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

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

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

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

Flow diagram of study selection for the meta-analysis.

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

Overexpressed miRNAs in TB sputum.

<p>Column “Name” contained the name of miRNA; Column “TB patients versus control” contained level ratio of TB/control; Column “Chromosome” meant distribution of each miRNA on chromosome.</p><p>Each miRNA spot was replicated for four times on the same slide and two microarray chips were used for each group. After normalization, obtained average values for each miRNA spot were used for statistics. The <i>P</i> values for these miRNAs were less than 0.05 in TB group compared with controls.</p

Hierarchical clustering of miRNA in sputum samples.

<p>Samples were clustered according to the signature profile of 97 differentially expressed miRNAs. Data from each miRNA were median centered. Samples were in columns and miRNAs in rows. Red and green indicated high relative level and low relative level, respectively. The <i>P</i> values for these miRNAs were less than 0.05 in TB group compared with controls.</p

Characteristics of participants.

<p>All patients had clinical signs and symptoms of active pulmonary TB; comprising, 79.3% cough, 72.4% fever, 67.2% weight loss, 55.2% night sweats, and 46.6% hemoptysis. Healthy controls involved in the study, were free of active TB infection, latent TB infection and any clinical symptoms of any infectious disease. Both TB patients and healthy controls were non-smokers.</p

Confirmation miRNA level by RT-qPCR.

<p>RT-qPCR analysis confirmed microarray data. After normalization to U6 RNA, data were presented as mean ± SD (n = 30) and obtained average value for each miRNA was used for statistics. MiR-19b-2* was underexpressed while miR-3179 and miR-147 were overexpressed in TB sputum compared with controls. The experiment was conducted in triplicate. ^#<i>P</i><0.05 versus control.</p