| Intracerebral hemorrhage is the most destructive type of the stroke, it has high incidence and high mortality. The survival of patients with about 30%-40% occurre in varying degrees of neurological dysfunction, 6 months later only about 20% of the patients can self-care. Therefore, it has important clinical significance to research the neurological damage and repair mechanisms of ICH, also to judge the prognosis of the disease early. Diffusion tensor imaging (DTI) is a new non-invasive examination means, which developed on the basis of diffusion weighted imaging (DWI). Its theoretical foundation is diffusion anisotropy characteristics of the sport of water molecules. DTI analyses the diffusion of water molecules sports in three-dimensional space at quantitative, reflects the pathological changes of the organization from a microscopic point of view. Diffusion tensor tractography (DTT) reconstructs the three-dimensional images of the white matter fiber bundles by the data DTI obtained. DTT can present the morphological structure and the distribution of the fiber bundle by three-dimensional visual. It also shows the direct or indirect affects which lesions did to white matter fiber tract. At present, some studies suggest that anisotropic diffusion of the lesion area in cerebral hemorrhage reduces. But there is scarcely study to posited the spatial relationship between the hemorrhagic foci and the fiber bundle, also to analize the extent of fiber damage quantitatively. Therefore, we selected 36 patients with cerebral hemorrhage involving the corticospinal tract(CST), collected their DTI parameters and rebuild DTT images using the original DTI data. We observed the changes of the fiber bundle morphology and course, and analyzed the extent of their injury quantitatively. All patients were evaluated to obtain the neurological deficit scores, at early onset, 2 weeks, a month and two months separately. Analyzing the relationship between the level of corticospinal tract damagement and the the degree of neurological deficit. Researching the value of early DTI, DTT inspection at the prognosis of patients with cerebral hemorrhage prediction. From this we can looking for a new theoretical basis to predict the clinical outcome and choose the treatment of cerebral hemorrhage patients.1 SubjectsFrom February 2008 to January 2009, 36 patients(19men,17 women, age range 38 to 87 years old,the average 59-year-old) with acute intracerebral hemorrhage in the first hospital of JiLin university were choosen as study cases. Inclusion standard:①Acute onset, diagnosed according to China's current diagnostic criteria of cerebral hemorrhage.②Mostly having the hemiplegia as clinical manifestation, lesions located in the basal ganglia or corona radiata district.③All patierts were Informed and consent. Exclusion standard:①Having obviously conscious disturbance and severe cognitive handicap.②Restlessness or aphasia patients.③The body has a fixed metal dentures, metallic foreign bodies or cardiac pacemakers.④Patients who died or interrupted the contact during the follow-up time lead to incomplete data.2 Experimental methods(1)Assessment of neurological function: The muscle strength and NIHSS score of all the patients were judged at the stage of onset, two-weeks after onset, a month after onset, two month after onset.(2)Image Acquisition: Every patients received and diffusion tensor imaging(DTI) and diffusion tensor tractography(DTT) at 7th～16th day after onset. MRI was performed on a 1.5 T system (Philips Achieva) with a maximum gradient strength of 40 mT/m, and 200 T/m·s slew rate with a eight-channel phased-array head coil. DTI sequence: The imaging parameters used were as follows: TR/ TE = 3900/ 76 ms, field of view(FOV) = 230 mm×230 mm, matrix = 112mm×89mm and a slice thickness of 5.0 mm. We acquired 44 contiguous slices parallel to the anterior commissure–posterior commissure line, b = 0 & 800 mm2 /s, with diffusion gradients applied in twelve non-collinear directions, two averages, acquisition time: 3.53minutes.(3)Postprocessing: We evaluated fiber connectivity using a three-dimensional fiber reconstruction algorithm contained within the software package. The FA values were measured on regions of interest in the FA map. We Chose damage region of ipsilateral CST and the corresponding regions of the contralateral CST as interested regions. We selected three regions on each side, then calculated the average. A seed region of interest was drawn on a two-dimensional FA color map at the mid-portion of the internal capsule and the cerebral peduncle to include the entire CST. The three-dimensional fiber tract was superimposed on the neighboring images in order to judge the injury degree of CST in the affected hemisphere.(4)Projects evaluated: We compared the FA values of bilateral CST in order to analyze the relevance between FA values decrease and the NIHSS score. Patients were allocated according to damage extent of the CST as DTT shown. We analyzed the correlation of muscle strength and NIHSS scores among the groups in order to judge the relevance of between CST injury and clinical prognosis.(5)Statistical treatment: We used the software SPSS10.0 to statistic by t test, correlation analysis andχ2 test.3 Results:①The FA values of the ipsilateral CST at damaged zone decreased according to the contralateral corresponding regions. It has a significant difference statistically (t=14.3758, p<0.05).②T he percentage which FA values reduced in the area of the affected CST had relevance with the NIHSS score values ( r=0.9516, p < 0.05).③Bilateral CST were reconstructed. The contralateral fibers that walked down from precentral gyrus to internal capsule, pontine and medulla oblongata arranged neatly and completely. Because of the hemorrhagic foci, the injured CST were oppressed, disfigurated or interrupted. The patients were divided into three groups according to the extent of CST damagement. There are 7 cases of grade 1(complete CST), 14cases of grade 2(CST were destroyed, the number of and interrupted fiber bundles were less than 1/3), 15cases of grade 3(CST were destroyed, the number of and interrupted fiber bundles were more than 1/3).④A total of 36 cases were involved in the result analysis. Injured degree of CST was siginificantly associated with hemiplegia muscle strength (at the atage of onset, a month after onset, two month after onset, p<0.05), Injured degree of CST was siginificantly associated with the NIHSS score (p<0.05), Injured degree of CST was siginificantly associated with turnover of the NIHSS score vesting at two month after onset. (p<0.05).4 Conclusion:①FA values could assess the neurological injury quantitatively. The percentage which FA values reduced in the area of the affected CST has relevance with the NIHSS score.②3D fiber tract maps could display the status of pyramidal tract more stereotacticly and judge their injury degree at early stage of the ICH. CST were injured to varying degrees in patients suffering from the acute ICH. The degree of the injury was associated with muscle strength and NIHSS score. The patients with complete CST would have lighter damage of the neurological function and better rehabilitation. It is indicated that it can be used for prognosis of rehabilitative treatment in patients with hemorrhage.In a word, any reason caused the pathological changes of CST and motor functional region structure, effected its transmission function, will cause muscle weakness. The injure degree of CST has negative correlation with muscle strength, and positive correlation. Patients with lighter injury degree of CST will have better prognosis. Diffusion tensor tractography is the unique examination that can evaluate the integrity of the cerebral white matter fiber tracts in three-dimensional without any intrusion. It can clearly show the changes of the white matter fiber tracts which influenced by neurological diseases. In the future, fiber tractography will supply great space for the development of DTI. Using this we can obtain more important information for clinical rehabilitative treatment and judging prognosis.
|
PDF Full Text Request