Ex vivo micro-computed tomography

 

Micro-CT is an imaging technique based on X-ray attenuation allowing non-destructive imaging of internal structures of  specimens. Micro-CT provided a 3D model at very high resolution and has the advantages of being a fast, non-invasive and low-cost modality. 

 

Additional notes

Scan charges are £23 per 6 hours for collaborators within the cardiovascular medicine department and £35 per 6 hours for external collaborators. 

Our micro-CT scanner (SkyScan 1172) has pixel size ranging from 26 µm to 1 µm, depending on the sample dimensions.

To increase the contrast of the soft tissues, staining agents such as Lugol and Phosphotungstic acid (PTA) are used to allow the investigation of mouse embryos and other biological samples. The vascular architecture of the organs can be probed by the perfusion of a casting agent in the vessels and arteries.

 

Anatomical imaging protocols

Example 1: Mouse embryos staged at 14.5/15.5 days gestation. 

-Staining process in Lugol for 4 days

-Embedding in tube for scanning: 4 to 6 embryos can fit in one tube

-Typically an embryo scanned at 5 µm resolution (pixel size) takes 2 hours

uCT liver heart brain

Above: Cross sections of the same mouse embryo stainned with lugol and scanned at 5 µm at the level of (left) the abdomen (middle) the heart (right) the brain.

uCT embryo
Above: 3D volume rending in CTVox of the same embryo scanned at 5 µm isotropic pixel size. We can observe the (left) external anatomy and (right) internal anatomy.
 
Note: This type of study can be extended and adapted to other specimens such as aquatic species, insects, or isolated organs.
 
Zak J, et al. “ASPP2 deficiency causes features of 1q41q42 microdeletion syndrome”. Cell Death Differentiation (2016) 23, (12), pp. 1973-1984.
 

Example 2: Heart from an adult rat perfused with Microfil

-Perfusion of heart with Microfil

-Fixation of the sample and embedding in agarose

-Typically a scan at 3.45 µm resolution (isotropic) takes 12 hours

Deliverables:  Three-dimensional visualization of organ vasculature, quantification of the diameter and number of vessels and arteries

Note: this method is suitable for other organs such as placenta vasculature, hind limps, kidneys, and tumours.

heart vasculature

Above: 3D volume rending in CTVox of an adult rat heart perfused with Microfil and scanned at 3.45 µm isotropic pixel size.