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[The value of targeted biopsies with endoscopic magnification and narrow band image vs. chromoendoscopy for the diagnosis of gastric metaplasia].

INTRODUCTION
Endoscopy is the better test to detect premalignant lesions, but its main problem is the sampling error.


OBJECTIVES
To evaluate the diagnostic usefulness of endoscopic biopsies using narrow band imaging (NBI) vs. chromoendoscopy for diagnosing gastric intestinal metaplasia.


METHODS
Forty one patients were studied with conventional endoscopy, NBI magnification endoscopy and chromoendoscopy (3% acetic acid, 0.6% indigo carmine) for examination of gastric antrum. Biopsies were taken randomly from the antrum, body and incisura angularis. Additional biopsies were taken from areas with villous or crypt pattern according to NBI and chromoendoscopy examination (targeted biopsies).


RESULTS
240 biopsies were taken, 205 randomized biopsies and 35 targeted biopsies. Intestinal metaplasia was found in 25 randomized biopsies and 9 directed samples (12% vs. 25.7%). The NBI and chromoendoscopy had sensitivity of 70% vs. 77%, specificity of 97% vs. 98%, with diagnostic accuracy of 96% vs. 97%, respectively. Random biopsies and targeted biopsies had a sensitivity of 91% vs. 74%, specificity of 51% vs. 95%, and diagnostic accuracy of 93% vs. 86%, respectively. The intra-observer variability showed a k value of 0.86 (range 0.74 to 0.99).


CONCLUSION
Targeted biopsies are more specific than random biopsies to detect gastric intestinal metaplasia. NBI and chromoendoscopy may be used similarly to guide biopsies.