Cystitis Glandularis: Analysis of Multiparametric MRI Appearance in 40 Patients.

Purpose Cystitis glandularis (CG) is a rare, benign proliferative and metaplastic disorder of the bladder mucosa. However, CG is often confused with bladder cancer due to similar clinical symptoms and imaging findings. The aim of this study was to investigate the multiparametric MRI manifestations of CG, with the goal of improving the diagnostic accuracy of CG. Methods Patients with pathologically confirmed CG who underwent pelvic MRI between November 2011 and September 2023 were retrospectively reviewed. The MR imaging characteristics of CG were analyzed and summarized. Additionally, apparent diffusion coefficient (ADC) values were measured to assess the diffusion restriction within the lesions. Results A total of 40 patients (mean age, 49.4 years ± 14.4 [SD]; 35 male) with CG were analyzed. The lesions were predominantly located in the trigone and/or bladder neck (36 of 40, [90.0%]). A characteristic multi-layered structure, referred to as the “floating water weeds sign”, was observed in 29 lesions (72.5%) on T2WI, with or without bubble-like high signal intensity. Based on MRI morphology, CG were classified into four types, and most patients showed nodular thickening type (24 of 40, 60.0%). The majority of lesions (34 of 40, 85.0%) exhibited marked enhancement, with 24 patients (60.0%) showing linear contrast enhancement on the lesion surface. Most lesions (36 of 40, 90.0%) showed no or mild diffusion restriction with a mean ADC value of 1.67 ± 0.38×10 ^− 3 mm ² /s. Conclusion There are several representative characteristic MRI findings for CG, especially on T2WI and DWI, which are valuable for differential diagnosis.