Quantification Of Viscera Lipid Deposition And Functional Assessment Of Kidneys Using MR Imaging For Diabetic Patients

Part 1:Fat Fraction and Diffusion Tractography Imaging of the Kidneys in Patients with Early-Stage Diabetic NephropathyPurpose:To identify differences in renal lipid deposition and molecular water diffusion features between non-diabetic volunteers and type 2 diabetic patients with or without microalbuminuria using three-point Dixon imaging and diffusion tensor imaging(DTI).Materials and Methods:Ethics approval as well as written informed consent from all participants were obtained.Fifty-three diabetic volunteers(normoalbuminuria:n = 32;microalbuminuria:n = 21)and thirty-four healthy volunteers were included in this study from April 2016 to December 2016.All participants received Dixon imaging and DTI using a 3.0-T MR imager.Dixon imaging parameters(renal fat fraction[RFF]and subcutaneous fat fraction[SFF])and DTI parameters(fractional anisotropy[FA]and apparent diffusion coefficient[ADC])were collected.All MRI parameters were compared between the cohorts using one-way ANOVA with Bonferroni post-hoc analysis.Pearson’s linear correlation analysis was used to assess the relationship between DTI parameters and eGFR.Results:The renal lipid percentage in the microalbuminuric group was significantly higher than that of the normoalbuminuric group and the healthy volunteer group(5.8%±1.3%,4.6%±0.7%and 4.3%±0.6%,respectively;P<0.001).However,the subcutaneous fat percentage in the microalbuminuric group was significantly lower than that of the other two groups(81.4%± 5.3%,85.0%±2.6%and 85.8%± 1.8%,respectively;P<0.001).The medullary FA values(r = 0.300 ± 0.06)were lower in the microalbuminuric group than those in the normoalbuminuric group(r = 0.384 ± 0.058,P<0.001)and the control group(r ＝0.426 ± 0.041,P<0.001).The cortical FA and ADC values were lower in microalbuminuric group(FA:r = 0.219 ± 0.04;ADC:[2.393 ± 0.264]× 10-3 mm2/s)than normoalbuminuric group(FA:r = 0.252±0.03,P = 0.009;ADC:[2.568 ± 0.244]× 10-3 mm2/s,P=0.022).The FA values were positively related to eGFR(cortex:r = 0.35,P =0.003;medulla:r = 0.333,P＝0.001),and the values of RFF were negatively correlated with medullary FA values(r =-0.332,P = 0.001).Conclusions:The three-point Dixon and DTI imaging of the renal parenchyma revealed renal lipid accumulation and water molecule diffusion abnormalities in diabetic volunteers.Thus,Dixon imaging and DTI have the potential for evaluating the progression of diabetic nephropathy.Part 2:Quantification of Organs Lipid Deposition with MR imaging in Type 2 DiabetesPurpose:Lipotoxicity plays an important role in the progression of diabetes and its complications,and the gold standards for organs’ lipid quantification are biopsy or histochemical staining,which are invasive and have their own limitations.Thus,our research was to identify the difference in organ lipid deposition between type 2 diabetic patients and healthy volunteers by using noninvasive three-echo T2*corrected Dixon imaging.Materials and Methods:Ethics approval as well as written informed consent from all participants were obtained.53 diabetic patients and 34 healthy volunteers were included in this study from April 2016 to December 2016.All participants underwent three-point Dixon with 3.0-T MR imager.Dixon imaging parameters(hepatic fat fraction[HFF],splenic fat fraction[SFF],pancreatic fat fraction[PFF])were collected.All of the MRI parameters were compared using independent-sample T test.Pearson’s linear correlation analysis was used to assess the relationship between HFF,SFF,PFF and BMI,age.Results:The hepatic and splenic lipid percentage in diabetic group(HFF =[5.04 ± 4.0]%;SFF =[3.7 ± 1.4]%)was significantly higher than healthy volunteers group(HFF =[2.9±1.4]%;SFF=[3.0± 0.9]%;P = 0.004,P = 0.01,respectively).However,we didn’t observe any significant difference in pancreatic fat fraction between diabetic and healthy groups([6.6±2.2]%vs[6.6 ± 2.9]%,P = 0.868).There were positive correlations between HFF,SFF,PFF and BMI(hepar:r = 0.379,P<0.01;spleen:r = 0.305,P<0.01;pancreas:r ＝ 0.306,P<0.01;).Moreover,only the positive correlation between pancreatic fat fraction and age were observed(r = 0.261,P<0.01).Conclusions:The three-point T2*corrected Dixon revealed the abnormalities of hepar and spleen lipid accumulation in diabetic patients.Thus,three-point T2*corrected imaging may potentially aid in evaluating the lipid deposition of abdominal organs.