Vessel network extraction and analysis of mouse pulmonary vasculature via X-ray micro-computed tomographic imaging

Abstract

In this work, non-invasive high-spatial resolution three-dimensional (3D) X-ray micro-computed tomography (μCT) of healthy mouse lung vasculature is performed. Methodologies are presented for filtering, segmenting, and skeletonizing the collected 3D images. Novel methods for the removal of spurious branch artefacts from the skeletonized 3D image are introduced, and these novel methods involve a combination of distance transform gradients, diameter-length ratios, and the fast marching method (FMM). These new techniques of spurious branch removal result in the consistent removal of spurious branches without compromising the connectivity of the pulmonary circuit. Analysis of the filtered, skeletonized, and segmented 3D images is performed using a newly developed Vessel Network Extraction algorithm to fully characterize the morphology of the mouse pulmonary circuit. The removal of spurious branches from the skeletonized image results in an accurate representation of the pulmonary circuit with significantly less variability in vessel diameter and vessel length in each generation. The branching morphology of a full pulmonary circuit is characterized by the mean diameter per generation and number of vessels per generation. The methods presented in this paper lead to a significant improvement in the characterization of 3D vasculature imaging, allow for automatic separation of arteries and veins, and for the characterization of generations containing capillaries and intrapulmonary arteriovenous anastomoses (IPAVA).

Quantitative Imaging Metrics for the Assessment of Pulmonary Pathophysiology: An Official American Thoracic Society and Fleischner Society Joint Workshop Report

“…These metrics correlate with invasive measures of arterial pressure and vascular resistance ( 188 ). Caveats: Quantification may be limited by ability to resolve distal lung structure (e.g., capillaries from larger vessels) ( 189 ). The spatial resolution of MRI is less than that of CT; thus, imaging of vascular trees is limited to visualized larger vessels .…”

AIENP‐Reinforced DISCO Method for Whole‐Tissue 3D Reconstruction of Pulmonary Capillaries

“…Using the AIENP‐reinforced DISCO method, accurate and unbiased assessment of pulmonary capillary vasculatures at micrometer‐scale can be obtained, providing significant insights for assessing subtle lesions in pulmonary capillaries in clinical settings and aiding in the early detection and monitoring of disease progression. [ 19 ] This method holds significant potential for advancing research and diagnostics in the field of pulmonary vascular imaging and disease detection.…”

Stereology and three-dimensional reconstructions to analyze the pulmonary vasculature

“…This step would be unnecessary if the resolution of the µCT was high enough to clearly delineate the arterial walls and allow their morphometric analysis. The potential of the combination of stereology and µCT has been documented already (Vasilescu et al 2013(Vasilescu et al , 2020 and the use of contrast agents (Hlushchuk et al 2018;Chadwick et al 2021) will help to increase the potential of performing stereological analysis of the vascular tree on scans. In addition, other methods of X-ray imaging (such as synchrotron X-ray tomographic microscopy) reach better resolutions and have been used for lung morphometry already (Barré et al 2014;Schittny 2018;Borisova et al 2021).…”