Semi-automated vectorial analysis of anorectal motion by magnetic resonance defecography in healthy subjects and fecal incontinence

J. Noelting, A. E. Bharucha, D. S. Lake, A. Manduca, J. G. Fletcher, S. J. Riederer, L. Joseph Melton, A. R. Zinsmeister

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Background Inter-observer variability limits the reproducibility of pelvic floor motion measured by magnetic resonance imaging (MRI). Our aim was to develop a semi-automated program measuring pelvic floor motion in a reproducible and refined manner. Methods Pelvic floor anatomy and motion during voluntary contraction (squeeze) and rectal evacuation were assessed by MRI in 64 women with fecal incontinence (FI) and 64 age-matched controls. A radiologist measured anorectal angles and anorectal junction motion. A semi-automated program did the same and also dissected anorectal motion into perpendicular vectors representing the puborectalis and other pelvic floor muscles, assessed the pubococcygeal angle, and evaluated pelvic rotation. Key Results Manual and semi-automated measurements of anorectal junction motion (r=0.70; P<0.0001) during squeeze and evacuation were correlated, as were anorectal angles at rest, squeeze, and evacuation; angle change during squeeze or evacuation was less so. Semi-automated measurements of anorectal and pelvic bony motion were also reproducible within subjects. During squeeze, puborectalis injury was associated (P≤0.01) with smaller puborectalis but not pelvic floor motion vectors, reflecting impaired puborectalis function. The pubococcygeal angle, reflecting posterior pelvic floor motion, was smaller during squeeze and larger during evacuation. However, pubococcygeal angles and pelvic rotation during squeeze and evacuation did not differ significantly between FI and controls. Conclusion & Inferences This semi-automated program provides a reproducible, efficient, and refined analysis of pelvic floor motion by MRI. Puborectalis injury is independently associated with impaired motion of puborectalis, not other pelvic floor muscles in controls and women with FI.

Original languageEnglish (US)
Pages (from-to)e467-e475
JournalNeurogastroenterology and Motility
Issue number10
StatePublished - Oct 2012


  • Anorectal
  • Defecography
  • Fecal incontinence
  • Magnetic resonance imaging
  • Pelvic floor
  • Puborectalis

ASJC Scopus subject areas

  • Physiology
  • Endocrine and Autonomic Systems
  • Gastroenterology


Dive into the research topics of 'Semi-automated vectorial analysis of anorectal motion by magnetic resonance defecography in healthy subjects and fecal incontinence'. Together they form a unique fingerprint.

Cite this