Meriwether Kate V, Hall Rebecca J, Leeman Lawrence M, Migliaccio Laura, Qualls Clifford, Rogers Rebecca G
Department of Obstetrics and Gynecology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA,
Int Urogynecol J. 2015 Apr;26(4):511-7. doi: 10.1007/s00192-014-2524-5. Epub 2014 Oct 25.
Women may experience anal sphincter anatomy changes after vaginal birth (VB) or Cesarean delivery (CD). Therefore, accurate and acceptable imaging options to evaluate the anal sphincter complex (ASC) are needed. ASC measurements may differ between translabial (TLUS) and endoanal (EAUS) ultrasound imaging and between 2D and 3D US. The objective of this analysis was to describe measurement variation between these modalities.
Primiparous women underwent 2D and 3D TLUS imaging of the ASC 6 months after VB or CD. A subset of women also underwent EAUS measurements. Measurements included internal anal sphincter (IAS) thickness at proximal, mid, and distal levels and the external anal sphincter (EAS) at 3, 6, 9, and 12 o'clock positions, as well as bilateral thickness of the pubovisceralis muscle (PVM).
There were 433 women presenting for US: 423 had TLUS and 64 had both TLUS and EAUS of the ASC. All IAS measurements were significantly thicker on TLUS than EAUS (all p < 0.01), while EAS measurements were significantly thicker on EAUS (p < 0.01). PVM measurements with 3D or 2D imaging were similar (p > 0.20). On both TLUS and EAUS, there were multiple sites where significant asymmetry existed in left versus right measurements.
US modality used to image the ASC introduces small but significant changes in measurements, and the direction of the bias depends on the muscle and location being imaged.
女性在经阴道分娩（VB）或剖宫产（CD）后可能会出现肛门括约肌解剖结构的变化。因此，需要准确且可接受的成像方法来评估肛门括约肌复合体（ASC）。经阴唇超声（TLUS）和经肛门超声（EAUS）成像以及二维和三维超声之间的ASC测量结果可能存在差异。本分析的目的是描述这些检查方式之间的测量差异。
初产妇在VB或CD后6个月接受ASC的二维和三维TLUS成像检查。部分女性还接受了EAUS测量。测量内容包括肛管内括约肌（IAS）在近端、中部和远端的厚度，以及肛管外括约肌（EAS）在3点、6点、9点和12点位置的厚度，还有耻骨直肠肌（PVM）的双侧厚度。
共有433名女性接受超声检查：423名接受了TLUS检查，64名同时接受了ASC的TLUS和EAUS检查。所有IAS测量结果在TLUS上均显著厚于EAUS（所有p<0.01），而EAS测量结果在EAUS上显著更厚（p<0.01）。三维或二维成像的PVM测量结果相似（p>0.20）。在TLUS和EAUS上，左右测量结果存在显著不对称的部位有多处。
用于ASC成像的超声检查方式会在测量中引入虽小但显著的变化，且偏差方向取决于所成像的肌肉和部位。
