Characterizing cardiac involvement in amyloidosis using cardiovascular magnetic resonance diffusion tensor imaging

Abstract

Background In-vivo cardiovascular magnetic resonance (CMR) diffusion tensor imaging (DTI) allows imaging of alterations of cardiac fiber architecture in diseased hearts. Cardiac amyloidosis (CA) causes myocardial infiltration of misfolded proteins with unknown consequences for myocardial microstructure. This study applied CMR DTI in CA to assess microstructural alterations and their consequences for myocardial function compared to healthy controls. Methods Ten patients with CA (8 AL, 2 ATTR) and ten healthy controls were studied using a diffusion-weighed second-order motion-compensated spin-echo sequence at 1.5 T. Additionally, left ventricular morphology, ejection fraction, strain and native T1 values were obtained in all subjects. In CA patients, T1 mapping was repeated after the administration of gadolinium for extracellular volume fraction (ECV) calculation. CMR DTI analysis was performed to yield the scalar diffusion metrics mean diffusivity (MD) and fractional anisotropy (FA) as well as the characteristics of myofiber orientation including helix, transverse and E2A sheet angle (HA, TA, E2A). Results MD and FA were found to be significantly different between CA patients and healthy controls (MD 1.77 ± 0.17 10 − 3 vs 1.41 ± 0.07 10 − 3 mm 2 /s, p < 0.001; FA 0.25 ± 0.04 vs 0.35 ± 0.03, p < 0.001). MD demonstrated an excellent correlation with native T1 ( r = 0.908, p < 0.001) while FA showed a significant correlation with ECV in the CA population ( r = − 0.851, p < 0.002). HA exhibited a more circumferential orientation of myofibers in CA patients, in conjunction with a higher TA standard deviation and a higher absolute E2A sheet angle. The transmural HA slope was found to be strongly correlated with the global longitudinal strain ( r = 0.921, p < 0.001). Conclusion CMR DTI reveals significant alterations of scalar diffusion metrics in CA patients versus healthy controls. Elevated MD and lower FA values indicate myocardial disarray with higher diffusion in CA that correlates well with native T1 and ECV measures. In CA patients, CMR DTI showed pronounced circumferential orientation of the myofibers, which may provide the rationale for the reduction of global longitudinal strain that occurs in amyloidosis patients. Accordingly, CMR DTI captures specific features of amyloid infiltration, which provides a deeper understanding of the microstructural consequences of CA. Electronic supplementary material The online version of this article (10.1186/s12968-019-0563-2) contains supplementary material, which is available to authorized users.

CMR Diffusion Tensor Imaging Provides Novel Imaging Markers of Adverse Myocardial Remodeling in Aortic Stenosis

“…Besides changes in myocardial diffusion, our investigation also revealed marked microstructural alterations in AS patients. Similar to previous reports in HCM and amyloidosis (18,19), the E2A sheet angle was elevated in AS patients. The significant correlation between the thickness of the septal wall and E2A substantiates the hypothesis that not only cellular hypertrophy or ECV expansion, but also exaggerated tilting of the laminar sheetlet orientation contributes to myocardial thickening.…”

“…The copyright holder for this this version posted August 19, 2020. ; https://doi.org/10.1101/2020.08.17.20176297 doi: medRxiv preprint amyloidosis, hypertrophic and dilated cardiomyopathy, characteristic alterations of those parameters have been described and partially correlated with functional LV impairment (17)(18)(19)(20).…”

Cardiac magnetic resonance imaging to detect ischemia in chronic coronary syndromes: state of the art

“…95 Finally, cardiac diffusion CMR allows an assessment of changes in myocardial extracellular volume and microstructure without the need for CM. [96][97][98] Another developing technique is hyperpolarized carbon-13 CMR, capable of visualizing the uptake of metabolic substrates and their FIGURE 4 Three -dimensional (3D) image fusion combining information from coronary computed tomography angiography (CCTA), computed tomography (CT)-derived fractional flow reserve (FFR), stress perfusion cardiac magnetic resonance imaging (CMR), and CMR with late gadolinium enhancement (LGE -CMR). Data from a 59-year -old male patient with severe 3-vessel coronary artery disease are shown.…”

Automating in vivo cardiac diffusion tensor postprocessing with deep learning–based segmentation

“…All remaining 69 test cases were used for further analysis. Measuring the axis from the LV center to the insertion points, a median angular difference of 10º [6,14] was measured for the insertion point positions between the experienced user and the U-Net. Like the Dice scores, we measured a similar range of angular differences among the cohorts: healthy 10 [6,14]; dilated cardiomyopathy 10 [5,16]; HCM 11 [5,16]; and Amyloid 8 [6,11].…”