Correlation analysis of renal ultrasound elastography and clinical and pathological changes in patients with chronic kidney disease .

OBJECTIVE

To analyze the correlations of renal tissue elastography with clinical biochemical indicators and pathological changes in patients with chronic kidney disease (CKD) as well as to explore the potential for renal tissue elastography as a new, noninvasive method for the dynamic monitoring of renal disease progression, efficacy assessment, and prognosis evaluation.

METHODS

Patients admitted to the Department of Nephrology of the First Affiliated Hospital of China Medical University from August 2014 to January 2015 who had undergone renal biopsies were selected. A total of 113 patients with CKD and 16 healthy controls were enrolled in this study, including 61 males and 52 females. In total, 23 cases of IgA nephropathy, 39 cases of membranous nephropathy, 15 cases of minimal-change nephropathy (MCN), and 7 cases of focal segmental glomerulosclerosis were included. The Young's moduli (YM) of the renal cortex and medulla were measured using an AixPlorer Doppler ultrasound with full digital color from Supersonic Imagine. The correlations between the YM of renal tissue and clinical biochemical indicators of blood and urine and the differences in Young's moduli among the different pathological changes in the patients with CKD were analyzed.

RESULTS

The YM of the CKD patients was significantly higher than that of the control group (p < 0.05), and the YM of the renal cortex and medulla gradually increased with the progression of CKD. The YM of the renal cortex in the stage-G5 CKD patients was significantly higher than that of the CKD patients in stages G1 - G3 (p < 0.05). The YM of the renal medulla of the CKD patients in stages G3 - 5 was significantly higher than that of the CKD patients in stages G1 - G2. On univariate analysis, the YM of the renal cortex was correlated with systolic blood pressure, serum creatinine, cystatin C, serum albumin, serum phosphorus, calcium and phosphorus products, uric acid, iPTH, urinary N-acetyl-glucosaminidase (NAG), eGFR, and hemoglobin levels. And the YM of the renal medulla was correlated with systolic blood pressure, serum creatinine, serum albumin, uric acid, iPTH, urinary microalbumin (MA), urinary NAG, and hemoglobin levels. On multivariate analysis, serum cystatin C (β = 0.485, p = 0.018) and uric acid (β = 0.418, p = 0.039) levels were independently correlated with the YM of the renal cortex, while serum creatinine (β = 0.380, p = 0.019) and uric acid (β = 0.482, p = 0.004) levels, as well as smoking (β = 0.337, p = 0.009), were independently correlated with the YM of the renal medulla. The YMs of the renal cortex in patients with membranous nephropathy and IgA nephropathy were significantly higher than those in the patients with CN (p < 0.05). The YM of the renal cortices of the patients in phases IV and V of IgA nephropathy based on the Lee grading system were significantly higher than those of the patients in phases II and III (p < 0.05). According to the Oxford classification for IgA nephropathy, the Young's moduli of the renal cortex and medulla in T1 and T2 patients were significantly higher than those in T0 patients (p < 0.05). The YM of the renal cortex and medulla showed no statistically-significant differences among the different stages of membranous nephropathy.

CONCLUSIONS: The YM of the renal cortex and medulla are associated with the progression of renal insufficiency, and renal ultrasound elastography shows promise as a new means of assessing the stage of CKD. Renal ultrasound elastography is expected to become a new, noninvasive method for the early diagnosis of CKD and the dynamic monitoring of disease progression as well as the assessment of efficacy and prognosis.
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