Figure 3.

ULM imaging of young and aged mouse brain. (A) Example ULM microvessel density maps images from a (left) young mouse brain and (right) an aged mouse brain. Local cortical and subcortical regions are selected and magnified to show the corresponding directional blood flow maps (blue toward the transducer, red away from the transducer). (B) An inset image demonstrating distinct vessel tortuosity phenotypes. The larger, straighter vessels have a relatively low measured tortuosity, whereas the smaller connecting vessels are more circuitous. A diagrammatic example of how the sum of angles metric was determined using the microbubble trajectory data. For each complete microbubble trajectory the total path length, end-to-end distance, and angle between every segment was used in the calculation. ULM images were rendered using MATLAB (R2019a, https://www.mathworks.com/).