Anorexia nervosa is an eating disorder occurring most frequently in adolescent females, characterized by 1/ voluntary dietary restriction, leading to lower than normal body weight and, often, loss of considerable amount of weight and, thereby, malnutrition, 2/ intense fear of gaining weight, even when the individual is already underweight, starved or malnourished and 3/ disturbed body image perception, including extreme emphasis on the appearance. Anorexia nervosa is characterized by the potential severity of its prognosis. While complete remission occurs in about 50% of cases, up to 20% of patients will develop a chronic relapsing form that leads to social disintegration. Moreover, anorexia nervosa has the highest mortality rate among psychiatric diseases with a risk of death of up to 10% (including suicide and clinical complications of severe malnutrition). If approximatively 30% of deaths in anorexia nervosa are attributed to cardiac complications, the nature and the frequency of such complications remain insufficiently described, and their screening at a preclinical stage is still poorly codified. Echocardiography findings are well documented and include reduced left ventricular mass, pericardial effusion (in 22 to 35% of cases), or mitral valve prolapse (in up to 35% of cases); in addition, systolic function, evaluated by the ejection fraction appears to be preserved whereas a global diastolic dysfunction, estimated with trans-mitral flow and global longitudinal strain, is reported. While the interest of cardiac echography has been well established, only one study used MRI (magnetic resonance imaging) as a means of cardiac evaluation in anorexia nervosa: interestingly, this study found local myocardial fibrosis in nearly 25% of patients with anorexia nervosa, which could potentially contribute to cardiac rhythm disorders. That said, no study has yet used T1-Mapping MRI to evaluate if diffuse myocardial fibrosis is prevalent in this population group.

The investigators aim to conduct a transversal, observational, monocentric study whereby malnourished patients with anorexia nervosa (n = 38) and age- and sex- matched, normal weight, healthy volunteers (n = 38) will undergo a gadolinium-enhanced cardiac MRI. The primary objective of this study is to evaluate and compare the frequency of cardiac fibrosis in those populations using cardiac MRI. Other morphological and functional cardiac MRI parameters will be described and compared as secondary objectives: local myocardial fibrosis using enhanced MRI; myocardial and left ventricular mass; myocardial triglyceride quantification using Proton spectroscopy; cardiac high-energy metabolism using Phosphore-31 spectroscopy. Moreover, non-cardiac parameters evaluated by MRI such as adipose tissue distribution (visceral fat, liver fat, bone marrow fat) in anorexia nervosa patients compared with controls.

In addition, patients with anorexia nervosa, a clinical, morphological and biological evaluation, including anthropometric parameters, biphotonic absorptiometry, resting electrocardiogram, cardiac echography and classical biological markers of malnutrition, will be done. Multivariate analysis will then be used to identify possible correlating factors between cardiac MRI findings and clinical, morphological and biological parameters in malnourished patients with anorexia nervosa, so as to shed light on possible new risk stratification models or predictive tools for cardiac complications that could be later evaluated by appropriate studies.