Photoacoustic microscopy for visualization of stents in multiple scenarios

Stents are frequently used when managing the narrowing of ducts and vessels. Even though stents are widely used, short-term and long-term monitoring of stent status is critically important because of various existing issues, including stent fractures and malapposition. However, readily available monitoring tools for stent status have disadvantages, such as using contrast agents or ionizing radiation and being invasive. In this work, acoustic-resolution photoacoustic microscopy (AR-PAM) was used to image stents in clinically relevant scenarios, namely stent fractures, overlapped stents, and a compressed stent. Then, assuming noninvasive, via-skin monitoring of the stents, AR-PAM imaging of ex vivo mouse skin-covered stents, including fractured stents, overlapped stents, a compressed stent, and a butter-covered stent (mimicking a plaque deposited over the stent), was performed as well. Illuminations at 670 nm and 1210 nm were used to image the stent covered by the butter to demonstrate the capability of discriminating the stent and the butter, while 670-nm illumination was used in other scenarios. The results show that AR-PAM is capable of monitoring the issues in stents through the skin. While more optimizations and validations should be carried out, our work shows that photoacoustic imaging has the potential to be a noninvasive, label-free monitoring tool for stents located in a relatively shallow region, like the carotid artery stent, superficial femoral artery stent, or stent in hemodialysis vascular access.