Photoacoustic Imaging System Maps Hidden Nerves and Vessels in Robotic Laparoscopy

Hidden neurovascular structures can be difficult to visualize during robot-assisted laparoscopy, increasing the risk of iatrogenic injury. Such injuries can cause hemorrhage, neurological deficits, and other serious complications that prolong recovery and raise costs. Surgeons need real-time, depth-resolved imaging that reveals anatomy beyond the visible surface. To help address this challenge, researchers have now integrated laser-induced acoustic, photoacoustic imaging into the minimally invasive workflow to map subsurface nerves and vessels during surgery.

Developed at Worcester Polytechnic Institute (WPI; Worcester, MA, USA) and presented at the 190th Meeting of the Acoustical Society of America (ASA) running May 11–15, the approach embeds photoacoustic (PA) imaging into robot-assisted laparoscopic procedures. The goal is to guide intraoperative decision-making and avoid hidden critical structures. The method targets an unmet need in pelvic and abdominal surgery where visualization is limited by small incisions and endoscopic optics.

The technology directs brief laser pulses into tissue, where optical absorption generates ultrasound-frequency pressure waves. Ultrasensitive microphones detect these waves, which are reconstructed into three-dimensional representations of subsurface anatomy. The system then overlays the resulting neurovascular maps onto the live feed from the laparoscopic camera, creating an augmented reality (AR) view that preserves spatial context for the operating surgeon.

A custom PA probe was incorporated into the laparoscopic workflow and used to generate real-time depictions of neurovascular bundles, which are clusters of nerves and blood vessels that surgeons strive to preserve. The technique was tested during radical prostatectomies, where precise dissection near critical structures is essential. The developers report that photoacoustic imaging can extend beyond this use case to other laparoscopic and image-guided procedures.

“This capability enables visualization of embedded anatomical structures and their depth locations, which is highly valuable for surgical planning and intraoperative monitoring,” said Kai Zhang, associate professor at Worcester Polytechnic Institute.

“We anticipate that this imaging instrumentation will be readily translatable to not only other laparoscopic procedures but also other image-guided procedures,” added Zhang.

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