血氧水平依赖磁共振成像评估早期慢性肾病肾缺氧的研究

Study on blood oxygen level-dependent magnetic resonance imaging for the assessment of early renal hypoxia in chronic kidney disease

目的:探讨肾脏血氧水平依赖(blood oxygen level-dependent,BOLD)磁共振成像(magnetic resonance imaging,MRI)评估慢性肾病(chronic kidney disease,CKD)早期肾缺氧的价值。方法 :52例CKD患者(CKD组)和年龄、性别匹配的52名健康体检者(对照组)接受冠状面BOLD-MRI检查,分别测量肾脏皮、髓质R2*值。同时检测CKD患者的血清肌酐水平,运用Cockcroft-Gault公式计算获得估算肾小球滤过率,按照美国肾脏病基金会公布的肾脏病生存质量指导指南将CKD患者分为1~5期。比较对照组与CKD组、各CKD分期亚组间的肾脏皮质、髓质R2*值间的差异。结果:CKD组及对照组肾脏的髓质R2*值明显高于皮质R2*值(P<0.05)。CKD组[(16.40±2.47)/s]及CKD 1期组[(16.55±2.12)/s]、CKD 4期组[(16.48±2.95)/s]、CKD 5期组[(13.99±2.21)/s]的肾髓质R2*值均低于对照组[(18.17±2.38)/s](P<0.05)。结论:肾脏BOLD-MRI检查可发现CKD 1期患者肾髓质R2*值的下降变化,提示BOLD成像对慢性肾病早期肾髓质缺氧变化敏感,可用于CKD早期肾功能损害的诊断。

Objective:To evaluate value of blood oxygen level-dependent(BOLD) magnetic resonance imaging(MRI) for early renal hypoxia assessment in chronic kidney disease(CKD).Methods:Fifty-two patients with CKD and 52age-and sex-matched health volunteers underwent BOLD MRI of the kidneys.Serum creatinine(sCr) levels and estimated GFR(eGFR) were collected.The patients were classified into 5 stages according to the National Kidney Foundation′ s Kidney Disease Outcomes Quality Initiative.Difference in R2*s were compared between patients and volunteers and among different stages of CKD.Results:In patients with CKD and volunteers,R2* of renal medulla was higher than that of renal cortex(P<0.05).Compared with those of volunteers,medulla R2*s in patients with CKD were significantly lower[(16.40 ± 2.47)/s vs(18.17± 2.38)/s,P<0.05].There were no differences in cortical R2*s among CKD stages and volunteers(P>0.05).However,medullar R2*s were lower in patients with CKD1 [(16.55 ± 2.12)/s],CKD4 [(16.48 ± 2.95)/s],or CKD5 [(13.99 ± 2.21)/s] than those in volunteers [(18.17± 2.38)/s](P<0.05).Conclusions:BOLD MRI is sensitive to renal medullary hypoxia,and which is helpful for diagnosing early stage of CKD.