title: Computed tomography assessment of intestinal gas volumes in functional gastrointestinal disorders.
abstract: OBJECTIVE
  Many patients with functional gastrointestinal disorders (FGIDs) rank sensations of bloating and distension among their most debilitating symptoms. Previous studies that have examined intestinal gas volume (IGV) in patients with FGIDs have employed a variety of invasive and imaging techniques. These studies are limited by small numbers and have shown conflicting results. The aim of our study was to estimate, using CT of the abdomen and pelvis (CTAP), IGV in patients attending FGID clinic and to compare IGV in patients with and without FGID.
  
  
  METHODS
  All CTAP (n = 312) performed on patients (n = 207) attending a specialized FGID clinic over 10-year period were included in this study. Patients were classified into one of 3 groups according to the established clinical grading system, as organic gastrointestinal disorder (OGID, ie, patients with an organic non-functional disorder, n = 84), FGID (n = 36) or organic and functional gastrointestinal disorder (OFGID, ie, patients with an organic and a functional disorder, n = 87). Two independent readers blinded to the diagnostic group calculated IGV using threshold based 3D region growing with OsiriX.
  
  
  RESULTS
  Median IGVs for the FGID, OGID, and OFGID groups were 197.6, 220.6 and 155.0 mL, respectively. Stepwise linear regression revealed age at study, gender, and calculated body mass index to predict the log IGV with an r(2) of 0.116, and P < 0.001. There was a significant positive correlation between age and IGV in OGID (Spearman's = 0.253, P = 0.02) but this correlation was non-significant in the other groups.
  
  
  CONCLUSIONS
  Although bloating is a classic symptom in FGID patients, IGV may not be increased compared with OGID and OFGID patients.
authors.affiliation: Department of Radiology, University College Cork and Cork University Hospital, Cork, Ireland.
authors.forename: Sebastian R
authors.initials: SR
authors.lastname: Mc Williams
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Mc Laughlin
authors.forename: Owen J
authors.initials: OJ
authors.lastname: O'Connor
authors.forename: Alan N
authors.initials: AN
authors.lastname: Desmond
authors.forename: Aine
authors.initials: A
authors.lastname: Ní Laoíre
authors.forename: Fergus
authors.initials: F
authors.lastname: Shanahan
authors.forename: Eamonn Mm
authors.initials: EM
authors.lastname: Quigley
authors.forename: Michael M
authors.initials: MM
authors.lastname: Maher
keywords: Gastrointestinal diseases; Irritable bowel syndrome; Tomography, X-ray computed