Mucosal vascular pattern in ulcerative colitis: observations using narrow band imaging colonoscopy with special reference to histologic inflammation

Background and aim  Narrow band imaging (NBI) is a novel endoscopy system, which enables a clear visualization of the mucosal vasculature of the gastrointestinal tract. The aim of this study is to determine whether this system may be of value for assessing the disease severity in ulcerative colitis (UC). Materials and methods  We observed the mucosal vascular pattern (MVP) in 157 colorectal segments of 30 patients with UC using both conventional and NBI colonoscopy. The MVP was determined to be normal or distorted under conventional colonoscopy and, subsequently, to be clear or obscure under NBI colonoscopy. The histologic variables in each segment were assessed in biopsy specimen. The possible correlation between MVP and the histologic grade of inflammation was evaluated. Results  The MVP under conventional colonoscopy was normal in 60 segments while it was distorted in 97 segments. In all of the former 60 segments, their MVP was clear under NBI colonoscopy. The MVP in the latter 97 segments were determined to be clear (n = 44) or obscure (n = 53) under NBI colonoscopy. Acute inflammatory cell infiltrates (26% vs. 0%, p = 0.0001), goblet cell depletion (32% vs. 5%, p = 0.0006), and basal plasmacytosis (2% vs. 21%, p = 0.006) were more frequently observed in segments with an obscure MVP than in those with a clear MVP. Conclusion  NBI colonoscopy may be of value for determining the grade of inflammation in patients with quiescent UC.