The Application Of Magnetic Resonance Imaging For The Evaluation Of Purpura Nephropathy

ObjectiveTo explore the values of 3.0T MRI diffusion tensor imaging(DTI)and diffusion tensor tractography(DTT)in the evaluation of renal impairment caused by Henoch-Schonlein purpura nephritis(HSPN),and to studythe correlation of MRIsignswith clinical biochemical tests,and the correlations between MRI findings and clinical and pathological grading.Clinically,the diagnosis of HSPN is based on renal biopsy that is the gold standard for a variety of diffuse renal diseases,and the therapeutic regimensof HSPN are made primarily according to itsclinical or pathological classification.However,renal biopsy is invasive and with a somewhat risk,hard to be accepted by most patients when used as diagnostic and follow-up means.As a commonly used clinical imaging modality,MRI hold high sensitivity to visualize soft tissue lesions,and have been used as an very important technology for the clinical evaluation of acute kidney injury and chronic kidney diseases.This study intends to use DTI as a diagnostic and follow-up tool to prospectively study a group of cases with HSPN and evaluate its clinical application value.MaterialsThe clinical and imaging data of 31 children who were hospitalized in the nephrology department of our hospital from June 2020 to February2021 and were diagnosed with HSPN through clinical screening and renal puncture pathological examination were collected.A prospective analysis of children with HSPN was carried out.The optimized MRI plain scan T2 WI sequence was used to measure whether there are differences in the imaging performance of the cortical and medulla of the kidneys,and the groups were divided into group A(the treatment group with abnormalities)and group B(the control group without observable abnormalities,That is).Compared and analyzed were the relationship between MRI-related signs and clinical biochemical indicators,pathological grades of the two groups of children with HSPN;the relationship between clinical types and pathological grades.Statistical software SPSS 21.0 was used for statistical processing of data,and the test methods included two independent sample t test or Mann-Whitney U test and Pearson chi-square test.To our best knowledge,few literature has focus on such a topic.Results1.T2 WI sequence:Abnormalities,manifesting as dotted or patchy high signal shadows,in the cortical signals of both kidneys were observed in children with HSPN of Group A and dominate in the right kidney;reduced medulla signals were also observed in a large fraction of the children;In children with acute nephritis of HSPN,the cortex is thickened and the cortex and medulla demarcation becameobscure.2.DTI sequence: The FA values and ADC values of the cortex and medulla between Group A and Group B wereboth statistically different(P<0.001);and the FA and ADC values of Group A were lower than those of Group B.3.Differences in biochemical indexes between the two groups of children with HSPN: The 24 hurine protein between Group A and Group B was statistically different(Z=-3.301,P=0.001);the urine protein both of the two groups were higher than the normal values,and that of Group A was higher than Group B.Among the biomarkers reflecting renal function,the uric acid was significantly different(Z=-4.348,P<0.001)between the two groups,other markers such as urea nitrogen(Z=-1.720,P=0.085)and creatinine(Z=-1.306),P=0.191)did not show difference.Among the protein markers,urinary transferrin showed significantly different(Z=-4.032,P < 0.001)between the two groups,but urinary microprotein was not significantly different(Z=-1.581,P=0.114);Among the proteinmarkers reflecting tubule function,there were significantly differences in urine cystatin C(Z=-2.847,P=0.004)and urineα-microglobulin(Z=-4.032,P<0.001)between the two groups.4.The proportion of the two groups of children with HSPN in clinical and pathological classification: For this cohort of patients with HSPN,their clinical classification were mainly hematuria and proteinuria and nephrotic syndrome,and their pathological classification were mainly grade Ⅱ and grade Ⅲ.5.DTT image analysis: All patients in Group A had abnormal renal functions and their DTT images all showed reduced and interrupted tract structures of the medulla.The more severe the HSPN,the more significant the changes on DTT images;On the contrary,the renal functionin Group B was all normal,as normal their DTT images.ConclusionWhen observed abnormal signals are observed for children with HSPN on their MRI T2 WI sequence,their MRI imaging results of DTI and DTT are further post-processed and compared with clinical biochemical tests,pathological classification,we can find that there are clear correlations between MRI imaging and clinical classification and pathologic stage,and also between MRI imaging and the key biochemical results.It indicates that MRI T2 WI,DTI and DTT sequences can be used for non-invasive evaluation of renal impairments in HSPN,and their in-depth clinical values needs to be uncovered by expanding the case size and in follow-up studies.