血氧水平依赖功能MRI及弥散张量成像评估IgA肾病患者肾功能

Blood oxygenation level dependent-functional MRI and diffusion tensor imaging for evaluation on renal function in patients with IgA nephropathy

目的观察血氧水平依赖功能MRI(BLOD-fMRI)及弥散张量成像(DTI)评估IgA肾病(IgAN)患者肾功能的价值。方法对50例经病理证实的IgAN患者(IgAN组)及30名健康志愿者(正常组)采集腹部BLOD-fMRI及DTI。IgAN组分期11例1期,10例2期,11例3期,9例4期,9例5期,分别归入相应亚组。比较正常组与IgAN各亚组间R2及各项异性分数(FA)差异,分析IgAN患者R2及FA与尿素氮的相关性。采用受试者工作特征(ROC)曲线,计算相应曲线下面积(AUC),评价MRI参数诊断IgAN的价值。结果正常组和IgAN组左、右侧肾皮、髓质R2及FA差异均无统计学意义(P均>0.05)。正常组及IgAN组肾髓质R2均明显高于皮质(t=47.87、71.14,P均<0.01)。IgAN各亚组肾皮、髓质R2与正常组总体差异均有统计学意义(F=23.57、20.65,P均<0.01);IgAN患者肾皮、髓质R2与尿素氮均呈正相关(r=0.58、0.59,P均<0.05)。正常组及IgAN组肾髓质FA明显高于皮质(t=56.39、70.84,P均<0.01)。IgAN各亚组肾皮、髓质FA与正常组间总体差异均有统计学意义(F=35.40、49.46,P均<0.01);IgAN患者肾皮、髓质FA与尿素氮均呈负相关(r=-0.66、-0.69,P均<0.05)。肾皮质R2、髓质R2及肾皮质FA、髓质FA诊断IgAN的AUC分别为0.84、0.85、0.82及0.84。结论BLOD-fMRI可监测IgAN患者肾脏血氧状态,DTI可检测其肾脏细微结构改变,二者均对评估IgAN肾功能具有一定临床价值。

Objective To observe the value of blood oxygenation level dependent-functional MRI(BOLD-fMRI)and diffusion tensor imaging(DTI)for evaluation on renal function of immunoglobulin A nephropathy(IgAN)patients.Methods Abdominal BLOD-fMRI and DTI were performed in 50 IgAN patients confirmed by pathology(IgAN group)and 30 healthy volunteers(normal group).There were 11 IgAN patients with stage 1,10 with stage 2,11 with stage 3,9 with stage 4 and 9 cases with stage 5,all were enrolled in corresponding subgroups.The R2 and fractional anisotropy(FA)of normal group and IgAN subgroups were compared,and the correlation of R2 or FA and urea nitrogen of IgAN patients were analyzed.The receiver operating characteristic(ROC)curve was used to explore the value of MRI parameters for diagnosing IgAN,and the areas under the curve(AUC)were calculated.Results No statistical difference of R2 nor FA between left and right renal cortex nor medulla was found in normal group or IgAN group(all P>0.05).The medullary R2 of normal group and IgAN group were both higher than those of cortex(t=47.87,71.14,both P<0.01).R2 of renal cortex and medulla in normal group and IgAN subgroups were statistically different(F=23.57,20.65,both P<0.01).Both the cortical and medullary R2 of IgAN were positively correlated with urea nitrogen(r=0.58,0.59,both P<0.05).The medullary FA of normal group and IgAN group were both higher than those of cortex(t=56.39,70.84,both P<0.01).The renal cortical and medullary FA of normal group and IgAN subgroups were statistically different(F=35.40,49.46,both P<0.01).Both the cortical and medullary FA of IgAN were negatively correlated with urea nitrogen(r=-0.66,-0.69,both P<0.05).The AUC of renal cortical R2,medullary R2,cortical FA and medullary FA in differential diagnosis of IgAN was 0.84,0.85,0.82 and 0.84,respectively.Conclusion BLOD-fMRI could be used to monitor the renal blood oxygen status of IgAN patients,while DTI could detect changes of renal fine structure in IgAN.Both of them had certain clinical value in evaluating renal function of IgAN patients.