The emerging role of cardiovascular magnetic resonance in the evaluation of cardiac involvement in systemic sclerosis.

Systemic sclerosis (SSc) is an autoimmune rheumatic disease, characterized by vascular, inflammatory and fibrotic alterations. Cardiac involvement is the « fatal tip of the iceberg» in SSc, as it leads to high morbidity/mortality. Cardiovascular imaging modalities play an important role in the early diagnosis and treatment assessment of cardiac involvement. Echocardiography is the corner stone for evaluation of cardiac involvement, providing information about function, wall motion, pulmonary pressure, pericardium and valvular disease. It is a low-cost modality, widely available, without radiation and with great experience among cardiologists. However, it is a window and operator dependent modality and cannot provide tissue characterization information, absolutely necessary for diagnosis and treatment of cardiac involvement in SSc. Cardiovascular magnetic resonance (CMR) can perform myocardial function and tissue characterization in the same examination without radiation, has excellent reproducibility and is window and operator independent. The great advantage of CMR is the capability to assess peri- myo-vascular inflammation, myocardial ischemia and presence of replacement and diffuse myocardial fibrosis in parallel with ventricular function assessment. The modified Lake Louise criteria including T2, native T1 mapping and extracellular volume fraction (ECV) has been recently used to diagnose inflammatory cardiomyopathy. According to expert recommendations, myocardial inflammation should be considered if at least 2 indices, one T2 and one T1 parameter are positive, whereas native T1 mapping and ECV assess diffuse fibrosis or oedema, even in the absence of late gadolinium enhancement (LGE). Moreover, transmural/subendocardial LGE following the distribution of coronary arteries and diffuse subendocardial fibrosis not related with epicardial coronary arteries are indicative of epicardial and micro-vascular coronary artery disease, respectively. To conclude, CMR can overcome the limitations of echocardiography by identifying acute/active or chronic myocardial inflammation/fibrosis, ischemia and myocardial infarction using classic and parametric indices in parallel with biventricular function assessment.