MR defecography in assessing stress urinary incontinence with or without symptomatic pelvic organ prolapse.

Purpose: Utilize magnetic resonance defecography (MRD) to analyze the primary pelvic floor dysfunctions in patients with stress urinary incontinence (SUI) associated with pelvic organ prolapse (POP), and in SUI patients with asymptomatic POP.

Method: We performed MRD in both SUI and POP subjects. As a primary analysis, the functional MR parameters were compared between the isolated POP and POP combined SUI groups. As a secondary analysis, the functional MR data were compared between the POP combined SUI and the SUI with asymptomatic POP (isolated SUI) groups.

Results: MRD noted the main characteristics of SUI combined moderate or severe POP, including the shorter closed urethra length (1.87 cm vs. 2.50 cm, p < 0.001), more prevalent urethral hypermobility (112.31° vs. 85.67°, p = 0.003), bladder neck funneling (48.28% vs. 20.51%, p = 0.020), lower position of vesicourethral junction (2.11 cm vs. 1.67 cm, p = 0.030), and more severe prolapse of the posterior bladder wall (6.26 cm vs. 4.35 cm, p = 0.008). The isolated SUI patients showed the shortest length of the closed urethra (1.56 cm vs. 1.87 cm, p = 0.029), a larger vesicourethral angle (153.80° vs. 107.58°, p < 0.001), the more positive bladder funneling (84.85% vs. 48.28%, p = 0.002) and a special urethral opening sign (45.45% vs. 3.45%, p < 0.001).

Conclusions: Patients with SUI accompanying POP primarily exhibit excessive urethral mobility and a shortened urethral closure. SUI patients with asymptomatic POP mainly show dysfunction of the urethra and bladder neck, characterized by the opening of the urethra and bladder neck and a shortened urethral closure.