title: Clinical study using novel endoscopic system for measuring size of gastrointestinal lesion.
abstract: OBJECTIVE
  To verify the performance of a lesion size measurement system through a clinical study.
  
  
  METHODS
  Our proposed system, which consists of a conventional endoscope, an optical device, an optical probe, and a personal computer, generates a grid scale to measure the lesion size from an endoscopic image. The width of the grid scale is constantly adjusted according to the distance between the tip of the endoscope and lesion because the lesion size on an endoscopic image changes according to the distance. The shape of the grid scale was corrected to match the distortion of the endoscopic image. The distance was calculated using the amount of laser light reflected from the lesion through an optical probe inserted into the instrument channel of the endoscope. The endoscopist can thus measure the lesion size without contact by comparing the lesion with the size of the grid scale on the endoscopic image. (1) A basic test was performed to verify the relationship between the measurement error eM and the tilt angle of the endoscope; and (2) The sizes of three colon polyps were measured using our system during endoscopy. These sizes were immediately measured by scale after their removal.
  
  
  RESULTS
  There was no error at α = 0°. In addition, the values of eM (mean ± SD) were 0.24 ± 0.11 mm (α = 10°), 0.90 ± 0.58 mm (α = 20°) and 2.31 ± 1.41 mm (α = 30°). According to these results, our system has been confirmed to measure accurately when the tilt angle is less than 20°. The measurement error was approximately 1 mm in the clinical study. Therefore, it was concluded that our proposed measurement system was also effective in clinical examinations.
  
  
  CONCLUSIONS
  By combining simple optical equipment with a conventional endoscope, a quick and accurate system for measuring lesion size was established.
authors.affiliation: Kiyoshi Oka, OK Fiber Technology Co., Ltd., Kizugawa-shi 619-0215, Kyoto, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Oka
authors.affiliation: Kiyoshi Oka, OK Fiber Technology Co., Ltd., Kizugawa-shi 619-0215, Kyoto, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Seki
authors.affiliation: Kiyoshi Oka, OK Fiber Technology Co., Ltd., Kizugawa-shi 619-0215, Kyoto, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Akatsu
authors.affiliation: Kiyoshi Oka, OK Fiber Technology Co., Ltd., Kizugawa-shi 619-0215, Kyoto, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Wakabayashi
authors.affiliation: Kiyoshi Oka, OK Fiber Technology Co., Ltd., Kizugawa-shi 619-0215, Kyoto, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Inui
authors.affiliation: Kiyoshi Oka, OK Fiber Technology Co., Ltd., Kizugawa-shi 619-0215, Kyoto, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Yoshino
mesh_terms: D000465:Algorithms; D001331:Automation; D001706:Biopsy; D002138:Calibration; D003111:Colonic Polyps / Q000175:diagnosis* / Q000601:surgery*; D019723:Endoscopes; D004724:Endoscopy / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D007834:Lasers; D015203:Reproducibility of Results
keywords: Endoscope; Grid scale; Lesion size; Low level laser; Non-contact measurement
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