Contrast-enhanced ultrasonography for assessment of tubular atrophy/interstitial fibrosis in immunoglobulin A nephropathy: a preliminary clinical study.

Abstract

To investigate the potential of contrast-enhanced ultrasonography (CEUS) for evaluating the severity of tubular atrophy/interstitial fibrosis (TA/IF) in immunoglobulin A nephropathy (IgAN) patients. A total of 80 patients with IgAN and 33 healthy adults were investigated. Patients were divided into three groups according to the TA/IF (T) grade of the Oxford classification: T0 (n=28), T1 (n=35), and T2 (n=17). Patients and control subjects underwent conventional ultrasound (US) and CEUS. Time-intensity curves of CEUS were drawn for regions of interest located in the renal cortex and medulla using QLab software. Conventional US and CEUS quantitative parameters were analyzed. One-way analysis of variance (ANOVA), binary logistic regression, and receiver operating characteristic (ROC) curves were used. There were no significant differences in renal size, cortical thickness, and medullary perfusion parameters (P>0.05), whereas the differences in peak intensity (PI), area under the time-intensity curve (AUC) and wash-in slope (WIS) of cortical perfusion parameters between the control subjects and patients were significant (P<0.05). PI was significantly lower with the increasing degree of T (P<0.05). PI was associated independently with the degree of T in IgAN patients (P<0.05). ROC analysis revealed that using the optimal cutoff values of 15.38dB for diagnosis of T0-T1 (sensitivity 83.30% and specificity 63.00%) and 14.69dB for diagnosis of T2 (sensitivity 100.00% and specificity 66.70%), the corresponding areas under the ROC curve were found to be 0.782 and 0.952, respectively. CEUS can potentially be used as a noninvasive imaging marker to evaluate the severity of TA/IF in IgAN patients.