2 Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
3 Department of Radiology, Namwon Medical Center, Jeollabuk-do, Korea.
AJR Am J Roentgenol. 2017 Dec;209(6):W374-W381. doi: 10.2214/AJR.17.18283. Epub 2017 Oct 12.
The purpose of our study was to review the diagnostic performance of DWI for differentiating high- from low-grade clear cell renal cell carcinoma (RCC).
MEDLINE, EMBASE, and Cochrane library databases were searched up to March 15, 2017. We included diagnostic accuracy studies that used DWI for differentiating high- from low-grade clear cell RCC compared with histopathologic results of Fuhrman grade based on nephrectomy or biopsy specimens in original research articles. Two independent reviewers assessed methodologic quality using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Sensitivity and specificity of the included studies were pooled and graphically presented using a hierarchic summary ROC plot. For heterogeneity exploration, we assessed the presence of a threshold effect and performed meta-regression analyses.
Eight retrospective studies (394 patients with 397 clear cell RCCs) were included. Pooled sensitivity was 0.78 (95% CI, 0.68-0.85) with a specificity of 0.86 (95% CI, 0.70-0.94). A considerable threshold effect was observed with a correlation coefficient of 0.811 (95% CI, 0.248-0.964) between the sensitivity and false-positive rate. At meta-regression analysis, apparent diffusion coefficient (× 10 mm/s) cutoff value (< 1.57 vs ≥ 1.57; p = 0.03) and location of ROI (solid portion vs whole tumor; p = 0.04) were significant factors affecting heterogeneity. Other factors with regard to patients and tumors, study, and MRI characteristics were not significant (p = 0.17-0.91).
DWI shows moderate diagnostic performance for differentiating high-from low-grade clear cell RCC. Substantial heterogeneity was observed because of a threshold effect. Further prospective studies may be needed; all included studies were retrospective.
本研究旨在回顾 DWI 对高低级别透明细胞肾细胞癌（RCC）的诊断性能。
截至 2017 年 3 月 15 日，我们检索了 MEDLINE、EMBASE 和 Cochrane 图书馆数据库。我们纳入了使用 DWI 对高低级别透明细胞 RCC 进行鉴别诊断的诊断准确性研究，这些研究与基于肾切除术或活检标本的 Fuhrman 分级的组织病理学结果进行了比较，原始研究文章中均有报道。两名独立的审查员使用诊断准确性研究的质量评估 2 工具评估了方法学质量。使用层次汇总 ROC 图汇总并图形化呈现了纳入研究的敏感性和特异性。为了探索异质性，我们评估了是否存在阈值效应，并进行了荟萃回归分析。
纳入了 8 项回顾性研究（394 例患者，397 例透明细胞 RCC）。汇总敏感性为 0.78（95%CI，0.68-0.85），特异性为 0.86（95%CI，0.70-0.94）。观察到显著的阈值效应，敏感性与假阳性率之间的相关系数为 0.811（95%CI，0.248-0.964）。在荟萃回归分析中，表观扩散系数（×10mm/s）截断值（<1.57 与≥1.57；p=0.03）和 ROI 位置（实体部分与整个肿瘤；p=0.04）是影响异质性的显著因素。其他与患者和肿瘤、研究和 MRI 特征相关的因素无显著差异（p=0.17-0.91）。
DWI 对高低级别透明细胞 RCC 的鉴别诊断具有中等诊断性能。由于阈值效应，观察到明显的异质性。可能需要进一步的前瞻性研究；所有纳入的研究均为回顾性研究。
