Abstract
BackgroundMicro-CT holds promising potential for phenotyping and histological purposes. However, few have clarified the difference in the neuroimaging quality between ex vivo and in vivo micro-CT scanners. In addition, no direct comparison has been made between micro-CT scans and standard microscopy. Furthermore, while the efficacy of various stains for yielding soft-tissue contrast in CT scans have been compared in other studies for embryos, staining protocols for larger samples have yet to be clarified. Lastly, post-acquisition processing for image enhancements have not been addressed.MethodsComparisons of postnatal rat brain micro-CT scans obtained through custom-built ex vivo and commercially available in vivo micro-CT scanners were made. Subsequently, the scanned rat brains were then H&E stained for microscopy. Neuroanatomy on micro-CT scanning and 4× microscopy of rat brain were compared.Diffusion and perfusion staining using iodine or PTA were trialled on adult and neonatal encapsulated rat brains. Different combinations of stain concentration and staining time were trialled.Post-acquisition denoising with NLM filter was completed using a modern General-Purpose Graphic Processing Unit (GPGPU) and custom code for prompt processing.ResultsEx vivo micro-CT scans of iodine-stained postnatal rat brains yields 3D images with details comparable to 4× H&E light micrographs. Neural features shown on ex vivo micro-CT scans were significantly more distinctive than those on in vivo micro-CT scans.Both ex vivo and in vivo micro-CT scans required diffusion staining through small craniotomy. Perfusion staining is ineffective. Iodine staining was more efficient than PTA in terms of time.Consistently, enhancement made by NLM denoising on in vivo micro-CT images were more pronounced than that on ex vivo micro-CT scans due to their difference in image signal-to-noise indexes.ConclusionsMicro-CT scanning is a powerful and versatile visualization tool available for qualitative and potential quantitative anatomical analysis. Simple diffusion staining via craniotomy with 1.5% iodine is an effective and minimal structural-invasive method for both in vivo and ex vivo micro-CT scanning for studying the microscopic morphology of neonatal and adult rat brains. Post-acquisition NLM filtering is an effective enhancement technique for in vivo micro-CT brain scans.
Highlights
Micro-CT holds promising potential for phenotyping and histological purposes
Staining of encapsulated postnatal rat brains for successful micro-CT neural imaging We first attempted 1.5% iodine perfusion staining on an adult rat of 27 days but with little success, as shown by Fig. 2a
Same staining techniques worked for neonatal rat brains but required only a staining period of 16 days; the resultant micro-CT scans yielded good neural anatomical information, as shown by Fig. 2c
Summary
Micro-CT holds promising potential for phenotyping and histological purposes. few have clarified the difference in the neuroimaging quality between ex vivo and in vivo micro-CT scanners. Three-dimensional visualization techniques may be divided into two categories: serial sectional image reconstruction and whole-volume imaging The former includes confocal microscopy, episcopic microscopy [1], and the latter includes optical projection tomography (OPT) [2], micro-magnetic resonance imaging (micro-MRI) [3, 4], and micro-computed tomography (micro-CT) [5]. Image reconstruction may be employed to obtain the entire 3D view of the sample, the process is laborious and often with operator-dependent results Episcopic microscopy overcomes this shortfall by adopting automatic serial slice alignment, and reconstructs relatively well-preserved images; such a process destroys the tissue sample post-imaging and prohibits further sample use [1, 7]. Many are still unaware of this versatile tool, micro-CT has gradually becoming a popular whole-volume scanning research method, in large part due to its versatility for volume exploration, ease of tissue preparation, and quantitative analysis potentials
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
