| Background and ObjectiveThe atherosclerotic stroke of hypoperfusion is the chronic ischemic damage of nervous system when the blood-supply of the patients who have the risk factors of cerebral atherosclerosis is below the physiological threshold. The researchers have been paying attention to it in the clinical diagnosis and therapy increasingly. During the development and application of the neuroimaging, the researchers have gradually realized that the hemodynamic change resulting for cerebral hypoperfusion is the major pathogenesis of the ischemic cerebrovascular disease. The final result of any pathogenesis is the cerebral hemodynamic disorder.The hemodynamics is effected by several factors, such as the degree of stenosis, the damage of cerebrovascular autoregulation, collateral circulation and so on. There may be severe hypoperfusion when the cerebral arteries are mild stenosises; in the other side, there may be not hypoperfusion when the cerebral arteries are serious stenosises. Therefore, we need to evaluate the morphous of cerebral vessels, the morphous and functional status of cerebral tissues comprehensively in the clinical diagnosis and therapy to formulate the optimal therapeutic regimens.Nowadays, the angioplasty is a new technique for the ischemic cerebrovascular diseases, and is more and more popular. As the technique is at the stage of development and crocidismus, there are not unitive therapeutic principles in the world. So it needs thorough reseach. There still are arguements about the correlations of the hemodynamic change, the types and gradings of collateral circulation and the degree of artery stenosis from the literatures and there aren't comprehensive study report in the internal and external literatures. The objective of this reseach is: According to the analysis for the patients of atherosclerotic stroke of hypoperfusion by using the comprehensive techniques of magnetic resonance imaging (MRI), digital subtraction angiography (DSA) and computed tomography perfusion imaging (CTPI), we are going to understand the morphology of cerebral tissues, the change of cerebral blood perfusion,the degree and location of stenosis or occlusion of cerebral arteries, collateral circulation and so on. With the statistical results, we can guide the therapeutic regimens in the clinic and achieve the best bonding of economy-efficiency-risk.Materials and MethodsThere were 40 inpatients of atherosclerotic stroke of hypoperfusion diagnosed in our department from the July, 2005 to the January, 2007. There were 28 men and 12 women. The patients of transient ischemic attack (TIA) were 32, and the patients of cerebral infarction (CI) were 8. The 40 patients performed the DSA, MRI and CTPI. We are going to evaluate the patients comprehensively from the 9 aspects as follow: 1.The correlations between the CI and gender or age; 2.The variances of the extracranial and intracranial artery stenosis or collateral circulations of different clinical symptoms (TIA and CI); 3.The correlations between CI and the types of collateral circulation; 4.The correlations between CI and the gradings of collateral circulation;5.The correlations between qualitative change of hemodynamics and the stenosises or locations of cerebral arteries; 6.The correlations between qualitative change of hemodynamics and the types or gradings of collateral circulation; 7.The correlation between the gradings of collateral circulation and the quantitative change of hemodynamics; 8.The mismatch of MRI and CTPI; 9.The correlation between the quantitative change of hemodynamics and CI. And then undertake the statistical analysis for the above indexes. p<0.05 is statistical significance.Results1.Every patient had more than one atherosclerotic factors; There was no correlation between the CI and gender, r=0.142, p=0.382; the age of CI in male and female had no statistical significance,p=0.655.2.There were no statistical significances in the degrees of the extracranial (p=0.998) and intracranial (p=0.201) artery stenosis and the types and gradings of collateral circulations in the patients of different clinical symptoms (TIA and CI). Because of the effect of blood pressure, we couldn't predict the severity of cerebral artery stenosis and the building of collateral circulation just according to the clinical symptoms. But there was intimate relationship between TIA and CI and the incidence of CI would increase obviously after TIA.3.There were statistical significances among the ACoA, PCoA, ACoA+PCoA and second collateral circulations in the effect of CI,p=0.024, 0.024 and 0.043, respectively. The primary collateral circulation was the signal of cerebral protection, and just the second collateral circulation was the prognostication of the increased rate of CI.4.There was good correlation between CI and the gradings of collateral circulation, r=0.546,p=0.000. The higher grading of collateral circulation, the lower rate of CI; in the other side, the lower grading of collateral circulation, the higher rate of CI.5.There was no correlation between the different stages of CTPI and different degrees of stenosis of extracerebral (r=0.081,p=0.57) and intracerebral (r=0.007,p=0.951) artery stenosis. Just according to the degrees and locations of cerebral artery stenosis, we couldn't judge the change of distal cerebral hemodynamics.6.The different gradings of