Emanuel Larsson

In Vivo Regenerative Properties of Coralline‐Derived (Biocoral) Scaffold Grafts in Human Maxillary Defects: Demonstrative and Comparative Study with Beta‐Tricalcium Phosphate and Biphasic Calcium Phosphate by Synchrotron Radiation X‐Ray Microtomography

BACKGROUND In recent years, there has been interest on the fabrication of systems using particulates or block-based approach for bone tissue engineering (TE) scaffolds, possessing porous interconnected structures. In fact, these particular morphologies greatly increase the surface area for more chemical and biological reactions to take place. PURPOSE This study was designed to demonstrate the unique capability of the synchrotron radiation x-ray microtomography (micro-CT) in offering an advanced characterization of coralline-derived (Biocoral) biomaterials placed in human maxillary defects as it allows, in a nondestructive way, a complete, precise, and high-resolution three-dimensional analysis of their microstructural parameters. Moreover, the comparison between Biocoral and other biomaterials was explored to understand the mechanism of their biological behavior as bone substitute. MATERIALS AND METHODS Implant survival, bone regeneration, graft resorption, neovascularization, and morphometric parameters (including anisotropy and connectivity index of the structures) were evaluated by micro-CT in Biocoral and the other biomaterials after 6 to 7 months from implantation in human maxillary bone defects. RESULTS After the in vivo tests, a huge amount of bone was detected in the retrieved Biocoral-based samples, coupled with a good rate of biomaterial resorption and the formation of a homogeneous and rich net of new vessels. The morphometric parameters were comparable to those obtained in the biphasic calcium phosphate-based control, with the exception of the connectivity index for which this control exhibited the most well-connected structure. This last result, together with those referred to the poor performances of the β-tricalcium phosphate block-based sample, suggests that the particular scaffold morphology may play a role in the hunt the optimal scaffold structure to be implanted. CONCLUSION In this limited study, implant success rate seems not strictly dependent on the biomaterial that is used, but on the scaffold morphology. Micro-CT technique was demonstrated to play a fundamental role in advanced characterization of bone TE constructs.

Functionalized synchrotron in-line phase-contrast computed tomography: a novel approach for simultaneous quantification of structural alterations and localization of barium-labelled alveolar macrophages within mouse lung samples

This study presents an approach to increase the sensitivity of lung computed tomography (CT) imaging by utilizing in-line phase contrast CT in combination with single-distance phase-retrieval algorithms and a dedicated image-processing regime. As demonstrated here, functional CT imaging can be achieved for the assessment of both structural alterations in asthmatic mouse lung tissue and the accumulation pattern of instilled barium-sulfate-labelled macrophages in comparison with healthy controls.

Quantitative evaluation of a single‐distance phase‐retrieval method applied on in‐line phase‐contrast images of a mouse lung

Quantitative analysis concerning the application of a single-distance phase-retrieval algorithm on in-line phase-contrast images of a mouse lung at different sample-to-detector distances is presented.

μCT of ex-vivo stained mouse hearts and embryos enables a precise match between 3D virtual histology, classical histology and immunochemistry

The small size of the adult and developing mouse heart poses a great challenge for imaging in preclinical research. The aim of the study was to establish a phosphotungstic acid (PTA) ex-vivo staining approach that efficiently enhances the x-ray attenuation of soft-tissue to allow high resolution 3D visualization of mouse hearts by synchrotron radiation based μCT (SRμCT) and classical μCT. We demonstrate that SRμCT of PTA stained mouse hearts ex-vivo allows imaging of the cardiac atrium, ventricles, myocardium especially its fibre structure and vessel walls in great detail and furthermore enables the depiction of growth and anatomical changes during distinct developmental stages of hearts in mouse embryos. Our x-ray based virtual histology approach is not limited to SRμCT as it does not require monochromatic and/or coherent x-ray sources and even more importantly can be combined with conventional histological procedures. Furthermore, it permits volumetric measurements as we show for the assessment of the plaque volumes in the aortic valve region of mice from an ApoE-/- mouse model. Subsequent, Masson-Goldner trichrome staining of paraffin sections of PTA stained samples revealed intact collagen and muscle fibres and positive staining of CD31 on endothelial cells by immunohistochemistry illustrates that our approach does not prevent immunochemistry analysis. The feasibility to scan hearts already embedded in paraffin ensured a 100% correlation between virtual cut sections of the CT data sets and histological heart sections of the same sample and may allow in future guiding the cutting process to specific regions of interest. In summary, since our CT based virtual histology approach is a powerful tool for the 3D depiction of morphological alterations in hearts and embryos in high resolution and can be combined with classical histological analysis it may be used in preclinical research to unravel structural alterations of various heart diseases.

Phase-contrast computed tomography for quantification of structural changes in lungs of asthma mouse models of different severity

Synchrotron inline phase-contrast computed tomography in combination with single-distance phase retrieval enables quantification of morphological alterations in lungs of mice with mild and severe experimental allergic airways disease in comparison with healthy controls.

Quantification of structural differences in the human calvarium diploe by means of X-ray computed microtomography image analysis: A case study

Accurate models for the human diploe have to take into account any structural differences in the four main areas of the calvaria bones. In this study the technique of Xray computed microtomography (μ-CT) along with image analysis was used in order to visualize and quantitatively analyze differences in the micro-architecture of the human calvarium diploe. A bone specimen from each area of the skull (temporal, frontal, parietal and occipital) was extracted from a human donor and each specimen was characterized in terms of density, specific surface area, trabecular thickness and anisotropy. The obtained results reveal that in the considered case there are structural differences which therefore can be useful for refining traditional models that assume equal conditions throughout the skull.

Morphological characterization of the human calvarium in relation to the diploic and cranial thickness utilizing X-ray computed microtomography

When attempting to establish accurate models for the human diploe, micro-scale morphological differences in the four main areas of the calvaria could also be considered. In this study, X-ray computed microtomography (μ-CT) images were analyzed in order to quantitatively characterize the micro-architecture of the human calvarium diploe. A bone specimen from each area of the skull (temporal, frontal, parietal and occipital) was extracted from a set of 5 human donors and each specimen was characterized in terms of density, specific surface area, trabecular thickness, trabecular spacing. The obtained results revealed that subject-individual structural differences could be related with the diploic as well as the total cranial thickness of the human skull bones. Some tendencies of dependency could also be made with respect to the age of the subject. A consideration of these individual variations can improve traditional models that assume equal conditions throughout the skull.

Quantification of structural alterations in lung disease—a proposed analysis methodology of CT scans of preclinical mouse models and patients

In this paper we have established a general investigative methodology for quantitative computed tomography (CT) lung image analysis in the sagittal, coronal and transversal orientation of lungs wit ...