Differential standard deviation of log-scale intensity based optical coherence tomography angiography

Area of Science:

• Biomedical Optics
• Medical Imaging
• Ophthalmology

Background:

• Optical coherence tomography angiography (OCTA) is crucial for visualizing microvasculature.
• Existing OCTA methods face limitations in spatial resolution and signal-to-noise ratio (SNR).
• Accurate microvascular imaging is vital for diagnosing and monitoring various medical conditions.

Purpose of the Study:

• To introduce and validate a novel algorithm, differential standard deviation of log-scale intensity (DSDLI), for enhanced OCTA microvascular imaging.
• To improve spatial resolution and SNR in en face microvascular images of human skin.
• To compare the performance of DSDLI against established OCTA techniques.

Main Methods:

• Developed the DSDLI algorithm utilizing variance in difference images of consecutive log-scale intensity structural scans.
• Generated en face microvascular images by calculating standard deviation of differential log-scale intensities within a specific depth range.
• Employed a self-adaptive sub-pixel image registration algorithm and 2D Fourier transform for motion artifact removal in in vivo experiments.

Main Results:

• DSDLI demonstrated improved spatial resolution and SNR in microvascular images compared to speckle variance OCT and power intensity differential methods.
• Phantom experiments showed an average SNR improvement of 7.3 dB for flowing particles.
• In vivo experiments achieved an average SNR improvement of 6.8 dB and a 21% increase in spatial resolution for blood vessel imaging.

Conclusions:

• The DSDLI-based OCTA method significantly enhances microvascular image quality in human skin.
• DSDLI offers superior performance in terms of spatial resolution and SNR compared to previous OCTA techniques.
• This advanced imaging approach holds promise for improved diagnosis and research in vascular diseases.