Diagnostic utility of contrast-enhanced ultrasound parameters in classifying lupus nephritis

Lupus nephritis (LN) is a severe complication of systemic lupus erythematosus (SLE), with renal biopsy as the diagnostic gold standard. However, biopsy is invasive. This study aims to evaluate the potential of contrast-enhanced ultrasound (CEUS) quantitative parameters as non-invasive predictors in differentiation proliferative LN from non-proliferative LN.

Fifty-eight biopsy-confirmed LN patients who underwent CEUS within 3 days before biopsy were included retrospectively. Patients were categorized into 38 cases of proliferative LN (Class III, IV, and III/IV + V) and 20 cases of non-proliferative LN (Class II and purely Class V). The clinical and laboratory data, conventional US parameters, and CEUS quantitative parameters derived from time-intensity curves (TICs) were analyzed. Multivariate logistic regression and receiver operating characteristic (ROC) curve analysis were performed to determine significant predictors and evaluate the diagnostic performance.

Patients with proliferative LN exhibited significantly higher absolute time to peak (∆TTP), half descending time (DT/2) and TIC area under curve (TIC-AUC) values than non-proliferative LN patients (P < .05). Logistic regression analysis identified TIC-AUC and anti-dsDNA antibody as independent predictors of proliferative LN. ROC analysis revealed that anti-dsDNA positive had an AUC of 0.745, with sensitivity of 87.5% and specificity of 61.5% for predicting proliferative LN. For TIC-AUC, a cutoff value of 8049.0 yielded an AUC of 0.810, sensitivity of 68.8% and specificity of 84.6% for predicting proliferative LN.

CEUS quantitative parameters, particularly TIC-AUC, provide a non-invasive approach for identifying proliferative LN, and complement conventional laboratory markers. These findings demonstrate the potential of CEUS in improving LN diagnosis and facilitating clinical evaluation.