Fig. 3

Anatomical details extracted from MRI data define transport model subdomains. Structure MRI scans and DCE-MRI data were used to build subdomains within the whole-brain finite-element model. Data were analyzed to determine transport parameters for each subdomain within the whole-brain model. A Subject-specific, 3D tetrahedral mesh of mouse brain in translucent white (crystal brain). Sagittal cross-section shows all five anatomical subdomains within the finite-element model. B Close up of segmentation between artery and periarterial space as 2D coronal slices (perpendicular to cross-section shown in (A)) along the left branch of the Circle of Willis, where lines depict the edges of tetrahedral mesh vertices. The width of the periarterial space ranges from three to nine vertices. Because the periarterial space is defined primarily by concentration, sometimes a buffer one or two vertices thick resides between the artery and the periarterial space that is indicative of boundaries between regions where one or more materials may reside in the same voxel and influence the measured signal (see “Sources of Error”). The artery, which holds no contrast agent, exhibits no post-contrast signal change, while the periarterial space, which has high contrast concentration, exhibits large post-contrast signal change. The intermediate region is a combination of both, which produces a signal in between thus excluding the voxel from the definitions of either the arterial or periarterial region. C 3D ‘crystal brain’ image of the surface (light grey) and branching (peach) periarterial subdomains. Translucent white shows the surface of the brain. D 3D ‘crystal brain’ image of arterial (red) and ventricular (blue) subdomains (lateral ventricle (LV), Third Ventricle (3 V), Fourth Ventricle (4 V), Circle of Willis (CoW))