Endoscopic measurement of lesion size: improved accuracy with image processing

Area of Science:

• Medical Imaging
• Gastroenterology
• Clinical Trial Design

Background:

• Endoscopic lesion measurement is vital for clinical trials, particularly in ulcer disease research.
• Wide-angle lenses in endoscopes introduce significant peripheral image distortion, affecting measurement accuracy.
• Existing measurement techniques, like open-biopsy forceps, have known inaccuracies.

Purpose of the Study:

• To evaluate the accuracy of the traditional open-biopsy forceps measurement technique.
• To compare the accuracy of forceps measurement with a novel computer-aided image-processing technique designed to correct lens distortion.
• To assess the effectiveness of the image-processing technique in both in vitro and in vivo endoscopic measurements.

Main Methods:

• Developed a computer program to correct wide-angle lens distortion in endoscopic images.
• Utilized an in vitro ulcer model to compare the error rates of forceps measurement versus the image-processing technique.
• Conducted in vivo measurements using a known-sized object (coated chewing gum) to validate accuracy improvements.

Main Results:

• The open-biopsy forceps technique underestimated lesion size by 41.8% +/- 23.3% in vitro.
• Image processing significantly reduced in vitro error to 1.8% +/- 2.2% (p < 0.05).
• In vivo, forceps measurement showed a mean error of 26.5% +/- 5.7%, which improved to 2.8% +/- 3.2% (p < 0.05) with image processing.

Conclusions:

• Image processing significantly enhances the accuracy of lesion size measurement during endoscopy.
• The developed computer program effectively corrects for wide-angle lens distortion.
• This improved accuracy has significant implications for the design and performance of clinical trials involving endoscopic measurements.