肾脏缺氧的血氧水平依赖性磁共振成像评估

目的：探讨3.0T血氧水平依赖性磁共振成像（blood oxygenation level-dependent MRI，BOLD-MRI）最大TE时间的选择在慢性肾病（chronic kidney disease，CKD）患者肾脏氧合状态评估中的价值。方法对44例CKD病例和13例健康志愿者，在3.0T磁共振扫描仪上，分别在6个回波链及12个回波链条件下采用多梯度重聚回波序列进行BOLD-MRI图像采集，在R2^＊图像上测得双肾皮髓质的R2^＊值，进行统计学分析。结果肾脏髓质的R2^＊值明显高于皮质（P〈0.01）；6个回波链和12个回波链条件下，左右两肾的皮质和髓质R2^＊值差异无统计学意义；不同回波链条件下重复测得的双肾皮质及髓质R2^＊值有一致性（ρc=0.983，P=0.000）；CKD组的双肾髓质R2^＊均值明显高于正常对照组（P〈0.01），且随肾功能临床分期的增加而增大。结论3.0T BOLD-MRI检查采用6个回波链即可满足肾脏R2^＊值的测量，且能够反映CKD肾脏的缺氧状态，为肾脏氧合状态的评估提供一种无创的影像学手段。

Objective To investigate the optimal maximum TE for 3.0T blood oxygenation level-dependent MRI（BOLD-MRI）in assessing renal oxygenation of chronic kidney disease（CKD）. Methods 13 healthy volunteers and 44 patients were enrolled into analysis,and they accepted the BOLD MRI examination on a GE 3.0T Signa HDx scanner. Multi gradient recalled echo with the echo train length of 6 and 12 was used for BOLD-MRI. All images were reviewed by two experienced residents together. The R2^＊values of renal cortex and medulla with the different maximum TE were measured on the R2^＊images using the analysis of histogram, and statistical analysis was conducted. Results The R2^＊of renal medulla was remarkably higher than that of renal cortex. There was a significant difference between the R2^＊of renal cortex and medulla（P〈0.01）,while there was no significant difference between the R2^＊of renal cortex with two maximum TE（P〉0.05）. Besides,there was a high concordance between repetitive measured R2^＊by 3.0T BOLD-MRI with two maximum TE（ρc=0.983,P=0.000）. The average R2^＊of renal medulla of both sides in the normal was significantly higher than that in CKD（P〈0.01）. Moreover,the average R2^＊of renal medulla increased with the clinical stage of CKD,and there was a statistical difference among different stages of CKD（P〈0.05）. Conclusion 3.0T BOLD-MRI with the echo train length of 6 is adequate for the renal R2^＊measurement and can detect the hypoxia of CKD,which have potential advantages in the evaluation of renal oxygenation as a noninvasive modality.