Virtual scale function of gastrointestinal endoscopy for accurate polyp size estimation in real-time: a preliminary study

Abstract

Significance: Polyp size is important for selecting the surveillance interval or treatment policy. Nevertheless, it is challenging to accurately estimate the polyp size during endoscopy. An easy and cost-effective function to assist in polyp size estimation is required.Aim: To propose a virtual scale function for endoscopy and evaluate its performance and expected accuracy.Approach: An adaptive virtual scale behavior was demonstrated. The measurement error of the virtual scale along the distance between the tip of the endoscope and the object plane was evaluated using graph paper. The accuracy of polyp size estimation by an expert endoscopist was compared with the accuracy of the biopsy forceps method using phantom images. Results:The measurement errors of the virtual scale were ≤ 0.7 mm when the distance to the graph paper, which faced the tip of the endoscope, varied from 4 to 30 mm. The accuracy with the virtual scale was significantly higher than that obtained with biopsy forceps (5.3 AE 5.5% versus 11.9 AE 9.4%, P < 0.001). Conclusions:The virtual scale function, which operates in real-time without any additional device, can be used to estimate polyp sizes easily and accurately with endoscopy.

Estimating colorectal polyp size with a virtual scale endoscope and visual estimation during colonoscopy: Prospective, preliminary comparison of accuracy

“…Similar to our study, Yoshioka et al also evaluated the size measurement performance of VSE using phantoms. 19 They compared the predicted lesion size on images showing both forceps and polyps with that measured by VSE. Evaluated the error between actual polyp size and measurements, however concluded that the VSE measurements had less error than the actual size of polyps (5.3 vs. 11.9%; P < 0.001).…”

“…Similar to our study, Yoshioka et al . also evaluated the size measurement performance of VSE using phantoms 19 . They compared the predicted lesion size on images showing both forceps and polyps with that measured by VSE.…”

“…The distance to the object is calculated from the position of the red laser beam, and a virtual scale is displayed on the monitor in real time. 19 Two types of virtual scales are available: linear and circular. In this study, a linear scale was evaluated to measure the width of the object.…”

Warning from artificial intelligence against inaccurate polyp size estimation

“…Although new through‐the‐scope devices for accurate measurement, such as graduated injection needles, ruler snares, calibrated hoods, virtual tape measures, or structured light laser probes have been explored, AI measurement does not require additional devices and would be more ideal for measuring polyp size. In this regard, endoscopy with a virtual scale function reported by Yoshioka et al ., 10 which calculates the length using the position of the laser spot from the endoscope, may also be convenient and useful.…”

Measuring polyp size using a virtual scale endoscope: a video tutorial with clinical case demonstration

“…2; ▶ Video 1). One recent study has evaluated the feasibility of the VSE in an ex vivo experiment and a second ex vivo study has demonstrated that size measurement is more accurate when using the VSE compared with visual size estimation [4,5]. We present a visually assisted instruction guide on how to use the VSE and demonstrate its application in ex vivo and in vivo examples (▶ Video 1).…”