title: Evaluation of oesophageal transit velocity using the improved Demons technique.
abstract: OBJECTIVE
  This paper presents a novel method to compute oesophageal transit velocity in a direct and automatized manner by the registration of scintigraphy images.
  
  
  METHODS
  A total of 36 images from nine healthy volunteers were processed. Four dynamic image series per volunteer were acquired after a minimum 8 h fast. Each acquisition was made following the ingestion of 5 ml saline labelled with about 26 MBq (700 µCi) technetium-99m phytate in a single swallow. Between the acquisitions, another two swallows of 5 ml saline were performed to clear the oesophagus. The composite acquired files were made of 240 frames of anterior and posterior views. Each frame is the accumulate count for 250 ms.At the end of acquisitions, the images were corrected for radioactive decay, the geometric mean was computed between the anterior and posterior views and the registration of a set of subsequent images was performed. Utilizing the improved Demons technique, we obtained from the deformation field the regional resultant velocity, which is directly related to the oesophagus transit velocity.
  
  
  RESULTS
  The mean regional resulting velocities decreases progressively from the proximal to the distal oesophageal portions and, at the proximal portion, is virtually identical to the primary peristaltic pump typical velocity. Comparison between this parameter and 'time-activity' curves reveals consistency in velocities obtained using both methods, for the proximal portion.
  
  
  CONCLUSIONS
  Application of the improved Demons technique, as an easy and automated method to evaluate velocities of oesophageal bolus transit, is feasible and seems to yield consistent data, particularly for the proximal oesophagus.
authors.affiliation: aDepartment of Physics, Faculty of Philosophy, Science and Language of Ribeirão Preto bDepartment of Medicine, Faculty of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil.
authors.forename: Michele N
authors.initials: MN
authors.lastname: De Souza
authors.forename: Fernando E B
authors.initials: FE
authors.lastname: Xavier
authors.forename: Marie
authors.initials: M
authors.lastname: Secaf
authors.forename: Luiz E A
authors.initials: LE
authors.lastname: Troncon
authors.forename: Ricardo B
authors.initials: RB
authors.lastname: de Oliveira
authors.forename: Eder R
authors.initials: ER
authors.lastname: Moraes
mesh_terms: D000328:Adult; D004947:Esophagus / Q000000981:diagnostic imaging* / Q000502:physiology*; D005260:Female; D005772:Gastrointestinal Transit; D064368:Healthy Volunteers; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging