The Clinical Value Of CT Perfusion Imaging Technique In Evaluating The Local Hemodynamics Of Patients With Internal Carotid Artery Stenosis

Objective: To study the hemodynamic features of cerebral artery and to assess its clinical value by CT perfusion imaging technique in patients with stenotic or occlusive lesions in carotid artery.Methods: From December 2006~December2008, 39 patients with carotid artery stenosis admitted to First Hospital of GXMU entered this study. Of the 39 cases, 25 were male and 14 were female. Age ranged from 46 to 73 years old (mean age 54.5±3.1 ). The clinical duration of varied from 3 months to 4 years (mean duration 54.5±3.1 month). Select the middle cerebral artery for the region of interest ,uses the mirror image method ,measures the trouble group and the opposite group CTP parameter value, supposes the carotid artery narrow group is the study team, the opposite group for the control group ,Grouping: (1) According to the stenosis extent, patients were divided in mild group (4 cases), moderate group (4 cases), severe group (18 cases), and occlusive group (13 cases); (2) According to the existence of compensatory circulation in Willis Circle, patients were divided in positive group (25 cases) and negative group (14 cases). The extent of stenosis and the development of compensatory circulation were evaluated with cerebral angiograms. The correlation among the stenosis extent of carotid artery, collateral circulation, and CTP (computed tomography perfusion) parameters were analyzed.Results: (1) TTP (Time to peak) of CT perfusion imaging was apparently delayed compared with that of controls (P=0.008).Moreover, TTP of mild group (P=0.048), moderate group (P=0.037), severe group (P=0.026), and occlusive group (P=0.008) was significantly delayed compared with that of controls, respectively.(2) CBV (Cerebral blood volume) or CBF (cerebral blood flow ) of mild group and occlusive group had no significant changes if it was compared with that of control group, respectively. CBV of moderate group markedly increased, and CBV of occlusive group markedly reduced compared with that of control group, respectively.(3) TTP of CT perfusion imaging in patients with or without collateral circulation was significantly delayed compared with that of controls. (4)Level of CBF and CBV in patients with stenotic lesions in carotid artery apparently decreased compared with that of control group, respectively. Level of CBF or CBV in patients with collateral circulation apparently higher than that in patients without collateral circulation.Conclusions: (1) Patients with stenotic or occlusive lesions in carotid artery had abnormal hemodynamic changes. The delay of CTP became more dramatically when stenosis of carotid artery aggravated. CTP was the most sensitive parameter to evaluate the stenosis of carotid artery.(2) The cerebral area involved could maintain a normal hemodynamic status by autoregulation in case of mild stenosis of carotid artery. Obvious hemodynamic abnormality could be seen in patients with moderate or more severe lesions.(3) Whether there was collateral circulation in Willis Circle or not, hemodynamic abnormality existed in patients with carotid artery stenosis.