Noninvasive evaluation of renal oxygenation in children with chronic kidney disease using blood-oxygen-level-dependent magnetic resonance imaging

Abstract

Background Renal hypoxia is considered a final pathway in the progression of chronic kidney disease (CKD). Blood-oxygenlevel-dependent magnetic resonance imaging (BOLD-MRI) has shown merit for evaluating renal oxygenation in adults.Objective To investigate renal cortical and medullary R2* values by CKD stage and by renal function index in children with chronic kidney disease. Materials and methods Twenty-one children with CKD Stage 1-3, 16 children with CKD Stage 4-5, and 6 healthy volunteers underwent a renal MRI using multigradient recalled-echo sequence with 16 echoes. We measured the R2* values of the renal cortex and medulla on BOLD-MRI. Results The cortical R2* value was ranked as CKD Stage 4-5 > CKD Stage 1-3 > healthy controls, and the medullary R2* value was ranked as CKD Stage 4-5 > CKD Stage 1-3. There was no significant difference in the medullary R2* value between CKD Stage 1-3 patients and the healthy controls. There was a positive correlation between the R2* values in the renal cortex (r=0.73) and medulla (r=0.89), and the serum creatinine level (P<0.001), and the renal cortical and medullary R2* values were negatively correlated with the estimated glomerular filtration rate (r=-0.71 and r=-0.89, respectively; P<0.001). Conclusion BOLD-MRI might contribute to noninvasive assessment of renal oxygenation in children with CKD in vivo but it did not reflect renal function in our sample.

Relative Hypoxia and Early Diabetic Kidney Disease in Type 1 Diabetes

“…Accordingly, to meaningfully examine early changes in RO 2 , it is important to normalize RO 2 to nephron mass or workload (GFR). Since GFR is one of the principal determinants of RO 2 by BOLD MRI (31)(32)(33), the RO 2 :GFR ratio provides a measure of relative renal hypoxia in young people with T1D (Fig. 1).…”

“…To our knowledge this is the first study using BOLD MRI to quantify relative renal hypoxia in people with T1D. Additionally, the majority of renal BOLD MRI studies have been limited by the use of estimated GFR in lieu of gold standard measurements of GFR, and by the lack of detailed assessments of insulin sensitivity and adiposity (31)(32)(33). Our current study took advantage of directly measured GFR and RPF, assessed in T1D and non-T1D cohorts, innovations in imaging techniques to define changes in RO 2 , and comprehensive metabolic phenotyping to define the earliest alterations in renal energetics that may contribute to the development of DKD in youth with T1D.…”

Machine learning-based multimodal MRI texture analysis for assessing renal function and fibrosis in diabetic nephropathy: a retrospective study

“…Renal fibrosis is probably one of the main causes of decreased ADC values during renal function impairment ( 32 ). Reduced renal blood flow and renal fibrosis make a contribution to the progression of renal dysfunction ( 33 , 34 ). On the other hand, the BOLD sequence is able to reflect hypoxia in the renal microenvironment.…”

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

“…Incorporating R2* values into machine learning algorithms was able to discriminate rejected from non-rejected transplants with a sensitivity of 100% (Shehata et al, 2019). Recently, cortical and medullary R2* values were positively correlated to serum creatinine level and negatively correlated to eGFR (Luo et al, 2020). In their study, cortical R2* value was ranked as CKD stage IV, V > CKD stage I-III > healthy controls and medullary R2* value was ranked as CKD stage IV, V > CKD stage I-III while no significant difference between controls and patients with CKD stage I-III.…”