title: Computerized 3-dimensional localization of a video capsule in the abdominal cavity: validation by digital radiography.
abstract: BACKGROUND
  Wireless video capsule endoscopy allows the noninvasive visualization of the small intestine. Currently, capsules do not provide localization information while traversing the GI tract.
  
  
  OBJECTIVE
  To report on the radiological validation of 3-dimensional localization software incorporated in a newly developed capsule. By using radiofrequency transmission, the software measures the strength of the capsule's signal to locate the position of the capsule.
  
  
  METHODS
  This study was performed at the University of Massachusetts Medical Center, Worcester, Mass.
  
  
  METHODS
  Thirty healthy volunteers consented to the experimental procedure.
  
  
  METHODS
  After ingestion of the capsule, subjects had 5 sets of anteroposterior and lateral radiographs taken every 30 minutes while the software calculated the position of the capsule. By using the radiographs, we calculated the location of the capsule in the abdominal cavity and compared the results with those generated by the software.
  
  
  RESULTS
  Average error (and standard deviation) among the 3-dimensional coordinates was X, 2.00 cm (1.64); Y, 2.64 cm (2.39); and Z, 2.51 cm (1.83). The average total spatial error among all measurements was 13.26 cm(3) (22.72). There was a correlation between increased subject body mass index and the 3-dimensional software measurement error.
  
  
  CONCLUSIONS
  This study was performed in healthy volunteers and needs further validation in patients with small intestinal disorders.
  
  
  CONCLUSIONS
  The new 3-dimensional software provides localization of the capsule consistent with radiological observations. However, further validation of the software's clinical utility is required with a prospective clinical trial.
authors.affiliation: University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors.forename: Neil
authors.initials: N
authors.lastname: Marya
authors.affiliation: University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Karellas
authors.affiliation: University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors.forename: Anne
authors.initials: A
authors.lastname: Foley
authors.affiliation: University of Massachusetts Medical School, Worcester, Massachusetts, USA; UMass Memorial Healthcare, Worcester, Massachusetts, USA.
authors.forename: Abhijit
authors.initials: A
authors.lastname: Roychowdhury
authors.affiliation: University of Massachusetts Medical School, Worcester, Massachusetts, USA; UMass Memorial Healthcare, Worcester, Massachusetts, USA.
authors.forename: David
authors.initials: D
authors.lastname: Cave
mesh_terms: D034841:Abdominal Cavity / Q000000981:diagnostic imaging*; D053704:Capsule Endoscopy; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011856:Radiographic Image Enhancement; D012984:Software