磁共振扩散张量成像技术评估男性2型糖尿病早期肾损伤的价值

Usefulness of Diffusion Tensor MRI to Identify Early Stage Kidney Disease in Male Subjects with Type 2 Diabetes Mellitus

目的探讨肾脏扩散张量成像(diffusion tensor imaging,DTI)评估男性糖尿病患者早期肾脏损伤的临床应用价值,分析成像参数与估算肾小球滤过率(estimated glomerular filtration rate,e GFR)和微量白蛋白尿的相关性。方法纳入27例慢性肾脏病(chronic kidney disease,CKD) 1期和2期的男性2型糖尿病患者和14名男性健康志愿者。使用3. 0 T临床磁共振仪进行肾脏DTI成像,分别计算肾皮、髓质感兴趣区的平均扩散系数(apparent diffusion coefficient,ADC)和各向异性分数(fractional anisotropy,FA),分析这两个DTI参数和估算肾小球滤过率e GFR和尿微量白蛋白的相关性。结果不同组间肾皮髓质FA值均差异有统计学意义。CKD 1期[e GFR≥90ml/(min·1. 73m2)]和CKD 2期组患者[e GFR 60～90ml/(min·1. 73m2)]较健康对照组皮髓质的FA值均显著减低(皮质FA,χ2=12. 037,P=0. 002;髓质FA,F=9. 078,P=0. 001)。CKD 2期患者髓质FA显著低于1期。糖尿病患者的皮髓质FA值与e GFR呈正相关,皮质FA值与尿α1微球蛋白肌酐比值(α1-microglobulin/creatinine ratio,UA1MCR)呈负相关。1期患者肾皮质和髓质ADC值有升高趋势,但差异无统计学意义(P> 0. 05)。结论肾DTI有助于评估男性糖尿病患者的早期肾功能损伤。

Objective To evaluate the clinical feasibility of diffusion tensor image(DTI)in early CKD stage male type 2 diabetic patients,correlating DTI parameters with estimated glomerular filtration rate and microalbuminuria.Methods Twenty-seven male diabetic patients and fourteen healthy volunteers were enrolled.DTI was examined on a clinical 3T scanner.The apparent diffusion coefficient(ADC)and fractional anisotropy(FA)values were calculated from the region-of-interest(ROI)of the renal cortex and medulla.The correlation between DTI-parameters,estimated glomerular filtration rate(eGFR)and urinary microalbumin were evaluated.Results Significant differences of the FA values measured in the renal cortex and medulla were found among groups.FA was significantly reduced in the CKD stage 1 group[eGFR≥90ml/(min·1.73m^2)]and stage 2 group[eGFR 60-90ml/(min·1.73m^2)]of the cortex and medulla compared with the control group(cortical FA,χ2=12.037,P=0.002;medullary FA,F=9.078,P=0.001).In stage 2 group,only medullary FA was significantly lower than in the stage 1 group.FA values of the renal cortex and medulla positively correlate with eGFR.The FA values of cortex negatively correlate with UA1MCR in the diabetic group.The ADC values of renal cortex and medulla in the stage 1 have an increasing tendency,but a statistically significant difference was not achieved.Conclusion Renal DTI is a promising method of assessing early renal function changes of male diabetic patients.