摘要目的:探讨MR减影图像在提高2019版Bosniak Ⅱ、ⅡF及Ⅲ类肾脏囊性病变（CRMs）观察者间评估的一致性中的价值。方法:回顾性连续收集2009年1月至2020年8月解放军总医院第一医学中心有手术病理结果和术前完整MRI序列图像（T 2WI、T 1WI预扫图像以及皮髓质期、实质期及排泄期增强MRI图像）的CRMs患者323例（335个CRMs）。由2名资深泌尿生殖方向影像学医师共同根据2019版Bosniak分类标准对CRMs进行分类，选取Bosniak Ⅱ、ⅡF及Ⅲ类病变。采用美国GE ADW 4.4工作站中的“Subtraction”功能对皮髓质期、实质期及排泄期增强图像进行减影重建。由另外2名影像学医师根据2019版Bosniak分类标准，分别在有和无MR减影图像的情况下对上述病变进行独立评估，2次评估间隔1个月。利用加权Kappa系数对上述评估结果进行一致性分析，并采用Gwet一致性系数对加权Kappa系数的差异进行比较。 结果:研究纳入Bosniak Ⅱ、ⅡF及Ⅲ类CRMs患者187例（187个CRMs）。在无和有减影图像的情况下，2名医师对Bosniak Ⅱ、ⅡF及Ⅲ类病灶的分类结果中一致者119、141例，不一致者68、46例；一致性加权Kappa系数分别为0.60（95%CI 0.53~0.68）、0.73（95%CI 0.66~0.80），有减影图像的观察者间一致性高于无减影图像的观察者间一致性，差异有统计学意义（ t=-2.56， P=0.011）。 结论:基于MRI的2019版Bosniak分类标准，MR减影图像可提高Bosniak Ⅱ、ⅡF及Ⅲ类CRMs观察者间一致性，有助于提高该分类系统的临床应用价值。

abstractsObjective:To investigate the value of MR subtraction images in improving the interobserver agreement for Bosniak Ⅱ, ⅡF, and Ⅲ cystic renal masses (CRMs) with Bosniak classification version 2019.Methods:From January 2009 to August 2020, 323 patients (335 CRMs) with surgical pathology results and complete preoperative MRI examination (T 2WI, T 1WI precontrast images and enhanced MRI in corticomedullary, nephrographic, and excretory phases) were retrospectively collected in the First Medical Center of PLA General Hospital. The CRMs of Bosniak Ⅱ, ⅡF, and Ⅲ were selected and classified by 2 experienced genitourinary radiologists according to the Bosniak classification version 2019. The "Subtraction" function in the American GE ADW 4.4 workstation was used to perform subtraction images reconstruction on the enhanced images in the corticomedullary, nephrographic, and excretory phases. Blinded to pathologic information, the other 2 radiologists independently classified the enrolled CRM cases with and without subtraction MR images, respectively, with an interval of 1 month. Ultimately, by using weighted Kappa value, interobserver agreement was evaluated, and the differences in weighted Kappa value were compared using the Gwet coefficient. Results:A total of 187 patients with 187 CRMs were enrolled in the study. The results of the classification of Bosniak Ⅱ, ⅡF, and Ⅲ CRMs categorized by 2 radiologists without and with subtraction images showed that 119 and 141 cases were consistent, and 68 and 46 were inconsistent, respectively. The weighted Kappa value for interobserver agreement among two radiologists without and with subtraction MR images was 0.60 (95%CI 0.53-0.68) and 0.73 (95%CI 0.66-0.80), respectively. The interobserver agreement was higher with subtraction images than that without subtraction images ( t=-2.56, P=0.011). Conclusion:According to the MRI criteria of Bosniak classification version 2019, the interobserver agreement for Bosniak Ⅱ, ⅡF, and Ⅲ CRMs could be improved using subtraction MR images, which may facilitate the popularization and application of Bosniak classification version 2019.