Use of endocytoscopy for identification of sessile serrated adenoma/polyps and hyperplastic polyps by quantitative image analysis of the luminal areas.

BACKGROUND AND STUDY AIMS:  Recent studies that used magnifying chromoendoscopy and endocytoscopy (EC) to investigate endoscopic features of sessile serrated adenoma/polyps (SSA/Ps) suggested that a dilated crypt opening was an important indicator of SSA/Ps. However, no studies to date have measured the actual extent of dilatation. Hence, we investigated retrospectively the luminal areas using EC to determine a cutoff value for differentiating SSA/Ps from hyperplastic polyps (HPs).

PATIENTS AND METHODS : A total of 101 lesions, including 25 SSA/Ps, 66 HPs, and 10 normal mucosal samples, assessed by an integrated-type EC were collected. For each lesion, 1 image that showed the widest lumen was selected and the average area of the contiguous 3 lumens were calculated. The cutoff value differentiating SSAPs from HPs was determined by receiver operating curve (ROC) analysis.

RESULTS:  The mean luminal areas of SSA/Ps and HPs were 4152 μm (2) and 2117 μm (2) , respectively. ROC analysis found that a luminal area cutoff of 3068 μm (2) had a sensitivity of 80.0 %, a specificity of 77.3 %, an accuracy of 78.0 %, and an area under the ROC curve of 0.865. Furthermore, a cutoff of ≥ 556 μm (2) was found to accurately distinguish between HPs and normal mucosa (sensitivity 98.5 %, specificity 100 %, accuracy 98.7 %, and AUC 0.998).

CONCLUSIONS:  EC analysis of the luminal area is useful for differentiating between SSAPs and HPs. This approach could be adapted for computer-aided diagnosis of SSA/P.