肾脏皮髓质分界与年龄相关性的无对比剂增强观察

Investigation of renal corticomedullary differentiation with age-related change on non-contrastenhanced

目的研究无对比剂增强稳态自由进动磁共振成像与选择性反转恢复成像技术在肾皮髓质分界和肾皮质厚度与年龄关系研究中的应用价值。方法2014年8月—2015年6月中国医科大学附属第一医院招募76名健康志愿者，分为21—40岁、41～60岁、61～80岁3个年龄组。使用3．0T磁共振扫描仪，对76名健康志愿者采用不同的反转恢复时间（TI）1000、1100、1200、1300、1400、1500、1600、1700ms进行无对比剂增强稳态自由进动磁共振成像。观察肾皮髓质的分界，测量肾皮质及。肾髓质信号强度，计算肾皮髓质信号强度比（CMC），此外对肾皮质厚度及肾脏大小进行测量。结果76名受检者均成功完成所有序列磁共振扫描，左右共152个有效。肾脏。肾皮髓质分界均能清晰显示，最佳，11与年龄负相关（r=-0．65，P〈0．01），且肾皮髓质对比度与年龄同样呈负相关（r=-0．35，P〈0．01）；平均肾皮质厚度为（5．33±0．71）mm，组间差异有统计学意义（F=104．23，P〈0．01），且与年龄负相关（r=-0．79，P〈0．01），男女间及左右肾之间肾皮质厚度差异均无统计学意义（均P〉0．05）。结论稳态自由进动磁共振成像在应用选择性反转恢复成像技术的条件下能够清晰的显示肾皮髓质分界，随着年龄的增加最佳TI降低，同时能够真实准确对肾皮质厚度进行测量。

Objective To evaluate the relationship between renal cortieomedullary differentiation, renal cortical thickness and age-related changes with non-contrast-enhanced steady-state free precession （SSFP） magnetic resonance imaging （MRI） and spatially selective inversion recovery（IR） pulse technology as well as its applied value . Methods A total of 76 healthy volunteers had been recruited from August 2014 to June 2015 in First Hospital of China Medical University. All volunteers were divided into three groups： 2 -40 years old, 41 -60 years old, 61 -80 years old. All 76 volunteers underwent non-contrast- enhanced steady-state free precession（SSFP） 3.0 T MRI scan using variable inversion times （TIs） （TI = 1 000,1 100,1 200,1 300,1 400,1 500,1 600,1 700 ms）. The renal cortieomedullary differentiation was observed and the signal intensity of renal cortex and medulla were measured respectively as well in order to calculate renal corticomedullary contrast ratio. Besides, renal cortical thickness and renal size were measured. Results All 76 volunteers were successfully performed all the sequences of MRI scan, including 152 useful imaging of kidney in total. The renal corticomedullary differentiation was clearly shown in all subjects. There was negative correlation between the optimal inversion time （TI） and age （ r = - 0. 65, P 〈 0. 01 ）. Similarly, negative correlation was observed between renal corticomedullary contrast ratio and age （r = -0. 35 ,P 〈0. 01 ）. The mean renal cortical thickness of all subjects was （5.33 ±0. 71 ）mm and there were statistically significant difference among those different groups ,which was negative-related with age（ r = -0. 79,P〈 0. 01 ）. There was no statistically significant difference between sexuality and renal cortical thickness. Additionally,renal cortical thickness had no statistically significant difference in both sides of kidneys. Conclusion The renal corticomedullary differentiation is depicted clearly by means of noncontrast-enhanced steady-state free precession MRI with spatially selective inversion recovery pulse technology. The optimal inversion time decreases along with the increase of age. In the meanwhile, the renal cortical thickness could be measured truthfully and accurately.