| The most main reason of ischemic cerebral infarction is atherosclerotic stenosis or occlusion of internal carotid artery(ICA) or middle cerebral artery(MCA), while we can't exactly predict whether patients exist cerebral ischemia or not and the level of ischemia only depending on the degree of vascular stenosis. Recently there are a few methods in detecting cerebral blood flow(CBF), however, there exists advantages and disadvantages in evaluating cerebral perfusion. Xe-CT system, which detects regional cerebral blood flow quantitively and provides absolute value of cerebral perfusion applying CT technology and the enhancement of stable xenon with the license of Food and Drug Administration (FDA), could be used to evaluate cerebral blood flow of patients with artery stenosis or occlusion and provide evidences for treatment and prognosis.We attempt to study the change of cerebral blood flow(CBF) in patients with internal carotid and middle cerebral artery stenosis or occlusion by Xe-CT perfusion imaging technology, analyze perfusion conditions and ischemic extent in different cerebral districts, to guide treatment and evaluate prognosis in patients with cranial artery stenosis and occlusion in intra or extra.Xe-CT was performed on 24 patients with unilateral internal carotid and middle cerebral artery stenosis or occlusion, who weredivided into two groups: ICA group which was short for unilateral internal carotid severe stenosis and MCA group which was short for middle cerebral artery severe stenosis depending on the cerebral vessels'condition such as TCD, MRA, CTA and DSA. CBF was measured with software automatic cortex six zonation and region of interest (ROI) described by hand-made, the qualitative and quantitative analysis was carried out on bilateral hemisphere.The research found that CBF of the affected side decreased with different extent in all patients:①in ICA group: CBFs of the affected side in ACA,MCA,ABZ,PBZ,IBZ regions were 32.56±20.13ml/(100g·min),30.91±8.51ml/(100g·min),36.98±15.67ml/ (100g·min),29.28±9.48ml/(100g·min),26.45±10.87ml/(100g·min) and 26.03±9.41ml/(100g·min); correspondingly CBFs of the contralateral side were 49.02±19.49ml/(100g·min),49.32±9.15ml/(100g·min),41.88±12.29ml/(100g·min),38.91±13.43ml/ (100g·min),37.28±8.92ml/(100g·min) and 34.00±9.69ml/(100g·min). CBF of the affected side was significantly lower than the contralateral side in ACA,MCA,ABZ,PBZ,IBZ regions with significantly statistical difference(P<0.05), while CBF in PCA region was also lower than the contralateral side but with no significantly statistical difference(P>0.05);②in MCA groups: CBFs of the affected side in ACA,MCA,PCA,ABZ,PBZ,IBZ regions were 39.40±11.46ml/(100g·min),41.13±9.44ml/(100g·min),38.12±12.74ml/(100g·min),36.79±11.38ml/(100g·min),30.04±10.03ml/(100g·min) and 35.35±13.16ml/(100g·min); correspondingly CBFs of the contralateral side were 44.53±15.37ml/(100g·min),54.85±15.03ml/(100g·min),40.75±9.41ml/(100g·min),37.56±13.42 ml/(100g·min),36.63±9.75ml/(100g·min) and 39.28±11.92ml/ (100g·min). CBF was significantly lower in the affected side as compared with the contralateral side(P<0.05) in MCA,PBZ regions, however, CBF decreased in other regions without significant differences(P>0.05).Xe-CT perfusion imaging technology is a safe and fast method of measuring CBF, which can provide highly precise,repeatedly measured and quantitative rCBF value. It has high sensitivity to detect CBF in the deep part of encephalic tissue; what's more, it has the advantages of convenience, shortcut and lower price. Among patients who was in group ICA, CBF in ABZ,PBZ,IBZ regions decreased significantly compared with the corresponding regions of the contralateral side(P<0.05), which hinted that affections of internal carotid affected not only the definite blood-supply regions, but also the blood-supply of brain tissue in borderline districts, what's more, we presumed that IBZ region was probably the earliest region which occurred ischemia, and was also the most significant region of cerebral perfusion descending. CBF in ACA and MCA regions were obviously less than the corresponding regions of the contralateral side with significant difference(P<0.05), which indicated affections of internal carotid in this group contributed tothe blood perfusion of the corresponding cerebral hemisphere making obvious descent of blood in ACA and MCA regions. However, CBF of the affected side in PCA region was lower than the contralateral side, we presumed there was relation with severe stenosis of internal carotid, breakup of posterior communicating artery and compensation of anterior circulation's cerebral blood supply by PCA. Among patients who was in group MCA, CBF in MCA and PBZ regions decreased significantly compared with the corresponding regions of the contralateral side(P<0.05), the descent of CBF in PBZ region was probably relative with few anastomosous blood vessels between MCA and PCA of meningina, what's more, PBZ region was probably the earliest region which occurred ischemia after severe stenosis of MCA. In this research, CBF in 2 cases of internal carotid TIA decreased to different degree during the attacking interval, which reminded us the clinical appearances improved a lot, but cerebral hypoperfusion did not improve virtually, if we did not restore perfusion in time, the clinical ischemic appearances would happen repeatedly, even leaded to cerebral infarction at last.Above all, we think Xe-CT perfusion imaging technology can provide accurately qualitative, quantitative and immediate changes of CBF in cerebral cortex in patients with unilateral ICA and MCA stenosis or occlusion, which is helpful for therapy; Xe-CT can detect CBF actively of watershed regions to find hypoperfusion regions intime in the earlier period, provide objective evidence after cerebral vasculopathy and prevent watershed infarction. |
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