[Accuracy of CT colonography for the detection of colorectal neoplasm: a subgroup Meta-analysis]

Objective: To assess the accuracy of computed tomographic colonography (CTC) for detection of colorectal neoplasm. Methods: Publications prior to January 2016 from the Medline, Embase, CNKI, WANFANG, and VIP literature databases were systematically reviewed. A QUADAS checklist was used to assess the quality of the studies. According to the sizes of tumor (≥6 mm or ≥10 mm), diagnostic test accuracy indexes (area under the curve, sensitivity and specific) were pooled and stratified. Spearman correlation and curve of summary receiver operating characteristic (SROC) were applied to comprehensively assess the threshold effect. A bi-variate mixed-effects model was used for testing the overall merging value and heterogeneity. Results: A total of 19 articles (n=11 540) were included in the analysis. A total of 18 studies were from Europe and Unite States, with 1 from Asia. Numbers of studies regarding information on general population, high-risk groups and clinical symptoms were 9, 5 and 5, respectively. In 19 articles, data on the accuracy of CTC diagnosis (≥6 mm group) was recorded, with another 17 on the group ≥10 mm. Area under the SROC curve in the ≥6 mm group was 0.92 (95% CI: 0.92-0.94). It was estimated that the pooled sensitivity and specificity were 0.80 (95% CI: 0.73-0.86) and 0.89 (95% CI: 0.86-0.92) respectively. In area under the SROC curve, the pooled sensitivity and specificity in ≥10 mm group were 0.87(95%CI:0.80-0.92), 0.97(95%CI:0.95-0.98), respectively. Results from the subgroup showed that the sensitivity of with or without the fecal tagging groups were 0.84 and 0.67 in the ≥6 mm group, 0.92 and 0.76 in the ≥10 mm group. It was also found that in the experienced or less experienced readers, rates of sensitivity were 0.83 and 0.75 in the ≥6 mm group, 0.91 and 0.79 in the ≥10 mm group. Conclusions: CTC had high diagnostic efficiency for colorectal neoplasm, especially in the ≥10 mm group. Fecal tagging and experience of the reasers can improve the diagnostic sensitivity.