[Cardiac MRI in nonischemic cardiomyopathies].

BACKGROUND

The classification of cardiomyopathies used in Germany goes back to the European Society of Cardiology (ESC) classification of 2008. The cardiomyopathies are subdivided according to the phenotype, so that magnetic resonance imaging (MRI) is able to differentiate between the various cardiomyopathies.

IMAGING AND DIFFERENTIAL DIAGNOSTICS

The strength of MRI is the ability to differentiate nonischemic cardiomyopathies from other diseases with similar morphofunctional aspects, based on the possibilities of tissue differentiation. In the case of dilated cardiomyopathy (DCM), for example, a differentiation from inflammatory DCM is possible. In the case of hypertrophic cardiomyopathy (HCM), obstructive and nonobstructive forms can be differentiated analogously to the echo but amyloidosis or Fabry disease can also be detected. Evaluation of the right ventricular function is reliable in arrhythmogenic right ventricular cardiomyopathy (ARVC). The use of MRI is also able to directly detect the characteristic fibrofatty degeneration. In the rare restrictive cardiomyopathies (RCM), MRI can track restriction and, for example by means of T1, T2 and T2* mapping, detect sphingolipid accumulation in the myocardium in the context of Fabry disease or iron overload in the context of hemochromatosis.

INNOVATIONS

The quantitative methods of parametric mapping provide the possibility of treatment monitoring but the clinical relevance of this monitoring is still the subject of current research. The unclassified cardiomyopathies can present clinically with similar symptoms to ischemic or inflammatory diseases, so that in the case of myocardial infarction without obstructive coronary arteries (MINOCA) in cardiac catheterization, MRI is a decisive diagnostic tool to determine the actual underlying disease. Similarly, in new cardiomyopathies such as noncompaction cardiomyopathy, MRI can pave the way for a morphological disease definition.