Gd-DTPA增强动态核磁共振诊断输尿管不全梗阻的实验研究

Gd-DTPA enhanced dynamic MRI in evaluation of the partially obstructed kidneys: An experimental study in rats

目的 探讨Gd DTPA增强动态磁共振成像 (MRI)诊断输尿管不全梗阻的意义。方法 将新生鼠输尿管交界处埋于腰大肌中制成输尿管不全梗阻模型 (n =10 )。 1年后用Gd DTPA增强动态MRI检查梗阻组和对照组 (n =12 )鼠的肾脏 ,并对不同时间记录的肾脏影像进行分析 ,计算出肾皮质、髓质和肾盂的相对信号强度。结果 使用Gd DTPA后 ,对照组肾皮质、髓质和肾盂信号强度相继减弱 ,3 0～ 60min后基本恢复。梗阻肾脏的变化明显较对照组慢 ,60min后仍未恢复。结论 Gd DTPA增强动态MRI可用于诊断输尿管不全梗阻并提供肾功能变化信息。

Objective To evaluate the dynamic changes in relative signal intensity (RSI) in normal and partially obstructed kidneys in rats by Gd DTPA enhanced dynamic MRI.Methods Twenty two 1 year old rats with partial unilateral ureteral obstruction (PUUO, n =10),and sham operated non obstructed kidneys ( n =12) were studied using Gd-DTPA enhanced dynamic MRI.PUUO was created in 1 or 2 day old rats by embedding the left ureter into the psoas muscle. MRI was performed previously at different time intervals ( 0.1 to 60?min ) after intravenous injection of Gd DTPA. The RSI changes in renal cortex,medulla and pelvis were plotted against time.Results The dynamic patterns of RSI between normal and partially obstructed kidneys differed significantly.In sham operated rats, a fast parenchymal uptake of Gd DTPA immediately after injection of Gd DTPA produced a rapid RSI decrease in the cortex. Thereafter,a RSI decrease in medulla and pelvis reached a minimum of 18% of pre GD DTPA injection. Finally,7 min after injection Gd TDPA,a significant RSI recovery was seen starting from the cortex to medulla and pelvis.Complete recovery was observed at 60?min. In partially obstructed kidneys,not only did the above events occur significantly slower than the controls,and the cortex,medulla and pelvis were also clearly shown to be different from those of the controls.Conclusions Gd DTPA enhanced dynamic MRI provide not only renal morphological but also functional information which can be used to differentiate a partially obstructed from a non obstructed kidney.