collateral circulation had statistically significant effect with the stage of CTPI, p<0.05; and the different types of collateral circulation had no statistically significant effect with the stage of CTPI,p>0.05. The better compensation of collateral circulation, the lighter injury of hemodynamics; in the other side, the worse compensation of collateral circulation, the heavier injury of hemodynamics.7.The different gradings of collateral circulation had statistically significant effect with the CBV CBF MTT and TTP of watershed (p=0.049, 0.049, 0.030 and 0.028, respectively) and non-watershed (p=0.042, 0.042, 0.038 and 0.026, respectively). The CBV,CBF,MTT and TTP of watershed and non-watershed had statistical significances when the grading of collateral circulation was 1, p=0.041, 0.046, 0.036 and 0.020; The MTT and TTP of watershed and non-watershed had statistical significances when the grading of collateral circulation was 2, p=0.040 and 0.037;But the CBV and CBF of watershed and non-watershed had no statistical significances when the grading of collateral circulation was 2, p=0.067 and 0.058. The better compensation of collateral circulation, the lighter degree of hypoperfusion; in the other side, the worse compensation of collateral circulation, the heavier degree of hypoperfusion. The watershed was the most easily damaged district when the hypoperfusion happened.8.The observation consistency of MRI and CTPI is 62.5%, and the chance element consistency is 53.3%, k=0.25. That was to say there were poor consistency and statistical significance of the mismatch between MRI and CTPI,p=0.001. CTPI could evaluate the risk of stoke and sieve the dangerous crowd and guide the clinical therapy.9.The CBV, CBF, MTT and TTP of watershed and non-watershed had statistical significances in the 20 patients with negative appearance of MRI (p=0.034,0.043,0.023 and 0.020, respectively) and positive appearance (p=0.041,0.037,0.023 and 0.031, respectively) of MRI. The CBV and CBF of the negative and positve appearance of MRI in the non-watershed had no statistical significances, p=0.105 and 0.078,respectively;But the MTT and TTP of the negative and positve appearance of MRI in the non-watershed had statistical significances, p=0.028 and 0.031,respectively. The CBV,CBF,MTT and TTP of the negative and positve appearance of MRI in the watershed had statistical significances,p=0.041,0.035,0.031 and 0.030, respectively.Conclusions1.The risk factors of atherosclerosis were hypertension, diabetes mellitus, hyperlipemia, hyper-homocysteic acidemia, smoking, excessive drinking, cardiac disease and age > 40 years and so on. There was no correlation between CI and gender,and the age of CI in male and female had no statistical significance.2. There were no statistical significances of the degrees of the extracranial and intracranial artery stenosis and the types and gradings of collateral circulations in the patients of different clinical symptoms (TIA and CI). Because of the effect of blood pressure, we couldn't predict the severity of cerebral artery stenosis and the building of collateral circulation just according to the clinical symptoms. But there was intimate relationship between TIA and CI and the incidence of CI would increase obviously after TIA.3.There were correlations between CI and the types of collateral circulation. The primary collateral circulations (ACoA and PCoA) were the marks of cerebral protection,and the only second collateral circulations were the indications of the high risk of cerebral infarction. There were correlations between cerebral infarction and the gradings of collateral circulation. That was to say the higher grading of collateral circulation, the better ability of compensation, and the lower rate of cerebral infarction; In the other side, the lower grading of collateral circulation, the worth ability of compensation, and the higher rate of cerebral infarction.4.There were no correlations between the stages of CTPI and the degrees of cerebral artery stenosis. It couldn't evaluate the change of distal hemodynamics with the degrees of cerebral artery stenosis. Therefore,we couldn't make the clinical therapeutic regimens with the degrees of cerebral artery stenosis.5.There was no correlation between the stages of CTPI and the types of collateral circulation, but there was correlation between the stages of CTPI and the gradings of collateral circulation. Whether the primary or the second collateral circulations, the higher grading, the more sufficient compensation, the lower injury of cerebral perfusion, and they could cut down the risk of stroke.6.There was mismatches between MRI and CTPI. With the connection of CTPI and MRI, we could judge the clinical pathogenesis and the existence of ischemic penumbra. The ischemic penumbra could provide the basises of active clinical therapy, and it could provide the evidences of judging clinical effect or evaluating prognosis.7.In the clinical diagnosis and therapy of the atherosclerotic stroke of hypoperfusion, we could evaluate the the morphology of cerebral tissues and cerebral vessels and the change of cerebral hemodynamics comprehensively with the techniques of MRI, CTPI and DSA. So that they could provide the basises of individualized treatment and sieve the indications of interventional therapy. |
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