Virtual histology of an entire mouse brain from formalin fixation to paraffin embedding. Part 2: Volumetric strain fields and local contrast changes
| Autor: | Griffin Rodgers, Bert Müller, Georg Schulz, Willy Kuo, Vartan Kurtcuoglu, Mario Scheel, Alexandra Migga, Christine Tanner, Christos Bikis, Timm Weitkamp |
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| Přispěvatelé: | University of Zurich, Tanner, Christine |
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: |
Materials science
media_common.quotation_subject 610 Medicine & health computer.software_genre 10052 Institute of Physiology Mice 03 medical and health sciences 0302 clinical medicine Voxel Formaldehyde Animals Contrast (vision) Image resolution 030304 developmental biology media_common Fixation (histology) 0303 health sciences Paraffin Embedding Strain (chemistry) Magnetic resonance microscopy General Neuroscience Brain 2800 General Neuroscience Histology X-Ray Microtomography 570 Life sciences biology Tomography computer Synchrotrons 030217 neurology & neurosurgery Biomedical engineering |
| Popis: | Background Fixation and embedding of post mortem brain tissue is a pre-requisite for both gold-standard conventional histology and X-ray virtual histology. This process alters the morphology and density of the brain microanatomy. New method To quantify these changes, we employed synchrotron radiation-based hard X-ray tomography with 3 μm voxel length to visualize the same mouse brain after fixation in 4% formalin, immersion in ethanol solutions (50%, 70%, 80%, 90%, and 100%), xylene, and finally after embedding in a paraffin block. The volumetric data were non-rigidly registered to the initial formalin-fixed state to align the microanatomy within the entire mouse brain. Results Volumetric strain fields were used to characterize local shrinkage, which was found to depend on the anatomical region and distance to external surface. X-ray contrast was altered and enhanced by preparation-induced inter-tissue density changes. The preparation step can be selected to highlight specific anatomical features. For example, fiber tract contrast is amplified in 100% ethanol. Comparison with existing methods Our method provides volumetric strain fields, unlike approaches based on feature-to-feature or volume measurements. Volumetric strain fields are produced by non-rigid registration, which is less labor-intensive and observer-dependent than volume change measurements based on manual segmentations. X-ray microtomography provides spatial resolution at least an order of magnitude higher than magnetic resonance microscopy, allowing for analysis of morphology and density changes within the brain’s microanatomy. Conclusion Our approach belongs to three-dimensional virtual histology with isotropic micrometer spatial resolution and therefore complements atlases based on a combination of magnetic resonance microscopy and optical micrographs of serial histological sections. |
| Databáze: | OpenAIRE |
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