静动态MRI评估产后不同类型盆底功能障碍性疾病盆底结构改变

Evaluation of pelvic floor structural changes in different types of postpartum pelvic floor dysfunction by static and dynamic MRI

目的:利用静态和动态MRI定量评估和比较经阴道分娩后不同类型盆底功能障碍性疾病(PFD)患者盆底结构的改变,探讨PFD的发病机制。方法:回顾性分析2015年10月-2017年12月在本院产科门诊进行产后42天常规复查的150例产妇的临床和MRI资料。根据临床盆腔器官脱垂定量评价系统(POP-Q)诊断标准和尿失禁问卷表简表评估产后PFD发生情况并进行分组,盆腔器官脱垂(POP)组、压力性尿失禁(SUI)组和正常组各50例。所有产妇行盆底MRI检查,静态扫描序列为TSE T_(2)WI,动态扫描序列为Balanced-TFE和单次激发TSE。由2位放射科医师分析和测量静息期及力排期各盆底结构的各项形态学指标,包括肛提肌损伤评分、盆膈裂孔面积(LHA)、H线和M线长度、膀胱颈和子宫最下缘至耻骨尾骨线的距离(B-PCL和U-PCL)、提肛板角(LPA)、尿道前倾角(AUA)、膀胱-尿道后角(RVA)、膀胱颈移动度(BND)、尿道高度(D)、膀胱颈至耻骨长轴中线距离(S)功能尿道的长度(FUL)及是否存在膀胱颈漏斗。采用组内相关系数(ICC)评价2位医师测量值的一致性。采用单因素方差分析或卡方检验比较各组间盆底结构各项指标值的差异。采用多因素logistic回归分析分别筛选与产后POP、SUI发生密切相关的指标。结果:两位医师测量的静息期和力排期盆底各指标的一致性良好,ICC值均大于0.75。单因素分析结果显示,力排期3组间LHA、B-PCL、U-PCL、H线和M线长度、D、S、FUL、RVA、AUA和BND的差异均有统计学意义(P<0.05)。进一步两两比较结果显示:POP组和SUI组的LHA、RVA、AUA和BND均大于正常组,B-PCL、D、S和FUL均小于正常组,POP组的M线和LPA大于正常组,U-PCL小于正常组,组间差异均有统计学意义(P<0.05);POP组的LHA、H线和M线长度、FUL、AUA和BND均大于SUI组,B-PCL、U-PCL、D、S和RVA均小于SUI组,组间差异均有统计学意义(P<0.05)。SUI组膀胱漏斗出现率为88%(44/50),POP组为48%(24/50),正常组为30%(15/50),3组间差异有统计学意义(χ^(2)=35.659,P<0.001)。静息期:SUI组和POP组肛提肌损伤程度均与正常组有显著差异(P均<0.05);3组间LHA、B-PCL、U-PCL、M线长度、D、FUL、AUA的差异均有统计学意义(P<0.05)。两两比较结果显示:POP组和SUI组的LHA和AUA大于正常组、D小于正常组,POP组的M线长度大于正常组、B-PCL和U-PCL小于正常组,SUI组的FUL小于正常组,POP组的U-PCL小于SUI组,上述指标的组间差异均有统计学意义(P<0.05)。多因素分析结果显示,力排期LHA和D与产后POP显著相关(OR值分别为1.002和0.876);力排期FUL和膀胱颈漏斗征与产后SUI显著相关(OR值分别为0.670和9.985)。结论:动、静态MRI能够全面评估产后盆底结构和功能变化,特定盆底结构异常提示不同类型PFD的发生;产后POP与力排状态下LHA增大和D减低相关;产后SUI与力排状态下FUL缩短和膀胱颈漏斗征相关。

Objective:To analyze and compare the changes of pelvic floor structures in women after vaginal delivery using static and dynamic MRI,and to explore the pathogenesis of different types of pelvic floor dysfunction(PFD)after delivery.Methods:The clinical and MRI data of 150 parturients who underwent routine reexamination on the 42nd day after delivery in the obstetrics clinic of our hospital were retrospectively analyzed.The pelvic floor MRI examination protocols included TSE T_(2)WI sequence,balanced turbo field echo(balanced-TFE)and single-shot turbo spin echo(SS-TSE).According to the pelvic organ prolapse quantification system(POP-Q)and international consultation on incontinence questionnaire-short form(ICIQ-SF),the occurrence of postpartum PFD was assessed,and then the patients were divided into pelvic organ prolapse(POP)group(n=50),stress urinary incontinence(SUI)group(n=50),and normal control(NC)group(n=50).The parameters or changes of pelvic floor structures,during rest and strain state,including levator ani injury score,levator ani hiatal area(LHA),length of H-line and M-line,distance of bladder neck or the lowest uterine margin to puboccygeal line(B-PCL or U-PCL),anal levator ani plate angle(LPA),anterior urethral angle(AUA),retro vesicourethral angle(RVA),bladder neck mobility(BND),urethral height(D),bladder neck to pubic long axis midline distance(S),functional urethral length(FUL),and whether there was bladder funnel were measured or evaluated by two radiologists.The measurements consistency between the two observers were calculated by intra-class correlation coefficient(ICC).One-way analysis of variance and chi-square test were used to compare the differences in pelvic floor indexes among the different types of PFD.Multivariate logistic regression analysis was used to screen pelvic floor parameters that were closely related to the occurrence of postpartum POP and SUI,respectively.Results:In univariate analysis,there were significant differences in LHA,B-PCL,U-PCL,length of H-line and M-line,D,S,FUL,RVA,AUA and BND among the three groups during strain state(all P<0.05).Furthermore,pair-wise comparison results showed that LHA,RVA,AUA,and BND were greater,and B-PCL,D,S,and FUL were less in the POP and SUI groups than those in the NC group;M-line length and LPA were greater,and U-PCL was less in the POP group than those in the normal group(all P<0.05);LHA,H-line length,M-line length,FUL,AUA,and BND were greater and B-PCL,U-PCL,D,S and RVA were less in the POP group than those in the SUI group(all P<0.05).The proportion of bladder funnel in three group were 88%(SUI group),48%(POP group)and 30%(NC group),respectively,which showed significant difference(χ^(2)=35.659,P<0.001).Resting state showed that the degree of levator ani muscle injury was different between SUI group,POP group and NC group(all P<0.05).There were significant differences in LHA,B-PCL,U-PCL,M-line length,D,FUL and AUA among the three groups(all P<0.05).Pairwise comparison results showed that LHA and AUA were greater and D was less in the POP and SUI groups than in the NC group(all P<0.05).The M-line length was greater,B-PCL and U-PCL were less in the POP group than those in the NC group,and FUL was less in the SUI group than that in the NC group,U-PCL was less in the POP group than that in the SUI group(all P<0.05).Multivariate analysis showed that LHA and D during the strain state were significantly associated with the occurrence of postpartum POP,with ORs of 1.002 and 0.876,respectively;FUL and bladder funnel during the strain state were significantly associated with the occurrence of postpartum SUI(OR=0.670 and 9.985,respectively).Conclusion:Dynamic and static MRI can comprehensively assess postpartum pelvic floor structural and functional changes,and specific pelvic floor structural abnormalities indicate the occurrence of different types of PFD diseases.Postpartum POP occurrence is associated with increased LHA and decreased D in the strain state;postpartum SUI occurrence is associated with shortened FUL and bladder neck funnel in the strain state,revealing that the pathogenesis is different in those with postpartum PFD by vaginal delivery.