论文部分内容阅读
目的:探讨磁敏感加权成像（SWI）定量评估糖尿病（DM）肾脏铁负荷的价值。方法:将32只健康新西兰大白兔随机分为DM组（n n=20）和对照（NC）组（n n=12）。经耳缘静脉注射5%四氧嘧啶溶液（100 ml/kg）建立DM模型，最终入组12只，NC组按同样方法注射同等剂量生理盐水。DM组和NC组经肌内注射60 mg/kg右旋糖酐铁。分别于注射铁剂后立即（0周）和饲养12周后行左肾MRI扫描，12周扫描结束后处死取左肾行HE、普鲁士蓝染色及原子吸收分光光度计检查。以原子吸收分光光度计测量的铁含量结果为金标准，评价SWI定量评估肾脏铁含量的价值。在SWI相位图上沿肾皮质走行区手动绘制感兴趣区，将所测相位值换算成角弧度值。采用Mann-Whitney U检验比较两组的血糖值及在0周、12周的角弧度值差异；采用独立样本n t检验比较两组的铁含量差异；采用非参数Wilcoxon符号秩检验分别比较DM组0周和12周、NC组0周和12周的角弧度值差异；采用Spearman相关分析研究角弧度值与原子吸收分光光度计结果的相关性。n 结果:DM组血糖值［28.0（10.6）mmol/L］明显高于NC组［6.5（1.9）mmol/L］，两组比较差异有统计学意义（U=0，n P0.05）；12周时，DM组角弧度值［0.22（0.17）］高于NC组［0.17（0.05）］，差异有统计学意义（U=35.50，n P<0.05）。DM组和NC组在12周的角弧度值均高于0周的角弧度值，且差异均有统计学意义（n P<0.05）。普鲁士蓝染色提示铁主要沉积于肾皮质，DM组蓝染较NC组明显。DM组12周时SWI图像上肾皮质信号较0周明显减低，NC组稍减低。DM组和NC组铁含量分别为（171.39±20.13）、（116.21±28.90）mg/kg，两组比较差异有统计学意义（n t=5.428，n P<0.001）。Spearman相关分析显示角弧度值与铁含量呈正相关（n r=0.67，n P<0.001）。n 结论:DM肾脏铁沉积较正常肾脏多。SWI作为一种无创的、简单方便的检查技术，有定量评估DM肾脏铁负荷的潜力。“,”Objective:To explore the value of susceptibility-weighted imaging (SWI) in quantitative evaluation of iron load in diabetic kidneys.Methods:Thirty two healthy New Zealand white rabbits were randomly divided into diabetic group (DM, n n = 20) and control group (NC, n n = 12). DM model was established by injecting 5% alloxan solution (100 ml/kg) through ear vein. 12 rats were finally enrolled into the group. NC group was injected with the same dose of normal saline. DM group and NC group were intramuscularly injected with 60 mg/kg iron dextran. The left kidney was scanned by MRI immediately after iron injection (0 weeks) and 12 weeks after feeding. The left kidney was killed after 12 weeks of scanning. The left kidney was examined by Prussian blue staining and atomic absorption spectrophotometer. The value of SWI in quantitative evaluation of renal iron content was evaluated by using the iron content measured by atomic absorption spectrophotometer as the gold standard. On SWI phase diagram, the region of interest (ROI) was manually drawn along the renal cortical vagal area, and the measured phase values were converted into angular radians. Mann Whitney U test was used to compare the blood glucose value and the angle radian value at 0 week and 12 week between the two groups; independent sample n t test was used to compare the difference of iron content between the two groups; nonparametric Wilcoxon signed rank test was used to compare the difference of angle radian between DM group and NC group at 0 and 12 weeks; Spearman correlation analysis was used to study the correlation between angle radian value and atomic absorption spectrophotometer results.n Results:The blood glucose level in DM group [28.0 (10.6) mmol/L] was significantly higher than that in NC Group [6.5 (1.9) mmol/L], and the difference was statistically significant (U = 0,n P0.05); at 12 weeks, the angle radian value of DM group [0.22 (0.17)] was higher than that of NC Group [0.17 (0.05)], the difference was statistically significant (U=35.50,n P<0.05). The angle radian of DM group and NC group at 12 weeks were higher than that of 0 weeks, and the differences were statistically significant (n P<0.05). Prussian blue staining showed that iron was mainly deposited in renal cortex, and the blue staining in DM group was more obvious than that in NC group. The signal intensity of renal cortex on SWI images in DM group was significantly lower than that in 0 week group at 12 weeks, and slightly decreased in NC group. The iron content of DM group and NC group were (171.39±20.13) mg/kg and (116.21±28.90) mg/kg, respectively, and the difference was statistically significant (n t=5.428, n P<0.001). Spearman correlation analysis showed that the angle radian was positively correlated with iron content (n r=0.67, n P<0.001).n Conclusions:Diabetic kidneys have more iron deposits than normal kidneys. As a non-invasive, simple and convenient examination technique, SWI has the potential to quantitatively evaluate the iron load of diabetic kidneys.