The Application Of Magnetic Resonance Spectroscopy In The Diagnosis Of Ischemic Cerebrovascular Disease

Part 1 The correlation of intracranial metabolites with cerebral blood flow and NIHSS score in ischemic cerebrovascular diseaseResearch background: Ischemic stroke is the most common cerebrovascular disease,with a high rate of disability and mortality.The severity of the disease,the possible prognosis,and the possibility of rehabilitation have been the most concern of the patients and their families.Although various scores,CT imaging and magnetic resonance imaging have been used to evaluate the patient's condition and prognosis,all these are indirect evidence,and there are still deficiencies in objective assessment of injury.Positron emission tomography can not only provide the cerebral blood flow and cerebral blood volume,but also effectively and accurately determine the tissue metabolism rate by cerebral oxygen uptake rate and cerebral oxygen metabolism,provide the basis for the diagnosis of ischemic stroke.But due to the high cost and long time check,its clinical application is limited.Magnetic resonance spectroscopy is a noninvasive method to detect and quantify metabolites in brain tissue.Other imaging methods can only provide the histological changes and the pathological process of indirect observation of the organization.MRS can observe the level of material metabolism,the reaction activity and function of the organization directly,providing a more direct and reliable evidence for the diagnosis from the point of view of organization functionObjective: 1.To compare the changes of bilateral brain tissue metabolites after ischemia;2.To analysis of the relationship between metabolism and perfusion of ischemic parts of cerebral ischemia patients;3.To explore the application value of MRS in the diagnosis and prognosis evaluation of cerebral ischemia patients.Methods: In Department of Neurosurgery,General Hospital of Shenyang military,thirty-six cases of carotid artery system or vertebral artery stenosis and cerebral ischemia symptoms,which diagnosed by DSA or CTA were enrolled in this study.The collected data includes the patient's basic information,history,NIHSS score and perform routine magnetic resonance,magnetic resonance spectroscopy,CT perfusion imaging.SPSS 22 statistical software was used to compare the difference between the focus center and the contralateral mirror area of metabolites and perfusion.The difference of metabolites and perfusion on both sides of brain was measured by paired T test.The relevance between metabolites,cerebral blood flow perfusion and NIHSS score was analyzed.Results:(1)There is a significant difference in the metabolic content of the brain tissue in the ipsilateral and the contralateral side of the stroke patients(P<0.01).(2)The CBF and CBV of the ischemic tissue was significantly lower than that of the contralateral mirror(P<0.01),MTT and TTP have significant prolonged(P<0.01).(3)There was a negative correlation between the NAA/Cr and NIHSS scores of the metabolites of ischemic tissue(rs=-0.477,P=0.003 < 0.01),There is no significant correlation between Cho/Cr,Cho/NAA and NIHSS scores(the correlation coefficients are rs=-0.025,P=0.884;rs=0.205,P=0.230);(4)There is no significant correlation between the metabolites of the ischemic site and the parameters of cerebral blood flow perfusion(P>0.05);(5)CBF,CBV,MTT and TTP had no significant correlation with NIHSS score,(the correlation coefficients were rs=0.095,P=0.58;rs=0.104,P=0.545;rs=-0.045,P=0.797;rs=-0.196 P=0.251.)Conclusion:1.After the occurrence of ischemic cerebrovascular disease,the metabolism of the affected side is obviously changed.MRS can effectively detect the change of metabolites and provide a direct diagnostic basis for the diagnosis of disease.2.The level of metabolites in the brain has a certain correlation with the neurological function of the patients,which is of certain significance for predicting the prognosis of the patients.3.There is no significant correlation between the level of the metabolites in the brain and the blood flow perfusion in the brain.MRS is superior to CTP in judging and evaluating the damage of nerve function.Part 2 Application of N-acetylasparagine in the diagnosis of ischemic cerebrovascular disease: Meta analysisResearch background: As one of the main metabolites of proton magnetic resonance spectroscopy,NAA detects the neuronal loss and gliosis in brain tissue after stroke in the reaction,which can be used to evaluate the nerve function damage degree of cerebral apoplexy.It is an important index for evaluation of neuronal function of proton magnetic resonance spectroscopy.The absolute concentration of NAA is affected by different patients,different locations,different machine checks and so on.Therefore,NAA comparison among different patients often use relative value.After reviewing previous literature,the relative value algorithms of different studies are different.The commonly used relative values are NAA/Cr,NAA/Cho,and r NAA.Different research results can lead to no cross comparison.There is no definite reference value to determine the result.Further discussion is needed.Objective:1.To summarize the changes of NAA level in ischemic cerebral vascular disease patients.2.To evaluate the value of NAA/Cr,NAA/Cho and r NAA as the evaluation of neuron damage index.3.To explore the effect scale of NAA concentration as a criterion for judging the standard of neuron damage.Methods:1.Retrieve the literatures published on Pub Med?Cochrane Library?Web of science?CNKI?VIP database and Wanfang database,both in the Chinese and English.And the period is from January 1995 to December 2017.2.According to the inclusion criteria and the exclusion criteria,the retrieved literature was screened and the data was extracted.3.The Newcastle-Ottawa Scale(NOS)scale was used to evaluate the methodological quality of the integrated research.4.Revman 5.3 software was used for Meta analysis,heterogeneity test,bias test,sensitivity analysis and subgroup analysis were used to draw conclusions and discuss.Results:A total of 24 articles,including 6 English articles and 18 Chinese literatures,were screened out in this study.908 patients were classified and analyzed for different data types.There are 18 articles in the study of NAA/Cr level,including 4 English literature and 13 Chinese literature.After heterogeneity test,the heterogeneity of NAA/Cr data is large(X2=467.04,P<0.00001,I2=97%=.After subgroup analysis,it was found that the chronic phase group had a great influence on the heterogeneity,and the data were combined in the hyperacute,acute and subacute phase(SMD=-0.47,95%CI[-0.59,-0.36]),and the chronic phase(SMD =-1.09,95%CI[-1.63,-0.55]).In 24 literature,NAA/Cho was used as the study index in 4 articles,including 139 patients.(SMD is-0.26,95%CI[-0.37,-0.51],P<0.00001=.There were 8 articles including or using r NAA as an observation index,including 265 patients.The result of heterogeneity test is I2 =97%.After the removal of a higher heterogeneity of the literature,the SMD is-0.47,95%[-0.52,-0.42],P<0.00001.Conclusion:1.The concentration of NAA after cerebral infarction can evaluate nerve injury,NAA/Cr is the most commonly used evaluation index,which can reflect the degree of nerve injury.2.As a evaluation index,NAA/Cho has good stability and sensitivity.3.As an observation index,r NAA can also identify the nerve injury after infarction.The sensitivity and stability are not as good as NAA/Cr and NAA/Cho.The application is relatively limited.