Role of diffusion tensor imaging in renal parenchymal changes

Abstract

Context:Diffusion Tensor Imaging (DTI) is a reliable noninvasive tool to assess renal function with medullary Fractional Anisotropy (FA) values showing the most consistent results.Aims:Evaluation of FA, Apparent Diffusion Coefficient (ADC) for detecting diabetic nephropathy (DN) using 1.5-Tesla magnetic resonance imaging (MRI). To determine FA and ADC values in chronic kidney disease (CKD) patients and controls, and comparing these with estimated glomerular filtiration rate (eGFR) and categorizing the stage of CKD.Patients and Methods:Thirty nondiabetic volunteers underwent DTI. The study included 83 diabetics, 30 frank urine proteinuric, 30 micro-albuminuric, 23 normo-albuminuric with only raised blood sugar patients. Patients were stratified by eGFR into groups: eGFR <60 and eGFR>60ml/min. ADC and FA values in cortex and medulla were compared between controls and study groups.Statistical Analysis Used:Analysis of variance and Pearson correlation using SPSS 16 were performed.Results:There was significant difference of FA medulla in controls versus albuminuric and micro-albuminuric versus frank proteinuric patients (P < 0.001). Also, there was significant difference between cortical ADC values between normal, microalbuminuric/proteinuric groups (P = 0.010, P =0.000, respectively). Significant difference between medullary FA values of patients with eGFR >60 and eGFR < 60 versus normal controls (P < 0.001) was noted. With declining renal function from normal to CKD category 5, a negative correlation between medullary FA (r= −0.785, P = 0.001) and ADC cortex values (r= −0.436, P = 0.001) was noted. A strong positive correlation between medullary FA and cortex ADC with eGFR (r = 0.598 and 0.344, respectively) was noted.Conclusion:Medullary FA of diabetics with relatively intact kidney function were significantly lower than those of controls. Hence, drop in medullary FA values can be an indicator of early nephropathy/patients at risk where eGFR is in near normal range. Cortical ADC and medullary FA demonstrated a significant correlation with eGFR with the latter showing a stronger positive correlation.

Study of renal parenchymal changes by diffusion tensor imaging in diabetic nephropathy

“…Similarly, Saini et al . [ 29 ] in their study found an increasing trend in cortical FA values with increasing level of proteinuria and with reducing eGFR, but unlike our study, they did not find a significant difference in FA values between the microalbuminuric group and those with overt proteinuria. Conversely, in a study by Hueper et al .…”

“…[ 28 ], and Saini et al . [ 29 ]. The declining trend in the FA values in the medulla can be attributed to several models of histopathology that were observed previously: a) tubular atrophy and cellular damage influence the direction of diffusion, as suggested by the rat model [ 27 ]; b) collagen deposition and inflammatory cell infiltration also contribute; and c) disruption of normal glomerular filtration membrane structure results in filtering of macromolecular proteins and red blood cells into the tubules, which congest the tubules and impair radial diffusivity, resulting in reduced FA values in the medulla [ 37 , 38 ].…”

“…Similar results have also been reported in the study by Saini et al . [ 29 ], who concluded that medullary FA was a reliable indicator in detecting early nephropathy changes, especially in diabetics.…”

Recent advances in medical image processing for the evaluation of chronic kidney disease

“…When histology is performed, FA was correlated with percent of glomerulosclerosis and the area of interstitial fibrosis as well as the degree of renal impairment (stages 1 to 5) (Feng et al, 2015). In CKD, a significant decline in medullary FA was reported in patients with chronic renal impairment (eGFR <60 mL/min/1.73 m 2 (Saini et al, 2018), renal failure caused by: nephroangiosclerosis, renal artery stenosis, medullary kidney cystic disease, DN, pyelonephritis, lithiasis, acute glomerulonephritis, analgesic abuse, interstitial nephritis, Wegener granulomatosis, LN, diuretic abuse (Gaudiano et al, 2013)) compared to control with normal renal function, and strongly correlated to eGFR (Gaudiano et al, 2013;Saini et al, 2018;. Tractography has also shown a good visual discrimination between the two subjects, where reduced number of tracts which do not have preferential orientation was presented with worsening renal function compared to a regular tracts arrangement with normal renal function (Gaudiano et al, 2013).…”

Kidney function, brain morphology and cognition in the elderly: sex differences in the Austrian Stroke Prevention Study

“…Both organs are affected by similar vascular risk factors such as age, hypertension, diabetes mellitus and smoking [2]. Individuals with chronic kidney disease (CKD) present a plethora of small vessel disease related brain changes [1][2][3][4] with focal and diffuse structural and microstructural abnormalities [5][6][7]. These include lacunar strokes, white matter abnormalities and microbleeds [3,8,9].…”