The role of cardiac magnetic resonance in hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is a common genetic cardiac disorder, typically characterized by a hypertrophied, non-dilated left ventricle (LV). Since the phenotypic expression of HCM varies widely, and other diseases may mimic it, imaging has a central role in its diagnosis. Though transthoracic echocardiography is the first-line imaging modality to study patients with HCM, cardiac magnetic resonance (CMR) imaging has evolved in recent years into a highly useful technique providing valuable additional information in the diagnosis of HCM and in differentiating it from other disorders. Unfortunately this technique is still considered by many clinicians as preclinical with limited use in daily clinical practice. In fact, CMR is currently the standard for morphological and functional cardiac assessment, and can easily evaluate the entire heart without technical or patient-related constraints. Moreover, no other noninvasive imaging technique can currently compete with CMR in terms of tissue characterization. These strengths applied in HCM patients provide an accurate means to morphologically describe phenotypic expression, to evaluate the impact on regional and global function and intraventricular flow patterns, and to quantify gradients and regurgitant fractions. Contrast-enhanced CMR can depict areas of scarring within abnormal myocardial segments, making CMR appealing for risk stratification. Moreover, concomitant pathology of the aortic valve and thoracic aorta, other primary or secondary myocardial disorders, and other conditions that may present with myocardial hypertrophy can be clearly depicted or ruled out. Finally, its non-invasive nature and excellent reproducibility favor CMR as a follow-up technique for evaluation of disease progression. It is our hope that this review paper will provide a better appreciation of the contribution of CMR among other imaging modalities in the diagnosis of HCM.