Philipp Nolte (Goettingen, DE), Marcel Brettmacher (Goettingen, DE), Chris Johann Gröger (Goettingen, DE), Tim Gellhaus (Goettingen, DE), Angelika Svetlove (Goettingen, DE), Arndt F. Schilling (Goettingen, DE), Frauke Alves (Goettingen, DE), Christoph Rußmann (Goettingen, DE; Boston, MA, US), PD Dr. Christian Dullin (Goettingen, DE; Heidelberg, DE)
Abstract text (incl. figure legends and references)
Introduction: Histological analysis of hard tissue is labor-intensive, destructive, and does not allow targeting regions of interest (ROI). We propose a novel workflow of microCT guided section for the generation of precisely positioned sequential histological sections through the inclusion of 3d printed phantoms.
Materials & methods: In addition to the classic histological workflow, three 3D-printed cone-shaped phantoms were embedded in combination with different tissue specimens in resin (Technovit 9100, Kulzer). After hardening, the blocks were scanned in a microCT (Perkin Elmer, QuantumFX) at a resolution of 80 µm. A priming cut is performed using a diamond bandsaw blade (Messner, CutGrinder Primus). The specimen is then further sectioned using a laser microtome (Tissue Surgeon. LLS Rowiak). Completed sections were imaged using a microscope (Zeiss, Axiovert 200 inverted microscope).
Results: We developed a workflow for microCT-aided hard-tissue histology, based on the inclusion of external markers visible in both microscopic and CT imaging. After the cutting process, the resulting section was comprised of the 2D slice of the specimen as well as the ellipsis resulting from the cones. Through the geometric parameters of the ellipsis, computed with the histological image, we obtained the major- and minor axis and iteratively search for the optimal corresponding region in the 3D microCT-scan of the specimen. This process was conducted for all phantoms, thus allowing for the reconstruction and extraction of the digital twin of the cutting plane in the CT data.
Conclusion: In our novel CT-aided workflow, we demonstrated a method to retroactively verify the position of the cutting procedure, thus allowing for the possible fusion of histology and microCT by overlaying corresponding CT slices and histological sections. The established geometrical correspondence could be proven beneficial when the color-coded, but to two dimensions limited histology is expanded through registration to a 3D context.