title: A novel technique to measure splanchnic transit time using microbubble ultrasound.
abstract: OBJECTIVE
  The objective of this study was to measure splanchnic transit time by intravenous injection of a microbubble.
  
  
  METHODS
  Ten volunteers were examined before and after eating. After Doppler indices of splanchnic circulation were obtained, the superior mesenteric artery (SMA) and vein (SMV) were simultaneously interrogated using power Doppler ultrasound after intravenous injection of a microbubble. Contrast arrival in the SMA and subsequently the SMV was recorded and splanchnic transit time calculated from differences in the time-intensity curves.
  
  
  RESULTS
  Splanchnic transit time decreased significantly after eating (mean 11 vs. 6.9 seconds; P = 0.007), reflecting splanchnic hemodynamics. Between-subject variability attributable to repeated measurements was least for the SMA resistive index (17%) but 56% for the new index, suggesting poor reproducibility.
  
  
  CONCLUSIONS
  Splanchnic transit time may be measured by microbubble injection but is subject to considerable measurement error. Newer microbubbles and imaging methods may allow more reproducible measurements.
authors.affiliation: Intestinal Imaging Centre, St. Mark's Hospital, London, UK.
authors.forename: Michele
authors.initials: M
authors.lastname: Marshall
authors.forename: Steve
authors.initials: S
authors.lastname: Halligan
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Eckersley
authors.forename: Andrew
authors.initials: A
authors.lastname: Williams
authors.forename: Martin J K
authors.initials: MJ
authors.lastname: Blomley
authors.forename: David O
authors.initials: DO
authors.lastname: Cosgrove
authors.forename: Clive I
authors.initials: CI
authors.lastname: Bartram
mesh_terms: D000328:Adult; D000940:Antigenic Variation; D004435:Eating / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008638:Mesenteric Arteries / Q000000981:diagnostic imaging*; D008642:Mesenteric Veins / Q000000981:diagnostic imaging*; D045423:Microbubbles; D015203:Reproducibility of Results; D013152:Splanchnic Circulation / Q000502:physiology*; D014465:Ultrasonics; D014463:Ultrasonography