Female Pelvic Medicine and Reconstructive Surgery (FPMRS), Division of Urogynecology, University of Chicago, Northshore University HealthSystem, 9650 Gross Point Road, Suite 3900, Skokie, IL, 60076, USA.
Translational Biomechanics Laboratory, Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.
Int Urogynecol J. 2024 Mar;35(3):537-544. doi: 10.1007/s00192-023-05707-x. Epub 2024 Jan 10.
Magnetic resonance defecography imaging techniques have been used widely to study pelvic floor function and diagnose pelvic organ prolapse (POP). The aim of this study was to investigate the diagnostic accuracy of the H-line to detect bladder descent compared with the current landmark, the pubococcygeal line (PCL).
In this retrospective cohort study, patients who underwent MR defecography in our medical center and were diagnosed with moderate to severe cystocele by radiological measurements were recruited. One rest image and one maximum evacuation image for each subject were used for the following measurements: bladder base perpendicular distance from the genital hiatus (GH), indicative of clinically significant bladder descent, PCL as the current radiological reference line, and the H-line, or minimal levator hiatus line, indicative of pelvic floor muscle and connective tissue support. Subjects were categorized as having clinically significant cystocele if the "bladder base" reached within 1 cm or lower of the GH (stage II or higher cystocele). A comparison was performed to assess differences and predictive capabilities of the reference lines relative to the GH measure.
Seventy subjects were included, 30 with clinically significant bladder descent based on distance to GH. Women with bladder descent were older (64.0 ± 11.8 vs 51.2 ± 15.6, p < 0.001), had increased parity (3 [1-7] vs 2 [0-5], p = 0.009), and had a bladder that descended lower than the H-line at rest (1.9 ± 0.5 vs 2.2 ± 0.4, p = 0.003) and evacuation (-2.4 ± 1.6 vs -0.7 ± 1.1, p < 0.001). Multivariate regression analysis confirmed that age, length of the H-line at evacuation, the perpendicular distances between the H-line and the lowest bladder point at rest, and the PCL to the lowest bladder point at evacuation significantly correlated with bladder descent. Receiver operating characteristic analysis was used to identify a measurement threshold to diagnose clinically significant cystocele for both measurements, bladder base to the H-line: -1.2 (80.0, 72.5) area under the curve (AUC) 0.82, and bladder base PCL: -3.3 (77.8, 79.5) AUC 0.86.
Our data support the application of using the minimal levator hiatus plane and specifically the H-line as a reliable landmark to diagnose bladder descent using MR defecography imaging.
磁共振排粪造影成像技术已广泛用于研究盆底功能和诊断盆腔器官脱垂（POP）。本研究旨在探讨 H 线检测膀胱下降的诊断准确性与当前的标志线——耻骨尾骨线（PCL）相比。
本回顾性队列研究招募了在我院行磁共振排粪造影检查并经影像学测量诊断为中重度膀胱膨出的患者。每位受试者的 1 张静息图像和 1 张最大排空图像用于以下测量：膀胱底至生殖器裂孔（GH）的垂直距离，提示有临床意义的膀胱下降，PCL 为当前的影像学参考线，H 线，或最小肛提肌裂孔线，提示盆底肌肉和结缔组织的支撑。如果“膀胱底”达到 GH 内 1cm 或更低（II 级或更高级别的膀胱膨出），则将受试者归类为有临床意义的膀胱膨出。对参考线与 GH 测量值进行比较，以评估其差异和预测能力。
共纳入 70 例患者，其中 30 例根据距离 GH 的程度存在有临床意义的膀胱下降。有膀胱下降的女性年龄更大（64.0±11.8 岁 vs 51.2±15.6 岁，p<0.001），产次更多（3[1-7]次 vs 2[0-5]次，p=0.009），且在静息时膀胱下降低于 H 线（1.9±0.5 厘米 vs 2.2±0.4 厘米，p=0.003）和排空时（-2.4±1.6 厘米 vs -0.7±1.1 厘米，p<0.001）。多变量回归分析证实，年龄、H 线在排空时的长度、H 线与静息时膀胱最低点之间的垂直距离、PCL 与排空时膀胱最低点之间的距离与膀胱下降显著相关。使用受试者工作特征曲线分析确定了两种测量方法诊断有临床意义的膀胱膨出的测量阈值，即膀胱底至 H 线：-1.2（80.0%，72.5%）曲线下面积（AUC）0.82，膀胱底 PCL：-3.3（77.8%，79.5%）AUC 0.86。
我们的数据支持使用最小肛提肌裂孔平面，特别是 H 线作为磁共振排粪造影成像诊断膀胱下降的可靠标志。
