Microstructural Analysis of Cardiac Endomyocardial Biopsies with Synchrotron Radiation-Based X-Ray Phase Contrast Imaging

Nowadays, unexplained cardiovascular diseases (CVD) and heart transplant response are assessed by qualitative histological analysis of extracted endomyocardial biopsies (EMB), which is a time consuming procedure involving structural damage of the tissue and the analysis in only a few slices of a 3D structure. In this paper we propose synchrotron radiation-based X-ray phase contrast imaging (X-PCI) as a suitable technique for the analysis of different cardiac microstructures, such as collagen matrix, cardiomyocytes and microvasculature, and how they are affected in abnormal conditions. Following an established procedure in clinics, biopsies from Wistar Kyoto rats are extracted, imaged with X-PCI, and processed in order to show that the quantification of the endomysial collagen matrix, cardiomyocytes and microvasculature is possible, thus demonstrating that the intrinsic properties of X-PCI make it a powerful technique for cardiac microstructure imaging and a promising methodology for a faster and more accurate EMB analysis for CVD diagnosis and evaluation

Microstructural Analysis of Cardiac Endomyocardial Biopsies with Synchrotron Radiation-Based X-Ray Phase Contrast Imaging

Nowadays, unexplained cardiovascular diseases (CVD) and heart transplant response are assessed by qualitative histological analysis of extracted endomyocardial biopsies (EMB), which is a time consuming procedure involving structural damage of the tissue and the analysis in only a few slices of a 3D structure. In this paper we propose synchrotron radiation-based X-ray phase contrast imaging (X-PCI) as a suitable technique for the analysis of different cardiac microstructures, such as collagen matrix, cardiomyocytes and microvasculature, and how they are affected in abnormal conditions. Following an established procedure in clinics, biopsies from Wistar Kyoto rats are extracted, imaged with X-PCI, and processed in order to show that the quantification of the endomysial collagen matrix, cardiomyocytes and microvasculature is possible, thus demonstrating that the intrinsic properties of X-PCI make it a powerful technique for cardiac microstructure imaging and a promising methodology for a faster and more accurate EMB analysis for CVD diagnosis and evaluation

Cardiac multi-scale investigation of the right and left ventricle ex vivo: a review

The heart is a complex multi-scale system composed of components integrated at the subcellular, cellular, tissue and organ levels. The myocytes, the contractile elements of the heart, form a complex three-dimensional (3D) network which enables propagation of the electrical signal that triggers the contraction to efficiently pump blood towards the whole body. Cardiovascular diseases (CVDs), a major cause of mortality in developed countries, often lead to cardiovascular remodeling affecting cardiac structure and function at all scales, from myocytes and their surrounding collagen matrix to the 3D organization of the whole heart. As yet, there is no consensus as to how the myocytes are arranged and packed within their connective tissue matrix, nor how best to image them at multiple scales. Cardiovascular imaging is routinely used to investigate cardiac structure and function as well as for the evaluation of cardiac remodeling in CVDs. For a complete understanding of the relationship between structural remodeling and cardiac dysfunction in CVDs, multi-scale imaging approaches are necessary to achieve a detailed description of ventricular architecture along with cardiac function. In this context, ventricular architecture has been extensively studied using a wide variety of imaging techniques: ultrasound (US), optical coherence tomography (OCT), microscopy (confocal, episcopic, light sheet, polarized light), magnetic resonance imaging (MRI), micro-computed tomography (micro-CT) and, more recently, synchrotron X-ray phase contrast imaging (SR X-PCI). Each of these techniques have their own set of strengths and weaknesses, relating to sample size, preparation, resolution, 2D/3D capabilities, use of contrast agents and possibility of performing together with in vivo studies. Therefore, the combination of different imaging techniques to investigate the same sample, thus taking advantage of the strengths of each method, could help us to extract the maximum information about ventricular architecture and function. In this review, we provide an overview of available and emerging cardiovascular imaging techniques for assessing myocardial architecture ex vivo and discuss their utility in being able to quantify cardiac remodeling, in CVDs, from myocyte to whole organ

Very High-Resolution Imaging of Post-Mortem Human Cardiac Tissue Using X-Ray Phase Contrast Tomography

International audienceThis paper investigates the 3D microscopic structure of ex-vivo human cardiac muscle. Usual 3D imaging techniques such as DMRI or CT do not achieve the required resolution to visualise cardio-myocytes, therefore we employ X-ray phase contrast micro-CT, developed at the European Synchrotron Radiation Facility (ESRF). Nine tissue samples from the left ventricle and septum were prepared and imaged at an isotropic resolution of 3.5 μm, which is sufficient to visualise cardio-myocytes. The obtained volumes are compared with 2D histological examinations, which serve as a basis for interpreting the 3D X-ray phase-contrast results. Our experiments show that 3D X-ray phase-contrast micro-CT is a viable technique for investigating the 3D arrangement of myocytes ex-vivo at a microscopic level, allowing a better understanding of the 3D cardiac tissue architecture

Very High-Resolution Imaging of Post-Mortem Human Cardiac Tissue Using X-Ray Phase Contrast Tomography

International audienceThis paper investigates the 3D microscopic structure of ex-vivo human cardiac muscle. Usual 3D imaging techniques such as DMRI or CT do not achieve the required resolution to visualise cardio-myocytes, therefore we employ X-ray phase contrast micro-CT, developed at the European Synchrotron Radiation Facility (ESRF). Nine tissue samples from the left ventricle and septum were prepared and imaged at an isotropic resolution of 3.5 \\\backslashupmu \\μm, which is sufficient to visualise cardio-myocytes. The obtained volumes are compared with 2D histological examinations, which serve as a basis for interpreting the 3D X-ray phase-contrast results. Our experiments show that 3D X-ray phase-contrast micro-CT is a viable technique for investigating the 3D arrangement of myocytes ex-vivo at a microscopic level, allowing a better understanding of the 3D cardiac tissue architecture