Increasing the Maximum Detectable Flow Velocity in High-Frequency Ultrasound Vector Doppler Imaging

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Ultrasound Technology

Background:

• High-frequency ultrasound (HFUS) Doppler imaging offers high resolution for small animal and human studies.
• Vector Doppler imaging (VDI) visualizes complex blood flow patterns independent of Doppler angle.
• Existing HFUS VDI systems face frame rate limitations, restricting velocity measurements.

Purpose of the Study:

• To develop an electrocardiography (ECG)-gating-based HFUS VDI system to overcome frame rate limitations.
• To enable accurate Doppler flow measurements without aliasing at high velocities.
• To validate the system's performance in phantoms and small animal models.

Main Methods:

• An ECG-gating technique was integrated with an HFUS VDI system using a Verasonics Vantage 256 research platform.
• Tilted plane waves were aligned with the ECG R-wave to optimize data acquisition.
• The system was tested using a steady-flow phantom and in vivo studies on mice.

Main Results:

• The developed HFUS VDI system achieved accurate flow velocity estimations with <10% error in phantom studies.
• Peak flow velocities in mouse carotid artery, left ventricle, and aortic arch were successfully measured.
• Complex flow patterns in a mitral regurgitation mouse model were visualized without Doppler aliasing.

Conclusions:

• The ECG-gating-based HFUS VDI system effectively overcomes conventional limitations in frame rate and velocity measurement.
• This technology demonstrates significant potential for vector flow visualization in small animals, even at high velocities.
• The developed system offers a valuable tool for preclinical research and cardiovascular imaging.