High frame rate doppler ultrasound bandwidth imaging for flow instability mapping

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Cardiovascular Science

Background:

• Flow instability in blood vessels is linked to cardiovascular and cerebrovascular events.
• Noninvasive detection of vascular flow instability remains a clinical challenge.

Purpose of the Study:

• Introduce Doppler ultrasound bandwidth imaging (DUBI) for assessing blood flow instability.
• Utilize high-frame-rate ultrasound and Doppler bandwidth analysis for in-view flow instability assessment.

Main Methods:

• DUBI estimates instantaneous Doppler bandwidth using autoregressive modeling on high-frame-rate ultrasound data.
• The principle is that flow instability increases velocity variations, leading to a larger Doppler bandwidth.
• Tested DUBI in nozzle-flow phantoms (laminar to turbulent) and carotid bifurcation phantoms (healthy and stenosed).

Main Results:

• DUBI visualized increased Doppler bandwidth (2.1 to 5.2 kHz) in unstable flow regions of nozzle phantoms.
• Achieved optimal sensitivity (0.72) and specificity (0.83) via ROC analysis.
• In carotid phantoms, DUBI detected increased bandwidth (1.4 to 7.7 kHz) correlating with stenosis severity (50% to 75%), indicating flow perturbation.

Conclusions:

• DUBI successfully detects unstable blood flow.
• This technique provides valuable hemodynamic information for diagnosing atherosclerosis.