Application Of Quantitative EEG In Monitoring Cerebral Perfusion Of Severe Stenosis Of Middle Cerebral Artery

BackgroundCerebrovascular disease has become one of the main threats to human health,with ischemic stroke accounting for approximately 79%of all strokes,and intracranial aortic atherosclerotic stenosis is the main cause of ischemic stroke[1]Intracranial aortic stenosis,especially the middle cerebral artery(MCA),is one of the common independent risk factors for ischemic cerebrovascular disease[2].In patients with severe intracranial atherosclerotic stenosis,the incidence of cerebral infarction and recurrent cerebral infarction are still high even with intensive drug therapy intervention,and the efficacy and safety of endovascular stent therapy remains controversial.The current interventional treatment is still in the anatomical era,that is.it is judged by the degree of stenosis,and the new precise medical model requires comprehensive evaluation from the collateral circulation of the diseased vessel,changes in cerebral perfusion after stenosis,and neuroelectrophysiology,but currently There is still a lack of research on this aspect of the assessment.Neuroelectric activity is a reflection of the state of brain function after cerebral ischemia.Quantitative electroencephalography(qEEG)can sensitively monitor the electrical activity of nerve cells in the corresponding area after vascular stenosis.Patients with severe stenosis of MCA under different collateral circulation conditions the change of qEEG has not yet been reported in related research.Our study found that qEEG can sensitively reflect brain function changes after cerebral ischemia in different degrees of extracranial stenosis under different degrees of cerebral perfusion.At the same time,the preliminary pre-experiment of this study showed that the compensation of collateral circulation of severe stenosis of MCA was not established.The same study,this study attempts to explore the changes of qEEG in patients with severe stenosis of MCA under different collateral circulation conditions,combining the collateral circulation of the diseased vessels with the changes of cerebral perfusion,and further explore the EEG combined with collateral circulation The guiding significance of interventional therapy for intracranial cerebral vascular stenosis.At present,there are two main treatments for cerebral vascular stenosis:drug and endovascular treatment.The efficacy of drugs in the treatment of atherosclerosis leading to intracranial lesions is not satisfactory,and the effectiveness of angioplasty and stent implantation in the treatment of atherosclerosis leading to intracranial stenosis has not been fully defined.A multicenter prospective trial evaluating stent implantation for intracranial stenosis showed a technical success rate of 95%and a recurrent stroke rate of 7.2%within 30 days.No deaths were found.The annual recurrent stroke was 10.9%,and the half-year restenosis rate was 35%[3].A large prospective multicenter clinical trial of the Wingspan study of 45 patients with atherosclerotic intracranial stenosis who developed cerebral infarction after drug treatment(stenosis>50%),this study reports technical success rate at 97.7%,30 days of recurrent stroke or mortality was 4.5%,the first year of ipsilateral stroke recurrence rate was 9.3%,and the half year restenosis rate was 7.5%.All patients with restenosis had no clinical symptoms[4].However,the well-known(SAMMPRIS)study suggests that the effect of drug-only intensive therapy is superior to stenting combined with drug-intensive therapy.This study is the world's first randomized controlled trial of intracranial stenting[5].Different from the interventional treatment after extracranial stenosis,the efficacy and safety of interventional therapy after intracranial stenosis are controversial at home and abroad.And intracranial vascular interventional treatment is expensive,and it is still necessary to take long-term medication to prevent restenosis of the stent in the stent after the stent is placed,which has a large family and social economic burden.Therefore,in the situation of cerebral infarction rate and recurrent cerebral infarction rate after intracranial stenosis,find a collateral circulation and brain that can reliably assess the lesions of patients with severe intracranial atherosclerotic stenosis.Changes in perfusion are particularly important for achieving a more significant effect on which treatment regimen to choose.It is clinically found that the severity of cerebral infarction caused by intracranial atherosclerotic stenosis is different,which is mainly related to the establishment of collateral circulation to increase the blood supply of ischemic penumbra and improve cerebral perfusion.The degree of