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Abstract
Background/Aims
Narrow band imaging (NBI) endoscopy can be used for gross differentiation between the types of colonic polyps. This study was conducted as a retrospective study for estimation of the interobserver and intraobserver agreement of the pit pattern of the mucosal surface and the accuracy of histology prediction.
Methods
A total of 159 patients underwent complete colonoscopy and 219 polyps examined by NBI endoscopy without magnification were assessed. Interobserver and intraobserver agreement were calculated by investigators in each group for determination of the surface pattern and prediction of histology based on the modified Kudo's classification using intraclass correlation coefficient.
Results
Interobserver agreement for the surface pit pattern and prediction of polyp type was 0.84 and 0.73 in experienced endoscopists, and 0.86 and 0.62 in trainees, respectively. Intra-observer agreement for the surface pit patterns and prediction of polyp type was 0.81, 0.83, 0.85, 0.83, 0.56, 0.84, 0.51, 0.83, and 0.71; and 0.71, 0.70, 0.82, 0.54, 0.72, 0.37, 0.51, 0.34, and 0.30, respectively. The diagnostic accuracy for prediction of polyp type was 69.4% for experienced endoscopists and 72.9% for trainees.
Conclusions
NBI endoscopy without magnification showed fairly good inter and intraobserver agreement for the pit pattern of the mucosal surface and the accuracy of histology prediction; however, it had some limitation for differentiation of colon polyp histologic type. Training and experience with NBI is needed for improvement of accuracy.
References
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Fig. 1.
Polyp pattern on narrow banding imaging (whitish color). (A) Circular pattern with dots. (B) Round-oval pattern. (C) Tubulogyrus pattern.(D) Irregular pattern.
Table 1.
Polyp Patterns by Narrow Banding Imaging Colonoscopy7
| Type 2 | Type 3 | Type 4 | Type 5 | |
|---|---|---|---|---|
| Pattern type | Circular pattern with dots | Round/oval | Tubulogyrus | Irregular/ sparse |
| Histology | Hyperplasia | Adenoma | Adenoma | Adenocar cinoma |
Table 2.
Characteristics of Colon Polyps Assessed by Narrow Band Imaging
| Investigator | Size (mm) | |||
|---|---|---|---|---|
| ＜5 | 6–10 | ＞11 | Total | |
| Hyperplasia | 3 | 3 | 1 | 7 |
| Adenoma (serrated adenoma) | 50 (1) | 111 (6) | 46 (1) | 205 (8) |
| Carcinoma | 0 | 0 | 7 | 7 |
| Total | 53 | 114 | 54 | 219 |
Table 3.
Interobserver Agreement for Pit Pattern and Differentiation of Polyp Type
| Investigator | Intraclass correlation coefficient | |
|---|---|---|
| Pit pattern | Polyp histologic type | |
| Experienced (n=3) | 0.84 | 0.73 |
| Trainees (n=6) | 0.86 | 0.62 |
Table 4.
Intra-observer Agreement for Pit Pattern and Differentiation of Polyp Type
| Investigator | Intraclass correlation coefficient | |
|---|---|---|
| Pit pattern | Polyp histologic type | |
| E1 | 0.81 | 0.71 |
| E2 | 0.83 | 0.70 |
| E3 | 0.85 | 0.82 |
| T1 | 0.83 | 0.54 |
| T2 | 0.56 | 0.72 |
| T3 | 0.84 | 0.37 |
| T4 | 0.51 | 0.51 |
| T5 | 0.83 | 0.34 |
| T6 | 0.71 | 0.30 |
Table 5.
Diagnostic Accuracy for Differentiation of Polyp Type Based on Pit Pattern
Table 6.
Diagnostic Accuracy for Differentiation of Polyp Type according to Size
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