Clinical Application Of ASL Combined With CTA In Internal Carotid Artery Stenosis

Background: Carotid artery stenosis can cause insufficient blood supply of brain tissue,which is one of the important causes of cerebral ischemic attack or cerebral infarction.The purpose of the treatment of carotid artery stenosis is to improve cerebral blood supply,prevent embolism caused by plaque shedding,relieve the symptoms of cerebral ischemia,and prevent transient ischemic attack(TIA)and ischemic infarction.Treatment is carried out according to the degree and clinical manifestation of carotid artery stenosis,including medical treatment,surgical treatment and interventional therapy.Carotid endarterectomy(CEA),as the main method for the treatment of severe carotid stenosis,has a history of nearly 70 years.A large number of clinical evidence from Europe,America and China have shown that CEA is safe and effective.Carotid endarterectomy can not only remove the lipid plaque of internal carotid artery,but also improve the blood supply of ischemic brain tissue and reduce the possibility of ischemic cerebral infarction and TIA.However,CEA also has its corresponding surgical risks,patients may have hemodynamic changes,headache,hyperactivity and insomnia caused by excessive cerebral perfusion.Cerebral hemorrhage may occur in severe cases.There are also patients with cerebral infarction caused by intraoperative plaque shedding or insufficient perfusion,which can lead to life-threatening.Cerebral hemorrhage caused by excessive perfusion is a serious clinical complication after internal carotid artery endarterectomy,which will lead to serious consequences once misdiagnosed or missed the best treatment opportunity.Therefore,if we can predict the amount of cerebral perfusion after operation,give enough attention and appropriate and timely treatment,it will reduce the pain of the disease and avoid heavy family losses.Objective: To explore the relationship between the number of primary collateral circulation and the increase rate of CBF after CEA by using proton spin labeling imaging technique of cerebral artery blood(ASL).The study on the correlation between the number of primary collateral circulation and the occurrence of hyperperfusion state.Methods:The clinical manifestations,imaging examination and pathology of 28 patients with(Internal Carotid stenosis,ICA)stenosis of internal carotid artery confirmed by pathology in the Department of Neurosurgery of the affiliated Hospital of Qingdao University from May 2017 to August 2019 were analyzed.All patients need internal carotid endarterectomy.CT angiography of carotid artery,CT angiography of cerebral artery and proton spin labeling imaging of cerebral artery blood were performed within one week before operation.CT angiography of carotid artery,CT angiography of cerebral artery and proton spin labeling imaging of cerebral artery blood were performed withinone week after operation.Three-dimensional images of cerebral vessels were processed by CTA of cerebral arteries.Two attending radiologists were asked to read the film together to determine the number of primary collateral circulation(anterior communicating artery and posterior communicating artery).Qualitative and quantitative analysis of cerebral blood flow(CBF)map: CBF improvement rate =(postoperative CBF-preoperative CBF)/ preoperative CBF(same time,same side),only CBF> 100%compared with preoperative baseline level,which is defined as hyperperfusion state.Finally,the correlation between the number of primary collateral circulation in patients and the improvement rate of postoperative CBF was analyzed,and the expectations that can be achieved by preoperative operation and the prevention of postoperative complications were made.Results:A total of 28 patients with internal carotid artery stenosis were included.CTA examination showed that the carotid artery stenosis was completely relieved and the surgical correlation reached the expected treatment.There were 17 cases of severe unilateral stenosis and 11 cases of bilateral stenosis.There were 26 males and 2 females with internal carotid artery stenosis,and the sex ratio was 13:1.The age ranged from 51 to 80 years,with an average of(65.89 �7.37)years.There were 12 patients with perennial high-fat diet(43%)and 16 patients with a history of smoking and drinking(57%).The course of disease ranged from 1 day to 4 years.The main clinical manifestation was limb weakness in 18 cases(64%).11 cases(39%)showed limb numbness.Dizziness was found in 6 cases(21%)with TIA attack.Blurred vision was found in 6 cases(21%).Headache occurred in 3 cases(11%).There were 2 cases of unclear speech(7%).Among the patients,15(54%)had hypertension-based diseases.Among the patients,10(36%)had diabetes-based diseases.Among the patients,7 cases(25%)had coronary heart disease.After CEA operation,the improvement rate of 1.5s CBF in operative side and non-operative side was statistically significant,while the improvement rate of 2.5s CBF in operative side and non-operative side was not statistically significant.In terms of imaging,no patients without primary collateral circulation were found in the samples.There were 17 patients with a primary collateral circulation.The improvement rates of1.5s and 2.5s CBF on the operative side were 50.27% and 29.85%,and the improvement rates of 1.5s and 2.5s CBF on the non-operative side were 18.56% and 15.30%.There were 6 patients with two primary collateral circulation,the improvement rates of 1.5s and2.5s CBF on the operative side were 106.13% and 31.39% respectively,and the improvement rates of 1.5s and 2.5s CBF on the non-operative side were 15.79% and24.52%,respectively.There were 5 patients with three primary collateral circulation.The improvement rates of 1.5s and 2.5s CBF on the operative side were 201.31% and 66.84%,and the improvement rates of 1.5s and 2.5s CBF on the non-operative side were 12.93%and 17.16%.But only the CBF improvement rate of 1.5s and 2.5s on the operative sidewas statistically significant.That is,there was a positive correlation between the improvement rate of 1.5s CBF and the number of collateral circulation on the operative side(r = 0.593,P < 0.05),but there was no correlation between the improvement rate of CBF and the number of collateral circulation on the operative side(P> 0.05),and there was a positive correlation between the number of primary collateral circulation and the occurrence of overperfusion(r = 0.653,P <0.05).Conclusion: 1.The improvement rate of CBF on the operative side was positively correlated withthe number of primary collateral arteries.2.The occurrence of hyperperfusion in patients is correlated with the number of primary collateral arteries,which may be used as an early warning index for predicting cerebral hyperperfusion syndrome before CEA.