title: Assessment of Obstructive Defecation by High-Resolution Anorectal Manometry Compared With Magnetic Resonance Defecography.
abstract: OBJECTIVE
  Patients with obstructive defecation have abnormalities of anorectal function and/or structure. Conventional anorectal manometry (ARM) can identify abnormal function and behavior (dyssynergia); however, agreement between manometry and defecography is only fair. High-resolution (HR)-ARM may improve diagnostic agreement by differentiating pressure effects caused by dyssynergia and obstruction. We compared HR-ARM findings with magnetic resonance (MR) defecography in the clinical assessment of patients with symptoms of obstructive defecation defined by Rome III criteria.
  
  
  METHODS
  HR-ARM (Manoscan AR 360; Given Imaging, Yoqeam, Israel) assessed anal sphincter function and pressure during simulated defecation. Abnormal manometric findings were classified according to the Rao system and compared with MR defecography as the reference standard.
  
  
  RESULTS
  A total of 188 consecutive patients (155 women; age, 19-93 y) with obstructive defecation underwent a full investigation. Compared with patients with dyssynergia on MR imaging (n = 66), patients with structural pathology (n = 87) had lower resting (P < .003) and squeeze pressures (P < .011), but a higher rectoanal pressure gradient (P < .0001) on HR-ARM. High intrarectal pressure with a steep, positive pressure gradient consistent with outlet obstruction on HR-ARM was present in 24 patients with intra-anal intussusception on MR imaging. This pattern was not observed in other patients. Interobserver agreement was substantial for HR-ARM diagnoses (κ = 0.67; 95% confidence interval, 0.559-0.779). Diagnostic accuracy for dyssynergia was 82% compared with MR imaging (sensitivity, 77% [51 of 66]; specificity, 85% [104 of 122]).
  
  
  CONCLUSIONS
  The diagnostic agreement between anorectal HR-ARM and MR defecography is high and pressure measurements accurately identify recto-anal dyssynergia and intra-anal outlet obstruction by structural pathology as causes of obstructive defecation.
authors: Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland; Division of Gastroenterology and Hepatology, Stadtspital Triemli, Zurich, Switzerland.
authors: Henriette
authors: H
authors: Heinrich
authors: Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland; Department of Internal Medicine, University Hospital Zurich, Zurich, Switzerland.
authors: Matthias
authors: M
authors: Sauter
authors: Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland; Nottingham Digestive Diseases Centre and Biomedical Research Unit, Queen's Medical Centre, Nottingham, United Kingdom. Electronic address: dr.mark.fox@gmail.com.
authors: Mark
authors: M
authors: Fox
authors: Institute for Radiology, Stadtspital Triemli, Zurich, Switzerland.
authors: Dominik
authors: D
authors: Weishaupt
authors: Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors: Marcel
authors: M
authors: Halama
authors: Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors: Benjamin
authors: B
authors: Misselwitz
authors: Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors: Simon
authors: S
authors: Buetikofer
authors: Institute for Radiology and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland.
authors: Caecilia
authors: C
authors: Reiner
authors: Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland; Zurich Centre for Integrated Human Physiology, Institute of Physiology, University of Zurich, Zurich, Switzerland.
authors: Michael
authors: M
authors: Fried
authors: Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland; Zurich Centre for Integrated Human Physiology, Institute of Physiology, University of Zurich, Zurich, Switzerland; Institute of Biomedical Engineering and Medical Informatics, ETH, University of Zurich, Zurich, Switzerland.
authors: Werner
authors: W
authors: Schwizer
authors: Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland; Division of Gastroenterology and Hepatology, Stadtspital Triemli, Zurich, Switzerland.
authors: Heiko
authors: H
authors: Fruehauf
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001259:Ataxia / Q000175:diagnosis* / Q000503:physiopathology; D003248:Constipation / Q000209:etiology*; D003672:Defecation; D019841:Defecography / Q000379:methods*; D005260:Female; D006801:Humans; D007415:Intestinal Obstruction / Q000175:diagnosis* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008365:Manometry / Q000379:methods*; D008875:Middle Aged; D055815:Young Adult
keywords: High-Resolution Anorectal Manometry; Magnetic Resonance Imaging; Obstructive Defecation