Myocardial Tagging with MR Imaging: Overview of Normal and Pathologic Findings

Abstract

Magnetic resonance tagging is used to evaluate the dynamic deformation of lines or grids superimposed on the myocardium during the cardiac cycle. From these data, a specific postprocessing procedure provides two kinds of metrics: (a) three orthogonal components of myocardial motion (longitudinal, circumferential, and radial), and (b) rotation and torsion. Strain expresses the local myocardial deformation and is prone to important physiologic heterogeneities. Peak systolic strain is in the range of -15% to -20% for the longitudinal and circumferential components (fiber shortening) and 30%-40% for the radial component (wall thickening). The helical arrangement of myofibers that run in opposite directions at the epicardium and endocardium explains systolic twist (~15°). This torsion may be enhanced during the early stage of several diseases (eg, hypertrophic cardiomyopathy) or in heart failure with a normal left ventricular ejection fraction. Strain is generally impaired in ischemic heart disease and cardiomyopathy, but the most diagnostically significant finding is the early identification of contractile dysfunction on the basis of longitudinal and circumferential strain reduction in patients with apparently preserved systolic function. Thus, strain impairment appears to be a sensitive and promising marker of subclinical disease, with the potential for improving patient management.

Myocardial Adaptation to High-Intensity (Interval) Training in Previously Untrained Men With a Longitudinal Cardiovascular Magnetic Resonance Imaging Study (Running Study and Heart Trial)

“…35 Circumferential strain values at systole in our study ranging from −10% to −25% are in agreement with the results of previous studies in healthy subjects. 36 Postinterventional decrease of Ecc in the HI(I)T group is probably related to a physiological process with transient myocardial adaptation leading to enhanced cardiac structure and function.…”

“…Normal distribution of the data was statistically (Shapiro-Wilk test) and graphically determined. Differences within groups were by guest on May 11, 2018 http://circimaging.ahajournals.org/ Downloaded from consistently analyzed by paired t tests. ANOVA with repeated measurements consequently adjusted on baseline values was performed to check time-related intergroup statistics.…”

Identification and Assessment of Cardiac Amyloidosis by Myocardial Strain Analysis of Cardiac Magnetic Resonance Imaging

“…CMR tagging has been established as an essential technique for measuring regional myocardial function. 7 It facilitates quantification of local intramyocardial motion and strain.…”

Multi-oriented windowed harmonic phase reconstruction for robust cardiac strain imaging

“…Hence, local functional indicators extracted from this analysis such as the strain tensor may provide a higher predictive value than global cardiac imaging parameters such as the ejection fraction (Axel et al, 2005;Simpson et al, 2013). The basis of MR tagging consists in the generation of a set of saturated magnetization planes which may be subsequently tracked throughout the cardiac cycle so as to estimate the motion of material points (Shehata et al, 2009;Ibrahim, 2011;Jeung et al, 2012). Usually, these planes are arranged in a parallel setting in such a way that the imaged magnetization is modulated by a given wave vector.…”