Objective DCE-MRI can be used to assess tissue and tumor vascular properties and is a rapidly evolving and noninvasive MRI technique. Although DCE is recommended by the European Society of Urogenital Radiology (ESUR) as a valuable functional technique in prostate cancer (PCa) detection [1], the accuracy of this method has seldom been systematically reviewed. Therefore, we performed a systematic review and meta-analysis of this technique to examine its diagnostic accuracy in the context of PCa. Methods Systematic electronic searched were conducted in database. We used patient-based and biopsy-based pooled weighted estimates of the sensitivity, specificity, and a summary receiver operating characteristic (SROC) curve for assessing the diagnostic performance of DCE. We performed direct and indirect comparisons of DCE and other methods of imaging. A total of 26 articles met the inclusion criteria for the analysis. Results Figure 1 provides an overview of the literature search and study selection. The results of the QUADAS-2 assessment are presented in Figure 2A-B. All included studies fulfilled the 7 criteria of the QUADAS-2 regarding methodological quality. Figure 3A shows the sensitivity and specificity of the individual studies, pooled estimates and SROC curve. Figure 3B shows the sensitivity and specificity of the individual studies, pooled estimates and SROC curve. DWI appeared to have a statistically higher pooled sensitivity (P<0.001); the pooled estimates for sensitivity and specificity were 0.43 (95% CI 0.36 to 0.51) and 0.90 (95% CI 0.84 to 0.94) for DCE and 0.54 (95% CI 0.42 to 0.67) and 0.89 (95% CI 0.83 to 0.92) for DWI. When we included four studies of the peripheral zone involving 325 patients that reported DCE compared with DWI, DWI appeared to have a statistically higher pooled sensitivity (P=0.0498). The pooled estimates for sensitivity and specificity were 0.56 (95% CI 0.35 to 0.74) and 0.82 (95% CI 0.69 to 0.91) for DCE and 0.67(95% CI 0.45 to 0.84) and 0.81(95% CI 0.57 to 0.93) for DWI. Figure4 A-C shows the sensitivity and specificity of the individual studies, pooled estimates and SROC plot with the 95% confidence region. Discussion In this study, it was showed that the specificity values for detection PCa on both whole gland and PZ were approximately 0.88, indicating that DCE-MRI can distinguish between normal tissues from PCa. Biger et al. demonstrated that PCa was associated with an approximately two-fold increase in the total number of vessels seen on histologic sections[2]. Based on the findings from Biger et al., Engelbrecht et al. reported that PCa showed more pronounced enhancement resulting in higher signal on DCE-MRI than surrounding normal prostate tissues [3]. Therefore, DCE-MRI shows its ability in the localizing of PCa. Moreover, it has high accuracy in detecting cancer recurrence who have undergone radical prostatectomy [4] or post-radiotherapy patients [5]. Meanwhile, our direct comparison study showed that the specificity of DCE was statistically superior to T2WI ( 0.89 vs 0.73, p<0.0001). However, the sensitivity value of DCE-MRI for locating PCa was relatively low on the whole gland (0.55) and PZ (0.70), suggesting that DCE-MRI had difficulty in distinguishing between malignant tumors and benign lesions. Agha et al. reported that some benign prostatic lesions, such as benign prostatic hyperplasia (BPH), may show enhancement pattern of nearby criteria to the PCa enhancement curves, and some unavoidable technical errors, such as rectal motions, may distort the relatively long timed dynamic sequences[6]. Although Tofts et al.[7] standardized acquisition parameters of quantitative analysis, there is also a problem of the rate constants overlapping between benign and malignant tissues [8]. Meanwhile, our direct comparison reflected that the sensitivity values of DCE were statistically lower on whole gland and relatively lower on PZ than the values from DWI. This could be explained at least in part by different approaches to evaluate DCE-MRI in a qualitative or quantitative way. However, Iwazawa et al. suggested that the prostate lesions were also missed when detection was attempted by DWI alone. Thus, excluding DCE from routine prostate MRI incurs a risk of failure in the detection of PCa, especially for lesions in the PZ [9]. Conclusions Our meta-analysis demonstrates that although DCE-MRI can provide informative supplementary diagnostic accuracy to detect PCa, it remains a confirmatory tool. As new quantitative techniques are developed to enhance the standards of optimal scans, DCE-MRI may attain important clinical status.

Acknowledgements

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References

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