双b值扩散加权成像在脑梗死诊断中的应用  

Application of Double b Value Diffusion-weighted Magnetic Resonance Imaging in Diagnosis of Brain Infarction

作　　者：高燕[1] 张冰茜[1] 樊树峰[1] 王浩初[1] 鄢广平[1] 

机构地区：[1]台州医院放射科,浙江317000

出　　处：《放射学实践》2008年第4期378-381,共4页Radiologic Practice

摘　　要：目的:比较双b值DWI对脑梗死体积及ADC值测量的影响,探讨较高b值DWI在脑梗死诊断中的应用价值。方法:回顾性研究30例脑梗死患者,年龄44～84岁,平均67岁,发病时间3～6d,DWI取b值1000和2000s/mm2,分析脑梗死DWI及ADC图,测量兴趣区与对侧正常部位的扩散系数(ADC)并计算相对扩散系数(rADC),测量并计算梗死灶体积。结果:急性和亚急性脑梗死灶均扩散受限,DWI呈高信号、ADC图呈低信号。与b值1000s/mm2相比,b值2000s/mm2DWI示脑灰白质对比度增加,病灶显示更清晰,还能发现新病灶。不同b值下rADC比较没有统计学意义(P=0.884,P>0.05),同侧ADC有统计学意义(P=0.005,P<0.05);对侧ADC有显著统计学意义(P<0.001)。较高b值下梗死体积较低b值增加,且有统计学意义(P=0.04,P<0.05)。结论:DWI是检测脑梗死的重要技术手段,rADC不受b值影响,rADC降低可指导脑梗死诊断;较高b值DWI上脑梗死灶体积测量更准确,有利于观察病灶演变和指导临床治疗。Objective：To assess the value of higher b value diffusion-weighted magnetic resonance imaging （DWI） in diagnosis of brain infarction. Methods.. Retrospective analysis of 1.5T MR examination findings in 30 subjects （age average, 67 years） 3-6 days after onset was studied,including conventional and double b value serial （b= 1000s/mm^2 and 2000s/mm^2 ）. ROIs were placed on infarct lesion and symmetrical contralateral normal brain tissue. The infarct volume,apparent diffusion coefficient （ADC） and relatively apparent diffusion coefficient （rADC） were calculated. Results： The acute and subacute brain infact had restricted diffusion which displayed hyper-intensity in DWI and hypo-intensity in ADC map. In comparison with DWI of b value 1000s/mm^2 ,DWI of b value 2000s/mm^2 could improve the contrast of the grey and white matter,and find new lesion. No significant change of relative ADC values was found between different b value groups （P= 0. 884, P〉0.05） ,but the isolateral and contralateral ADC values were significantly different between DWi at b value 1000s/mm^2 and 2000s/mm^2 （P=0. 005,P〈0. 001,P〈0.05, respectively）. The infarct volume on the higher b value DWI was larger than that on the lower b value DWI （P=：0.04,P〈0. 05）. Conclusion .. DWI is an important method to detect infarct lesion. Different b values have no effect on relatively apparent diffusion coefficient which can guide the diagnosis of brain infarct. The higher b value DWI is superior to lower b value DWI in calculating infarct volume more exactly, which was helpful in finding the time course of lesion development and provideing meaningful information for clinical therapy.

关 键 词：磁共振成像 脑梗死 扩散加权成像 

分 类 号：R743.3[医药卫生—神经病学与精神病学]