Published online May 27, 2023. doi: 10.4240/wjgs.v15.i5.882
Peer-review started: December 12, 2022
First decision: January 2, 2023
Revised: January 16, 2023
Accepted: March 30, 2023
Article in press: March 30, 2023
Published online: May 27, 2023
Perianal fistulising Crohn's disease (PFCD) and glandular anal fistula have many similarities on conventional magnetic resonance imaging. However, many patients with PFCD show concomitant active proctitis, but only few patients with glandular anal fistula have active proctitis.
To explore the value of differential diagnosis of PFCD and glandular anal fistula by comparing the textural feature parameters of the rectum and anal canal in fat suppression T2-weighted imaging (FS-T2WI).
Patients with rectal water sac implantation were screened from the first part of this study (48 patients with PFCD and 22 patients with glandular anal fistula). Open-source software ITK-SNAP (Version 3.6.0, http://www.itksnap.org/) was used to delineate the region of interest (ROI) of the entire rectum and anal canal wall on every axial section, and then the ROIs were input in the Analysis Kit software (version V3.0.0.R, GE Healthcare) to calculate the textural feature parameters. Textural feature parameter differences of the rectum and anal canal wall between the PFCD group vs the glandular anal fistula group were analyzed using Mann-Whitney U test. The redundant textural parameters were screened by bivariate Spearman correlation analysis, and binary logistic regression analysis was used to establish the model of textural feature parameters. Finally, diagnostic accuracy was assessed by receiver operating characteristic-area under the curve (AUC) analysis.
In all, 385 textural parameters were obtained, including 37 parameters with statistically significant differences between the PFCD and glandular anal fistula groups. Then, 16 texture feature parameters remained after bivariate Spearman correlation analysis, including one histogram parameter (Histogram energy); four grey level co-occurrence matrix (GLCM) parameters (GLCM energy_all direction_offset1_SD, GLCM entropy_all direction_ offset4_SD, GLCM entropy_all direction_offset7_SD, and Haralick correlation_all direction_ offset7_SD); four texture parameters (Correlation_all direction_offset1_SD, cluster prominence _angle 90_offset4, Inertia_all direction_offset7_SD, and cluster shade_angle 45_offset7); five grey level run-length matrix parameters (grey level nonuniformity_angle 90_offset1, grey level nonuniformity_all direction_offset4_SD, long run high grey level emphasis_all direction_offset1_SD, long run emphasis_all direction_ offset4_ SD, and long run high grey level emphasis_all direction_off
The model of textural feature parameters showed good diagnostic performance for PFCD. The texture feature parameters of the rectum and anal canal in FS-T2WI are helpful to distinguish PFCD from glandular anal fistula.
Core Tip: Crohn's disease (CD) is a localized, segmental chronic granulomatous inflammation that can affect the digestive tract from the oral cavity to the anus, and its pathophysiology is non-caseous necrotic granuloma. Nearly 10% of patients with CD have an anal fistula before presenting gastrointestinal symptoms. At the same time, perianal fistulising CD (PFCD) and glandular anal fistula have many similarities on conventional magnetic resonance imaging (MRI); therefore, it is difficult to differentiate between these conditions in the early stages with conventional MRI. Texture analysis based on conventional MRI images can quantitatively analyze image pixel information and reflect the internal heterogeneity and pathological characteristics of the lesion. Currently, this approach is widely used to distinguish between benign and malignant tumors, predict tumor stage, and evaluate treatment efficacy. In addition to the application of texture analysis in the study of tumors or substantial organs, some studies have applied texture analysis to hollow organs such as the intestine. Many patients with PFCD show concomitant active proctitis, but only few patients with glandular anal fistula have active proctitis. Based on this theory, we analyzed the texture of the rectum and anal canal wall in the PFCD group and glandular anal fistula group in this study to explore whether the texture feature parameters are valuable in identifying and differentiating these two lesions.