Accuracy of i-Scan for Optical Diagnosis of Colonic Polyps: A Meta-Analysis

<div><p>Background</p><p>i-Scan is a novel virtual chromoendoscopy system designed to enhance surface and vascular patterns to improve optical diagnostic performance. Numerous prospective studies have been done to evaluate the accuracy of i-Scan in differentiating colonic neoplasms from non-neoplasms. i-Scan could be an effective endoscopic technique for optical diagnosis of colonic polyps.</p><p>Objective</p><p>Our aim of this study was to perform a meta-analysis of published data to establish the diagnostic accuracy of i-Scan for optical diagnosis of colonic polyps.</p><p>Methods</p><p>We searched PubMed, Medline, Elsevier ScienceDirect and Cochrane Library databases. We used a bivariate meta-analysis following a random effects model to summarize the data and plotted hierarchical summary receiver-operating characteristic (HSROC) curves. The area under the HSROC curve (AUC) serves as an indicator of the diagnostic accuracy.</p><p>Results</p><p>The meta-analysis included a total of 925 patients and 2312 polyps. For the overall studies, the area under the HSROC curve was 0.96. The summary sensitivity was 90.4% (95%CI 85%-94.1%) and specificity was 90.9% (95%CI 84.3%-94.9%). In 11 studies predicting polyps histology in real-time, the summary sensitivity and specificity was 91.5% (95%CI 85.7%-95.1%) and 92.1% (95%CI 84.5%-96.1%), respectively, with the AUC of 0.97. For three different diagnostic criteria (Kudo, NICE, others), the sensitivity was 86.3%, 93.0%, 85.0%, respectively and specificity was 84.8%, 94.4%, 91.8%, respectively.</p><p>Conclusions</p><p>Endoscopic diagnosis with i-Scan has accurate optical diagnostic performance to differentiate neoplastic from non-neoplastic polyps with an area under the HSROC curve exceeding 0.90. Both the sensitivity and specificity for diagnosing colonic polyps are over 90%.</p></div

Hierarchical summary receiver-operating characteristic (HSROC) curve for the diagnostic performance of i-Scan.

<p>The size of the blue circles indicates the number of polyps in the individual studies. The summary sensitivity and specificity is shown with a dark red square and the 95% confidence region is plotted in short lines. The area under the HSROC curve (AUC) was 0.96 (95%CI 0.94–0.97).</p

Study characteristics.

<p>* These two studies were identified from one literature.</p><p>** These two studies were identified from one literature.</p><p>⁺ This study did not describe their diagnostic criteria in detail.</p><p>N.A.C., a previously described classification system developed on the base of characterization of colonic polyps using FICE; ICE-classification, i-Scan classification for endoscopic diagnosis which is a simple classification built upon Kudo classification and NICE classification; NICE, Narrow Band Imaging International Colorectal Endoscopic Classification; N, not mentioned.</p><p>Study characteristics.</p

Flow diagram of study selection for the meta-analysis.

<p>* Finally, 13 studies were identified from the 10 articles and 1 abstract.</p

Deeks’ funnel plot to evaluate publication bias.

<p>The vertical axis displays the inverse of the square root of the effective sample size (1/root(ESS)). The horizontal axis displays the diagnostic odds ratio (DOR). P = 0.533 indicates a symmetrical funnel shape and suggests that publication bias is absent.</p

Hierarchical summary receiver-operating characteristic (HSROC) curve for the diagnostic performance of i-Scan to predict colonic polyps histology in real-time.

<p>The size of the blue circles indicates the number of polyps in the individual studies. The summary sensitivity and specificity is shown with a dark red square and the 95% confidence region is plotted in short lines. The AUC was 0.97 (95%CI 0.95–0.98).</p