Abstract
Background and study aims Real-time diagnosis of colorectal polyps is needed to prevent unnecessary resection
of benign polyps. The vessels in hyperplastic polyps sometimes mimic the characteristic
meshed capillary network of neoplastic lesions on non-magnified narrow-band imaging
(NBI). Endocytoscopy in conjunction with NBI (EC-NBI) enables more detailed vessel
observation. The current study evaluated whether EC-NBI can accurately diagnose small
colorectal lesions with visible vessels on non-magnified NBI.
Patients and methods This retrospective study was conducted from January to December 2016. During colonoscopy,
lesion images were obtained using NBI and EC-NBI. On EC-NBI, lesions were classified
as having “clear,” “unclear,” or “invisible” blood vessel margins. All specimens were
resected and pathologically examined, and the association between vessel margin findings
and pathological diagnosis was assessed. The lesion surface to vessel depth was measured
in clear, unclear, and invisible lesions.
Results Among 114 adenomas, 108 were clear, while six were unclear. Among 36 hyperplastic
polyps, eight were clear, while 28 were unclear. A micro-network (MN) pattern was
seen in 106 of 114 adenomas, and four of 36 hyperplastic polyps. The sensitivity,
specificity, correct diagnostic rate, and positive and negative predictive values
of clear blood vessel margins or a MN pattern as an adenoma index were 98.2 %, 69.4 %,
91.3 %, 91.1 %, and 92.6 %, respectively. EC-NBI correctly diagnosed 69.4 % (25/36)
of hyperplastic polyps. The lesion surface–blood vessel distance was greater in unclear
versus clear lesions (P < 0.001), and invisible versus unclear lesions (P < 0.001).
Conclusions EC-NBI may effectively differentiate hyperplastic polyps with visible vessels from
adenomas. Blood vessel depth affects visibility.
