Benefits of Endoscopic Ultrasonography for Prevalent Gallbladder Polyp Among Koreans

Abstract

Purpose: Patients of the gallbladder (GB) polyp usually do not have any symptoms. Hence, prevalence of the GB is not often accurately known. Abdominal ultrasonography is a typical tool for detection of GB polyp, but is known to show false negative sometimes. Endoscopic ultrasonography (EUS) is reported as having higher resolution and better chance to detect GB polyps. The aim of this study is to confirm the benefits of EUS over the abdominal US for particularly prevalent GB polyp among Koreans. Methods: Five thousand seventy-nine patients who had undertaken abdominal US in the Healthcare Center of Ewha Womans University Mok-dong Hospital were included. The prevalence and predictive factors for GB polyp was analyzed with this data. Another group of fifty three patients who had undertaken EUS in the same institute above were also included in the study. They received EUS after the abdominal US for further evaluation of GB polyp. Differences between the two tools are found in both accuracy and diagnostic results. The accuracy was scored from one to ten points by three independent examiners. Results: The prevalence of GB polyp was 11.4% (581 of the total 5079). The 57.8% of the patients with GB polyp was male (336 of the 581). The mean age of the patients with GB polyp was 46.6 years (±8.7SD, range 21-80), which is higher than the group with no GB polyp (45.7 ±9.2SD, t=2.195, p=0.028). But the age was not a predictive factor (p=0.055). Male patients had a higher rate of GB polyp (p=0.015). The GB polyp was frequent among people with BMI greater than 23kg/m2 which makes 12.3% of the patients with GB polyp (p=0.009). However, other factors such as the level of cholesterol, history of diabetes mellitus, hypertension, hepatitis B virus infection, and smoking had not the predictive values. When comparing two methods, the mean of maximum diameter of the largest polyp was not statistically different (5.3 mm ± 2.7SD vs. 5.9 mm ± 2.5SD, p=0.400) in each groups. The cases of increasing size were 26 cases (49 %, maximum 5 mm), and decreasing cases were 16 cases (39 %, maximum 7 mm). Additional findings were founded in 32 percent (17 of total 53 cases) of patients who had taken EUS after abdominal US. Seven cases of increasing number of polyps, five cases of adenomyomatosis, and concomitant stones or sludge had detected. When compare the accuracy of images, EUS has much more clear images and high resolution than abdominal US (8.3 ± 0.5SD vs. 6.2 ± 1.0SD, p=0.006). Conclusion: The prevalence of GB polyp in Koreans was 11.4%. It was more prevalent in male and patients with high BMI. And EUS has good diagnostic value in detecting GB polyps with high accuracy and additional lesions in GB compared to abdominal US.