| Objective: To establish a theoretical model with fidelity to the hemodynamic characteristics of both normal cerebral circulation and cerebral arteriovenous malformation (AVM); to analyze hemodynamic variance of cerebral AVM; and to explore the calculating method of the hemodynamic parameters of AVM feeding artery and the hemodynamic causes of AVM hemorrhage.Methods: (1)Model establishment: The hemodynamic model based on electrical circuit analysis was established by simulating hemodynamic parameters with electrical ones.(2)Data measurement: Flow velocity measured by transcranial Doppler and blood pressure measured by a guiding catheter of 6F Casasco or by a micro-catheter of Traker-18 connecting a pressure transducer, data and waves of flow velocity and pressure were recorded at common carotid, vertebral and basilar artery, as well as at the A1, M1 and P1 segment of anterior, middle and posterior artery to the cerebral AVM group(37 cases) and normal control group(15 cases without any cardio- and brain vascular disease). Diameters of the above arteries were also measured in angiograms.(?)Calculation: Flow rate and vessel wall shear stress calculated with flow velocity and diameter; vessel peripheral resistance, flow resistance, capacity and inductance calculated with flow rate, pressure and vessel geometric data. Statistic figures of the above constructional parameters and a real input pressure wave were inputted into the model, simulating flow rate, pressure and input impedance were calculated according Kirchhoff Principle.(4)Comparisons were made as follow: the relative concepts, parameters, formulae and laws between hemodynamics and electricity in order to argue the rationality of simulating blood flow by electrical current; the results between the model calculation and clinical measurement to testify the veracity of the model; and the similarities and differences of the hemodynamic parameter between normal cerebral circulation and cerebral AVM to interpret the regularity of the... |
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