Quantitative assessment of renal lipid deposition and oxygenation changes in chronic kidney disease based on qDixon-MRI: a pilot study

Renal ectopic lipid accumulation and oxygenation-related alterations have been implicated in CKD progression, highlighting the necessity for precise noninvasive monitoring. However, a comprehensive quantitative assessment of renal fat content and oxygenation across CKD stages is lacking. To investigate changes in renal fat fraction (FF) and relaxation rate (R2*) values based on qDixon MRI across CKD stages and to evaluate their performance in distinguishing renal impairment and CKD severity. A total of 25 healthy volunteers (controls) and 70 patients with CKD (Stages 1–5) underwent 3.0T qDixon MRI to quantify FF an R2*. Patients with CKD were stratified based on estimated glomerular filtration rate (eGFR). Differences in FF and R2* among groups were analyzed using one-way ANOVA and Welch’s ANOVA, respectively. Spearmen’s correlation assessed relationships with variable, and receiver operating characteristic (ROC) curve analysis evaluated stage-specific diagnostic performance. Cortical and medullary FF differed significantly across CKD stages and were higher in the advanced-stage groups, particularly CKD stages 4 and 5. However, R2* values were higher in CKD stages 1 and 2 than in controls, but lower in the later-stage groups. In mild CKD (stages 1–2), only medullary R2* correlated negatively with eGFR ( r = -0.456, p = 0.003); FF showed no correlation. While, in moderate-severe CKD (stages 3–5), both FF and R2* values in renal cortex and medulla were significantly correlated with eGFR. Notably, R2* showed good performance in identifying mild CKD from controls (cortex, AUC = 0.967; medulla, AUC = 0.972), and all parameters showed good ability to differentiate mild from moderate-severe CKD. qDixon MRI may provide quantitative information on renal ectopic fat deposition and oxygenation-related alterations reflected by R2* in patients with CKD, with potential value for evaluating renal involvement across CKD stages.