Evaluation of Microvascular Patterns Alone Using Endocytoscopy with Narrow-Band Imaging for Diagnosing Gastric Cancer

Abstract

Introduction: Although endocytoscopy (EC) with narrow-band imaging (NBI) is effective in diagnosing gastric cancer, no diagnostic system has been validated. We explored a specific diagnostic system for gastric cancer using EC with NBI.

Methods: Equal numbers of images from cancerous and noncancerous areas (114 images each) were assessed by endoscopists with (development group: 33) and without (validation group: 28) specific training in magnifying endoscopy with NBI. Microvascular and microsurface patterns (MS) in each image were evaluated. Lesions were diagnosed as cancerous when patterns were deemed "irregular." The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of a diagnosis according to patterns on EC with NBI (microvascular pattern [MV] alone, MS alone, and both) were evaluated and compared between groups to determine the diagnostic performance.

Results: In the development and validation groups, diagnoses based on the MV alone had significantly higher accuracy (91.7% vs. 76.3%, p < 0.0001 and 92.5% vs. 67.5%, p < 0.0001, respectively) and sensitivity (88.6% vs. 68.3%, p < 0.0001 and 89.5% vs. 38.6%, p < 0.0001, respectively) than those based on the MS alone. In both groups, there were no significant differences in diagnostic accuracy between using the MV alone and both patterns.

Discussion/conclusion: Evaluation of the MV alone is a simple and accurate diagnostic method for gastric cancer. This system could find widespread applications in clinical practice.

Keywords: Diagnostic system; Gastric carcinoma; Magnifying endoscopy; Microsurface pattern.

Fig. 1

Microvascular and MS classification (VS classification) based on endocytoscopy with NBI. If either the MV or the MS is “irregular,” lesions are diagnosed as cancers. In this study, we evaluated endocytoscopy with NBI by applying this classification. The details of the classification are as follows: MV: a uniform blood vessels (regular). b Blood vessels that expand locally and have different caliber meander (irregular). c No vascular findings (absent). MS (form of white line): d uniform surface structure (regular). e Nonuniform surface structure (irregular). f No surface structure (absent). VS, vessel plus surface; NBI, narrow-band imaging; MS, microsurface pattern; MV, microvascular pattern.

Fig. 2

Flow diagram showing the inclusion of patients.

Fig. 3

Images from 6 cases of misdiagnosis using EC with NBI. The irregular MV was not recognized by the endoscopist in a–f, even though they are images of cancerous areas. EC, endocytoscopy; NBI, narrow-band imaging; MV, microvascular pattern.