Visualizing Periampullary Tumors with Intraductal Ultrasound utilizing an Intracardiac Echocardiography Catheter: A...

Early detection of pancreatic cancer is crucial for survival, but detecting smalllesions remains challenging. Intraductal Ultrasound (IDUS) using intracardiac echocardiography (ICE) catheters for B-mode and Shear-Wave Elastography (SWE) potentially offers improved visualization and characterization of small tumors. This study assesses the feasibility of IDUS using ICE catheters to detect and visualize periampullary tumors in surgically resected specimens.

In this two-phase ex-vivo feasibility study, 25 pancreatic specimens were included, of which the first 10 were used to establish and standardize the imaging protocol, followed by technical feasibility evaluation in the remaining 15 specimens. Catheters were introduced into the pancreatic duct, common bile duct, or positioned extraductally to enable tumor visualization with B-mode imaging and shear-wave elastography (SWE). Tumor visualization rates, catheter insertion success, SWE measurements in normal and tumor tissue, and image quality were assessed.

ICE catheter insertion was successful in 12 of 15 specimens; unsuccessful access was primarily related to large tumor size (>4 cm) or unidentifiable ductal anatomy following surgical resection. However, extraluminal imaging successfully visualized tumors in one of these cases. Median shear-wave speed and elastic modulus for normal pancreatic parenchyma were 1.58 m/s and 7.6 kPa, respectively. SWE measurements in tumor tissue were suboptimal, likely due to ex-vivo tissue variability and catheter strain during repeated use.

IDUS with ICE is feasible for qualitative B-mode visualization of periampullary tumors and enables SWE assessment of pancreatic parenchyma in an ex-vivo setting. Reliable elastography of tumor tissue remained challenging, indicating the need for further technical refinement and in-vivo validation.