Comparison of diagnostic accuracy between linked color imaging and autofluorescence imaging in patients with ulcerative colitis: A prospective observational study.

BACKGROUND AND AIM: Image enhancement endoscopy techniques, such as linked color imaging (LCI) and autofluorescence imaging (AFI), have shown promise in diagnosing mucosal inflammation in ulcerative colitis (UC). However, no studies have directly compared the diagnostic efficacy of LCI and AFI. This prospective observational study aimed to compare their diagnostic accuracy for histological healing in UC.

METHODS: This study included 81 UC patients, resulting in a total of 204 endoscopic images captured using LCI and AFI, respectively. Spearman's rank correlation coefficients assessed the correlation between LCI and AFI coloration and Geboes histopathology score (GHS). Six endoscopists, who were blinded to clinicopathological features, evaluated these images, and subsequently, the diagnostic accuracy was evaluated.

RESULTS: Spearman's rank correlation coefficients between LCI index, AFI index (reverse gamma value), and GHS were 0.324 and -0.428, respectively (P < 0.001), indicating a significant correlation between LCI and AFI coloration and histological healing. In LCI and AFI classifications, mean values for diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 76.3 ± 2.2 versus 77.8 ± 2.7, 91.8 ± 4.0 versus 83.2 ± 7.6, 53.4 ± 10.0 versus 70.0 ± 5.3, 74.0 ± 3.5 versus 80.0 ± 1.6, and 82.9 ± 5.2 versus 75.5 ± 7.5, respectively. No significant difference in diagnostic accuracy existed between LCI and AFI classifications. However, LCI displayed higher sensitivity than AFI while AFI showed higher specificity compared with LCI (P < 0.05).

CONCLUSIONS: LCI and AFI offer comparable diagnostic accuracy for histological healing. Clinically, it is necessary to recognize diagnostic features characterized by higher sensitivity in LCI and greater specificity in AFI.