Numerical analysis of the autofluorescence intensity of neoplastic and non-neoplastic colorectal lesions by using a novel videoendoscopy system

Background: Autofluorescence endoscopy (AFE) may improve detection and diagnosis of colorectal lesions. Recently, AFE based on a high-resolution video endoscope was developed. Objective: A novel high-resolution video AFE system was used to quantify autofluorescence of colorectal lesions to determine the characteristics of non-neoplastic and neoplastic lesions. Design: Retrospective observational Study. Setting: Single-center referral hospital. Patients: Ninety-seven patients with 103 colorectal lesions (22 non-neoplastic and 81 neoplastic lesions) who Underwent AFE and were treated by using endoscopy or by surgery. Intervention: Recorded digital AFE images were analyzed to quantify autofluoresccnce. The following autofluorescence indexes were calculated: the green/red (G/R) ratio for each lesion, the color-contrast index between each lesion, and the corresponding normal region. Main Outcome Measurements: The G:R ratio, color-contrast index, and histopathologic characteristics for each colorectal lesion. Results: The mean G/R ratio was significantly higher in non-neoplastic lesions (1.17 [95% CI 1.10-1.24], n = 22) than in neoplastic lesions (0.65 [95% CI, 0.63-0.68], n = 81) (P < 001). Mean color-contrast indexes were significantly lower in non-neoplastic lesions (7.99 [95% CI, 6.40-9.58], n = 22) than neoplastic lesions (35.06 [95% CI, 32.79-37-33], n = 81; P < .001). With a cutoff value of 1.01 for the G/R ratio and 13.94 for color-contrast index, AFE had a sensitivity and specificity of 98.8% and 86.4% respectively, for G/R ratio, and 98.8% and 90.9%, respectively, for color contrast index, in differentiating neoplastic from non-neoplastic colorectal lesions. Limitations: Retrospective design. Conclusions: The quantification of digital AFE images obtained from the novel high-resolution videoendoscopy system revealed that autofluorescence was significantly different between non-neoplastic and neoplastic lesions, and color tone in AFE may represent the histopathologic characteristics of the lesion. (Gastroinest Endosc 2009;69:726-33.)