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 autofluorescence. 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.