| Objective: Subcortical arteriosclerotic encephalopathy (SAE) is acommon type of vascular dementia, and is one of the major diseases whichcauses cognitive impairment in elderly people. Research indicates that elderlypeople ischemic white matter lesions (WMIL) incidence rate is50%to98%,and with the development of medical imaging and the aging of the socialpopulation, its incidence is increasing year by year. Hydrogenproton magneticresonance spectroscopy (~1HMRS) is a noninvasive method that detects thehuman body compound concentration directly. According to the~1HMRS, thelesions can be penetrated to the level of cell metabolism, and which is of greatimportance to the pathophysiological changes, diagnosis, the prognosis andtreatment evaluation of lesions. Event related potentials (ERPs) P300is ancrucial examination for cognitive impairment, the latency (PL) is theindicators of cognitive processing time. This research by analyzing the riskfactors for WMIL patients and the characteristics of~1HMRS metabolites, P300latency and amplitude in WMIL patients, is designed to achieve the purpose ofearly prevention, early diagnosis and early treatment of SAE.Method：We chose50patients with WMIL in July2011to December2012as research subjects, and divided them into two groups based on clinicalfeature: group SAE (30cases) and group non-SAE (group N-SAE,20cases),meanwhile selected20normal cases as a control group. Patients in group SAEmet the SAE diagnostic criteria which was proposed by Guo Hongzhi,including male18cases and female12cases, age55to80years, average age65.20±12.19years old. All subjects completed medical history collection,Mini-Mental Status Examination (MMSE) score, magnetic resonance imaging(MRI),~1HMRS and P300examination,~1HMRS multi-voxel collection rangeincluded white matter around the lateral ventricle. Compared medical history of50WMIL patients with20normal subjects. Analyzed the characteristics ofwhite matter lesion around the lateral ventricles’ metabolite: N-acetylaspartate(NAA), creatine(Cr), choline (Cho), NAA/Cr, and compared with the controlgroup; Analyzed the characteristics of P300latency and amplitude in SAEgroup, N-SAE group and control group. Observed whether there wascorrelation between~1HMRS metabolite values and MMSE score in SAEgroup and N-SAE group. Drew the ROC curves according to the results of the~1HMRS and P300and calculated the area under the curve. All data wasanalyzed by SPSS13.0statistical software, measurement data usingnon-parametric signed rank test and count data using chi-square test,correlation analysis used Spearman correlation analysis. The two test resultsmapping plotted the ROC curve.Results:1The risk factors for WMIL: Medical history (included hypertension,stroke, diabetes, hyperlipaemia) were compared between50WMIL patientsand20normal controls. The results: history of hypertension:43cases inWMIL group with hypertension history (86%),12cases in control group withhypertension history (60%), the difference was statistically significant(P<0.05); history of stroke:39cases in WMIL group with stroke history(78%),6cases in control group with stroke history (30%), the difference wasstatistically significant (P<0.05); history of diabetes:33cases in WMIL groupwith diabetes history (66%),8cases in control group with diabetes history(40%), the difference was statistically significant (P<0.05); history ofhyperlipaemia:31cases in WMIL group with hyperlipaemia history (62%),7cases in control group with hyperlipaemia history (35%), the difference wasstatistically significant (P<0.05).2SAE Group: MMSE score of30cases was average22.966±2.722(ranged from18to29), MMSE score was lower than the MMSE score ofN-SAE group, the difference was statistically significant (P<0.05); the NAAlevel was lower than those in N-SAE group, and the difference wasstatistically significant (P<0.05); NAA/Cr was lower than those in N-SAE group, and the difference was statistically significant (P<0.05); the level ofCho compared with N-SAE group, the difference was not statisticallysignificant (P>0.05); the level of Cr compared with N-SAE group, thedifference was not statistically significant (P>0.05); P300latency extended,and amplitude decreased, compared with the N-SAE group, both thedifferences were statistically significant (P<0.05).3N-SAE Group: MMSE score of N-SAE group was average26.350±1.599(ranged from24to30), MMSE score was lower than the MMSE scoreof control group, the difference was statistically significant (P<0.05); the NAAlevel was lower than those in control group, and the difference wasstatistically significant (P<0.05); NAA/Cr was lower than those in controlgroup, and the difference was statistically significant (P<0.05); the level ofCho compared with control group, difference was not statistically significant(P>0.05); the level of Cr compared with control group, the difference was notstatistically significant (P>0.05); P300latency extended, and amplitudedecreased, compared with the control group, both the differences werestatistically significant (P<0.05).4Correlation between~1HMRS metabolites and MMSE score:~1HMRSmetabolic NAA and MMSE score of SAE group were positive correlation(r=0.746, P=0.000);~1HMRS metabolic NAA and MMSE score of N-SAEgroup were positive correlation (r=0.730P=0.000).5ROC curve analysis showed that the area under the curve of magneticresonance spectroscopy NAA was greater than the area under the curve ofP300latency (AUC=0.975, standard error=0.018, P=0.000; AUC=0.868,standard error=0.051, P=0.000).Conclusions:1Hypertension, stroke, diabetes and hyperlipaemia may be the riskfactors for WMIL.2~1HMRS as a non-invasive detection of nerve tissue metabolitesquantitative analysis technique, is a more specific description of brain tissueischemia and injury severity than conventional MRI. 3~1HMRS metabolites NAA reflects the degree of cognitive impairmentin patients with WMIL, and predicts the risk of only leukoaraiosis (LA)progress to SAE. It means that, more lower NAA level of only LA patients,more serious cognitive impairment, more higher risk of progression to theSAE.4~1HMRS can find whether the only LA patient has cognitive impairmentand its severity earlier than P300, therefore it has more contributes to the earlydiagnosis of SAE.5~1HMRS is able to display the characteristics of neuronal metabolism ofwhite matter lesions in patients with SAE and only LA.~1HMRS can be used asan objective basis for early assessment of cognitive impairment, earlydiagnosis and treatment in SAE patients. |
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