Dynamic magnetic resonance imaging of the female pelvis: the relationship with the Pelvic Organ Prolapse quantification staging system.
OBJECTIVE
Magnetic resonance imaging (MRI) was performed to determine anatomical correlations with respect to physical examination using the Pelvic Organ Prolapse (POP) staging system. In addition, the standard POP staging system was analyzed to obtain normative data and determine any risk factors for prolapse.


METHODS
A total of 52 continent women 19 to 67 years old participated in our study. Pelvic MRI was performed at 1.5 Tesla. The vagina, bladder and rectum were opacified. Subjects performed pelvic floor contraction, relaxation and straining maneuvers for T1-weighted imaging. One-way analysis of variance, Fisher's exact test and multinomial logistic regression were used to analyze the data.


RESULTS
POP stage is quantified from 0 to IV. Stage was 0 to II in 56%, 27% and 17% of cases. POP stage was not significantly influenced by the number of cesarean sections (p = 0.64) or smoking (p = 0.91) but the number of vaginal deliveries significantly correlated with stage. Women with 1 vaginal delivery were at increased risk for a stage I condition (p = 0.018), whereas those with more than 1 were at increased risk for stage II (p = 0.013). On MRI stages 0 versus I or II differed significantly in regard to bladder descent (p = 0.01 and <0.0001, respectively), while stages 0 versus I differed in regard to levator angle (p = 0.007). No significant staging differences were observed in regard to the posterior urethrovesical angle or stages I versus II with respect to all 3 MRI measurements.


CONCLUSIONS
MRI appears to detect anatomically measurable changes in POP stage 0 versus other stages in regard to bladder descent and the levator angle and yet it is not sensitive enough to detect differences in stages I and II. It is not unusual for continent women to have a moderate degree of pelvic prolapse and previous vaginal delivery appears to increase this risk.
Hodroff
Marc A
MA
Department of Urology, University of Iowa, Iowa City, Iowa, USA.
Stolpen
Alan H
AH
Denson
Melody A
MA
Bolinger
Lizann
L
Kreder
Karl J
KJ
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D014596:Uterine Prolapse / Q000175:diagnosis / Q000473:pathology*