Evaluation Of Early Renal Function In Type 2 Diabetes Mellitus Patients By Diffusion Tensor Imaging And Blood Oxygen Level Dependent Imaging

Objective:To evaluate the abnormal diffusion and oxygenation level of the kidney in early diabetic kidney disease patients with diffusion tensor imaging(DTI)and blood oxygen level dependent(BOLD)imaging,and to evaluate the renal function damage.Materials and methods:From June 2018 to November 2019,22 patients with type 2 diabetes mellitus in the Affiliated Hospital of North Sichuan Medical College were collected.According to whether there was microalbumin in urine,they were divided into two groups:diabetes mellitus group without nephropathy(diabetes mellitus,DM group=15)and early diabetic kidney disease group(diabetic kidney disease,DKD group=7).At the same time,13 normal volunteers were recruited as the control group.All the subjects in the three groups were scanned by conventional MRI?DTI and BOLD.Both DTI and BOLD parameters were measured,including DTI parameters:fractional anisotropy(FA),apparent diffusion coefficient(ADC)and BOLD parameter:apparent spin-spin relaxation ratio(R2*)value.The three groups were compared and analyzed within and between groups,and the correlation between the above parameters and eGFR was analyzed.The area under ROC curve of each parameter was analyzed to judge the diagnostic efficiency of DKD group and DM group.Results:1.ADC value of renal cortex in normal volunteers,DM group and DKD group(normal volunteers:2.154±0.134,DM group:2.126±0.091,DKD group:2.167 ± 0.170)were higher than that in medulla(normal volunteers:1.914± 0.148,DM group:1.925± 0.087,DKD group:1.960 ±0.124)(P<0.001);There was no significant difference in ADC value of cortex and medulla among the three groups(cortex:F=0.312,P=0.734;medulla:F=0.343,P=0.712).FA value of renal cortex(normal volunteers:0.128±0.010,DM group:0.125± 0.004,DKD group:0.123 ± 0.003)were lower than that of medulla(normal volunteers:0.303± 0.035,DM group:0.265±0.040,DKD group:0.220± 0.053)(P<0.001).The FA value of renal medulla in DKD group was lower than that in DM group and normal volunteers group,and that in DM group was lower than that in normal volunteers group(F=9.472,P<0.05).There was no significant difference in FA of the renal cortex(F=1.114,P=0.341)among the three groups.R2*value of renal cortex(normal volunteers:15.761±0.811,DM group:16.608±1.156,DKD group:17.661±0.547)were lower than that of medulla(normal volunteers:28.864 ± 2.573,DM group:33.671±1.216,DKD group:31.459±1.405)(P<0.001).The R2*value of renal cortex in DKD group was higher than that in DM group and normal volunteers group,and that in DM group was higher than that in normal volunteers group(F=9.422,P<0.05);the R2*value of renal medulla in three groups(F=22.989,P<0.001)was statistically significant,and DM group was the highest,followed by DKD group and normal volunteers group.2.In DKD group,FA value of renal cortex was positively correlated with eGFR(r=0.829,P=0.021);in DM group,R2*value of renal medulla was negatively correlated with eGFR(r=-0.524,P=0.045).The value of R2*in renal cortex has a good diagnostic effect,with AUC of 0.810,cut-off value of 15.542,sensitivity and specificity of 0.857 and 0.667,respectively.Conclusions:Diffusion tensor imaging and blood oxygen level dependent imaging can reflect the changes of renal diffusion and oxygenation in patients with early diabetic kidney disease,and can be used to evaluate the renal function damage in patients with early diabetic kidney disease.