collateral circulation can not only assess the prognosis of patients with ischemic stroke,but also evaluate the efficacy and risk prevention of endovascular treatment.Patients with good collateral circulation have high recanalization rate of endovascular treatment and postoperative bleeding.There are few complications such as hyper-perfusion syndrome.Electroencephalogram can reflect the neuronal activity of the brain in the corresponding region under different perfusion conditions,and can detect brain function changes after cerebral ischemia in a timely and sensitive manner[6].However,studies on EEG combined with collateral circulation in perfusion of intracranial stenosis have not been reported.This study started from the correlation between EEG and collateral circulation and cerebral vascular stenosis morphology in interventional therapy,and explored the quantitative changes of EEG in the case of severe stenosis of MCA in different collateral circulation,and further quantified EEG and collateral circulation are used in the evaluation of the effectiveness and safety of intracranial vascular interventional therapy to explore whether it can be a valuable test index for stent placement and one of the long-term review indicators after stent placement.After cerebral artery stenosis or occlusion,the collateral circulation is divided into three levels,and the collateral circulation provides a new direction for the prevention and treatment of cerebrovascular diseases.The primary collateral circulation depends primarily on the integrity of the intracranial Willis ring.The Willis ring is composed of the anterior,middle and posterior cerebral arteries and the anterior and posterior communicating arteries.The anterior and posterior communicating arteries are responsible for communicating the blood flow between the anterrior cerebral artery(ACA)and the middle cerebral artery(MCA)and between the MCA and the posterior cerebral artery(PCA).In the normal body state,the anternor and posterior communicating arternes are in a state of no function and no opening.When the body is severely stenotic(>70%)or occluded due to various reasons,the blood flow forces on both sides will occur.Changes can 't maintain a normal balance,which leads to a decline in blood supply to the affected side.In order to avoid further necrosis of the brain tissue,the body will ensure the stenosis or occlusion of blood flow in the blood supply area of the blood vessel by opening the primary collateral circulation to avoid brain tissue function lost.The secondary collateral circulation includes blood flow compensation formed by the communication of the ophthalmic artery and the pia mater.When the internal carotid artery segment is severely stenosis or occlusion,when the open primary collateral circulation still cannot meet the body's needs,the collateral circulation between the internal carotid artery and the external carotid artery is established through the ophthalmic artery,and the pial membrane is also opened accordingly.The vascular network avoids infarction in the narrow distal blood supply area.The third-stage collateral circulation refers to new blood vessels,and its establishment mechanism is still unclear,and it is also a hot spot in the current research field[7].The collateral circulation imaging assessment can explain the signs and symptoms of cerebral ischemia,preoperative evaluation for endovascular treatment,selection of treatment options,and evaluation of drug efficacy and assessment of prognosis.Ischemic stroke collateral circulation assessment and intervention Chinese expert consensus:collateral circulation is an important predictor for assessing the clinical outcome of ischemic stroke,and is one of the important factors affecting treatment decision-making.It is recommended to treat ischemic cerebrovascular disease as much as possible.The patient underwent a comprehensive collateral circulation assessment[8].Liebeskind et al.evaluated the collateral circulation of DSA in 287 patients with internationally renowned WASID experiments.The study found that the collateral circulation of patients is closely related to the stroke of the stenotic blood supply area,and the degree of stenosis is 70%-99%.Patients with abundant collateral circulation reduce the risk of stroke in patients with intracranial AS[9].EEG is a highly sensitive electrophysiological test.EEG is a monitoring tool that can effectively reflect brain function after cerebral ischemia,and EEG is often accompanied by clinical symptoms of cerebral ischemia.Clinical auxiliary examination has good timeliness.However,there are few studies on EEG in vascular stenosis.Some studies have shown that EEG may be a slow a wave after cerebral artery stenosis,and it can be used as a method for detecting cerebral