Search bioRxiv⌕ Search

Biology subjects

de Bakker, B.

Publications and source records attributed to de Bakker, B..

2 recordsLinked to original sources

Hierarchical Phase-Contrast Tomography Imaging: Applicability in biomedical research

ObjectivesHierarchical Phase-Contrast Tomography (HiP-CT) enables non-destructive, multi-scale imaging of whole human organs. We describe how HiP-CT is utilized for biomedical research within the Human Organ Atlas Hub through three case studies: mapping the enteric nervous system (ENS) of the human colon, analysing myocardial and AV conduction architecture in Tetralogy of Fallot (TOF), and characterizing ductal organization in breast carcinoma. The challenges we faced with this novel biomedical data are discussed. MethodsWhole-organ and region-of-interest scans of three types of human organs were acquired at the European Synchrotron Radiation Facility (ESRF) with isotropic voxel sizes ranging from 20 {micro}m to 0.8 {micro}m. For the colon, voxel binning and RootPainter were employed to tackle data size to segment the ENS. For the heart, voxel-wise myocyte orientation mapping was calculated in terabyte-scale datasets with a high-performance computational framework (Cardiotensor). Breast carcinoma samples were correlated with histopathology for structure validation. ResultsHiP-CT revealed the large-scale organization of the ENS in the colon, enabling visualisation of the 3D structures of the ENS across the colon In TOF hearts, analysis uncovered abnormal myocardial structure and heterogeneous conduction system morphology. In breast carcinoma, HiP-CT resolved the full hierarchy of ductal structures and vascular relationships within tumour and peritumoral regions. ConclusionsHiP-CT provides unprecedented, hierarchical insight into intact human organ structure, bridging the gap between histology and radiology. Advances in knowledgeHiP-CT establishes a new ex vivo radiological modality capable of linking microscale pathology to whole-organ context, advancing translational research in neurogastroenterology, cardiology, and oncology

biophysics↗

Resolving near-micron scale features within a whole sheep head using Hierarchical Phase-Contrast Tomography

BackgroundHierarchical Phase-Contrast Tomography (HiP-CT) was developed to image ex vivo intact human soft-tissue organs with local near-micron scale resolution. PurposeWe demonstrate the application of HiP-CT in combination with the recently developed Eikonal Phase Retrieval (EPR) for resolving anatomical features in large hard and soft tissue structures on a sheep head, and show the applicability for zooming to resolve anatomical features with near-micron scale resolution. Materials and MethodsWe imaged an entire skinned sheep head prepared in 70 % ethanol with HiP-CT at an isotropic voxel size of 16.5 {micro}m using the recently developed Eikonal Phase Retrieval (EPR) to reduce artefacts from bones. Local tomography zooms were taken in regions of interest: the eye (4.23 {micro}m voxels) and the coronal suture (2.20 {micro}m voxels). To compare to clinical imaging, we acquired T2-weighted MRI and CT of the sheep head and evaluated the contrast-to-noise ratio for differentiation of white and grey matter in the brain for all modalities. Further evaluations on HiP-CT images include structure tensor analysis for structural orientation in the brain as well as fibre tracking in the coronal suture. ResultsHiP-CT combined with EPR achieved high contrast for both hard and soft tissue. Comparison to MRI showed similar soft-tissue contrast, but much higher spatial resolution. Structure tensor analysis in the brain revealed the orientation of the major white matter bundles. In the eye, near-micron scale features such as retinal layers and the bundles in the optic nerve were visualized. Fiber tracking allowed analysis of the orientation of collagen fiber bundles in the coronal suture. ConclusionThis work highlights the potential of HiP-CT to image a complete sheep head, ex vivo, and hierarchically zoom without sectioning to resolve few-microns features locally, enabling comprehensive three-dimensional visualization of intricate cranial structures and their spatial interrelations. Summary statementTechnical developments in HiP-CT enable ex vivo X-ray imaging of an intact sheep head with local resolution to near-micron scale, demonstrating future viability on a human head. Key resultsO_LIA whole sheep head was imaged with synchrotron-based hierarchical phase-contrast tomography coupled with Eikonal Phase-retrieval with 16.5 {micro}m isotropic voxels. C_LIO_LIThe high contrast for both hard and soft tissue enabled differentiation of brain white and grey matter, the optic nerve and bone features within the skull. C_LIO_LILocal tomography zoom scans in an eye (4.23 {micro}m voxels) and coronal suture (2.20 {micro}m voxels) allowed visualization and analysis of near-micron sized features. C_LI

bioengineering↗