Intravascular Optical Diffuse Spectroscopy for Direct Blood Flow Assessment

The patent replaces the mechanical pressure wire system with an optical measurement system. Light sources (lasers or LEDs) emit light through optical fibers into the blood vessel, and photodetectors capture the scattered light from moving red blood cells. This optical system directly measures blood flow velocity and characteristics, eliminating the need for mechanical pressure measurements and providing superior measurement precision without requiring complex mechanical components.

The patent uses red blood cells as natural tracers or intermediaries in the blood flow. Instead of introducing external mechanical sensors into the blood stream, the system utilizes the inherent optical properties and movement of red blood cells to infer blood flow characteristics. The light scattering from these natural particles provides direct information about flow velocity and patterns, achieving high precision measurement without mechanical intervention.

The patent replaces indirect mechanical pressure-based wall sheer stress assessment with direct optical measurement. By measuring the velocity and distribution of red blood cells using light scattering, the system directly calculates wall sheer stress from observed flow patterns near the vessel wall. This eliminates the need for complex mechanical sensor arrays and provides more accurate local wall sheer stress measurements.

The patent creates an optical copy or representation of the blood flow field by capturing light scattering patterns from red blood cells. This optical information serves as a proxy that directly reflects the physical state of blood flow, including velocity gradients near the wall that determine wall sheer stress. The optical measurement copy provides more faithful representation of the actual flow conditions than mechanical pressure sensors.