title: Computer vision-based diameter maps to study fluoroscopic recordings of small intestinal motility from conscious experimental animals.
abstract: BACKGROUND
  When available, fluoroscopic recordings are a relatively cheap, non-invasive and technically straightforward way to study gastrointestinal motility. Spatiotemporal maps have been used to characterize motility of intestinal preparations in vitro, or in anesthetized animals in vivo. Here, a new automated computer-based method was used to construct spatiotemporal motility maps from fluoroscopic recordings obtained in conscious rats.
  
  
  METHODS
  Conscious, non-fasted, adult, male Wistar rats (n=8) received intragastric administration of barium contrast, and 1-2 hours later, when several loops of the small intestine were well-defined, a 2 minutes-fluoroscopic recording was obtained. Spatiotemporal diameter maps (Dmaps) were automatically calculated from the recordings. Three recordings were also manually analyzed for comparison. Frequency analysis was performed in order to calculate relevant motility parameters.
  
  
  RESULTS
  In each conscious rat, a stable recording (17-20 seconds) was analyzed. The Dmaps manually and automatically obtained from the same recording were comparable, but the automated process was faster and provided higher resolution. Two frequencies of motor activity dominated; lower frequency contractions (15.2±0.9 cpm) had an amplitude approximately five times greater than higher frequency events (32.8±0.7 cpm).
  
  
  CONCLUSIONS
  The automated method developed here needed little investigator input, provided high-resolution results with short computing times, and automatically compensated for breathing and other small movements, allowing recordings to be made without anesthesia. Although slow and/or infrequent events could not be detected in the short recording periods analyzed to date (17-20 seconds), this novel system enhances the analysis of in vivo motility in conscious animals.
authors.affiliation: Grupo de Computación de Altas Prestaciones y Optimización, Dpto. Ciencias de la Computación, Arquitectura de Computadores, Lenguajes y Sistemas Informáticos, Estadística e Investigación Operativa, Universidad Rey Juan Carlos (URJC), Móstoles, Madrid, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Ramírez
authors.affiliation: Grupo de Computación de Altas Prestaciones y Optimización, Dpto. Ciencias de la Computación, Arquitectura de Computadores, Lenguajes y Sistemas Informáticos, Estadística e Investigación Operativa, Universidad Rey Juan Carlos (URJC), Móstoles, Madrid, Spain.|Grupo de Excelencia Investigadora URJC-Banco de Santander-Computer Vision and Image Processing (CVIP), Móstoles, Madrid, Spain.
authors.forename: J J
authors.initials: JJ
authors.lastname: Pantrigo
authors.affiliation: Grupo de Computación de Altas Prestaciones y Optimización, Dpto. Ciencias de la Computación, Arquitectura de Computadores, Lenguajes y Sistemas Informáticos, Estadística e Investigación Operativa, Universidad Rey Juan Carlos (URJC), Móstoles, Madrid, Spain.|Grupo de Excelencia Investigadora URJC-Banco de Santander-Computer Vision and Image Processing (CVIP), Móstoles, Madrid, Spain.
authors.forename: A S
authors.initials: AS
authors.lastname: Montemayor
authors.affiliation: Unidad del Dolor, Servicio de Anestesiología, Hospital General Universitario Gregorio Marañón (HGUGM), Madrid, Spain.|Grupo de Excelencia Investigadora URJC-Banco de Santander-Grupo Multidisciplinar de Investigación y Tratamiento del Dolor (i+DOL), Móstoles, Madrid, Spain.
authors.forename: A E
authors.initials: AE
authors.lastname: López-Pérez
authors.affiliation: Grupo de Excelencia Investigadora URJC-Banco de Santander-Grupo Multidisciplinar de Investigación y Tratamiento del Dolor (i+DOL), Móstoles, Madrid, Spain.|Área de Farmacología y Nutrición y Unidad Asociada al Instituto de Química Médica (IQM) y al Instituto de Investigación en Ciencias de la Alimentación (CIAL) del Consejo Superior de Investigaciones Científicas (CSIC), Universidad Rey Juan Carlos (URJC), Alcorcón, Madrid, Spain.
authors.forename: M I
authors.initials: MI
authors.lastname: Martín-Fontelles
authors.affiliation: Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, Australia.
authors.forename: S J H
authors.initials: SJH
authors.lastname: Brookes
authors.affiliation: Grupo de Excelencia Investigadora URJC-Banco de Santander-Grupo Multidisciplinar de Investigación y Tratamiento del Dolor (i+DOL), Móstoles, Madrid, Spain.|Área de Farmacología y Nutrición y Unidad Asociada al Instituto de Química Médica (IQM) y al Instituto de Investigación en Ciencias de la Alimentación (CIAL) del Consejo Superior de Investigaciones Científicas (CSIC), Universidad Rey Juan Carlos (URJC), Alcorcón, Madrid, Spain.
authors.forename: R
authors.identifier: http://orcid.org/0000-0002-6726-8795
authors.initials: R
authors.lastname: Abalo
mesh_terms: D000818:Animals; D001185:Artificial Intelligence; D005471:Fluoroscopy / Q000379:methods*; D005769:Gastrointestinal Motility; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D007421:Intestine, Small / Q000502:physiology; D008297:Male; D009119:Muscle Contraction; D017208:Rats, Wistar; D014741:Video Recording
keywords: Computer vision-based methods; Dmaps; fluoroscopy; frequency; rat