Dixon-MRI和BOLD-MRI对成年男性代谢综合征早期肾损伤的定量对比研究

Quantitative comparative study of Dixon-MRI and BOLD-MRI on early renal injury in adult male with metabolic syndrome

目的比较Dixon-MRI和血氧水平依赖磁共振成像(blood oxygenation level-dependent magnetic resonance imaging,BOLD-MRI)定量参数对成年男性代谢综合征(metabolic syndrome,MetS)早期肾损伤的诊断价值。材料与方法前瞻性纳入42例成年男性志愿者,年龄(33.88±8.30)岁,行肾脏Dixon-MRI和BOLD-MRI检查,记录身高、体质量、腰围、臀围及血压等基本信息,测定血清学指标、计算肾小球滤过率(estimate glomerular filtration rate,eGFR)。根据是否存在MetS,分为MetS组(24例)和非MetS组(18例)。测量肾脏皮质、髓质的脂肪分数(fat fraction,FF)和表观自旋-自旋弛豫率(apparent relaxation rate,R2^(*)),分析组间差异,探讨肾脏脂肪分数(fat fraction,FF)、R2^(*)、eGFR、血清肌酐(serum creatinine,Scr)及胰岛素抵抗指数(homeostasis model assessment 2-IR,HOMA2-IR)间的相关性以及比较Dixon-MRI和BOLD-MRI定量指标在轻度肾损伤中的诊断效能。结果MetS组肾脏皮质FF值(4.21%±0.79%)显著高于非MetS组(2.51%±0.75%),P<0.001;MetS组肾髓质R2^(*)值(27.02±1.38 s-1)显著低于非MetS组(31.29±1.17 s-1),P=0.008,但两组间肾髓质FF值和皮质R2^(*)值差异无统计学意义(P>0.05)。校正年龄后,两组间肾皮质FF值及髓质R2^(*)值仍具有统计学意义(P值分别为<0.001及0.035)。校正年龄后,肾脏皮质FF值与eGFR呈负相关(r=-0.37,P=0.017),与Scr、HOMA2-IR呈正相关(r=0.39,P=0.012;r=0.34,P=0.026),肾脏髓质R2^(*)值与eGFR、Scr无相关性(r=-0.25,P=0.119;r=0.27,P=0.086)。肾皮质FF鉴别肾功能正常和轻度肾功能损伤的曲线下面积(area under the cure,AUC)、敏感度和特异度分别为82.7%、85.7%和71.4%。髓质R2^(*)鉴别肾功能正常和轻度肾功能损伤的AUC、敏感度和特异度分别为74.2%、50.0%和89.3%。结论Dixon-MRI和BOLD-MRI均可无创定量检测MetS相关潜在或早期肾损伤,但是肾皮质FF或许更具有评估MetS相关潜在或早期肾损伤的潜力。

Objective:To compare the diagnostic value of Dixon-MRI and blood oxygenation level-dependent magnetic resonance imaging(BOLD-MRI)in the early renal injury of adult males with metabolic syndrome.Materials and Methods:Forty-two adult male volunteers(age 33.88±8.30)were enrolled prospectively.Renal Dixon-MRI and BOLD-MRI examinations were performed in all patients.The height,weight,waist circumference,hip circumference,and blood pressure were recorded.Serological indicators were determined and the glomerular filtration rate(eGFR)was calculated.According to the presence of metabolic syndrome(MetS),patients were divided into MetS group(n=24)and non-MetS group(n=18).The fat fraction(FF)and apparent relaxation rate(R2^(*))of renal cortex and medulla were measured,and the differences between groups were compared.The correlations between FF,R2^(*),eGFR,serum creatinine(Scr)and homeostasis model assessment 2-IR(HOMA2-IR)were further analyzed.Then compared the diagnostic efficacy of Dixon-MRI and BOLD-MRI in mild renal injury.Results:The fat fraction(FF)values of renal cortex in MetS group were significantly higher than that in non-MetS group,P<0.001.The R2^(*)values of the renal medulla in the MetS group(27.02±1.38 s-1)were significantly lower than that in the non-MetS group(31.29±1.17 s-1),P=0.008,but there were no statistically significant differences in FF values of renal medulla and R2^(*)values of cortex between the two groups(P>0.05).After adjusting for age,the FF values of renal cortex and the R2^(*)values of medulla were still statistically significant between two groups(P<0.001 and 0.035,respectively),while the FF values of renal cortex were negatively correlated with eGFR(r=-0.37,P=0.017),and positively correlated with Scr and HOMA2-IR(r=0.39,P=0.012;r=0.34,P=0.026),while the R2^(*)values of renal medulla were not correlated with eGFR and Scr(r=-0.25,P=0.119;r=0.27,P=0.086).The area under the curve(AUC),sensitivity,and specificity of cortical FF in differentiating normal renal function from mild renal function injury were 82.7%,85.7%,and 71.4%,respectively.The AUC,sensitivity,and specificity of medullary R2^(*)in differentiating normal renal function from mild renal function injury were 74.2%,50.0%,and 89.3%,respectively.Conclusions:Dixon-MRI and BOLD-MRI can noninvasively and quantitatively detect MetS-related potential or early renal injury,but Dixon-MRI has more potential to evaluate Mets-related potential or early renal injury than BOLD-MRI.