Gastroesophageal chromoendoscopy in the dog

Chromoendoscopy, or chromoscopy, refers to the topical application of stains or dyes at the time of endoscopy in an effort to enhance tissue characterization, differentiation, or diagnosis. The stains that are used for chromoendoscopy are classified as absorptive (or vital), contrast, or reactive. Absorptive stains, such as Lugol’s solution and methylene blue, identify specific epithelial cell types by preferential absorption or diffusion across the cell membrane. Contrast stains, such as indigo carmine, seep through mucosal crevices and highlight surface topography and mucosal irregularities. For most chromoendoscopic applications, a spray catheter is used to apply a uniform mist of the staining agent onto the mucosa.