Flexible spectral imaging color enhancement in colon capsule endoscopy: Scoping review of evidence for lesion detection and characterization

Abstract Second-generation colon capsule endoscopy (CCE) has achieved high diagnostic accuracy for polyp detection. However, its widespread adoption as a filter test is hampered by major cost-effectiveness concerns, due to significant follow-up endoscopy rates (FER), quantified as high as 42%, thus revealing a potential paradox: CCE superior detection of un-characterized lesions may worsen the economic problem. Flexible spectral imaging color enhancement (FICE) is a standard virtual chromoendoscopy tool, but its role in CCE has been considered uncertain. This scoping review aimed to evaluate available evidence on FICE in addressing CCE limitations in lesion detection and characterization. A systematic literature search identified studies investigating use of FICE in CCE, focusing on studies analyzing FICE performance in improving detection rates and differentiating polyp histology. Two key studies representing complementary evidence were analyzed. Regarding detection, a prospective trial demonstrated that FICE significantly improved overall per-lesion sensitivity compared with white light (WL) (79% vs. 61%). Specifically, FICE outperformed WL for 6-9-mm polyps (93% vs. 65%), flat/non-protruding lesions (75% vs. 53%), and serrated polyps (74% vs. 57%). Regarding characterization, a quantitative colorimetric analysis identified that the color difference between polyps and mucosa in FICE reliably discriminates histology, yielding a 0.928 area-under-the-curve (AUC), with 91.2% sensitivity and 88.2% specificity. FICE may play a complementary role in CCE, significantly improving detection of high-risk flat/serrated lesions and providing objective data for differentiating adenomas from hyperplastic polyps. Integrating FICE into diagnostic workflows could provide a smart solution to address CCE high FER and cost-effectiveness barriers.