The Application Of Proton Magnetic Resonance Spectroscopy In Acute Cerebral Infarction

Objective:Cerebral infarction is an important lethal and disabled factorto aged people. It was reported that its survival rate was83%in one month,71%in one year and and46%in five years. At present the most effectivetreatment is thrombolysis and stroke units. Ideal therapeutic time window forthrombolysis is limited to4.5hours, so early thrombolysis is critical forfunctional recovery, increasing survival rate and improving the life quality.Therefore, it has become an important topic to diagnose cerebral infarctionand predict the prognosis in the early period. To date,¹H magnetic resonancespectroscopic imaging(¹HMRS) is the only noninvasive detection ofbiochemical and metabolic changes in vivo. It can detect the dynamic changesof the metabolites in acute cerebral infarction and provide additional clinicalevidence for the early diagnosis, treatment and prognosis. Our researchobserved all the index of DWI and¹HMRS, which belong to function MRI, inacute cerebral infarction patients in order to explore the application value ofDWI and¹HMRS in cerebral infarction.Methods:Thirty patients with acute cerebral infarction within3days ofclinical onset were studied in neurology department of our hospital. They allmet the diagnostic criteria from Fourth National Cerebrovascular DiseaseConference and had neurologic impairment. Conventional MRI,MRA,DWIand¹HMRS were performed on all patients by a Siemens Tim-avanto1.5Tsuperconductance magnetic resonance on admission and two weeks later.¹HMRS multi-body grain collection scope included lesion and normal braintissue of opposide side, getting the metabolites value of the¹HMRS:N-acetylaspartate (NAA), choline compounds (Cho), creatine (Cr), lactate (Lac) andMRI. All the patients,National Institutes of Health Stroke Scale (NIHSS)score evaluated on admission and two weeks later were named NIHSS₁, NIHSS₂. The NIHSS₁, NIHSS₂score and metabolite concentration andrelative concentration detected by¹HMRS were analyzed. The data wasanalyzed by SPSS13.0statistic software, Measurement data meeting normaldistribution used the t test and meeting nonnormal distribution usenon-parament test, correlation analysis used Spearman correlation.Results:1In all the patients, NIHSS score was average6.80±4.44(ranged from1to18) and and NIHSS score was averaged3.83±2.96(ranged from0to16).After treating for two weeks, neurologic impairement was improved andNIHSS score was declined. The difference was significant(P<0.05).2Thirty seven lesions were found in30patients.18lesions in T₂WIshowed fuzzy boundary hyperintense,2showed isointensity and17wereborder clear long T₁, T₂signal,2signal, in DWI, all37lesions werehyperintense. After two weeks, all lesions displayed typical infarct images,which were obviously long T₁and long T₂signals with clear boundary.Compared with initial MR scanning, in the DWI3lesions expanded,1turnedsmall, and the remaining variation was not obvious.3According to the extent of the lesion in DWI, we could get therespective MRS spectroscopy. Compared with the contralateral side, NAA,Crof lesion side decreased, Cho level of18patients decreased,12cases elevated,Lac peak may be detected in the lesion side, among these,13patients werealso detected Lac peak, but the peak was low.4In30patients with MRS examination, NAA in the center of the infarctarea was lower than opposite mirror image, two samples confirmedstatistically significant (Z=-4.762,P=0.000). Cr in the center of the cerebralinfarction was lower than opposite mirror image, two samples showed that thedifference was significant (Z=-3.569,P=0.000).Increased Lactic acid peakcould be seen in the infarct area of all patients, and after two weeks lactic acidpeak began to decrease but still maintain a relatively high level. NIHSS₂wasoberviously lower than NIHSS₁, and the difference was significant. The rNAAvalue of lesion sites on admission were different from that of two weeks later, but the difference was not significant(P>0.05), and rCr,rCho,Lac/Cr were notstatistically significance.5In all patients, NAA of infarct center had negative correlation withNIHSS₁and NIHSS₂(r=0.801P=0.000,r=0.623P=0.000). Lac of infarctcenter had positive correlation with NIHSS₂(r=0.468P=0.009), had nocorrelation with NIHSS₁.Conclusions:1¹HMRS can sensitively detect the early infarct brain metabolite changes,so it can offer important and reliable imaging accordance for diagnosis ofacute cerebral infarction.2Magnetic resonance spectrum (MRS) analysis techniques can detectdynamic changes of metabolites in acute cerebral infarction patientsnon-invasively, which can get more clinical evidence for early diagnosis,treatment and prognosis of the disease.3The patients with acute cerebral infarction were examined¹HMRSassociated DWI, which could get the evidence of etiological and locationaldiagnosis in order to choose more reasonable therapy for clinician.