstitial fibrosis, as well as iron overload, lipid deposition, edema, and protein infiltration (18)(19)(20). Compared with LGE, native T1 mapping and ECV could potentially provide more information about myocardial tissue.…”