Study Of Dynamic MRI In Anterior Vaginal Wall Prolapse And Its Application In The Clinical Assessment Of Pelvic Surgery

Part I Study of dynamic MRI in anterior vaginal wall prolapseObjective To assess the pelvic shape,movement and function of anterior vaginal wall prolapse(AWP) by dynamic magnetic resonance imaging (MRI) and to discuss the influence factors of AWP.Methods Between May2012and January2013,33patients with AWP,as well as30age-matched healthy women were enrolled and examined by dynamic MRI at Siemens3.0Tesla MRI scanner.Pelvic shape and movement were observed and compared between AWP group and control group. Make the influenced factors screened with monovariable regression model as independent variables, and the degree of AWP as dependent variable,then compared these factors’influence to the degree of AWP with multivariate regression model.Results (1) Compared with control group, AWP group has three morphologic characteristics:downward movement, vaginal " cupping",and distal portion of vagina rotates centered on the inferior pubic(P<0.001).(2) At rest,contraction,and strain, bladder neck of AWP group was lower than control group(P<0.001),at rest and strain, vaginal apex of AWP group was lower than control group(P<0.05),the location of perineal body is further in dorsal side and lower in caudal side than control group(P<0.05).(3) At rest,contraction,and strain, LH and ML of AWP group are longer than control group(P<0.05).(4) At rest and strain, vaginal length of AWP group is longer than control group(P<0.05).(5) Vaginal length, vaginal apex and bladder neck are independent influence factors of AWP. as the degree of influence, vaginal length>apex>bladder neck,the formulation is as follows:Y=-0.475+0.635BN+0.699Apex+0.273VL(r=0.932,P<0.05).(6)The most distal vaginal wall at rest is positively correlated with the degree of prolapse(r=0.727, P<0.01).Conclusions (1) Dynamic MRI can precisely display the shape change of anterior viganal wall.AWP at strain in dynamic MRI shows three morphologic characteristics: downward movement, vaginal "cupping",and distal portion of vagina rotates centered on the inferior pubis.(2) Dynamic MRI can evaluate the function of levator ani muscle and perineal body,and provide more information before operation.(3) Vaginal length, apex, bladder neck are independent influence factors of AWP,which should be considered in the clincal therapy.(4) The most distal vaginal wall at rest can reflect the degree of AWP to some extent.Part II Application of dynamic MRI in the clinical assessment of pelvic surgery Objective To approach the usefulness of dynamic MRI in the clinical assess-ment of traditional pelvic repair surgery.Methods21patients with symptomatic POP underwent traditional pelvic repair surgery. Before surgery as well as1and3months after surgery, the pelvic organ positions were measured on dynamic MRI during rest and maximal straining.Prolapse was quantified using the POP-Q system,and subjective symptoms were investigated by valid questionnaire Before and3months after surgery.Results (1) MRI and clinical data of16patients were acquired,the mean age was64.9±8.8y.(2) Dynamic MRI showed significantly anatomical improvement after operation,especially in bladder base and cervix/vaginal cuff during maximal straining.(P<0.01)(3) Dynamic MRI shows13cases of recurrent POP, with9cases in original compartments,4cases in untreated compartments,recurrent POP mainly in anterior vaginal wall(10cases).(4) Both POP-Q and subjective symptoms investigation showed significantly improved (P<0.05)3months after surgery.(5) Seven patients reported symptoms after surgical repair, and MRI showed pathologic changes in six of these patients. While in nine patients with no symptoms,7cases showed different pathologic changes in dynamic MRI.Conclusions (1) Dynamic MRI could verify the anatomical and functional recovery after pelvic repair surgery,follow-up dynamic MRI is helpful in detecting early recurrence and understanding the mechanism of recurrence.(2) The objective recurrence rate of traditional pelvic repair surgery is high,but the subjective recurrence rate is low. Recurrences after operation focus on anterior vaginal wall.(3) The diagnosis of early recurrent or newly developed POP of dynamic MRI may be earlier than symptoms and physical examination, further investigations with long-term follow-up are necessary to evaluate the clinical values and significance of MRI detected findings of early POP after operation.