Abstract 17479: Cardiac Amyloid Burden Estimated with Myocardial T1 Mapping is Associated with Severity of Cardiac Disease

Abstract

Introduction: Quantification of post-contrast myocardial T1 times with T1-mapping in cardiac magnetic resonance (CMR) has potential diagnostic value in cardiac amyloidosis. A lower ratio is indicative of increased interstitial space and potentially higher amyloid burden.

Hypothesis: The amount of amyloid deposition as estimated by the degree of post-contrast myocardial T1 reduction is associated with the severity of left ventricular (LV) remodeling and diastolic dysfunction.

Methods: Consecutive patients referred for 3.0 Tesla CMR and with a final diagnosis of cardiac amyloidosis (defined as positive cardiac biopsy or typical diffuse, predominantly subendocardial pattern of delayed contrast enhancement) were retrospectively evaluated. The septal E/E’ ratio as an index of LV filling pressures was measured with doppler echocardiography. Indexed LV volumes and mass, LV ejection fraction, and basal anteroseptal and inferolateral wall thicknesses were determined from cine CMR. The ratio of myocardial/blood and myocardial/skeletal muscle T1 times after Gd-DTPA administration were quantified on Look-Locker sequences using dedicated software.

Results: We included 22 patients (15 males [68.2%], age 69±13 years) with a final diagnosis of cardiac amyloid. There was an inverse correlation between myocardial/skeletal muscle T1 ratio and septal E/E’ (r=-0.534, p=0.049). In addition, the myocardial/blood T1 ratio was inversely correlated with basal anteroseptal (r=-0.570, p=0.007; Figure) and inferolateral (r=-0.530, p=0.013) wall thickness. No significant associations were noted with LV volumes, ejection fraction, or mass.

Conclusion: The myocardial/blood and myocardial/skeletal muscle T1 ratio is associated with markers of disease severity in cardiac amyloidosis, suggesting a potential role of T1-mapping for the noninvasive estimation of myocardial amyloid burden with CMR.