A novel method to explore intrarenal arterial tree using micro-CT

The minimally invasive approach for renal surgeries, among others, requires preoperative determination of intrarenal arteries. Their proper identification based on standard preoperative CT images is still not a fully solved problem. Therefore, we decided to resolve this issue by providing a tree topology model using post-mortem kidneys. The number of vessels that compose intrarenal tree is so large, that it cannot by analyzed manually without the aid of image processing techniques. So that, the vessels has to be first depicted using an imaging technique that enables to provide superior resolution in comparison to standard CT scan. In this paper, we present a research on various injection materials enabling to fill the vascular beds in order to scan them using micro-CT and further reconstruct as a 3D model. The evaluated materials were chosen so that they are widely available and affordable. We compare them in terms of their ability to absorb ionizing radiation and penetrate vascular beds (density, viscosity), homogeneity, solidification rate, resistance to solvents and durability. We also present the technique of injecting kidney arteries with the use of the selected material - two-part epoxy adhesive with 10% iodine. In contrast to standard corrosive endocast preparation, in our case there is no need to remove soft parenchymal tissue which takes about two weeks using corrosive materials such as strong acids and bases. The proposed filling material enables to enhance vascular tree to such extend that micro-CT scans of the whole kidneys can be performed. This enables instantaneous substance injection and imaging without permanently destroying the soft tissue material. This approach can be used in various scenarios in which a filling material with the ability to increase radiation absorption is required and there is a need to maintain the integrity of the structure. To the best of our knowledge, this is the first such attempt. The obtained vascular trees by the means of micro-CT confirm the validity of the presented approach.