A high-sensitivity high-resolution intravascular photoacoustic catheter through mode cleaning in a graded-index fiber

Intravascular photoacoustic imaging has been developed to evaluate the possibility of plaque rupture in atherosclerosis by high spatial resolution imaging of lipid. However, the detection sensitivity and spatial reso-lution are compromised by the poor focusing caused by a multimode fiber. In this work, we report an intra-vascular photoacoustic catheter with mode self-cleaning in a graded-index fiber to improve the beam quality and the sensitivity for lipid detection. Compared with the higher-order modes in a step-index multimode fiber, the lower-order modes generated by the self-cleaning effect in the graded-index fiber greatly enhanced the photo-acoustic spatial resolution and detection sensitivity. The dominant ringing artifact caused by laser absorption of the ultrasound transducer was further reduced by using stripe suppression. A lipid plaque mimicking phantom was imaged for evaluation. Lipid particles with a small diameter of 75.7 mu m were clearly observed.

Automated summary

This work reports an intravascular photoacoustic catheter with mode self-cleaning in a graded-index fiber, which improves the sensitivity and spatial resolution for plaque detection. The lower-order modes generated by the self-cleaning effect in the graded-index fiber greatly enhance the photoacoustic spatial resolution and detection sensitivity compared to the higher-order modes in a step-index multimode fiber. The dominant ringing artifact caused by laser absorption of the ultrasound transducer is further reduced by using stripe suppression. A lipid plaque mimicking phantom was imaged for evaluation, and lipid particles with a small diameter of 75.7 μm were clearly observed.