BACKGROUND: Transcranial Doppler(TCD) spectrum analysis techniques cannot measure the diameters of blood vessels and therefore and not be used to calculate the changes of brain blood flow. A formula was designed for regional cerebral blood flow loss index(rCBFLI) following arteriostenosis when arteriostenosis index formula was deduced; the former may provide a reference to assess cerebral function.OBJECTIVE: To introduce the formula of cerebral blood flow loss ratio obtained basing on TCD results.DESIGN: Retrospective controlled study based on patients with cerebral middle arteriostenosis diagnosed with TCD and healthy people.SETTING: At the departments of neurology in a university hospital and in a military medical university affiliated hospital of Chinese PLA.PARTICIPANTS: Between October 1994 and December 2000,43 patients who were confirmed of arteriostenosis with TCD at outpatient or neurological ward of the First Affiliated Hospital of Fujian Medical University were enrolled into this study,and their TCD results were compared with 908 normal controls between March 1992 and September 2000.METHODS: Stenosis index (STI) formula was deduced from TCD results of 31unilateral and 12 bilateral stenoses at middle cerebral artery(MCA) . STI = 1- [ normal average blood velocity (Vm0) ÷ average blood velocity at stenosisSince(PI1 ÷PI0) may be equal to [post-stenosis blood flow(Q1) ÷ normal blood flow(Q0)],regional cerebral blood flow loss index is concluded as:MAIN OUTCOME MEASURES: rCBFLI,relationship between STI and Vm,as well as between rCBFLI and STI.RESULTS: rCBFLI formula was used to calculate the rCBFLI of 31 patients following unilateral MCA stenosis. rCBFLI of these 31 patients was obtained by Pearson statistical analysis. STI was found to be related to the average blood velocity at stenosis with relative coefficient(Vm) of(r) =0.76( P ＜ 0. 001 )and r = 0. 83 ( P ＜ 0. 001 ) . rCBFLI was proved to be correlated with Vm and STI with r = 0. 76( P ＜ 0. 01 ) and r = 0. 81 in 55 side MCA stenoses,and the difference was of statistical significance( P ＜ 0. 001 ).CONCLUSION: rCBFLI can be used to assess the decrement of regional brain blood flow due to the stenosis of supplying artery; also,it can be used to observe the changes of brain hemodynamics if combined with STI.%背景:经颅多普勒超声(TCD)频谱分析技术无法测量血管管径大小,因此,无法计算脑血流量的改变.在推导动脉狭窄指数公式中,发现动脉狭窄后局部脑血流量丧失指数(rCBFLI)的计算方法,试图为评估脑功能提供参考.目的:介绍一种根据TCD检查的资料推导出脑血流量丧失比率的计算公式.设计:以经TCD检查为大脑中动脉狭窄和正常人群为研究对象,回顾性研究.单位:一所大学医学的神经内科和一所军医大学医院的神经内科.对象:1994-10/2000-11福建医科大学附属第一医院神经内科住院及门诊TCD资料中大脑中动脉狭窄43例和1992-03/2000-09本院908例经TCD检查正常的资料.方法:研究分析31例一侧和12例双侧大脑中动脉(MCA)狭窄的TCD检查资料,推导出MCA狭窄的狭窄指数(STI)公式:STI=1-[平均血流速度(Vm0)÷狭窄处平均血流速度(Vm1)]·[狭窄后脉动指数(PI1)÷正常脉动指数(PI0)],并推导出(PI1÷PI0)可能等于[狭窄后血流量(Q1)÷正常血流量(Q0)],则:局部脑血流量丧失指数(rCBFLI)=[1-(Q1÷Q0)]·100%=[1-(PI1÷PI0)]·100%.主要观察指标:rCBFLI,TI和Vm的相关性,CBFLI和STI的相关性.结果:采用rCBFLI公式计算出31例一侧MCA狭窄后的rCBFLI.采用Pearson法统计分析,得出31例一侧MCA狭窄的iCBFLI,TI与狭窄处平均血流速度(Vm)相关系数(r)=0.76(P＜0.001)和r=0.83(P＜0.001);将55侧MCA狭窄的rCBFLI值分别与Vm,TI比较,=0.76(P＜0.01)和r=0.81(P＜0.001).结论:推荐rCBFLI作为评估颅内某支动脉狭窄后该动脉供血区局部脑血流量下降程度的指标之一,结合STI指数观察脑血流动力学的改变.
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