Water intake pancreatic ultrasonography improves pancreatic body and tail visualization: contributing factors revealed by quantitative analysis

Purpose Transabdominal pancreatic ultrasound is simple and noninvasive; however, the image quality is often degraded by visceral fat and gastrointestinal gas. Water intake pancreatic ultrasonography (WPUS) may help address this limitation, but quantitative evidence remains limited. We evaluated the effects of WPUS and examined the 10-grade Pancreatic Image Scale (PIS) as a quality control metric. Methods We retrospectively reviewed the medical records of 581 patients who underwent WPUS. The PIS (0–9) was recorded before and after water intake, and improvements were analyzed for associations with body mass index (BMI), age, and sex to identify factors influencing pancreatic visualization. We added a reproducibility study in which three gastroenterologists independently re-scored 30 anonymized cases three times. Results WPUS improved pancreatic visualization in 82% of cases; the proportion achieving PIS ≥ 6 increased from 17% in pre-water supine scans to 54–71% after WPUS ( P < 0.001). Higher BMI was associated with lower baseline PIS ( β = − 0.12, P < 0.001). WPUS-related improvement was significantly greater in women than in men ( β = 0.99, 95% CI 0.56–1.42, P < 0.001). PIS demonstrated moderate-to-good repeatability (intra-reader ICC 0.80; inter-reader ICC 0.71). Conclusion Factor analysis indicated no sex difference in pre-WPUS pancreatic visualization, but women exhibited greater improvement after water intake. WPUS significantly improved visualization of the pancreatic body and tail, as reproducibly quantified using PIS. These findings support WPUS as a practical tool for routine clinical assessment and as a potential adjunct to early detection strategies for pancreatic disease.