title: Accuracy of the size estimation in wireless capsule endoscopy: calibrating the M2A PillCam (with video).
abstract: OBJECTIVE
  To describe the accuracy and precision of a size estimation in wireless capsule endoscopy (WCE) and to develop a simple device that facilitates learning of an exact size estimation in WCE.
  
  
  METHODS
  A prospective study with an animal model. Seventy-five medical students were compared with 21 physicians not performing WCEs and 21 experts actively performing WCEs.
  
  
  METHODS
  Video sequences were recorded with a PillCam wireless endoscope in a porcine small-bowel model after implantation of "lesions" of defined sizes. Volunteers estimated the diameter of these "lesions" with and without the use of a calibrator device, which was a picture from a black-and-white grid taken with the PillCam in direct contact with the transparent dome.
  
  
  RESULTS
  The students overestimated the diameters of the lesions by 26%. The physicians and experts underestimated the diameters by 32% and 31%, respectively. With the help of the calibrator device, the students underestimated the diameters by 15%. Physicians underestimated the diameters by 21%, whereas experts still underestimated the diameters by 35%. The interindividual log-scale standard deviation (SD) of the estimated diameters from the true diameter decreased during training in all groups, whereas intraindividual SDs decreased in students and increased in experts.
  
  
  CONCLUSIONS
  An animal model.
  
  
  CONCLUSIONS
  All investigators agree better when a calibrating device was offered. Experts who performed more than 400 WCEs tended to be more precise.
authors: Department of Internal Medicine I, University Clinic Tübingen, Tübingen, Germany.
authors: Florian
authors: F
authors: Graepler
authors: Manuel
authors: M
authors: Wolter
authors: Reinhard
authors: R
authors: Vonthein
authors: Michael
authors: M
authors: Gregor
mesh_terms: D000818:Animals; D002138:Calibration / Q000592:standards; D053705:Capsule Endoscopes / Q000592:standards*; D053704:Capsule Endoscopy / Q000379:methods*; D004195:Disease Models, Animal; D004867:Equipment Design; D006801:Humans; D007410:Intestinal Diseases / Q000175:diagnosis*; D007421:Intestine, Small; D015203:Reproducibility of Results; D013552:Swine