vascular stenosis to some extent[10].Hong Zhen et al[11,12]scholars believe that the EEG symmetry index has certain clinical value and advantages in monitoring the collateral circulation and postoperative evaluation of internal carotid artery and middle cerebral artery stenosis.Quantitative EEG was first used to monitor cerebral ischemia in internal carotid artery deprivation.When unilateral internal carotid artery stenosis or clipping,the index of quantitative EEG will change significantly with cerebral perfusion.The recovery will also change accordingly,and changes in brain electrical activity in the ischemic state indirectly reflect changes in brain function after ischemia[10].The middle cerebral artery(MCA)is the most common artery in ischemic stroke,and the MCA region can be divided into the superficial MCA region and the lenticular artery(LSA)region[13].Patients with superficial MCA infarction often cause severe stroke[14].Patients with superficial MCA regional infarction may be associated with involvement of the LSA region.The LSA usually originates from the near segment of the MCA trunk(Ml segment)[15].The diameter of LSA is<0.5 mm,which is the most common and important vascular structure in the human brain and is also the site of many neurological diseases[16].Ischemic and hemorrhagic strokes often occur in areas of the brain that are supplied by these perforating arteries.Basal ganglia infarction accounts for approximately 20%of all infarct rates,and cerebral hemorrhage involving the basal ganglia accounts for 35%-44%[17].Therefore,patients with infarction in the superficial MCA region with LSA infarction have different ranges of affected arteries,which may lead to different mechanisms of stroke.In addition,patients with infarction in the superficial MCA region with LSA involvement may suggest that 1)MCA is blocked by a larger thrombus,which may result in a larger infarction in the donor area of the MCA;2)a more extensive involvement of adjacent corticospinal tracts may result in more severe Motor dysfunction;3)The risk of cerebral palsy is higher due to a larger infarction[18].All of these factors can affect a patient's prognosis.In addition,the mechanism of stroke leading to infarction in the MCA region may vary,depending on whether the infarction in the LSA region is combined.Related studies[18]have shown that patients with infarction in the superficial MCA region are often accompanied by more severe clinical symptoms and a larger infarct volume.The bean-arterial blood supply area includes the main body of the upper part of the caudate nucleus,the shell nucleus,the outer part of the globus pallidus,the upper part of the forelimb and hind limb of the inner sac,the knee,and one third of the outer side of the inner sac[171.The involvement of LSA is almost the most powerful predictor of poor functional outcomes and stroke mortality.Therefore,attention to LSA lesions is of great significance for the prevention and treatment of cerebral small vessel disease.In the case of ischemia caused by stenosis or occlusion of the middle cerebral artery,the lenticular artery(LSA)and other perforating arteries may play a role in the supply of collaterals.Bean-like arteries(LSAs)are perforating arteries that supply the inner capsule and basal ganglia.They are one of the most important vascular structures in the human brain and are the origin of many neurological diseases,such as infarction or hemorrhage.Infarction due to acute occlusion of these perforating arteries leads to severe clinical symptoms.There are only a handful of studies on LSAs,mainly because the visualization of the LSA branch is difficult.Recently,the LSA branch has been successfully visualized by magnetic resonance angiography(MRA)with a field strength of 7.0T.Despite the high field strength,the spatial resolution of small details is limited,and the availability and usefulness of the 7.OT MR imaging system is very limited and limited to experimental sites[19].Therefore,in clinical practice,visualization of the perforating arterioles is primarily achieved by digital subtraction angiography(DSA).We found on the conventional DSA that the bean vein arteries are not always like the brush brush described in the book,and most of them are re-issued on the basis of one or two or more large blood vessel trunks.We think that this large blood vessel trunk once Occlusion or arterial rupture will result in severe clinical symptoms and poor clinical outcomes.We believe that understanding the anatomical variation of the bean vein helps to prevent the occurrence of cerebral small vessel disease.To the best of our knowledge,a few studies have found anatomical vanations in the bean vein arteries.Kang et al[19]observed that 61.2%of the bean vein originated from a single vessel