title: Quantification and variability in colonic volume with a novel magnetic resonance imaging method.
abstract: BACKGROUND
  Segmental distribution of colorectal volume is relevant in a number of diseases, but clinical and experimental use demands robust reliability and validity. Using a novel semi-automatic magnetic resonance imaging-based technique, the aims of this study were to describe: (i) inter-individual and intra-individual variability of segmental colorectal volumes between two observations in healthy subjects and (ii) the change in segmental colorectal volume distribution before and after defecation.
  
  
  METHODS
  The inter-individual and intra-individual variability of four colorectal volumes (cecum/ascending colon, transverse, descending, and rectosigmoid colon) between two observations (separated by 52 ± 10) days was assessed in 25 healthy males and the effect of defecation on segmental colorectal volumes was studied in another seven healthy males.
  
  
  RESULTS
  No significant differences between the two observations were detected for any segments (All p > 0.05). Inter-individual variability varied across segments from low correlation in cecum/ascending colon (intra-class correlation coefficient [ICC] = 0.44) to moderate correlation in the descending colon (ICC = 0.61) and high correlation in the transverse (ICC = 0.78), rectosigmoid (ICC = 0.82), and total volume (ICC = 0.85). Overall intra-individual variability was low (coefficient of variance = 9%). After defecation the volume of the rectosigmoid decreased by 44% (p = 0.003). The change in rectosigmoid volume was associated with the true fecal volume (p = 0.02).
  
  
  CONCLUSIONS
  Imaging of segmental colorectal volume, morphology, and fecal accumulation is advantageous to conventional methods in its low variability, high spatial resolution, and its absence of contrast-enhancing agents and irradiation. Hence, the method is suitable for future clinical and interventional studies and for characterization of defecation physiology.
authors.affiliation: Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: M
authors.initials: M
authors.lastname: Nilsson
authors.affiliation: Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: T H
authors.initials: TH
authors.lastname: Sandberg
authors.affiliation: Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: J L
authors.initials: JL
authors.lastname: Poulsen
authors.affiliation: Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: M
authors.initials: M
authors.lastname: Gram
authors.affiliation: Mech-Sense, Department of Radiology, Aalborg University Hospital, Aalborg, Denmark.|Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.
authors.forename: J B
authors.initials: JB
authors.lastname: Frøkjaer
authors.affiliation: Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.
authors.forename: L R
authors.initials: LR
authors.lastname: Østergaard
authors.affiliation: Neurogastroenterology Unit, Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: K
authors.initials: K
authors.lastname: Krogh
authors.affiliation: Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Aalborg, Denmark.|Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: C
authors.initials: C
authors.lastname: Brock
authors.affiliation: Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Aalborg, Denmark.|Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.
authors.forename: A M
authors.initials: AM
authors.lastname: Drewes
mesh_terms: D000328:Adult; D003106:Colon / Q000033:anatomy & histology*; D003672:Defecation; D064368:Healthy Volunteers; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009929:Organ Size; D015203:Reproducibility of Results; D055815:Young Adult
keywords: colorectal; defecation; magnetic resonance imaging; variability; volume