Yang Jing, Yang Shuohui, Xu Yizeng, Lu Fang, You Lan, He Zheng, Zhan Songhua, Ye Chaoyang, Liu Mengxiao, Fu Caixia, Wang Chen
Department of Nephrology, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China,
TCM Institute of Kidney Disease, Shanghai University of Traditional Chinese Medicine, Shanghai, China,
Nephron. 2021;145(6):653-663. doi: 10.1159/000516637. Epub 2021 Jun 28.
The basic pathophysiologic derangement of chronic kidney disease (CKD) begins with the loss of nephrons, leading to renal hemodynamic changes, eventually causing a reduced nephron count and renal hypoxia. The purpose of this study was to observe the renal oxygenation and renal hemodynamics of patients with CKD using blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) and intrarenal Doppler ultrasonography (IDU).
The study enrolled 39 patients with stage 1-4 CKD and 19 healthy volunteers (HVs). Based on their estimated glomerular filtration rate (eGFR), CKD patients were divided into 2 subgroups: a mild renal impairment (MI) group and a moderate to severe renal impairment (MSI) group. We monitored the participants' mean cortical T2* (COT2*) and mean medullary T2* (MET2*) values on BOLD-MRI, and measured the peak systolic velocities (PSVs), end-diastolic velocities (EDVs), renal resistive index (RI), and kidney length by IDU. We also recorded clinical indicators such as age, sex, body mass index (BMI), 24-h urinary protein (24-h Upr), serum creatinine (sCr), blood urea nitrogen (BUN), and eGFR. BOLD-MRI, IDU measurements, and the clinical indicators were compared in CKD patients and HVs by the analysis of variance and Kruskal-Wallis H test. Spearman's correlation was used to assess the relationship between data from BOLD-MRI and IDU and clinical indicators.
The COT2* values were significantly higher than the MET2* values in the HV, MI, and MSI groups. COT2*, MET2*, EDV, PSV, and kidney length gradually decreased in the HV, MI, and MSI groups (all p < 0.05), whereas RI and 24-h Upr gradually increased (both p < 0.05). Spearman correlation analysis showed that COT2* and MET2* were significantly positively correlated with eGFR, PSV, EDV, and kidney length but were significantly negatively correlated with sCr, BUN, and 24-h Upr (all p < 0.05). There was no correlation observed between the COT2* and MET2* and the RI and BMI values.
Renal oxygenation and blood flow velocities were found declined as the CKD stage progressed. The BOLD-MRI and IDU techniques may have clinical value by measuring intrarenal oxygenation and renal blood perfusion to judge the severity of renal damage in patients with CKD.
慢性肾脏病（CKD）的基本病理生理紊乱始于肾单位的丧失，导致肾血流动力学改变，最终导致肾单位数量减少和肾缺氧。本研究的目的是使用血氧水平依赖（BOLD）磁共振成像（MRI）和肾内多普勒超声（IDU）观察CKD患者的肾氧合和肾血流动力学。
本研究纳入了39例1-4期CKD患者和19名健康志愿者（HV）。根据估计的肾小球滤过率（eGFR），将CKD患者分为2个亚组：轻度肾功能损害（MI）组和中度至重度肾功能损害（MSI）组。我们在BOLD-MRI上监测参与者的平均皮质T2*（COT2*）和平均髓质T2*（MET2*）值，并通过IDU测量收缩期峰值流速（PSV）、舒张末期流速（EDV）、肾阻力指数（RI）和肾脏长度。我们还记录了年龄、性别、体重指数（BMI）、24小时尿蛋白（24-h Upr）、血清肌酐（sCr）、血尿素氮（BUN）和eGFR等临床指标。通过方差分析和Kruskal-Wallis H检验比较CKD患者和HV的BOLD-MRI、IDU测量值和临床指标。采用Spearman相关性分析评估BOLD-MRI和IDU数据与临床指标之间的关系。
HV、MI和MSI组的COT2值均显著高于MET2值。HV、MI和MSI组的COT2*、MET2*、EDV、PSV和肾脏长度逐渐降低（均p<0.05），而RI和24-h Upr逐渐升高（均p<0.05）。Spearman相关性分析显示，COT2和MET2与eGFR、PSV、EDV和肾脏长度显著正相关，但与sCr、BUN和24-h Upr显著负相关（均p<0.05）。未观察到COT2和MET2与RI和BMI值之间的相关性。
随着CKD分期的进展，肾氧合和血流速度下降。BOLD-MRI和IDU技术通过测量肾内氧合和肾血流灌注来判断CKD患者肾损伤的严重程度，可能具有临床价值。