trunk,and 38.8%originated from two or more vessel trunks.In addition,they describe that among these trunks,most are found to be from the MCA,while a smaller number is from the ACA or from the ICA fork.In a previous study by Umansky[20]et al,it was found that the LSA of a single vessel trunk accounted for approximately 50%,and the other 50%originated from the common brush-like shape.It is difficult to describe in vivo visualization of these small arteries using conventional angiographic imaging methods,and DSA provides sufficient spatial and temporal resolution.With the spatial resolution of non-invasive imaging such as MR and CT angiography,continuous improvement in acquisition time and post-processing capabilities(for three-dimensional reconstruction),the demand for cerebral angiography is decreasing.However,digital subtraction angiography provides dynamic information about the presence of arteriovenous shunt,collateral vessel supply,and parenchymal perfusion,a feature that is still not available with the most advanced CT or MRI techniques.Most importantly,digital subtraction angiography remains the best way to identify tiny vascular structures in the brain,neck and spine.According to the study of single-detector spiral CT,the sensitivity of CT angiography to intracranial aneurysms>3 mm is between 83%and 100%.However,for intracranial aneurysms of 3 mm or less,the sensitivity is reduced to 51%-98%,so it needs to be confirmed by digital subtraction angiography[15,21].Because DSA has a very high resolution and good resolving power for tiny blood vessels,it is the most accurate imaging tool for clinical observation and evaluation of tiny blood vessels.Part 1 Lenticulostriate Artery under digital subtraction angiographyObjective According to digital subtraction angiography(DSA),explored the origin,morphology and symmetry of the lenticulostriate artery(LSA)and classified base on its morphology.Methods A total of 316 patients who have performed digital subtraction angiography(DSA)were enrolled and the 543 normal side of the middle cerebral artery were selected.To observe the origin,morphology and symmetry of the lenticulostriate artery(LSA)and classify according to morphologically.Results Our research find that the lenticulostriate artery mainly originates from the M1 segment of the middle cerebral artery and the segment A1 of the anterior cerebral artery by DSA.Excluding the 33 side(6.1%)lenticulostriate artery are poor development,observe the remaining 510 side:the brush type had 254 sides(49.8%);the single dry type 145 side(28.4%);the double dry type 68 side(13.3%);more dry type 43 side(8.4%).There are consistent 69 patients with bilateral lenticulostriate arteries,accounting for 30.4%of all patients enrolled bilaterally.Conclusion The development rate of the lenticulostriate artery was 93.9%by DSA,which mainly originated from the M1 segment of the middle cerebral artery and the segment A1 of the anterior cerebral artery.It is common for the co-drying phenomenon,some lenticulostriate arteries even have two or more trunks.Bilateral lenticulostriate arteries are not always symmetrically distributed.Understanding the lenticulostriate arteries has important clinical significance for the discovery,diagnosis and evaluation of cerebral small vessel disease.Part 2 Application of quantitative EEG in monitoring cerebral perfusion of severe stenosis of middle cerebral arteryObjective Base on CT perfusion,to investigate the application of quantitative electroencephalography(QEEG)in monitoring the cerebral perfusion of severe stenosis of middle cerebral artery(MCA).Methods A total of 60 patients with unilateral severe stenosis of middle cerebral artery confirmed by brain angiography(DSA).According to brain CT perfusion imaging,it is divided into Pre-cerebral infarction I group,Pre-cerebral infarction II group and cerebral infarction group.The 16-lead EEG was performed in all cases,and the spatial brain symmetry index(sBSI),temporal brain symmetry index(tBSI)and Delta and theta/alpha+ beta ratio(DTABR)were calculated by MATLAB software.Analysis of the correlation between different groups of sBSI,tBSI and DTABR.Results The differences in tBSI and sBSI between the three groups were statistically significant,and there were significant differences between any two groups(p<0.05).DTABR was statistically significant between the Pre-cerebral infarction I group and cerebral infarction group(p<0.05).The tBSI,sBSI,and DTABR were negatively correlated with brain perfusion.Conclusion As a non-invasive and objective examination method,quantitative EEG has certain significance for monitoring cerebral perfusion of unilateral middle cerebral artery stenosis.The tBSI,sBSI,and DTABR were negatively correlated with cerebral perfusion of vascular stenosis.