Magnetic Resonance Diffusion Tensor Imaging Provides New Insights Into the Microstructural Alterations in Dilated Cardiomyopathy

The comparison of diffusion tensor imaging in human hearts between 1.5 T and 3.0 T

BACKGROUND

The aim was to compare the diffusion tensor imaging (DTI) indices derived from human hearts between 1.5 T and 3.0 T scanners. Additionally, the reproducibility of DTI indices was assessed between 1.5 T and 3.0 T scanners.

METHODS

A total of 18 ex-vivo hearts were derived from patients who underwent heart transplantation. The DTI schemes were performed at 1.5 T and 3.0 T, respectively. Then, the same slices from each ex-vivo heart were selected for image analysis. The student's t-test or Wilcoxon-rank test was used to compare the statistical differences. The agreement of DTI indices was mainly reported as the interclass correlation coefficient (ICC).

RESULTS

No significant differences (all P > 0.05) were found in the DTI indices between 1.5 T and 3.0 T scanners. Interestingly, the ICC of all DTI indices was relatively lower with a low b-value. The reproducibility of the helix angle (HA) was relatively lower when compared to the other DTI indices.

CONCLUSION

The DTI indices of ex-vivo human hearts between 1.5 T and 3.0 T scanners had no significant differences. The consistency of DTI indices needed caution using a low b-value with different field strengths, and the relatively low reproducibility of HA should be considered.

A tomographic microscopy-compatible Langendorff system for the dynamic structural characterization of the cardiac cycle

Introduction

Cardiac architecture has been extensively investigated ex vivo using a broad spectrum of imaging techniques. Nevertheless, the heart is a dynamic system and the structural mechanisms governing the cardiac cycle can only be unveiled when investigating it as such.

Methods

This work presents the customization of an isolated, perfused heart system compatible with synchrotron-based X-ray phase contrast imaging (X-PCI).

Results

Thanks to the capabilities of the developed setup, it was possible to visualize a beating isolated, perfused rat heart for the very first time in 4D at an unprecedented 2.75 μm pixel size (10.6 μm spatial resolution), and 1 ms temporal resolution.

Discussion

The customized setup allows high-spatial resolution studies of heart architecture along the cardiac cycle and has thus the potential to serve as a tool for the characterization of the structural dynamics of the heart, including the effects of drugs and other substances able to modify the cardiac cycle.

Innovative imaging methods in heart failure: a shifting paradigm in cardiac assessment. Position statement on behalf of the Heart Failure Association of the European Society of Cardiology

Myriad advances in all fields of cardiac imaging have stimulated and reflected new understanding of cardiac performance, myocardial damage and the mechanisms of heart failure. In this paper, the Heart Failure Association assesses the potential usefulness of innovative imaging modalities in enabling more precise diagnostic and prognostic evaluation, as well as in guiding treatment strategies. Many new methods have gradually penetrated clinical practice and are on their way to becoming a part of routine evaluation. This paper focuses on myocardial deformation and three-dimensional ultrasound imaging; stress tests for the evaluation of contractile and filling function; the progress of magnetic resonance techniques; molecular imaging and other sound innovations. The Heart Failure Association aims to highlight the ways in which paradigms have shifted in several areas of cardiac assessment. These include reassessing of the simplified concept of ejection fraction and implementation of the new parameters of cardiac performance applicable to all heart failure phenotypes; switching from two-dimensional to more accurate and reproducible three-dimensional ultrasound volumetric evaluation; greater tissue characterization via recently developed magnetic resonance modalities; moving from assessing cardiac function and congestion at rest to assessing it during stress; from invasive to novel non-invasive hybrid techniques depicting coronary anatomy and myocardial perfusion; as well as from morphometry to the imaging of pathophysiologic processes such as inflammation and apoptosis. This position paper examines the specific benefits of imaging innovations for practitioners dealing with heart failure aetiology, risk stratification and monitoring, and, in addition, for scientists involved in the development of future research.