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Measuring size of smaller colorectal polyps using a virtual scale function during endoscopies
  1. Daniel von Renteln1,2,
  2. Roupen Djinbachian2,
  3. Melissa Zarandi-Nowroozi3,
  4. Mahsa Taghiakbari1,4
  1. 1University of Montreal, Montreal, Quebec, Canada
  2. 2Department of Medicine, Division of Gastroenterology, CHUM, Montreal, Quebec, Canada
  3. 3Internal Medicine, University of Montreal Hospital Centre, Montreal, Quebec, Canada
  4. 4CRCHUM, Montreal, Quebec, Canada
  1. Correspondence to Dr Daniel von Renteln, University of Montreal, Montreal, Quebec, Canada; danielrenteln{at}

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Polyp size measurements are important for polyp risk stratification, choice of polypectomy technique and follow-up interval decisions. We present the first clinical experience of measuring colorectal polyp size during live colonoscopies using a new endoscope with a laser-based size measurement function (virtual scale endoscope, VSE). VSE superimposes a virtual linear or circular ruler onto objects in the endoscopist’s field of view. A total of 59 patients were enrolled and visual, VSE and reference size measurement obtained in 36 polyps up to 20 mm. When using VSE, we found higher relative accuracy for polyp size measurements (85.4%) compared with visual size estimation (66.8%; p<0.001) as compared with polyp size measurement after removal. When looking at the percentage of size measurements that were within 25% of true size (as compared with polyp size measurement after removal), we found that 33.3% for visual polyp size estimation and 86.1% for VSE were within 25% of true size (p<0.001).

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Accurate size estimation of colorectal polyps informs the appropriate choice of polypectomy technique and is also crucial for assigning postcolonoscopy surveillance intervals.1 Furthermore, our understanding of the prevalence of certain polyp pathologies (ie, high grade or serrated pathology) is in relation to their size.2 Although accurate polyp size measurement is essential for adequately managing patients, we still rely on the endoscopists’ subjective visual estimation of polyp size in routine practice. Current literature shows that subjective visual size estimation of polyp size can be incorrect.3 4 This can result in erroneous selection of polypectomy techniques and inadequate surveillance intervals. We used a novel endoscope (Scale eye, FUJIFILM, Tokyo, Japan) with an integrated virtual scale function allowing polyp size measurement during live colonoscopies. The high-definition endoscope emits a red laser beam from its tip diagonally onto the mucosa. The position of the laser beam on the …

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  • Contributors DvR developed the study concept, design and obtained funding. DvR, RD, MT collected all data. MT performed the statistical analysis. All authors interpreted the data. MT, RD, MZ-N and DvR drafted the manuscript. All authors revised the manuscript. All authors have approved the final draft.

  • Funding The study was supported by a research grant from Fujifilm.

  • Competing interests DvR is supported by a 'Fonds de Recherche du Québec Sante' career development award. He has also received research funding from ERBEElektromedizin, Ventage, Pendopharm, Fujifilm and Pentax, and has received consultant or speaker fees from Boston Scientific, ERBE Elektromedizin and Pendopharm.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Provenance and peer review Not commissioned; internally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.