A comparison of three different micro-tomography systems for accurate determination of microvascular parameters

The investigation of micro-vessel dimensions in 3D is currently problematic due to their complex structures and fine scale. Quantification of vascular parameters is important in several fields of biomedicine; including embryogenesis, wound healing, diseases characterized by uncontrolled angiogenesis (e.g. tumor growth and metastasis) and the development of implantable bio-materials where a functional vascular supply is critical to their successful integration into host tissue. However, techniques that can resolve the micron-scaled features of these capillary beds, such as scanning electron and confocal microscopy, do not allow for total image reconstitution in 3D in thick tissue samples [1]. The present study describes the use of an in vivo corrosion casting technique that provides a stable replica of the microvascular network and the subsequent evaluation of three different μCT systems in order to accurately quantify vessel dimensions. Stable replicas of micro-vascular networks in neonatal mouse eyes were first created using in vivo vascular corrosion casting and then imaged using a unique, laboratory scale, μCT unit. This system combines a LaB₆ cathode with high-performance electron optics to obtain a high resolution x-ray source. Novel image analysis was then applied to the reconstructions to quantify the morphological parameters of the hyaloid vascular plexi in the developing eyes of post-natal day 2 (P2) wild-type mice. These results are compared to synchrotron scans, establishing vascular casting and x-ray μCT as a valid laboratory scale experimental method for accurate 3D quantification of the microvasculature, with potential applications to a wide variety of fields in biological and medical research.