Intravascular tri-modality system: Combined ultrasound, photoacoustic, and elasticity imaging

We have developed a hybrid intravascular imaging system for the early detection of vulnerable plaque by combining three complementary imaging techniques: ultrasound imaging (USI), photoacoustic imaging (PAI), and photoacoustic elasticity imaging (PEI). As a loading-free elasticity detection method, PEI can quantitatively obtain the tissue elasticity through the photoacoustic phase. By sharing the same ultrasound detection system, USI and PAI could be organically combined. Meanwhile, the optical absorption and elasticity images of plaque are simultaneously reconstructed by the same photoacoustic pulses. To prove the imaging capabilities and complementarity of the system, mimicking phantom experiments were conducted. Furthermore, ex-vivo experiments were performed on the rabbit abdominal aorta to achieve an early assessment of atherosclerosis by detecting the presence and the development extent of lipid plaques. The results illustrate that the system can simultaneously detect the structural composition and the mechanical properties of plaque, thereby showing great potential for accurately diagnosing the atherosclerosis.