This retrospective observational study explored, for the first time, whether carotid perivascular fat density (PFD) as measured on preoperative CT angiography (CTA) could help identify patients at higher risk of developing covert brain infarction (CBI) following carotid endarterectomy (CEA). The analysis included 185 patients who underwent CTA before CEA and MRI postoperatively to detect CBI. CBI occurred in 24.3% of the cohort. These patients exhibited significantly higher PFD values (−41.46 ± 8.12 HU) than those without CBI (−59.95 ± 10.13 HU; P < 0.001). Logistic regression models confirmed PFD as a strong independent predictor of CBI (OR: 1.203, 95% CI: 1.139–1.271; P < 0.001), even after multivariable adjustment. A threshold of −51.7 HU yielded high diagnostic performance, with 93.3% sensitivity and 84.3% specificity. These findings indicate that increased carotid PFD on CTA may serve as a reliable imaging biomarker for preoperative risk stratification, helping identify subjects more likely to develop covert brain infarction after CEA.