| Background:Acute ischemic stroke is the most common cerebrovascular disease with high mortality and morbidity which endangers the patients to illness. It still remains hot-spot topics that how to prevent the cerebral infarction and how to eliminate the disability caused by ischemic lesions. Although up-to-date treatments was focused on the infarction lesion and its peripheral tissues, autopsy, pathology and animal experiments have attested to secondary injury such as demyelination of nerve fibers, axonal degeneration and neuronal cell loss occurred in distant areas after focal cerebral infarction. The clinic research about this secondary damage goes further with the development of medical imaging technology. In the early phase, people noticed that low-density signals would occur at cerebral peduncle and pons supported by the cerebral middle artery after cerebral hemisphere’s infarction. This is the first case to show the secondary injury observed in living patient. The research of MRI reveals that platy long T1, T2with unclear border or high signal areas on DWI might happen at mesencephalon, pons and medulla oblongata after supratentorial cerebral infarction in acute phase, subacute phase and recovery phase. This enriches the knowledge of the secondary impairment at the distant areas. Diffusion tensor imaging (DTI) not only can yield up the morphology of secondary injury at distant areas in graph, but also accurately reveal the extent of those damage in digital which promote the researches to a new level. The study applied with DTI illustrates that signal weaken area contrast to the fibers’route of pyramidal tract infarction appears in the fractional anisotropy chart after local cerebral infarction with pyramidal tract involved in while it can’t be seen in the apparent diffusion coefficient chart. The analysis of these parameter declares that the decrease of FA value and unobvious change or slightly increase of MD at those infarction areas which shows DTI’s prevalence. Previous studies stated that the distant areas would take place the secondary impairment which had nerve fiber connection with infarction after cerebral infarction and this happened to substantia nigra after the infarction of corpus striatum. Locus ruber and substantia nigra all belongs to cerebral nuclei in basal ganglia region and have extensive fiber connection with corpus striatum etc. Nevertheless whether the red nuclei will appear the secondary injury after corpus striatum infarction or not, its characters and significance remains unclear. Our study is to observe the changes of red nucleus’s dispersion amount parameter in patients suffered striatum infarction by diffusion tensor imaging(DTI) and to discuss its characteristic and significance as well.Objective:We used DTI to dynamically observe the changes of the signal and parameters of DTI in red nuclei under focal striatum infarction in our prospective study and to analyze the relationship of these data and neuron functional recovery, following to approach its evolution and clinic significance.Methods:Nine consecutive patients with cerebral infarction hospitalized in the neurology department at the First Affiliated Hospital of GuangXi Medical University from March2009to May2010were included in the experiment group. Those patients must be in line with these following conditions such as:①initial attack within the acute phase;②unilateral striatum infarction should be confirmed by conventional MRI and DWI without any abnormal signals in other regions;③patients with a history of the central nervous system diseases such as cerebral infarction, cerebral hemorrhage, encephalitis, multiple sclerosis etc or patients with palingenetic infarction during follow-up period were excluded. Nine healthy volunteers in the control group matched with the experiment group in gender and age. Patients in the experiment group underwent DTI respectively in the first week, forth week and the twelfth week while patients in the control group only proceeded one time DTI. All the patients were evaluated with the National Institutes of Health Stroke Scale(NIHSS) and the Barthel Index(BI) to assess the loss of neuron function and ability of daily life between each DTI. All the data were unitively analyzed after this experiment. Voxel equivalent with2of the region of interest in the lesion side’s red nuclei region was chosen and mean diffusivity(MD)and fractional anisotropy(FA)were separately measured.Results:The signals in infarcted region got more evident along with the time prolonged in regular MRI, ADC figure, FA figure, false color map and FA. Red nuclei position of the midbrain plane with the same side of the lesion at W1, W4and W12in regular MRI and ADC figure, FA figure, false color map and FA had not seen any anomalous signals. According to the analysis of DTI’s data, FA value in the lesion notably reduced(P<0.05) at W1(0.41±0.12), W4(0.31±0.07) and W12(0.27±0.08) while MD value evidently increased(P<0.05) at W1(0.57±0.13), W4(0.66±0.11) and W12(0.81±0.07) compared to the corresponding positon in the control group. According to the analysis of DTI’s data in red nuclei, FA values in the red nuclei lesion at W1, W2and W3all reduced with the trend of W12> W4> W1while were still lower than the control group, MD value increased at W1(0.66±0.09)(P<0.05) but had no statistical significance at W4(0.60±0.11) and W12(0.58±0.11)(P>0.05) compared to the corresponding positon in the control group. MD values at W4and W12were bigger than MD value at W1(P<0.05). During three months of the observation, FA value had the increasing trend while were still lower than the control group and MD value increased in the first month. There was correlation between percentage absolute value of FA value’s change in the red nuclei of the lesion’s side with percentage absolute value of BI grade’s change(P <0.05).Conclusion:The striatum infarction can lead to the secondary injury of red nuclear in the midbrain plane below the same side while it can’t be detected by conventional MRI and DTI image can’t reveal the lesion. The analysis of the DTI’s parameters can find and accurately quantize the the extent of damage in the form of data. This secondary damage eases gradually over time prolonged which indicates that there appears the remodeling phenomenon after the secondary damage. The phenomenon of nerve remodeling profit to patients’ recovery of nervous function. |
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