Introduction
Data evaluating the utility of Blue light Imaging (BLI) and Linked Color Imaging (LCI) in the diagnosis of gastric intestinal metaplasia (IM) and atrophic gastritis (AG) is limited.
Aims & Methods
We aimed to evaluate and compare the diagnostic accuracy of BLI and LCI without magnification for the detection of IM and AG.
Single centre prospective study involving consecutive patients aged ≥18 years undergoing diagnostic upper gastrointestinal endoscopy (UGIE), endoscopic follow-up of intestinal metaplasia or gastric cancer screening. Exclusion criteria: previous gastrectomy, contraindication to UGIE due to comorbidities, no gastric mucosal biopsies, refusal of consent. Endoscopy was initially performed with white light image (WLI), followed by BLI and LCI. Standardized photodocumentation of stomach was performed with WLI, BLI and LCI. Imaging features suggestive of IM: lavender color sign and whitish flat elevation with LCI, and light blue crest and white opaque substance with BLI. EGGIM and Kimura-Takamoto Classification (KTC) were applied when IM and AG were suspected. Systematic random biopsies of the antrum, incisura angularis and corpus along with targeted biopsies of suspicious gastric mucosal lesions were obtained. Histology was considered gold standard. Performance of endoscopic imaging in the detection of IM, AG and EGC was evaluated.
Initially, 134 patients were evaluated and 64 were excluded: previous gastrectomy-22, pending histology-20, non-BLI imaging-15, intolerance to UGIE-3, refusal of consent-1, esophageal stenosis-1 and contra-indication to biopsies-2. Final sample included 70 patients.
Qualitative data expressed as percentage were compared with Chi-square test. A p value of <0.05 was considered significant.
Results
Median age was 56 (19-86), with 49 (63%) female. There was family history of gastric cancer in 12(15%) and history of smoking in 35 (44%).
Histological AG was found in 15 (19%) and IM in 20 (26%) patients. WLI was suggestive of IM in 14(20%), confirmed histologically in 9 (64%). IM was suspected by LCI and BLI in 24 (34%) and 23 (32%) cases, confirmed by histology in 16 (67%) and 17 (74%), respectively.
WLI classified 56 (71%) as EGGIM 0 and after LCI and BLI, 10 (18%) and 8 (15%) of these cases had EGGIM 1 or 2. In 10 patients, EGGIM 1-2 with WLI, only 1 was upgraded to EGGIM 3-4 with LCI and BLI. In 3 (4%) EGGIM 3-4 with WLI, after LCI and BLI,1 had extensive IM (EGGIM 6). Among 19(24%) patients EGGIM 1-2 with LCI, 3(16%) had EGGIM 0 with BLI.
Atrophy was suspected by WLI and LCI in 9(12%) and 15(21%) patients, confirmed by histology in 6(67%) and 8(53%) cases, respectively. According to KTC, 5 (6%) were classified as C1, 2 (3%) as C2 and 4 (5%) as O3 with WLI. With LCI images, 8 (10%) were classified as C1, 3(4%) as C2 and 4(5%) as O3. The sensitivity (Sens), specificity (Spec), accuracy, positive predictive value (PPV), negative predictive value (NPV) of WLI, BLI and LCI in detecting AG and IM are shown in table 1.
Table 1. Sens, Spec, accuracy, PPV and NPV in detecting AG and IM with WLI, LCI and BLI.
| Sens (%) | Spec (%) | Accuracy (%) | PPV (%) | NPV (%) |
| Intestinal metaplasia |
| WLI | 47 | 90 | 79 | 61 | 83 |
| LCI | 80 | 84 | 83 | 62 | 92 |
| BLI | 85 | 88 | 97 | 70 | 94 |
| Atrophic gastritis |
| WLI | 40 | 94 | 80 | 71 | 83 |
| LCI | 53 | 87 | 78 | 58 | 85 |
Conclusion
Both BLI and LCI are promising advanced endoscopic imaging techniques with BLI having higher accuracy than LCI in detection of IM.
References
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