Visualization of two-dimensional transverse blood flow direction using optical coherence tomography angiography

Area of Science:

• Biomedical Optics
• Medical Imaging
• Vascular Biology

Background:

• Assessing vessel patency and blood flow direction is crucial for diagnosing ischemic diseases and guiding vascular surgeries.
• Optical coherence tomography angiography (OCTA) visualizes vasculature but lacks blood flow direction information, a significant limitation.

Purpose of the Study:

• To demonstrate a novel two-dimensional (2D) transverse blood flow direction imaging technique within en face OCTA.
• To overcome the limitations of current OCTA methods in providing directional blood flow data.

Main Methods:

• Implemented a series of triangular beam scans for fast axis imaging in horizontal and vertical directions.
• Utilized inter A-line OCTA with stepwise slow axis scans to calculate decorrelation differences.
• Derived 2D transverse flow direction from the ratio of horizontal and vertical decorrelation differences.

Main Results:

• Verified OCTA flow direction imaging using flow phantoms with varying flow conditions.
• Identified the flow speed range for reliable directional measurements.
• Successfully visualized 2D transverse blood flow orientations in mouse brain vasculature in vivo.

Conclusions:

• The developed OCTA technique provides essential 2D transverse blood flow direction information.
• This imaging method holds potential for diverse clinical applications and preclinical research.