Primary Study Of Chronic Kidney Disease With MR Diffusion Tensor Imaging And Blood Oxygenation-level Dependent Imaging

Objective：All Chronic Kidney Disease(CKD)patients were scanned by renal conventionalMagnetic Resonance Imaging (MRI), Diffusion Tensor Imaging (DTI) and BloodOxygenation Level Dependent（BOLD）Imaging. The renal cortex and medullafractional anisotropy（FA）values,Apparent Diffusion Coefficient（ADC）valuesand R2*values were measured and analysed the relationship with glomerularfiltration rate，so as to explore the applied value of DTI and BOLD in staging ChronicKidney Disease and renal function.Materials and methods:54CKD patients with clinical diagnosis,28males and26females, aged from23to76years (mean±SD,45±15years),and20healthy volunteers11males and9females, aged from24to64years (mean±SD,41±12years), participated in this studyat the Department of Radiology, the second Affiliated Hospital of NanchangUniversity between November2012to September2013. All imaging studies wereperformed on a3.0T GE magnetic resonance system(GE，Signa HDXt) with8channel phased-array coil named TORSO. Conventional MRI was obtained first，andthen the kidney oblique coronal DTI and BOLD scanned. All images wereautomatically imported GE Medical Systems AW4.4workstation with Functoolsoftware for processing and data measurement. A region of interest (ROI) analysis ofb value for0sec/mm2maps was performed to obtain measures of mean cortical andmedullary ADC and FA and R2*values for each subject，by two young specialistswho were blinded to patient’s condition. Slices nearest to the renal hilum of the rightkidneys of each subject were selected for the ROI analysis.The inclusion of thecalyces and renal pelvis of the kidney avoided. One oval ROI wes placed over therenal cortex and medulla ROIs were placed for upper, lower poles and renal hilum.99Tcm-DTPA renal dynamic imaging was use to measure the unilateral glomerularfiltration rate.54patients were divided into four groups: A, B and C groups were on bahalf of stage1,2and3of CKD respectively，and D group was on behalf of stage4and stage5,which were based on kidney disease outcomes quality initiative. Due tothe patients of stage4and stage5relatively small, the patients of the two stage werenamed group D.Results：(1)comparing cortical MR paramerers with medulla;The cortical ADC and R2*values were higher than medulla for both control group and CKD patients (P<0.01),while the cortical FAvalues were lower than medulla (P <0.01).(2)comparsion among control group and the subgroups of CKD patients: forcortical FA values, there was no significant difference in the comparasion of controlgroup with group A, A group with group B, group B with group C, group C withgroup D (P>0.05) and the result of the comparison of other groups is the opposite (P<0.05).For medulla FA values, there was significant difference in the comparasionamong control group and and the subgroups of CKD patients(P<0.05),except forcontrol group with group A. For cortical R2*values, there was no significantdifference in the comparasion of control group with group A, A group with group B,group C with group D (P>0.05), and the result of the comparison of other groups isthe opposite (P <0.05). For medulla R2*values, there was significant difference inthe comparasion among control group and and the subgroups of CKD patients(P<0.05),except for control group with group A.Correlation analysis between MRparamerers and GFR: There were a positive between cortical FA, medullary FA of thepatients and GFR (r=0.408,0.536, respectively, P <0.05).(3)There were a negative correlation between cortical R2*, medullary R2*of thepatients and GFR (r=-0.547,-0.723, respectively, P <0.05) There were a nocorrelation between corticalADC, medullary ADC of the patients and GFR (P>0.05).Conclusion：DTI and BOLD were used in chronic kidney disease patients. FA value is moresensitive than the ADC value in evaluating CKD early diagnosis and renal function.FA values and R2*values have certain value in evaluating CKD early diagnosis andrenal function.FA values and R2*values(cortex and medulla) showed a goodcorrelation with GFR. It can be seen that CKD patients with kidney DTI and BOLD scanning can be used to evaluate renal function.