Diffusion Tensor Cardiovascular Magnetic Resonance in Cardiac Amyloidosis

Abstract

Background Cardiac amyloidosis (CA) is a disease of interstitial myocardial infiltration, usually by light chains or transthyretin. We used diffusion tensor cardiovascular magnetic resonance (DT-CMR) to noninvasively assess the effects of amyloid infiltration on the cardiac microstructure. Methods DT-CMR was performed at diastole and systole in 20 CA, 11 hypertrophic cardiomyopathy, and 10 control subjects with calculation of mean diffusivity, fractional anisotropy, and sheetlet orientation (secondary eigenvector angle). Results Mean diffusivity was elevated and fractional anisotropy reduced in CA compared with both controls and hypertrophic cardiomyopathy ( P <0.001). In CA, mean diffusivity was correlated with extracellular volume ( r =0.68, P =0.004), and fractional anisotropy was inversely correlated with circumferential strain ( r =−0.65, P =0.02). In CA, diastolic secondary eigenvector angle was elevated, and secondary eigenvector angle mobility was reduced compared with controls (both P <0.001). Diastolic secondary eigenvector angle was correlated with amyloid burden measured by extracellular volume in transthyretin, but not light chain amyloidosis. Conclusions DT-CMR can characterize the microstructural effects of amyloid infiltration and is a contrast-free method to identify the location and extent of the expanded disorganized myocardium. The diffusion biomarkers mean diffusivity and fractional anisotropy effectively discriminate CA from hypertrophic cardiomyopathy. DT-CMR demonstrated that failure of sheetlet relaxation in diastole correlated with extracellular volume in transthyretin, but not light chain amyloidosis. This indicates that different mechanisms may be responsible for impaired contractility in CA, with an amyloid burden effect in transthyretin, but an idiosyncratic effect in light chain amyloidosis. Consequently, DT-CMR offers a contrast-free tool to identify novel pathophysiology, improve diagnostics, and monitor disease through noninvasive microstructural assessment.

Comparison of interpolation methods of predominant cardiomyocyte orientation from in vivo and ex vivo cardiac diffusion tensor imaging data

“…This might be an advantage compared with the low-rank and rule-based models for studies on pathology accompanied by altered sheet angles, such as dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), cardiac amyloidosis, and aortic stenosis. 69,[73][74][75][76]…”

Multidisciplinary Approaches for Transthyretin Amyloidosis

“…b Concentric hypertrophy of the ventricular wall is demonstrated in the short-axis view MRI has also been demonstrated to help diagnose cardiomyopathy in ATTR amyloidosis patients [76]. Finally, a recent study suggested the utility of diffusion tensor imaging for the detection of cardiac amyloidosis, including ATTR amyloidosis [79].…”

The year in cardiovascular medicine 2020: imaging

“…Preliminarni rezultati ove inovativne in vivo tehnike upućuju na nove patofiziološke mehanizme i poboljšanu dijagnostiku, pružajući obećavajuće nove dimenzije u procjeni poremećaja srčanog mišića. 22 Registar hipertrofičnih kardiomiopatija (Registar HCMR) uključio je 2755 bolesnika s HCM-om iz 44 centra u 6 država, a uključuje CMR, genske i podatke biomarkera kako bi se poboljšala predikcija rizika. Osnovni podatci identificiraju 2 podskupine bolesnika: grupu s pozitivnim mutacijama sakromera i većom fibrozom na CMR te grupu s negativnim mutacijama sarkomera i manjom fibrozom.…”

“…The preliminary results of this innovative in vivo technique suggest novel pathophysiological mechanisms and improved diagnostics, proving a promising new dimension in the assessment heart muscle disorders. 22 The Hypertrophic Cardiomyopathy Registry (HCMR Registry) recruited 2755 patients with HCM from 44 sites in 6 countries, and includes CMR, genetic, and biomarkers data in order to improve risk prediction. The baseline data identified two distinct subgroups of patients: a group with sarcomere positive mutation and more fibrosis by CMR and a group sarcomere mutation negative with less fibrosis.…”