Large Arteriolar Component of Oxygen Delivery Implies Safe Margin of Oxygen Supply to Cerebral Tissue

Abstract

What is the organization of cerebral microvascular oxygenation and morphology that allows adequate tissue oxygenation at different activity levels? We address this question in the mouse cerebral cortex using microscopic imaging of intravascular O2 partial pressure and blood flow combined with numerical modeling. Here we show that parenchymal arterioles are responsible for 50% of the extracted O 2 at baseline activity and the majority of the remaining O 2 exchange takes place within the first few capillary branches. Most capillaries release little O 2 at baseline acting as an O 2 reserve that is recruited during increased neuronal activity or decreased blood flow. Our Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:

Magnetic resonance imaging metrics of oxygen extraction fraction: Contradictions or insight into pathophysiological mechanisms?

“…This heterogeneity gives rise to the unintuitive observation that venular SO 2 increases with cortical vessel diameter 6 . The most likely explanation of this observation is that among the heterogeneous flow paths between arterioles and venules those with higher flow tend to have higher SO 2 6 . Venular SO 2 is therefore a flow‐weighted averaging of the SO 2 of the microvascular paths.…”

Laplacian Flow Dynamics on Geometric Graphs for Anatomical Modeling of Cerebrovascular Networks

“…We compared the performance of our modeling scheme with other efficient methods used to generate graphed skeletons for tubular or vessel-like structures. These methods are: the classical 3D-thinning (Voxel-based) [9] 1 , mesh-based meancurvature skeletonization (Mesh-based) [12] 2 , 3D points-cloud contraction (PC-based) [13] 3 , multiple stretching of open active contours (SOAX-based) [23] 4 and geodesic minimum spanning trees extraction (VTrails-based) [16] 5 . For quantitative assessments of the structural errors produced by the various skeletonization methods, we use the DIADEM metric [33] 6 .…”

“…1 Institute of Biomedical Engineering, École Polytechnique de Montréal, Montreal, QC, Canada; 2 Department of Electrical Engineering, École Polytechnique de Montréal, Montreal, QC, Canada; 3 Research Centre, Montreal Hearth Institute, Montreal, QC, Canada; 4 Department of Computer and Software Engineering, École Polytechnique de Montréal, Montreal, QC, Canada. rafat.damseh@polymtl.ca neurovascular coupling and neuro-metabolic activity [5]. It is also important to investigate neuropathologies associated with a deterioration in cerebral oxygen transport [6], [7].…”

Sub-voxel Perfusion Modeling in Terms of Coupled 3d-1d Problem

“…In [16], a 0.7mm × 0.7mm × 0.7mm piece of mouse brain microvasculature was imaged using two-photon microscopy. To obtain a realistic geometry for our model, we used this data to generate a 3d mesh of the extravascular space in which vessel segments corresponded to 1d mesh edges.…”