Efficacy of a novel auto-fluorescence imaging system with computer-assisted color analysis for assessment of colorectal lesions.
OBJECTIVE
To evaluate the efficacy of computer-assisted color analysis of colorectal lesions using a novel auto-fluorescence imaging (AFI) system to distinguish neoplastic lesions from non-neoplastic lesions and to predict the depth of invasion.


METHODS
From January 2013 to April 2013, consecutive patients with known polyps greater than 5 mm in size who were scheduled to undergo endoscopic treatment at The Jikei University Hospital were prospectively recruited for this study. All lesions were evaluated using a novel AFI system, and color-tone sampling was performed in a region of interest determined from narrow band imaging or from chromoendoscopy findings without magnification. The green/red (G/R) ratio for each lesion on the AFI images was calculated automatically using a computer-assisted color analysis system that permits real-time color analysis during endoscopic procedures.


RESULTS
A total of 88 patients with 163 lesions were enrolled in this study. There were significant differences in the G/R ratios of hyperplastic polyps (non-neoplastic lesions), adenoma/intramucosal cancer/submucosal (SM) superficial cancer, and SM deep cancer (P < 0.0001). The mean ± SD G/R ratios were 0.984 ± 0.118 in hyperplastic polyps and 0.827 ± 0.081 in neoplastic lesions. The G/R ratios of hyperplastic polyps were significantly higher than those of neoplastic lesions (P < 0.001). When a G/R ratio cut-off value of > 0.89 was applied to determine non-neoplastic lesions, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 83.9%, 82.6%, 53.1%, 95.6% and 82.8%, respectively. For neoplastic lesions, the mean G/R ratio was 0.834 ± 0.080 in adenoma/intramucosal cancer/SM superficial cancer and 0.746 ± 0.045 in SM deep cancer. The G/R ratio of adenoma/intramucosal cancer/SM superficial cancer was significantly higher than that of SM deep cancer (P < 0.01). When a G/R ratio cut-off value of < 0.77 was applied to distinguish SM deep cancers, the sensitivity, specificity, PPV, NPV, and accuracy were 80.0%, 84.4%, 29.6%, 98.1% and 84.1%, respectively.


CONCLUSIONS
The novel AFI system with color analysis was effective in distinguishing non-neoplastic lesions from neoplastic lesions and might allow determination of the depth of invasion.
Hiroko Inomata, Naoto Tamai, Hiroyuki Aihara, Kazuki Sumiyama, Shoichi Saito, Tomohiro Kato, Hisao Tajiri, Department of Endoscopy, The Jikei University School of Medicine, Tokyo 105-8461, Japan.
Hiroko
H
Inomata
Naoto
N
Tamai
Hiroyuki
H
Aihara
Kazuki
K
Sumiyama
Shoichi
S
Saito
Tomohiro
T
Kato
Hisao
H
Tajiri
D000236:Adenoma / Q000473:pathology*; D000368:Aged; D000704:Analysis of Variance; D019540:Area Under Curve; D003111:Colonic Polyps / Q000473:pathology*; D003113:Colonoscopy / Q000379:methods*; D003116:Color; D015179:Colorectal Neoplasms / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006965:Hyperplasia; D007090:Image Interpretation, Computer-Assisted; D007564:Japan; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D061848:Optical Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve
Autofluorescence imaging; Colon; Colonoscopy; Computer-aided diagnosis; Neoplasia