Background and study aims: A newer colonoscope series has optical magnification and improvement in image freezing
function. We aimed to assess the impact on image capture, image quality, and polyp
discrimination.
Patients and methods: In consecutive patients undergoing outpatient colonoscopy images of colorectal polyps
were taken with Olympus 190 or 180 series instruments. The number of image captures
needed to obtain an adequate image, quality of stored images, proportion of polyps
with a high confidence estimate of likely histology, and accuracy of interpretations
were compared.
Results: An acceptable image at the first attempt was obtained in 97.3 % of photos with the
190 device vs. 83.8 % with the 180 instrument (P < 0.001). In the 190 group narrowband imaging (NBI) provided high confidence readings
in 9 % more cases than in the 180 group, but did not improve accuracy of polyp categorization.
The quality of the stored images was judged better for the 190 device. However, when
images that had provided high confidence estimates of polyp histology were re-interpreted
later by the original endoscopist, there was agreement with the original interpretation
for > 98 % of polyps in both the 180 group and the 190 group. A second endoscopist
agreed with the original high confidence interpretations for 90 % of polyps imaged
with either the 180 or the 190 scope.
Conclusion: The new colonoscope had less image blurring, improved subjective quality of stored
images, and increased the proportion of high confidence endoscopic estimates of polyp
histology, but did not improve accuracy in estimating polyp histology.
