Background: Carotid atherosclerotic plaque inflammation plays a critical role in guiding the prevention of secondary stroke. Increased perivascular adipose tissue attenuation observed on computed tomography angiography (CTA) may indicate local inflammation. Our objective was to investigate whether pericarotid adipose tissue (PCAT), as a local inflammation biomarker, could distinguish between different stages of carotid atherosclerotic disease plaques.Methods: We prospectively enrolled 45 consecutive acute stroke patients with carotid artery stenosis from September 2019 to September 2021. We then matched them to non-stroke patients (n=67) and no carotid atherosclerotic disease controls (n=65) based on gender, age, and cardiovascular risk factors. We compared PCAT attenuation, carotid plaque features on CTA, clinical risk factors, and serum inflammatory factors across the different groups. To detect the association of PCAT attenuation with stage of carotid atherosclerotic disease, we used multivariable logistic regression analysis.Results: Patients with acute stroke had a higher PCAT attenuation (-78.80 +/- 11.62 HU) than patients with non-stroke (-89.01 +/- 10.81 HU, P<0.001) and no carotid atherosclerotic disease controls (-95.24 +/- 10.81 HU, P<0.001). PCAT attenuation was significantly increased in non-stroke patients compared to non-stroke patients over no carotid atherosclerotic disease controls (P=0.004). The association between PCAT attenuation and the stage of carotid atherosclerotic disease was independent of age, gender, cardiovascular risk factors, and CTA plaque characteristics. No interaction was observed between clinical features and CTA plaque characteristics on PCAT attenuation.Conclusions: PCAT attenuation, which is an imaging biomarker of local inflammation, independently distinguishes patients with different stages of carotid atherosclerotic disease. Quantitative evaluation of PCAT attenuation in carotid atherosclerotic disease is expected to guide targeted surgical treatment of carotid plaque.