Imaging Characteristics And Hemodynamic Analysis Of Carotid Web

Carotid web(CaW)is one of the most important causes of cryptogenic ischemic stroke.It is usually located in the posterior wall of the carotid artery bulb and presents as a membrane-like luminal protrusion.However,because of its small size and uncommon,it is easy to be overlooked in clinical examination.Contrast-enhanced ultrasonography(CEUS)can provide better image quality and more quantified data,but its value in clinical diagnosis of CaW is unclear.CaW and carotid atherosclerosis(CAS)are relatively similar in imaging,and both can lead to the onset of stroke through thrombosis.The formation of thrombus is closely related to the hemodynamic changes of the lesions,but the hemodynamic differences between the two diseases are poorly studied at present.The hemodynamic difference between CaW and CAS can be further explored by computational fluid dynamics(CFD),which provides a reference for further understanding of the pathogenesis of stroke.In this study,51 patients with CaW diagnosed and hospitalized in the Department of Neurology,The First Affiliated Hospital of University of Science and Technology of China and Eastern Theater Command General Hospital from August 2019 to December 2022 were retrospectively included,to explore the diagnostic value of CEUS in CaW examination,and to compare the clinical characteristics of the elderly group(≥60 years old)and the non-elderly group(<60 years old).At the same time,18 patients with CaW who received CTA examination were retrospectively included,and 18 patients with CAS and 18 normal control patients were matched.The three groups were matched according to age(50～65 years old).The mean stenosis rate of CaW group and CAS group was mild stenosis(<50%),and the normal control patients were patients who underwent CTA examination without carotid artery stenosis.The hemodynamic differences between CaW patients and CAS patients were explored based on the hemodynamic parameters of the CFD simulation results.The results showed that among various risk factors of CaW patients,hypertension accounted for a higher proportion(64.7%),and the elderly group of hypertension patients was significantly more than the non-elderly group(P=0.034).In addition,there was a significant difference in thrombosis between the elderly group and the nonelderly group(non-elderly group:5(25.0%),elderly group:22(71.0%),P=0.002).In terms of imaging,CaW showed delayed contrast filling and delayed emptying on CEUS,indicating the presence of stagnant blood flow.In terms of diagnostic accuracy,the diagnosis rate of CEUS was higher than that of conventional ultrasound.The results of CFD simulation showed that the wall shear stress in CaW group was significantly lower than that in CAS group at peak ejection period and middle filling period(P<0.017).Meanwhile,the time-averaged wall shear stress in CaW group was lower than that in CAS group and normal control group(P<0.001).The area of TAWSS<0.4 Pa in CaW group was larger than that in CAS group and normal control group,and the difference was statistically significant(P<0.010).The streamline showed that CaW formed disordered blood flow at the lesion.The flow velocity was reduced,and the flow velocity center was obviously shifted.The comparison of these CFD parameters suggests that CaW can produce greater hemodynamic changes than CAS,which has an important influence on the formation of thrombosis.This study for the first time compared the differences in clinical characteristics of patients with CaW in different age groups.The results suggest that elderly patients with CaW may be more prone to thrombosis,and CEUS has potential application value in the diagnosis of CaW,which can improve the diagnosis rate of CaW.In addition,CaW can produce greater hemodynamic changes than CAS and may be more prone to thrombosis.