Dynamic microvascular monitoring with miniaturized omnidirectional broadband photoacoustic imaging system for living entities (MOBILE).

Abstract

Microcirculation monitoring is crucial for evaluating cardiovascular health and detecting organ dysfunction early, but existing bedside imaging techniques often cannot provide sufficient resolution and depth for dynamic assessment during natural physiological activities. Here, we present MOBILE (Miniaturized Omnidirectional Broadband Photoacoustic Imaging System for Living Entities), a photoacoustic imaging system that allows unrestricted microcirculatory monitoring with 40 µm resolution and penetration depth of 10 mm, allowing stratified visualization of dynamic vascular responses. This platform features an ultracompact fibre-optic sensor capable of omnidirectional ultrasound-based detection across a large bandwidth (0.3-80 MHz). The compact design of the system facilitates point-of-care monitoring through seamless integration with portable devices or existing clinical systems. Through a comprehensive evaluation of the patient's haemodynamic parameters, MOBILE reveals distinct dynamic responses of vessels at different tissue depths, from superficial microvessels to deep subcutaneous vessels, capturing vessel-specific changes in diameter, haemoglobin concentration, and tissue oxygenation during numerous physiological challenges. This platform offers possibilities for understanding microcirculatory responses and improving critical care management through high-resolution vessel monitoring.