MRI imaging features of perianal Crohn's disease patients with proctitis

Objective To investigate the MRI imaging features of perianal Crohn's disease patients with and without proctitis. Methods A total of 57 perianal Crohn's disease patients in the Affiliated Hospital of Yangzhou University and the Affiliated Hospital of Nanjing University of Chinese Medicine from September 2017 to July 2021 were enrolled and their clinical data were retrospectively analyzed. According to their rectal inflammation, they were divided into two groups: a proctitis group and a non-proctitis group. The thickness, the apparent diffusion coefficient (ADC), and the T2 signal intensity of the rectal wall were measured, respectively. Furthermore, the location of fistula (whether its opening was connected to the rectum), and the presence of a fistula or abscess on the levator animuscle were also evaluated. Results The independent sample t-test showed that there were significant differences in rectal wall thickness and ADC between the proctitis and non-proctitis groups (P<0.001). Chi-square test results revealed that the ratio of moderate to severe increase of T2 signal was significantly higher in the proctitis group than that in the non-proctitis group (χ²=18.426;P<0.001). Fisher's exact probability method indicated that there was statistical difference in the incidence of high fistula (P=0.044), without statsitcal differences in the incidence of fistula and abscess on levator ani muscle between the two groups (all P>0.05). Conclusions Perianal Crohn's disease patients with proctitis are characteristic in MRI images, compared with those without proctitis.