Dynamic magnetic resonance imaging of the behavior of the mid-urethra in healthy and stress incontinent women


Corresponding author: Kirsi Marja Rinne, Department of Obstetrics and Gynecology, Kuopio University Hospital, PL 1777, 70211 Kuopio, Finland. E-mail: kirsi.rinne@kuh.fi


Objectives. Support of the mid-urethra is thought to be an essential element of urinary continence in the female. Our aim was to image the behavior of the mid-urethra in healthy volunteers and in stress urinary incontinence (SUI) patients by dynamic magnetic resonance imaging (MRI). Design. Prospective study. Setting. Gynecology outpatient clinic association with Department of Radiology in University Hospital of Kuopio, Finland. Sample and methods. Fifteen healthy volunteers and 40 SUI women underwent dynamic MRI at rest, during pelvic floor muscle contraction, coughing and voiding with a bladder volume of 200 ml. Our aim was to determine the precise location and movement of the mid-urethra during these activities. Main outcome measure. The co-ordinate location and movement of the mid-urethra. Results. Continent volunteers can elevate their mid-urethra significantly higher than incontinent women. Moreover, the mid-urethra of incontinent women rotated significantly more dorsocaudally during straining and coughing than in continent women. Conclusions. Elevation of the mid-urethra was more marked in continent compared to urinary incontinent women on pelvic floor muscle contraction suggesting sufficient support of the urethra. Downward movement of the mid-urethra was more significant in stress incontinent women than in continent volunteers.