Medical Imaging Center, First Affiliated Hospital, Jinan University, Guangzhou, China.
Int J Gynaecol Obstet. 2013 Jun;121(3):233-9. doi: 10.1016/j.ijgo.2013.01.022. Epub 2013 Mar 19.
To evaluate levator ani morphology and function in healthy nulliparous women using static and dynamic magnetic resonance imaging.
Eighty asymptomatic, healthy nulliparous Chinese women (mean age, 25.3±3.5years) volunteered for the present study. Static T2-weighted fast spin-echo images were employed to evaluate levator ani morphology; dynamic T2-weighted fast imaging employing steady-state acquisition was used to evaluate its function. A 2 samples t test was employed to compare groups.
No morphologic abnormality was detected in the 80 healthy nulliparous women. However, 15% (12/80) of women had various degrees of pelvic organ descent below the pubococcygeal line. In these women, the width of the pubic portion of the levator ani was significantly reduced during straining, whereas the levator plate angle, the levator hiatus area, and the H and M line lengths were enlarged. These changes were associated with weakened levator ani function and pelvic floor laxity.
Functional abnormality of the levator ani muscle was noted in nulliparous women at static and dynamic magnetic resonance imaging. Further follow-up investigation is needed to confirm whether women with functional abnormality are more likely to develop a prolapse after vaginal birth.
采用静态和动态磁共振成像评估健康初产妇的肛提肌形态和功能。
本研究招募了 80 名无症状、健康的中国初产妇（平均年龄 25.3±3.5 岁）。采用 T2 加权快速自旋回波序列评估肛提肌形态；采用稳态采集的 T2 加权快速成像评估其功能。采用两样本 t 检验进行组间比较。
80 名健康初产妇未发现形态异常。然而，15%（12/80）的女性存在不同程度的盆腔器官下降至耻骨尾骨线以下。在这些女性中，肛提肌耻骨部在用力时明显变窄，而肛提肌板角、肛提肌裂孔面积和 H、M 线长度增大。这些变化与肛提肌功能减弱和盆底松弛有关。
初产妇在静态和动态磁共振成像时存在肛提肌功能异常。需要进一步随访研究来确认是否存在功能异常的女性在阴道分娩后更有可能发生脱垂。
