In vivo Visualization of Brain Vasculature in Alzheimer’s Disease Model Mice through High-Resolution Ultrasound Blood Flow Mapping
Cerebrovascular disorders are associated with Alzheimer’s disease. Functional analysis of the cerebral vasculature requires an in vivo approach to visualize the blood flow in small animal brains. This paper proposes high-frequency micro-Doppler imaging (HFμDI) technology for mapping mouse cerebral vasculature. A minimal vessel diameter of 48 μm could be determined without using microbubbles by using a 40-MHz transducer. The cortical and hippocampal vessel density in young (4-month-old) wild-type mice was similar to that in middle-aged (11-month-old) wild-type mice. Compared with the vessel density in middle-aged wild-type mice, that in middle-aged mice with AD was significantly lower, particularly in the hippocampus.
In vivo Visualization of Vasculature in Adult Zebrafish by using High-Frequency Ultrafast Ultrasound Imaging
Zebrafish has recently become a crucial animal model for studying human diseases. However, when a zebrafish matures completely, its body loses transparency, making conventional optical imaging techniques difficult for visualizing the vessels. In the present study, high-frequency (40-MHz) micro-Doppler imaging (HFμDI) based on ultrafast ultrasound imaging was proposed for adult zebrafish dorsal vascular mapping in vivo. Blood flow signals were extracted using an eigen-based clutter filter. Blood vessels were clearly observed in 2D and 3D HFμDI. The minimal diameter of vessel can be detected was 36 μm. The maximum flow velocity range was approximately 3–4 mm/s on the dorsal vessels.