Blood oxygenation level-dependent MRI for evaluating renal function in chronic kidney disease: A preliminary retrospective study

Abstract

Renal hypoxia is a key factor in the progression of chronic kidney disease (CKD), yet it is challenging to evaluate non-invasively. This study utilized Blood Oxygenation Level-Dependent (BOLD) MRI to assess renal oxygenation and function in CKD patients and healthy volunteers (HVs). We retrospectively analyzed BOLD MRI data from 128 CKD patients and 25 HVs. CKD patients were categorized into mild (CKD stages 1-2), moderate (stage 3), and severe (stages 4-5) impairment groups based on their estimated glomerular filtration rate (eGFR). The study measured cortical and medullary T2* values (COT2* and MET2*), investigating their differences and correlations with eGFR and clinical indicators such as serum creatinine (Scr), cystatin C (Cys C), beta-2 microglobulin (β2-MG), and blood urea nitrogen (BUN). Our findings indicated that both COT2* and MET2* values were significantly higher in HVs than in all CKD groups and decreased progressively with advancing CKD (P < 0.001). Notably, the decrease in T2* values correlated significantly with worsening renal function, evidenced by positive correlations with clinical indicators such as Scr, Cys C, β2-MG, and BUN (all P < 0.001), and negative correlations with eGFR (P < 0.001). No significant correlations were found between T2* values and UA (P > 0.05). Receiver operating characteristic (ROC) analysis further refined the clinical utility of BOLD MRI, identifying optimal cut-points for differentiating between stages: COT2* values were 62.25 ms between HVs and CKD stages 1-2, 52.58 ms between CKD stages 1-2 and 3, and 42.76 ms between CKD stages 3 and 4-5; MET2* values were 36.17 ms, 29.42 ms, and 23.33 ms, respectively, for these comparisons.This study highlights BOLD MRI's potential for non-invasively monitoring renal hypoxia and functional deterioration in CKD, advocating its integration into clinical diagnostics.