title: 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.
authors.affiliation: Departments of Radiology B, University Hospital of Strasbourg, NHC, 1 Place de l'Hôpital, 67091 Strasbourg, France. Mi-Young.Jeung@chru-strasbourg.fr
authors.forename: Mi-Young
authors.initials: MY
authors.lastname: Jeung
authors.forename: Philippe
authors.initials: P
authors.lastname: Germain
authors.forename: Pierre
authors.initials: P
authors.lastname: Croisille
authors.forename: Soraya
authors.initials: S
authors.lastname: El ghannudi
authors.forename: Catherine
authors.initials: C
authors.lastname: Roy
authors.forename: Afshin
authors.initials: A
authors.lastname: Gangi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D057918:Fiducial Markers; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis*