Changes Of Perfusion Weighted Image At Distant Parts In Rats After Acute Infarction

Background and Purpose:Ischemic cerebrovascular disease with high mortality rate and high incidence rate has been seriously threatening human quality and health of life. With the the accelerated speed of population aging in China, the incidence rate of the disease have gone up year by year. Supratentorial local cerebral injury can cause the functional changes in romote regions, of which relevant mechanism still be disputed by now. the great majority of scholars considered that the mechanism may be correlated to the theory diaschisis and often occurred in the patients with ischemic cerebrovascular disease. Dynamic susceptibilit contrast-enhanced perfusion weighted imaging is an magnetic resonance technology with non trauma, and detect the blood perfusion and analyse the informations of the hemodynamics ang functional changes. The technology can reflect the state of microvascular distribution and blood perfusion of tissue, and provide the referential value for clinical diagnosis and treatment.The traditional approach Suture method can be used in our reseach, in which we should establish the the cerebral ischemic models of middle cerebral artery occlusion (MCAO) with high reproducibility and greater stability with similar characteristic of human cerebral vessel. The states of anatomical structure of tissue and blood perfusion in different regions models of MCAO can be examined by MR techology at differet time(lh,3h,9h,24h), then the brain tssue should be dyeing using2,3,5-triphengltetrazolium chloride. To discuss: 1. the application value of DSC-PWI Parameter in remote regions of MCAO models at different times, and then to provide experimental and theoretical foundation of DSC-PWI technology for evaluating diaschisis in acute infarction.2. the relevant mechanism of remote regions diaschisis in acute infarction.Materials and Methods:1. To choose50health male SD rat, weight280～320g, average (301.2±9.7)g, were randomly divided into two groups:the control group of10rats only exposing the left middle cerebral artey and no electric coagulating; the experiment group wirh40rats of MCAO models.2. The experiment group and the control group was examined of the sagital T2-weighted imaging(T2WI), the sectional T1-weighted imaging (T1WI), T2-weighted imaging (T2WI) and DWI imaging sequence, using3.0T high-field superconducting magnetic resonance scanner of GE in U.S and multichannel rat coil of chengguang in Shanghai. The brain of two rats in each group were cut into slices every3mm according to the level of sectional T2WI, to observe the deying information of brain tissue sample after2,3,5-triphengltetrazolium chloride (TTC) staining at different time.3. We observe and record the condition in the diffusion weighted image(DWI) of brain tissue in left supratentorial cortex, basal ganglia, bilateral thalamus and bilateral cerebellum follow time, accord the cerebral perfusion parameter including relative cerebral volume(rCBV) and relative cerebral blood flow(rCBF) at different time. Then we compared the discrepancy of rCBV and rCBF value in left supratentorial cortex, basal ganglia, bilateral thalamus and bilateral cerebellum at different time between the experiment group and the control group, and the dependablity of perfusion(rCBF value) between left supratentorial cortex, basal ganglia, thalamus and right cerebellum at different time.4. All data are analysed by SPSS16.0package in statistics, and the quantitative data was expressed by X±SD.We use three statistical method including t test, single factor analysis of variance and Pearson correlation test to analysis the variables correlation, and p<0.05as statistically significant difference.Results:1. The abnoemal volume become large as the time course in the DWI and maps of rCBF and rCBV. It exsit significant discrepanncy of rCBF and rCBV value in infarction core(basal ganglia) compared with the control group.2. the change of PWI in bilateral thalamus at different time:compared with the control group, at1h and3h, there was evident decrease(P<0.05) of the rCBF value in left thalamus, no statistically significant difference of the rCBF value in right thalamus(P>0.05) and of the rCBFV value in bilateral thalamus(P<0.05). Compared with the control group, at9h, there was evident decrease of the rCBF value in bilateral thalamus(P<0.01) and of the rCBV value in left thalamus(P>0.05), and no statistically significant difference of the rCBV value in right thalamus(P<0.05). Compared with the control group, at24h, there was evident decrease(P<0.01) of the rCBF value in bilateral thalamus and of the rCBV value in bilateral thalamus(left P<0.01, right P>0.05).3. the change of PWI in bilateral cerebellum at different time:compared with the control group, at1h, there was evident decreaseof the rCBF value inbilateral thalamus(right P<0.01, leftP<0.05) and no statistically significant difference of the rCBV value inbilateral cerebellum(P>0.05). Compared with the control group, at3h and3h, there was evident increase(P<0.05) of the rCBF and rCBV value in left cerebellum, no statistically significant difference of the rCBF and rCBV value in right cerebellum (P>0.05).Compared with the control group, at9h, there was evident decrease of the rCBF value in bilateral cerebellum(P<0.05), and no statistically significant difference of the rCBV value in right thalamus(P<0.05). Compared with the control group, at24h, there was evident decrease of the rCBF value in bilateral cerebellum(P<0.01) and of the rCBV value in right cerebellum(P<0.05), and no statistically significant difference of the rCBV value in left thalamus(P<0.05).4. the dependablity analysis between the different regions in supratentorial infarction side and infratentorial paraliteral cerebellum:There was no correlation between the cortex in left frontal and parietal lobe, left basal ganglia, left thalamus and right cerebellum at11h,3h,9h and24h5. the result of TTC dyeingThe rat brain of the control group showed red after TTC dyening and that of the experiment group white. With the time lasting, the volume of supratentorial infarction become larger involving the adjacent cortex. But the rat brain tissue of bilateral thalamus and cerebellum showed red.Conclusion:1. DSC-PWI can detect the diaschisis after supratentorial infarction.2. the phenomenon of diaschisis in remote regions after acute supratentorial infarction3. the perfusion parameter in remote regions(thalamus and cerebellum) demonstrat changes as the supratentorial infarction core, which can illustrat that it exsit close relation between diaschisis and nerve conduction.4. no correlation of hypoperfusion degree between acute supratentorial infarction in the cortex, basal ganlia, thalamue of infarction side and infratentorial antiliteral cerebellum.