In Vivo Quantitative Imaging of Coronary Blood Flow by Intracoronary Doppler OCT

Objective: This work aims to develop a novel approach for in vivo quantitative imaging of coronary blood flow using intracoronary Doppler OCT. Methods: A 200 kHz swept-source OCT system with an endoscopic catheter probe was used to acquire both structural and Doppler OCT images. In the Doppler measurement, raw OCT phase signal was processed with timing variation and motion compensation to reduce the phase noise. Furthermore, the Doppler measurement angle was inferred by pullback image data and used to correct the measurement error due to oblique imaging caused by non-coaxial alignment of the imaging catheter. To validate our system, the flow rate measurement was performed using an ex vivo phantom and in vivo experiments were conducted in living swine coronary arteries. Results: After oblique imaging compensation, the measurement error was reduced from 3.0±11.4% to 0.7±8.1%. A minor systematic difference of 4.2±8.7% was found between preset (0 – 240 ml/min) and calculated flow rate for all the measurements. The feasibility of imaging coronary flow in vivo was successfully demonstrated in a living swine. Conclusion: The experimental results show that Doppler OCT can be an accurate approach for quantitative assessment of the intracoronary flow in vivo. Significance: To our knowledge, this is the first in vivo catheter-based Doppler OCT coronary blood flow measurement.