From the Department of Radiology and Diagnostic Imaging, University of Alberta, 2B2.41 WMC, 8440-112 St NW, Edmonton, AB, Canada T6G 2B7 (M.P.W., D.P., P.K., G.L.); Evidence-based Practice Center, Mayo Clinic, Rochester, Minn (M.H.M.); and Departments of Radiology and Epidemiology, University of Ottawa/The Ottawa Hospital Research Institute, Ottawa, Canada (M.D.F.M.).
Radiology. 2020 Sep;296(3):511-520. doi: 10.1148/radiol.2020192070. Epub 2020 Jun 30.
Background Lipid-poor angiomyolipomas (AMLs) are challenging to differentiate from other renal lesions at imaging and often necessitate biopsy or surgery. If sufficiently accurate, MRI may play a role as a replacement test for biopsy. Purpose To perform a systematic review to evaluate the diagnostic performance of MRI for lipid-poor AMLs in patients with renal masses. Materials and Methods A systematic review of MEDLINE, EMBASE, Scopus, the Cochrane Library, and the "gray literature" (conference proceedings) was performed without language restriction through July 18, 2019, with the assistance of a health sciences librarian. Original articles with more than 10 patients evaluating the diagnostic performance of MRI, with histopathologic findings used as the reference standard, for the diagnosis of lipid-poor AMLs in patients with renal masses were included. Studies including AMLs with macroscopic fat and studies with insufficient data were excluded. Patient, clinical, MRI, and diagnostic performance parameters were independently acquired by two authors. Meta-analysis was performed by using a random-effects or bivariate mixed-effects regression model depending on the number of studies. Risk of bias of individual studies was evaluated by using Quality Assessment of Diagnostic Accuracy Studies-2. Results Twenty-three studies with 2196 patients and 25 contingency tables were included. The pooled sensitivity, specificity, and area under the receiver operating characteristic curve were 83% (95% confidence interval [CI]: 72%, 90%), 90% (95% CI: 84%, 94%), and 0.93 (95% CI: 0.91, 0.95), respectively. Considerable variability was present for several variables, including MRI parameters; however, subgroup analysis did not identify MRI sequence or field strength as sources for variability. All studies were at high risk of bias for index test domain because no reported thresholds were prespecified. Conclusion MRI shows promising accuracy for detecting lipid-poor angiomyolipomas (area under the receiver operating characteristic curve, >0.9), indicating a potential role as a replacement test for biopsy in selected patients. Studies evaluating MRI accuracy with a pragmatic algorithm and prespecified threshold may be helpful to confirm this potential role in the management pathway. © RSNA, 2020
背景 脂质乏脂肪性血管平滑肌脂肪瘤（AML）在影像学上与其他肾脏病变难以区分，通常需要进行活检或手术。如果 MRI 足够准确，它可能可以替代活检作为一种替代检查。目的 进行系统评价，以评估 MRI 对肾脏肿块患者脂质乏脂肪性 AML 的诊断性能。
材料与方法 对 MEDLINE、EMBASE、Scopus、Cochrane 图书馆和“灰色文献”（会议记录）进行了系统评价，检索时间截至 2019 年 7 月 18 日，检索过程中得到了一位健康科学图书馆员的帮助。检索纳入了超过 10 例患者的原始研究，这些研究评估了 MRI 的诊断性能，使用组织病理学发现作为参考标准，用于诊断肾脏肿块患者的脂质乏脂肪性 AML。纳入的研究包括有肉眼脂肪的 AML 研究和数据不足的研究。两位作者独立采集患者、临床、MRI 和诊断性能参数。根据研究数量，采用随机效应或双变量混合效应回归模型进行荟萃分析。采用诊断准确性研究质量评估-2 评估单个研究的偏倚风险。
结果 共纳入 23 项研究，共 2196 例患者，有 25 个四格表。汇总后的敏感度、特异度和受试者工作特征曲线下面积分别为 83%（95%置信区间：72%，90%）、90%（95%置信区间：84%，94%）和 0.93（95%置信区间：0.91，0.95）。多个变量存在较大的变异性，包括 MRI 参数；但是，亚组分析未发现 MRI 序列或场强是变异性的来源。由于没有报告预设的阈值，所有研究在索引测试域都存在较高的偏倚风险。
结论 MRI 对检测脂质乏脂肪性血管平滑肌脂肪瘤（受试者工作特征曲线下面积>0.9）具有较高的准确性，表明它在某些患者中可能可以替代活检作为一种替代检查。评估 MRI 准确性的前瞻性研究和预设阈值可能有助于确认 MRI 在管理路径中的这一潜在作用。
