Angiogenesis in colon hyperplastic polyp

Sano's capillary pattern classification for narrow-band imaging of early colorectal lesions

Narrow-band imaging enhances visualization of the mucosal surface structure and vascular network and helps to increase the visibility of neoplasia by improving contrast. Sano and his colleagues first reported its efficacy for endoscopic use in the gastrointestinal tract and later proposed a sequential classification of the mucosal vascular network patterns according to histopathological categories. Sano's 'capillary pattern classification' was established to facilitate diagnosis of early colorectal lesions on a step-by-step basis. This review focuses on the utility and effectiveness of Sano's capillary pattern classification when examining early colorectal lesions using narrow-band imaging.

Effectiveness of narrow-band imaging magnification for invasion depth in early colorectal cancer

AIM

To evaluate the surface microvascular patterns of early colorectal cancer (ECC) using narrow-band imaging (NBI) with magnification and its effectiveness for invasion depth diagnosis.

METHODS

We studied 112 ECC lesions [mucosal/submucosal superficial (m/sm-s), 69; sm-deep (sm-d), 43] > or = 10 mm that subsequently underwent endoscopic or surgical treatment at our hospital. We compared microvascular architecture revealed by NBI with magnification to histological findings and then to magnification colonoscopy pit pattern diagnosis.

RESULTS

Univariate analysis indicated vessel density: non-dense (P < 0.0001); vessel regularity: negative (P < 0.0001); caliber regularity: negative (P < 0.0001); vessel length: short (P < 0.0001); and vessel meandering: positive (P = 0.002) occurred significantly more often with sm-d invasion than m/sm-s invasion. Multivariate analysis showed sm-d invasion was independently associated with vessel density: non-dense [odds ratio (OR) = 402.5, 95% confidence interval (CI): 12.4-13 133.1] and vessel regularity: negative (OR = 15.9, 95% CI: 1.2-219.1). Both of these findings when combined were an indicator of sm-d invasion with sensitivity, specificity and accuracy of 81.4%, 100% and 92.9%, respectively. Pit pattern diagnosis sensitivity, specificity and accuracy, meanwhile, were 86.0%, 98.6% and 93.8%, respectively, thus, the NBI with magnification findings of non-dense vessel density and negative vessel regularity when combined together were comparable to pit pattern diagnosis.

CONCLUSION

Non-dense vessel density and/or negative vessel regularity observed by NBI with magnification could be indicators of ECC sm-d invasion.