Clinical and diagnostic value of transrectal ultrasound in assessing the severity of ulcerative colitis

Abstract

Background. Endoscopic and histological studies play a decisive role in the diagnosis of inflammatory bowel diseases, as they allow confirming the diagnosis, determining the degree of inflammatory activity, the extent of intestinal damage, and monitoring the course of disease and the effectiveness of therapy. Howe­ver, it is not possible to assess the state of all intestinal layers with colonoscopy. Modern non-invasive methods such as ultrasound, computed tomography, and magnetic resonance imaging cope best with this purpose. With their help, you can assess the state of the intestinal wall and obtain a cross-sectional image of the intestine, evaluate extraintestinal structures (lymph nodes, vessels, fatty tissue). It can be said that endoscopy and ultrasound search for the same type of information but look at different things. Deepening the knowledge about the role of ultrasound of the distal parts of the colon in ulcerative colitis (UC) will contribute to the improvement of diagnosis, development of methods for determining the activity of UC, control of therapy, which will allow optimizing the choice of adequate treatment measures. The goal of the work: to improve the diagnosis of ulcerative colitis based on the study of ultrasonographic parameters of the rectum. Materials and methods. Transrectal ultrasound was performed on an expert-class SonoScape S60 ultrasound scanner using a low-frequency convex probe of 3.5 MHz and a rectovaginal convex probe of 6 MHz. Transperineal and transrectal approaches were used. Results. Wall thickness and submucosal thickness differed significantly in moderate and severe UC. Analysis of transrectal ultrasound indicators depending on the endoscopic activity of the UC revealed no significant differences in the rectal wall thickness. But there was a tendency to increase in the thickness of the mucous layer and the coefficient of deformation with increasing endoscopic activity. Most patients had an increase in the degree of blood flow density, which depended on the disease severity. During the regression analysis, a relationship was found between the intestinal wall thickness (r = 0.44; p = 0.0121) and submucosal layer thickness (r = 0.86; p = 0.006) with the Mayo index. A correlation was revealed between the thickness of the colon wall and the frequency of bowel movements (r = 0.37; p = 0.018), leukocytosis (r = 0.38; p = 0.016) and erythrocyte sedimentation rate (r = 0.35; p = 0.027). The blood flow density in the intestinal wall positively correlated with the presence of edema (r = 0.32; р = 0.045), the severity of the vascular pattern (r = 0.42; р = 0.008), the presence of erosions (r = 0.4; р = 0.011) and bleeding of the mucous membrane (r = 0.50; p = 0.001). The coefficient of deformation positively correlated with the presence of flatulence (r = 0.35; р = 0.048). Conclusions. Endoscopic exa­mination in patients with UC should be supplemented with transrectal ultrasound. A correlation was found between the intestinal wall thickness and the thickness of the submucosal layer in patients with UC and the Mayo index. A tendency to increase in the thickness of the mucous layer and the coefficient of deformation with increasing endoscopic activity was determined. Relationships between endoscopic and ultrasound parameters can be used to assess disease activity.