探讨声辐射力脉冲弹性成像（ARFI）技术检测剪切波速度（SWV）鉴别诊断中老年急性肾损伤（AKI）与慢性肾病（CKD）患者的应用价值。

选择2015年2月至2016年12月中日友好医院及浙江省人民医院收治的中老年肾病患者64例（肾病组）。其中CKD患者43例（CKD组），AKI患者21例（AKI组，合并CKD15例，不合并CKD6例）。选择同期中日友好医院29名体检健康的中老年志愿者（健康对照组）。采用ARFI技术测量所有受检者肾脏中部SWV值。采用方差分析比较健康对照组受检者、AKI组、CKD组患者肾脏长径、肾皮质厚度、肾皮质SWV值，进一步组间两两比较采用LSD-t检验。采用方差分析比较健康对照组受检者、不合并及合并CKD的AKI组、CKD组患者肾皮质SWV值，进一步组间两两比较采用LSD-t检验。绘制ARFI技术诊断肾病的操作者工作特性（ROC）曲线。

健康对照组受试者、AKI组、CKD组患者SWV值分别为 （2.88±0.63）、（2.42±0.83）、（2.06±0.72）m/s。AKI组、CKD组患者SWV值均小于健康对照组，且差异均有统计学意义（t=2.158，P=0.033；t=5.234，P<0.001）；CKD组患者SWV值小于AKI组患者，但两者差异无统计学意义。不合并及合并CKD的AKI组患者SWV值分别为（2.60±0.84）、（1.80±0.45）m/s。合并CKD的AKI组患者及CKD组患者SWV值均低于健康对照组受试者及不合并CKD的AKI组患者，且差异均有统计学意义（与健康对照组比较，t=2.916、P=0.004，t=5.318、P<0.001；与不合并CKD的AKI组比较，t=2.054、P=0.043，t=-2.517、P=0.013），但合并CKD的AKI组与CKD组患者、不合并CKD的AKI组患者与健康对照组SWV值差异均无统计学意义。ROC曲线显示，以肾皮质SWV值2.40 m/s作为诊断肾病的阈值，曲线下面积为0.767（95% CI 0.689~0.898，P=0.000），敏感度及特异度分别为57.1%及81.9%。

中老年CKD及AKI患者SWV值明显小于健康志愿者。合并CKD的AKI患者SWV值较不合并CKD的AKI患者低。ARFI技术在诊断中老年肾病患者中具有较好的临床应用价值。

To investigate the efficacy of the shear wave velocity (SWV) based on acoustic radiation force impulse (ARFI) elastography in the differentiation of normal population with chronic kidney disease (CKD) and acute kidney injury (AKI) in middle aged and elderly patients.

Sixty-four middle aged and elderly patients referred to China-Japan Friendship Hospital and Zhejiang Provincial People′s Hospital with AKI or CKD were enrolled in this study from February 2015 to December 2016 (kidney disease group). Among them, 43 patients were CKD (CKD group), and 21 patients were AKI (AKI group, 15 patients combined with prior CKD, 6 patients without prior CKD). Twenty-nine middle aged and elderly healthy volunteers from China-Japan Friendship Hospital were enrolled at the same time (healthy control group). The SWV values of the renal middle pole cortex were acquired using the ARFI elastography. The differences of the kidney length, cortical thickness and SWV values among healthy control group, AKI and CKD group were compared by variance analysis. The LSD-t analysis was used for the advanced comparison between any two groups. The differences of cortical SWV values among healthy control group, AKI combined with prior CKD group, AKI without prior CKD group and CKD group were compared by variance analysis. The LSD-t analysis was used for the advanced comparison between any two groups. The receiver operating characteristic (ROC) curves of the cortical SWV values for diagnosing kidney disease was drawn.

The mean cortical SWV values of healthy control group, AKI and CKD groups were (2.88±0.63), (2.42±0.83) and (2.06±0.72) m/s, respectively. The SWV values of AKI and CKD groups were significantly lower than that of healthy control group (t=2.158, P=0.033; t=5.234, P<0.001). The SWV values of CKD group were lower than that of AKI group, but there were no significant differences. The SWV values of AKI without previous CKD group and AKI combined with prior CKD group were (2.60±0.84) and (1.80±0.45) m/s, respectively. The SWV values of AKI combined with prior CKD group and CKD group were significant lower than that of healthy control group and AKI without prior CKD group (compared with healthy control group: t=2.916, P=0.004 and t=5.318, P<0.001; compared with AKI without prior CKD group: t=2.054, P=0.043 and t=-2.517, P=0.013). But there were no significant differences between AKI combined with prior CKD group and CKD group, so as to the AKI without prior CKD group and healthy control group. The cutoff value of cortical SWV for diagnosing kidney disease was 2.40 m/s, with an area under ROC curve was 0.767 (95% CI 0.689-0.898, P=0.000). The sensitive and specificity were 57.1% and 81.9%, respectively.

The SWV values of kidneys in middle aged and elderly CKD and AKI patients were significantly lower than those of apparently normal kidneys. The SWV values of AKI patients combined with prior CKD were lower than AKI patients without prior CKD. Determining cut-off SWV values based on ARFI elastography between normal and damaged renal parenchyma can help in the diagnosis of kidney disease in middle aged and elderly patients.