3.0TBOLDMR技术对大鼠急性单侧输尿管梗阻肾损害的研究

目的探讨3.0T血氧水平依赖功能MRI（fMRI-BOLD）技术对急性单侧输尿管梗阻大鼠肾血氧水平改变的评估。材料与方法 16只健康SD大鼠,其中3只死亡出组,13只入组大鼠分别在结扎单侧输尿管前、结扎后1h及解除结扎后1h进行常规MR轴位T2WI及冠状位BOLD扫描。观察T2WI像上不同组别间双肾皮髓质信号及解剖结构改变,分别进行信噪比对比分析;在ADW4.4工作站进行BOLD图像重建,测量三次扫描双肾皮髓质R2＊值,分别进行R2＊值的对比分析。根据患侧肾盂扩张率不同,将其分为重度梗阻与轻度梗阻,并将其与R2＊变化率进行对比分析;根据解除组患侧肾盂恢复率不同,将其分为缓解组与未缓解组,并分析其与梗阻程度及R2＊变化率的关系。结果 T2WI像上梗阻前大鼠双肾皮质、髓质信噪比分别一致,双肾解剖结构清晰显示;梗阻后大鼠患侧肾实质信噪比均较梗阻前明显增高,皮、髓质分界欠清,肾盂均有不同程度扩张;解除组患侧肾实质信噪比高于梗阻前组,低于梗阻后组,皮髓质分界清晰,肾盂扩张不同程度恢复,健侧肾较梗阻前均未见明显变化。梗阻前组大鼠左、右肾髓质R2＊值均高于相应肾皮质;左肾与右肾皮质、髓质R2＊值无统计学差异。梗阻后组患肾髓质R2＊值低于梗阻前组髓质R2＊值,患侧肾皮质R2＊值与梗阻前组无差异;健侧肾皮质R2＊值略低于梗阻前组,髓质R2＊值略高于梗阻前组。解除组患肾髓质R2＊值低于梗阻前组,高于梗阻后组,患侧皮质R2＊值与梗阻前、后组皮质R2＊值无统计学差异;解除组健侧肾皮质R2＊值略低于梗阻后组,髓质R2＊值略高于梗阻后组。轻度梗阻R2＊变化率低于重度梗阻。缓解组的梗阻程度及R2＊变化率均低于未缓解组。结论 3.0TfMRI-BOLD技术通过测量R2＊值能反映肾脏皮、髓质在正常情况下及急性单侧输尿管梗阻时氧代谢的变化。

BOLD MRI of rat kidney changes during acute unilateral ureteral obstruction at 3.0 T

Objective： To evaluate the renal oxygenation changes during acute unilateral ureteral obstruction in rats using blood oxygen level-dependent MR imaging （BOLD MRI） in 3.0 T MR. Materials and Methods： Sixteen healthy SD rats, 3 rats died because of anesthesia, 13 rats were performed kidney T2WI and coronal BOLD imaging respectively before UUO, 1 hour after UUO and 1 hour after release of UUO. Observed the signal and anatomical structure changes among the different groups of renal cortex and medulla, compared the SNR of renal parenchyma among three groups. BOLD images were reconstructed on 4.4 workstation, R2＊ values were determined in the cortex and medulla of the obstructed and the contralateral nonobstructed kidneys, then comparative analysis of R2＊values of renal cortex and medulla among different groups. Compared with the rate of R2＊ values changes between the mild obstruction and severe obstruction; Analyze the relationship of relief group and no relief group with obstructions and R2＊ changes. Results： The SNR between left and right renal were the same, and renal anatomy was showed clearly before UUO. After UUO the SNR of 13 rats affected side renal was significantly higher than before, the boundaries of cortex and medulla show blurry, and the pelviectasis in varying degrees. After release of UUO, the SNR higher than the obstruction former group, lower than the obstruction group, the boundaries got clearly, and the renal pelvis recovery in varying degrees. Before UUO, the R2＊ values of medulla was significantly higher than that of renal cortex, but during the UUO was associated with a decreased R2＊ in medulla, and after release of obstruction the medulla R2＊ were increased slowly. The R2＊ showed no statistical difference in the cortex and nonobstructed kidneys among three groups. The rates of R2＊ change in mild obstruction slightly less than in severe obstruction. The obstruction and the R2＊ changes in relief group were lower than those in no relief group. Conclusions： 3.0 T BOLD MRI provides a useful tool in UUO which is associated with altered renal oxygen consumption.