Quantitative Susceptibility Mapping for Evaluating Renal Functional Injury in Chronic Kidney Disease Patients: A Pilot Study

Chronic kidney disease (CKD) is an increasing global health problem, resulting in gradual loss of renal function and irreversible renal injury. The noninvasive detection, monitoring, and timely intervention of CKD might benefit the patients' prognosis. This study aims to assess renal functional injury in CKD patients by using magnetic resonance imaging (MRI) of quantitative susceptibility mapping (QSM). One hundred thirty-four consecutive CKD patients with stage (S) 1-5 and 28 healthy volunteers (HVs) underwent MRI to obtain renal susceptibility values and renal volumes. Clinical information and serum biomarkers were collected. Differences in susceptibility values and renal volumes were compared among HVs and CKD patients. Correlations between susceptibility values, renal volumes, and clinical indicators were analyzed. The performance of QSM in discriminating HVs, S1-2, and S3-5 CKD patients was evaluated using areas under the curve (AUCs). Susceptibility values were significantly lower in CKD S3-5 patients than in both HVs and CKD S1-2 patients, and lower in CKD S1-2 patients than in HVs (all p < 0.05). No significant difference in renal volumes was found among HVs, CKD S1-2, and S3-5 patients (p = 0.117). Significant correlations were observed between estimated glomerular filtration rate (eGFR) and renal volumes (r = 0.296, p < 0.001), and between eGFR and susceptibility values (r = 0.579, p < 0.001). Susceptibility values were significant for discriminating patients with CKD S1-2 from HVs (AUC = 0.698, p < 0.001), S3-5 from HVs (AUC = 0.896, p < 0.001), and S3-5 from S1-2 (AUC = 0.701, p < 0.001). Therefore, QSM was feasible for assessing renal functional injury in CKD patients. The QSM parameter exhibits potential values in differentiating HVs, CKD S1-2, and S3-5 patients.