Quantifying and Visualizing Vascular Branching Geometry with Micro-CT: Normalization of Intra- and Inter-Specimen Variations
This work addresses the problem of characterizing vascular geometry for researchers in biomedical imaging, enabling future studies on disease states based on vascular branching, but it is incremental as it applies existing methods to new data.
The study tackled the problem of quantifying and visualizing vascular branching geometry in rat kidneys using Micro-CT, showing that key geometrical properties and perfused tissue have little inter-specimen variation, with fractal scaling differing between non-symmetric and symmetric branching.
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.