| Objective: This study investigates the value of non-invasive assessment of early renal impairment and staging in patients with type 2 diabetes mellitus(T2MD)using functional magnetic resonance intravoxel uncorrelated motion(IVIM),diffusion kurtosis imaging(DKI),and diffusion tensor imaging(DTI)techniques.Methods: Forty-six patients diagnosed with T2 DM from September 2020 to June2022 in the Department of Endocrinology,Affiliated Hospital of Yunnan University were selected,and the patients were divided into diabetic without nephropathy group(DM group,n=13),early diabetic nephropathy group(early DKD group,n=20)and mid-late diabetic nephropathy group(mid-late DKD group,n=13)based on estimated glomerular filtration rate(Estimated glomerular filtration rate,eGFR)results,while 33 sex-and age-matched cases with normal eGFR were recruited as healthy controls.A Philips Ingenia 3.0T MRI scanner with an 8-channel abdominal coil was used to acquire conventional MRI,IVIM,DKI,and DTI images of the abdomen in all subjects.The true diffusion coefficient(D),false diffusion coefficient(D*),perfusion fraction(f),mean diffusion kurtosis(MK),mean diffusivity(MD),anisotropy fraction(FA),and apparent diffusion coefficient(ADC)were measured in the cortex and medulla of both kidneys of the subjects,respectively.One-way ANOVA and rank sum test were used to compare the differences in clinical data between the four groups.The intra-group correlation coefficient(ICC)was used to compare the consistency of the measured renal IVIM,DKI,and DTI values;the paired-samples t-test was used to compare the differences in each of the bilateral renal IVIM,DKI,and DTI values,and each of the ipsilateral renal cortical and medullary values;The one-way ANOVA and the Bonferroni test(chi-square)or LSD-t test(chi-square)were selected to compare the differences in the values of each renal parameter between the four groups.Pearson correlation and Spearman correlation analysis were used to compare the correlation between renal IVIM,DKI,and DTI values and biochemical parameters.Binary logistic regression and ROC curves were used to analyse the diagnostic value of IVIM,DKI,and DTI values alone and their combined application on early renal impairment and staging in patients with T2DM;p< 0.05 was considered a statistically significant difference.Results:(1)There were no statistically significant differences in gender,age,BMI,waist-to-hip ratio,systolic blood pressure(SBP),diastolic blood pressure(DBP),triglycerides(TG),total cholesterol(TC),high-density lipoprotein cholesterol(HDL-C),and low-density lipoprotein cholesterol(LDL-C)among the four groups of subjects(all P > 0.05).Compared with the control group,fasting blood glucose(FPG)and blood urea nitrogen(BUN)were significantly higher in the DM group,early and mid-late DKD groups,with statistically significant differences(P < 0.001);compared with the DM group,glycosylated hemoglobin(Hb A1c)and eGFR(P < 0.001)were gradually decreased in the early and mid-late DKD group,and ACR,urinary globulin(IGU),urinary albumin(UAlb),urinary α1 microglobulin(A1M),and urinary transferrin(TRF)were significantly higher,and the difference was statistically significant(P < 0.001);compared with the DM group,ACR,A1 M,and TRF were differentially higher in the early DKD group,and the difference between groups was statistically significant(P < 0.05);compared with the NC group,UAlb,A1 M,and TRF were significantly higher in the early and mid-late DKD groups.A1 M and TRF were significantly higher in the early and mid-late DKD groups compared with the NC group,and the difference between the groups was statistically significant(P <0.001).(2)The values of each IVIM,DKI,and DTI parameter measured by the two physicians in the renal cortex and medulla were well reproducible.(3)There was no statistically significant difference in the values of IVIM,DKI,and DTI parameters between the left and right kidneys(all P > 0.05).(4)The differences between the paired tests of renal cortical and medullary IVIM,DKI,and DTI parameter values were statistically significant(all P < 0.05),The values of D,f,MD and ADC in the renal cortical were higher than in the medullary,MK and FA in the renal cortical were lower than in the medullary in all four groups,D* in the renal medullary were higher than in the cortical in the control,early and mid-late DKD groups,D* in the renal cortical were higher than in the medullary in the DM group,and the differences were not statistically significant(P > 0.05).(5)IVIM: Renal medullary D values showed a low positive correlation with eGFR(r=0.339,P<0.01)and a low negative correlation with IGU,UALB,and A1M(IGU: r=-0.336,P<0.01;UALB: r=-0.328,P<0.01;A1M: r=-0.317,P<0.01);cortical D* values showed a low negative correlation with SCr,IGU,UALB,and TRF showed a low negative correlation(SCr: r=-0.396,P<0.001;IGU: r=-0.300,P<0.01;UALB:r=-0.338,P<0.001;TRF: r=-0.311,P<0.01);cortical f values showed a low positive correlation with TRF(r=-0.303,P<0.01),medullary f showed a low positive correlation with eGFR(r=0.308,P<0.01)and a low negative correlation with ACR(r=-0.301,P<0.01).DKI: Renal cortical and medullary MK values showed a low negative correlation with eGFR(C-MK: r=-0.318,P<0.01;M-MK: r=-0.419,P<0.01);medullary MK values showed a low positive correlation with ACR,UALB,and A1M(ACR: r=0.337,P<0.01;UALB: r=0.303,P<0.01;A1M: r=0.334,P<0.01).There was no significant correlation between cortical and medullary MD values and eGFR.DTI: Renal medullary ADC values showed a low positive correlation with eGFR(r=0.372,P<0.001)and a low negative correlation with A1M(r=-0.304,P<0.05);cortical and medullary FA values did not correlate significantly with eGFR.(6)To differentiate the control group from the early DKD group,the medullary MD values had higher diagnostic efficacy in single parameter values,the combination of DTI(parameter values FA,ADC)parameter values had higher diagnostic efficacy in the combined diagnosis,and the combination of DKI and DTI parameter values had higher diagnostic efficacy in the combination of the two.Cortical f-values,and IVIM(parameter values D,D*,f)parameter values discriminated the DM group from the early DKD group.The combination of IVIM and DKI parameter values had higher diagnostic efficacy in differentiating the DM group from the early DKD group.The combination of medullary MK values,DKI(parameter values MD,MK)and DKI with DTI parameter values had higher diagnostic efficacy in differentiating the early from the middle and late DKD groups.Conclusions:1.IVIM,DKI and DTI sequences can dynamically reflect the changes of renal function at different stages according to the changes of renal injury in T2 DM patients,providing diagnostic imaging basis for dynamic monitoring of the disease.2.The DKI sequence has a good evaluation of DKD,and the cortical MK value can detect early renal function changes in T2 DM patients,which is more sensitive than eGFR.3.The diagnostic efficacy of the combination of IVIM,DKI,and DTI sequences is greater than that of a single sequence.The optimal parameter values and combination sequences for distinguishing renal injury in T2 DM patients at different stages are different,and can be flexibly selected based on the patient’s situation and clinical needs.It also provides an evaluation of renal function changes in T2 DM patients from multiple perspectives. |
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