Measurement of Lateral and Axial Blood Flow Velocity Components of the Mouse Spinal Cord Microvasculature Using High Frequency Ultrafast Imaging

Approximately 250k to 500k individuals are newly afflicted with spinal cord injuries (SCI) globally each year. There is growing evidence that blood perfusion deficits in microvasculature may be a promising therapeutic target for rescuing injured nervous tissue and enhancing neuronal function. Various approaches have been developed to improve the blood perfusion after injury. However, validation of these approaches requires longitudinal assessment of blood perfusion in animal models. Therefore, we propose a new method to quantify blood flow velocity in both the axial and lateral directions in microvasculature using high frequency ultrasound. Results show that vessels having different blood flow directions can be identified in the axial and lateral blood flow velocity maps of the spinal cord. The peak blood flow velocity of the artery reaches −8.3 mm/s in the $z$ direction (transverse to the spinal cord), and 25.8 mm/s in the $x$ direction (along the spinal cord), with a pulse rate of approximately 600 beats per minutes. These results indicate that the proposed high frequency ultrasound velocimetry approach can be used to measure the 2D blood flow velocity of the mouse spinal cord, which could be used to quantify spinal hemodynamic response for SCI therapeutic development.