Abstract：
OBJECTIVE: Endovaginal ultrasound has long been hypothesized to have a significant effect on locations of what it visualizes. However, little work has directly quantified its effect. This study aimed to quantify it.
METHODS: This cross-sectional study consisted of 20 healthy asymptomatic volunteers who underwent both endovaginal ultrasound and MRI. The urethra, vagina, rectum, pelvic floor, and pubic bone were segmented in both ultrasound and MRI using 3DSlicer. Then, using 3DSlicer\'s transform tool the volumes were rigidly aligned based on the posterior curvature of the pubic bone. The organs were then split into thirds along their long axis to compare their distal, middle, and proximal sections. Using Houdini, we compared the location of the centroid of each of the urethra, vagina, and rectum and the surface-to-surface difference of the urethra and rectum. The anterior curvature of the pelvic floor was also compared. Normality of all variables was assessed by Shapiro-Wilk test.
RESULTS: The largest amount of surface-to-surface distance was observed in the proximal region for the urethra and rectum. Across all three organs, the majority of the deviation was in the anterior direction for geometries obtained from ultrasound versus those from MRI. For each subject, the trace defining the midline of the levator plate was more anterior for ultrasound compared to MRI.
CONCLUSIONS: While it has often been assumed that placing a probe in the vagina probably distorts the anatomy, this study quantified the distortion and displacement of the pelvic viscera. This allows for better interpretation of clinical and research findings based on this modality.
METHODS: This cross-sectional study consisted of 20 healthy asymptomatic volunteers who underwent both endovaginal ultrasound and MRI. The urethra, vagina, rectum, pelvic floor, and pubic bone were segmented in both ultrasound and MRI using 3DSlicer. Then, using 3DSlicer\'s transform tool the volumes were rigidly aligned based on the posterior curvature of the pubic bone. The organs were then split into thirds along their long axis to compare their distal, middle, and proximal sections. Using Houdini, we compared the location of the centroid of each of the urethra, vagina, and rectum and the surface-to-surface difference of the urethra and rectum. The anterior curvature of the pelvic floor was also compared. Normality of all variables was assessed by Shapiro-Wilk test.
RESULTS: The largest amount of surface-to-surface distance was observed in the proximal region for the urethra and rectum. Across all three organs, the majority of the deviation was in the anterior direction for geometries obtained from ultrasound versus those from MRI. For each subject, the trace defining the midline of the levator plate was more anterior for ultrasound compared to MRI.
CONCLUSIONS: While it has often been assumed that placing a probe in the vagina probably distorts the anatomy, this study quantified the distortion and displacement of the pelvic viscera. This allows for better interpretation of clinical and research findings based on this modality.
摘要：
目的：阴道超声长期以来一直被认为对其可视化的位置有显著影响。然而,很少的工作直接量化了它的效果。本研究旨在对其进行量化。
方法：这项横断面研究包括20名健康无症状志愿者，他们同时接受了阴道内超声和MRI检查。尿道,阴道,直肠,盆底,使用3DSlicer在超声和MRI中分割耻骨。然后，使用3DSlicer的变换工具，根据耻骨的后曲率将体积严格对齐。然后将这些器官沿着它们的长轴分成三分之一，以比较它们的远端，中间,和近端部分。利用胡迪尼,我们比较了每个尿道质心的位置，阴道,和直肠以及尿道和直肠的表面之间的差异。还比较了盆底的前曲率。通过Shapiro-Wilk检验评估所有变量的正态性。
结果：在尿道和直肠的近端区域观察到最大量的表面到表面距离。在所有三个器官中，从超声获得的几何形状与从MRI获得的几何形状相比，大部分偏差是在前方向。对于每个主题，与MRI相比,超声检查确定提上板中线的迹线更靠前.
结论：虽然人们通常认为在阴道中放置探头可能会扭曲解剖结构，这项研究量化了盆腔脏器的变形和移位。这可以基于这种方式更好地解释临床和研究结果。
方法：这项横断面研究包括20名健康无症状志愿者，他们同时接受了阴道内超声和MRI检查。尿道,阴道,直肠,盆底,使用3DSlicer在超声和MRI中分割耻骨。然后，使用3DSlicer的变换工具，根据耻骨的后曲率将体积严格对齐。然后将这些器官沿着它们的长轴分成三分之一，以比较它们的远端，中间,和近端部分。利用胡迪尼,我们比较了每个尿道质心的位置，阴道,和直肠以及尿道和直肠的表面之间的差异。还比较了盆底的前曲率。通过Shapiro-Wilk检验评估所有变量的正态性。
结果：在尿道和直肠的近端区域观察到最大量的表面到表面距离。在所有三个器官中，从超声获得的几何形状与从MRI获得的几何形状相比，大部分偏差是在前方向。对于每个主题，与MRI相比,超声检查确定提上板中线的迹线更靠前.
结论：虽然人们通常认为在阴道中放置探头可能会扭曲解剖结构，这项研究量化了盆腔脏器的变形和移位。这可以基于这种方式更好地解释临床和研究结果。
