Evolving diagnostic and prognostic imaging of the various cardiomyopathies

Several noninvasive imaging modalities, particularly cardiac magnetic resonance (CMR), have of late provided important diagnostic and prognostic insights into various cardiomyopathies. Myocardial delayed enhancement on CMR after administration of contrast accurately delineates a scar, a powerful marker of poor prognosis in dilated cardiomyopathy. Also in heart failure, loss of integrity of the cardiac sympathetic nervous system, as demonstrated by reduced myocardial uptake of the radioisotope meta-iodo-benzylguanidine with nuclear imaging similarly provides information on outcomes. The presence/absence of a scar on CMR has emerged as an important diagnostic and/or prognostic tool for specific cardiomyopathies, such as Tako-Tsubo, sarcoidosis, or hypertrophic cardiomyopathy. In addition, the quantification of the myocardial parameter T2* on CMR has been validated for accurate quantification of iron myocardial overload and as the strongest predictor for incident heart failure. In these diseases, coronary angiography with computed tomography (CT) may be very useful in ruling out underlying coronary disease noninvasively.