A contrast-enhanced ultrasound-based nomogram for preoperative prediction of pseudocapsule status in localized clear...

The pseudocapsule (PC) status of clear cell renal cell carcinoma (ccRCC) is closely associated with tumor aggressiveness and surgical strategy, yet accurate preoperative non-invasive assessment remains challenging. This study aimed to develop and internally validate a contrast-enhanced ultrasound (CEUS)-based prediction model for assessing PC status in patients with ccRCC.

This retrospective study enrolled 254 patients with pathologically confirmed ccRCC who underwent surgery at Shanghai General Hospital, between August 2021 and December 2024. All patients received preoperative conventional ultrasound and CEUS examinations. Independent risk factors for PC absence or penetration were identified using multivariable binary logistic regression analysis. These factors were then incorporated into a nomogram to construct a predictive model. The model's discriminatory performance was assessed by the area under the receiver operating characteristic (ROC) curve (AUC). Internal validation was performed using bootstrap resampling to generate calibration curves and evaluate goodness-of-fit via the Hosmer-Lemeshow test. Finally, the clinical utility of the nomogram was determined using decision curve analysis (DCA).

Three CEUS features-incomplete PC sign, peak hypoenhancement, and rapid washout pattern-were independent predictors in the final model. The nomogram showed acceptable discrimination [training AUC: 0.779, 95% confidence interval (CI): 0.692-0.867; validation AUC: 0.749, 95% CI: 0.600-0.898] and calibration (Hosmer-Lemeshow P>0.05). DCA supported its potential clinical utility.

In conclusion, a CEUS-based nomogram was developed and internally validated to preoperatively predict PC status in ccRCC. This practical, non-invasive tool can guide and optimize surgical planning.