Improved visualization with an adjustable-light modified macroscopic on-site evaluation technique enhances specimen adequacy and diagnostic accuracy in EUS-FNA for pancreatic lesions: A randomized crossover trial

Abstract Objective Determine whether a modified macroscopic on-site evaluation （MOSE) technique, by enhancing visualization of the macroscopic visible core (MVC) in 22G/25G fine needle aspiration (FNA) specimens, improves specimen adequacy and pathological diagnostic accuracy. Methods This single-center, prospective, randomized crossover trial enrolled 90 consecutive patients with solid pancreatic lesions scheduled for EUS-FNA from the Department of Gastroenterology at the Third People’s Hospital of Chengdu between February 2023 and August 2024. Patients were randomly assigned (1∶1) via a computer-generated sequence to Group A (first pass using traditional MOSE, second pass using modified MOSE) or Group B (first pass using modified MOSE, second pass using traditional MOSE). The core modification was the use of an adjustable white light source from 35 to 1 700 LUX at a fixed distance (37.2 mm) from the slide. Specimen adequacy was defined as MVC≥4 mm. The primary outcome was the specimen adequacy rate between groups. Secondary outcomes included the diagnostic accuracy of cytopathology and histopathology. Bias was controlled through blinded assessment (pathologists and data analysts were unaware of group allocation) and standardized operating procedures. Results The specimen adequacy rate was significantly higher in the modified MOSE group (70.0%, 95%CI: 59.9 to 78.5%) than in the traditional MOSE group (43.3%, 95%CI: 33.6 to 54.6%; χ²=13.714, P