Relationship between narrow-band imaging magnifying observation and pit pattern diagnosis in colorectal tumors

The aim of this study was to examine the relationship between narrow-band imaging (NBI) magnifying observation using the surface pattern as the main evaluation criterion and pit pattern diagnosis on the basis of magnifying observation using a dye in relation to the characteristics of colorectal tumors according to their morphologies.

In this study, NBI observation and pit pattern diagnosis using a dye with magnifying observation were simultaneously performed in our hospital, and the consecutive 786 cases of colorectal lesions (hyperplasia, adenomata and early carcinomas) that had been endoscopically or surgically resected were retrospectively analyzed. NBI magnifying observation was in conformance with the Hiroshima classification and pit pattern diagnosis was in conformance with the Kudo and Tsuruta classification. The relationship between NBI magnifying observation and pit pattern diagnosis and that between NBI magnifying observation and the histological type/invasion depth were examined in relation to colorectal tumor morphology.

Type A corresponded to the type II pit pattern, type B corresponded to the type III(S), type III(L) and type IV regular pit patterns, type C1 corresponded to the type V(I) slightly irregular pit pattern, type C2 corresponded to the type V(I) highly irregular pit pattern and type C3 corresponded to the type V(N) pit pattern. In the protruded type, the irregularity of type C1 or C2 lesions agreed with the type V(I) slightly or highly irregular pit pattern, respectively, in 114 cases (64.0%). Moreover, the irregularity was higher with NBI magnifying observation than with pit pattern diagnosis in 58 cases (32.6%). In the superficial type, the irregularity of type C1 or C2 lesions agreed with the type V(I) slightly or highly irregular pit pattern, respectively, in 63 cases (71.6%). Moreover, the irregularity was higher with NBI magnifying observation than with pit pattern diagnosis in 19 cases (21.6%). In the case of type C1 or C2 lesions, the irregularity tended to be higher with NBI magnifying observation than with pit pattern diagnosis in the protruded type compared to the superficial type (p = 0.087).

The surface pattern, which was visible in NBI magnifying observation, differed from the pit pattern findings obtained by magnifying endoscopic observation using a dye. Findings were more detailed in pit pattern diagnosis using a dye than in NBI magnifying observation.