CP-RADS Grade 2 Carotid Plaques: The Association Between Ultrasound Features and the Risk of Ischemic Stroke

To investigate whether the composite ultrasound feature-characterized by intraplaque punctate calcification with contrast enhancement-serves as an independent predictor for new ischemic stroke in these presumed "low-risk" plaques, and to develop and validate a nomogram prediction model that integrates clinical and imaging features.

In this retrospective study, 3317 patients initially underwent carotid ultrasound. After stringent exclusions, 404 with CP-RADS grade 2 plaques were enrolled and randomly split 7:3 into training (n = 282) and validation (n = 121) sets. Three senior doctors, blinded to clinical data, independently assessed ultrasound features with excellent intra‑ and inter‑observer agreement (ICC > 0.80). Univariate and multivariate logistic regression identified independent risk factors, and a nomogram was developed. Model performance was evaluated using ROC analysis, calibration curves, and decision curve analysis (DCA).

The composite imaging feature (punctate calcification with contrast enhancement) was an independent predictor of new‑onset cerebral infarction (OR = 3.60, 95% CI: 1.33-9.77, p = 0.012). The nomogram showed excellent discrimination in the validation set (AUC = 0.84; sensitivity 79%, specificity 86%), with good calibration between predicted and actual risk.

The composite "active plaque" feature-intraplaque punctate calcification with contrast enhancement-serves as an independent predictor of new‑onset cerebral infarction in CP‑RADS grade 2 carotid plaques. Our nomogram demonstrates good predictive performance and clinical applicability, providing reliable imaging support for early risk stratification and individualized intervention in this presumed "low‑risk" population.