Movie S3 from Enhanced wall shear stress prevents obstruction by astrocytes in ventricular catheters

Method to measure a 2D velocity profile at a z-slice. The subsequent fluorescent images were binarized by a contrast-thresholding technique to extract particles that are in focus. The binarized images were processed by our in-house particle tracking code to estimate the velocity field at a given z-slice. By assembling 2D velocity profiles at different z-levels, we constructed 3D velocity profiles, as shown in Figure 12 of the main article. Here, λ is 60 μm, which is 7% of the hole depth, d is 1.18 mm, and the diameter of the fluorescent particles is 5 μm. The video plays 0.01x.