A method for fast, sensitive, and quatitaive imaging of blood flow networks

Background

The ability to quantitatively image three-dimensional blood flow, particularly within micro-circulatory networks like capillaries, is crucial for medical diagnosis but presents significant technical hurdles. A primary challenge lies in achieving high-sensitivity detection of minute blood flows at fast imaging speeds. Existing optical Doppler tomography (ODT) techniques rely on detecting small Doppler phase changes, which are a product of flow rate and imaging duration. Consequently, capturing slow capillary flows quickly results in extremely small phase shifts that are difficult to distinguish from noise. While swept-source optical coherence tomography (SS-OCT) offers advantages in speed and signal-to-noise ratio, it inherently suffers from high phase noise originating from the swept laser, severely limiting its utility for sensitive flow imaging.

Technology

Researchers at Stony Brook University developed an optical coherence Doppler tomography (OTD) system designed to image capillary flow with high speed and signal quality. The novel technology enables high-sensitivity minute flow detection while maintaining fast lateral scan rates. Wavelength division multiplexing is integrated into the imaging method to reduce phase noise, particularly in swept-source optical Doppler tomography (SS-ODT), thereby enhancing sensitivity and suppressing background noise for cerebral capillary flow imaging. The system can also optionally incorporate fluorescence imaging to concurrently examine cellular activity.