Ultrasound and Photoacoustic Guided Gastrostomy to Prevent Colonic Injury

Gastrostomy tube (G-tube) placement is a common surgical procedure, and pediatric surgeons prefer laparoscopic-assisted percutaneous endoscopic gastrostomy. However, a limitation of this approach is the lack of a noninvasive image-guidance modality to identify the presence of the transverse colon in the pathway of the puncture needle. A new approach has been proposed that utilizes externally induced bio-safe agents to detect the transverse colon through photoacoustic (PA) imaging, which has the potential to distinguish the stomach and transverse colon. A feasibility study was conducted using colon- and stomach-mimicking phantoms. The colon was coated with IR-806 indocyanine green (ICG), while the stomach remained with natural blood contrast. Co-registered ultrasound (US) and PA images were acquired in real time as the two fibers moved closer to the tissue boundaries. While navigating the puncture needle, the difference between the acquired PA signals at the two wavelengths was used to identify the tissue in front of the needle. At a distance of about 1 mm from the colon mimic, a stronger PA signal was observed at 800 nm compared to 532 nm, indicating the presence of the colon. In contrast, a weaker PA signal at 800 nm compared to 532 nm was observed on the stomach side, where blood is the primary absorber. The presence of the contrast agent-coated colon can be detected non-invasively and distinguished from the stomach by exploiting the difference in the PA signals. This novel approach overcomes the limitations of traditional imaging techniques and minimizes the risk of colonic injury during G-tube placement. The use of a low-cost, bio-safe, and FDA-approved PA contrast agent provides a cost-effective and accessible clinical solution that has the potential to revolutionize G-tube placement procedures. This development has led to a novel non-invasive US and PA-guided gastrostomy, consistently minimizing colonic injury risks during G-tube placements.