Quantifying and Visualizing Vascular Branching Geometry with Micro-CT: Normalization of Intra- and Inter-Specimen Variations

TL;DR

This study uses micro-CT imaging and automated analysis to quantify and visualize the vascular branching geometry in rat kidneys, revealing low inter-specimen variation and potential for disease characterization.

Contribution

The paper introduces an automated method for analyzing micro-CT images to quantify vascular branching geometry and normalize variations across specimens.

Findings

Vascular parameters show minimal inter-specimen variation.

Fractal scaling differs between symmetric and non-symmetric branching.

Perfused tissue regions are consistent across specimens.

Abstract

Micro-CT images of the renal arteries of intact rat kidneys, which had their vasculature injected with the contrast agent polymer Microfil, were characterized. Measurement of inter-branch segment properties and the hierarchical structure of the vessel trees were computed by an automated algorithmic approach. The perfusion territories of the different kidneys, as well as the local diameters of the segmented vasculature were mapped onto the representative structures and visually explored. Various parameters were compared in order to outline key geometrical properties, properties which were shown to not have a wide range of inter-specimen variation. It is shown that the fractal scaling in non-symmetric branching reveals itself differently, than in symmetric branching (e.g., in the lung the mean bronchial diameters at each generation are closely related). Also, perfused tissue is shown to have very little inter-specimen variation and therefore could be used in future studies related to characterizing various disease states of tissues and organs based on vascular branching geometry.