A Novel Digital Method for Accurate Endoscopic Size Measurement of Gastric Lesions: A Comparative Study With Visual...

Accurate measurement of the lesion size during endoscopy is crucial; however, it frequently relies on visual estimation, which is prone to errors. This study investigated these inaccuracies and introduced a novel depth-estimation algorithm (DEA) to evaluate its performance against conventional methods, visual estimation, and forceps-assisted estimation.

Nineteen endoscopists (6 experts, 13 novices) measured 15 artificial lesions (6-39 mm) within a 3-dimensional (3D)-printed stomach model using visual estimation (VE), forceps-assisted estimation (FE), and DEA. Measurement accuracy was evaluated using median percentage error (MdPE) and interquartile range (IQR). Subgroup analyses were conducted according to the endoscopist's experience and lesion size, location, and shape for each measurement method.

VE resulted in the highest MdPE at 33.33% (IQR, 17.24%-60.00%), while FE showed greater accuracy at 30.00% (IQR, 11.11%-48.72%; P<0.01). Unlike experts, novices exhibited no significant improvement in FE compared to VE (P=0.09). Conventional methods have demonstrated high error rates for polyp-shaped lesions and those located in the fundus, middle to high body, or the greater curvature. DEA achieved the highest accuracy, with an MdPE of 7.78% (IQR, 3.33%-16.67%), significantly outperforming both VE and FE (P<0.01) regardless of lesion characteristics, and showed consistent performance across endoscopist experience (P=0.18).

Given the observed error patterns in VE, endoscopists should exercise caution when evaluating polyp-shaped lesions and those located in the proximal stomach and greater curvature. The DEA outperformed conventional methods, especially for novices. Its integration into endoscopic practice can enhance the precision of lesion size measurements, ultimately improving clinical decision-making and outcomes.