Functional photoacoustic noninvasive Doppler angiography in humans

TL;DR

PANDA is a novel photoacoustic Doppler technique that noninvasively images deep blood flow in humans up to one centimeter, significantly surpassing previous optical methods and enabling clinical applications.

Contribution

This work introduces PANDA, a portable, noninvasive imaging modality combining photoacoustic and Doppler effects for deep, 3D blood flow visualization in humans.

Findings

Measured blood flow up to 1 cm depth in vivo.

Achieved approximately tenfold depth improvement over optical methods.

Demonstrated clinical feasibility with healthy subjects and patients.

Abstract

Optical imaging of blood flow yields critical functional insights into the circulatory system, but its clinical implementation has typically been limited to shallow depths (~1 millimeter) due to light scattering in biological tissue. Here, we present photoacoustic noninvasive Doppler angiography (PANDA) for deep blood flow imaging. PANDA synergizes the photoacoustic and Doppler effects to generate color Doppler velocity and power Doppler blood flow maps of the vascular lumen. Our results demonstrate PANDA's ability to measure blood flow in vivo up to one centimeter in depth, marking approximately an order of magnitude improvement over existing high-resolution pure optical modalities. PANDA enhances photoacoustic flow imaging by increasing depth and enabling cross-sectional blood vessel imaging. We also showcase PANDA's clinical feasibility through three-dimensional imaging of blood flow in healthy subjects and a patient with varicose veins. By integrating the imaging system onto a mobile platform, we have designed PANDA to be a portable modality that is primed for expedient clinical translation. PANDA offers noninvasive, single modality imaging of hemoglobin and blood flow with three-dimensional capability, facilitating comprehensive assessment of deep vascular dynamics in humans.