Evaluation Of Clinical Prognosis In Patients With Acute Cerebral Infarction By Diffusion Tensor Imaging

Background and Purpose Ischemic stroke accounts for about 70-80% of the total incidence of cerebrovascular disease and is a foremost cause of human disability and death. It is a kind of common and frequently-occurring disease which seriously threats human health.Common sequelae include paralysis, abnormal sensation aphasia, and so on. For acute cerebral infarction, we are no longer confined to the simple diagnosis, but also to try to evaluate the degree of motor function impairment and to determine the clinical prognosis of the patients. Magnetic resonance diffusion tensor imaging(DTI) can provide abundant information on corticospinal tract(CST) injury. In this study, we explored the correlation between the information obtained by DTI and the limb injury in patients with acute cerebral infarction, which may bring new insight into the prognosis of the stroke in early stage.Material And Methods 1.We observed those patients who were in hospital in the Department of Neurology,Affiliated Hospital of Hebei University from July 2013 to January 2015, due to acute cerebral infarction. We selected 42 patients who presented in motor dysfunction, with no previous history of neurological disease. Records of patients with general personal information, anamnesis, etc.2. Multimodal MR imaging, including DTI sequence was performed within 72 hours of stroke onset and on the 12 th week on those paients. The DTI parameters,apparent diffusion coefficient(ADC) and fractional anisotropy(FA) values were measured at multiple white matter locations. We drew a mark at the three-fifths of the cerebral peduncle, regarding it as the starting point for corticospinal tract imaging. According to the correlation between positions of infarctions and CST, we divided CST into 3 grades, grade CST-1: CST was mild damaged; grade CST-2: CST was moderate damaged; grade CST-3:CST was severe damaged. All patients were divided into 3 groups accordingly.The clinical scores of the National Institutes of Health Stroke Scale(NIHSS) were assessed on admssion,on the 1st week, 4th weeks and 12 th weeks. According to the NIHSS score on the 12 th weeks,we divided the patients into two groups, NIHSS-1: patients with mild impairment of nerve function; NIHSS-2: patients with moderate impairment of nerve function. 3.We statistic the date by SPSS 16.0.RESULTS Comparing to the contralateral side, FA and ADC values were significantly decreased after stroke onset(FA 0.49±0.14,p<0.001; ADC 0.76±0.13,p <0.001), that is, the measured FA value and ADC value can provide a reference for the diagnosis of cerebral infarction. The NIHSS score decreased significantly over the time points from stroke onset to4 th weeks(The mean rank of NIHSS score at different time points in CST-1 group : on admission 4 points, 1st week of the admission 4 points,1st month of the admission 1 points,3rd months of the admission 1 points; The mean rank of NIHSS score at different time points in CST-2 group:on admission 5 points, 1st week of the admission 6 points,1st month of the admission 3 points, 3rd months of the admission 2 points; The mean rank of NIHSS score at different time points in CST-3 group:on admission 18 points, on admission 16.5 points,1st month of the admission 16 points, 3rd months of the admission 12 points), it shows that the nerve function of the patients improved by 3 months, recovery. Significant difference have found with FA values of the two different NIHSS score groups(the FA value of NIHSS-1group:0.30±0.12, the FA value of NIHSS-1 group:0.14±0.09, p< 0.001), while no difference were found in ADC values(the ADC value of NIHSS-1 group:0.47±025, the ADC value of NIHSS-2 group:0.52±0.16, p=0.82). Through Wilcoxon rank sum test, significant difference were found between r FA and NIHSS score(the mean rank of r FA value was 49.05, the mean rank of NIHSS score was 29.95,p < 0.05); The extent of CST damage and motor dysfunction gradation shows a strong significant difference(the mean rank of CST-1 group was 8.96,the mean rank of CST-2 group was 22.15,the mean rank of CST-3 group was 34.75,p <0.001)?We used the logistic regression to analyze FA, r FA and the grade of CST with the NIHSS scores at the 3rd months, we found that the extent of CST damage was determined to be independently related to clinical outcome scores(OR=46.64).CONCLUSION The DTI parameters, FA and r FA, can evaluate motor function outcome in acute stroke patients, which also deserves further research. Furthermore, we found that the degree of CST damaged could help to assess aspects of a patient's individual recovery potential and to determine optimal neuro-rehabilitative interventions, undoubtedly. There is no clear evidence shows that ADC is associated with the prognosis of the patients with acute cerebral infarction.