Cardiovascular magnetic resonance features of caseous calcification of the mitral annulus

Cardiovascular Magnetic Resonance (CMR) is unrivalled as an imaging modality for the evaluation of cardiac and pericardial masses. Caseous calcification of the mitral annulus is a rare [1-4] form of degeneration of the fibrous skeleton of the mitral annulus that should be included in the differential diagnosis of myocardial masses. Usually found in elderly patients, it's typically located in the posterior mitral annulus. We studied with CMR two cases of caseous calcification of the mitral annulus; in both cases the diagnosis was confirmed with a CT scan.Patient 1. A 87-year-old woman was referred to our Hospital with suspicion of an atrial mass. A CMR study (Figure 1) showed appearances compatible with extensive caseous calcification of the posterior mitral annulus, with dimensions of 3 × 2.5 cm and a circumferential extension of about 5 cm, in the basal inferior wall of the left ventricle and bulging into the posterior left atrium, without significant mitral valve regurgitation.Patient 2. A 70-year-old male, who had undergone bone marrow transplantation for a follicular non-Hodgkin's lymphoma, was referred after transthoracic echocardiography had identified a hyperechogenic intramyocardial mass in the postero-lateral basal wall. CMR (Figure 2) and CT scan (Figure 3) confirmed the diagnosis of caseous calcification of the mitral annulus.Both patients were asymptomatic at the time of diagnosis and were treated conservatively.The CMR findings of the two patients are similar. In T1-weighted (T1W) sequences (Panel A in Fig. 1 and 2) the masses are dark, and in fat suppressed T2-weighted (T2W) STIR sequences (Panel B in Fig. 1 and 2) they lack signal. The combination of dark T1W and T2W tissue signal is unusual for a cardiac mass [5] and suggests calcification. In balanced steady state free precession (bSSFP) images the regions of caseous calcification (* in Panel C in Fig. 1 and 2) appear only slightly darker than the normal myocardium, with a well-defined intramyocardi