Ultrasound-Supplemented Scoring Method for Evaluating the Activity of Idiopathic Retroperitoneal Fibrosis

To investigate the diagnostic value of contrast-enhanced ultrasound (CEUS) in idiopathic retroperitoneal fibrosis (IRPF) activity and establish an optimal ultrasound-supplemented scoring method to evaluate the activity of IRPF. The retrospective study included 139 CEUS examinations of 59 IRPF patients treated in our hospital from January 2017 to January 2025. They were divided into the IRPF active group (66 examinations) and the inactive group (73 examinations). The parameters between the 2 groups were compared by univariate analysis. Spearman rank correlation was used to analyze the association between the parameters and IRPF activity. Significant parameters were scored according to the correlation coefficients (rs). The receiver operating characteristic (ROC) curve was drawn to evaluate the diagnostic efficiency of the scoring method. Univariate analysis showed that the incidence of back pain, ESR, CRP, lesion thickness, and CEUS grade was higher in the active group than in the inactive group (P<0.01). The CEUS grade and thickness had the strongest association with IRPF activity [rs=0.710 (95% CI: 0.616-0.784) and 0.703 (95% CI: 0.608-0.778), respectively]. The total score of the active group was significantly higher than that of the inactive group (P<0.001). The ROC curve showed that the optimal cutoff value was 3 scores. The sensitivity, specificity, positive, and negative predictive values were 84.85%, 83.56%, 82.35%, and 85.92%, respectively. The area under the ROC curve was 0.935 (95% CI: 0.880-0.970). In conclusion, CEUS was an excellent noninvasive diagnostic tool for assessing the activity of IRPF.