【作者】 吴立文；

【导师】 任卫东；

【作者基本信息】 中国医科大学 ， 影像医学与核医学， 2004， 硕士

【摘要】 前言 近年来随着人口的老龄化，缺血性脑血管病患者有逐年增加的趋势，已成为继心脏病和肿瘤之后人群三大死亡原因之一，颈动脉粥样硬化存在与否、严重程度、进展情况、粥样硬化斑块的形态、是否容易脱落成栓子等，在脑梗塞的发病中起重要作用。血管内皮功能受损是动脉粥样硬化的一个早期标志，通过检测血管内皮功能可及早地发现血管内皮功能失调，及时进行治疗。 传统的彩色多普勒超声能够准确测量颈动脉内中膜厚度及判定斑块形态，但对斑块性质却只能粗略的区分，不能够提供定量的信息。背向散射积分(IBS)是近年发展起来的一项新的超声组织定征技术，是基于背向散射原理，通过对组织射频信号的检测、处理和分析，定量的反映生物组织细微结构的病理改变。本研究应用IBS技术对颈动脉斑块性质进行检测，为脑梗塞发生的可能性提供定量参考指标。 材料与方法 一、材料 1．研究对象 病例组76例脑梗塞患者，对照组60例，临床上无脑血管疾病症状、体征的体检者。 2．仪器 应用Philips公司Sonos 5500型彩色超声诊断仪，配有7.5MHz线阵探头，ECG同步信号显示，声学定量分析系统软件及光盘存储器。 二、方法 1．二维超声检查 受检者仰卧位，依次显示颈总动脉，颈动脉分叉部、颈外动脉及颈内动脉颅外段。测量三个心动周期舒张末期的各段动脉的内径和CCA内中膜厚度。 2.确定斑块的标准为:二维超声测得局部IMT值〕1 .20~，或比邻近部位厚0 .5~，或妻近邻部位的1 .5倍，或彩色图像显示血管腔某处彩色血流缺损，缺损处面积蒸10~，。 3.动脉狭窄率的计算 狭窄率二(1一刀N)x 100%，其中A为狭窄的管腔面积，N为该处管腔正常面积，按照狭窄率大于50%计算狭窄动脉数。 4.彩色多普勒血流显像 将二维图像同彩色多普勒血流结合起来进一步判断管腔的血流充盈情况。 5.频谱多普勒检测、 测量各动脉收缩期峰值(S)、平均血流速度(N)、舒张末期血流速度(D)、脉动指数(PI)、阻力指数(RI)。一‘ 6.IBS值的测定 启动AD系统并设置在背向散射积分(IBs)状态，将感兴趣区(Ror)放置在斑块邻近管腔内及斑块的强回声部分，低回声部分和弱回声部分分别取样，进行连续2 .48秒的检测。 7.血流介导血管内皮功能的测定 用超声方法测量肪动脉内径变化率。 8.数据的统计分析 计量资料、计数资料用SPSS数据库软件11 .0进行统计处理。结果 一、颈动脉IMT值和内径的比较 1.病例组的颈总动脉的IMT平均值(1 .17土0.24~)明显高于对照组的IMT平均值(0.77土0.17~)，差异有统计学意义，P<0.01。 2.病例组的颈动脉各段内径，包括CCA(8 .44土1 .16~)、IcA(6.65土1 .04rnrn)、ECA(5.58土0.90nun)及BIF(10.45土l.47rnm)分别与对照组相比CCA(7.91士0.88nun)、ICA(5.85土0.65nnn)、ECA(4.95土0.64~)、BIF(9 .68土1 .01~)都相对扩张，差异有统计学意义，P<0.01。 二、血流动力学指标 1.颈总动脉、颈内动脉、颈外动脉病例组与对照组在收缩期峰值流速、舒张末期流速、及平均流速上均无差异。病例组的脉动指数C以(1.86士0.41)、ICA(1 .17土0.37)、ECA(2.57土0.92)分别高于对照组脉动指数CCA(1 .46土0.40)、ICA(1.00土0.32)、ECA(1.95*0.47)。病例组的阻力指数CCA(0.78土0.01)、ICA(0.64土0.01)、ECA(0.84*0.01)分别高于对照组阻力指数CCA(一72士0.11)、I以(0.印土0.11)、ECA(0.50，0.01)，差异有统计学意义，P<0.01。 三、颈动脉斑块 1.发生斑块病例数 病例组斑块发生比例63%，明显高于对照组出现斑块比例30%，差异有统计学意义，P<0.01。 2.比较两组狭窄动脉数 病例组狭窄动脉比例(37.9%)明显高于对照组.(l1.1%)，差异有统计学意义，P<0.01。 3.颈动脉斑块部位分布._.… 病例组颈内动脉的斑块(46%)最多，其次是颈总动脉(24%)，再其次是分叉处(17%)，颈外动脉的斑块最少(13%)。 4.颈动脉斑块回声性质 4.1对照组斑块回声性质特征 对照组颈动脉斑块以强回声(51%)和低回声(26%)为主，弱回声和混合回声分别仅占8%和巧%。 4.2病例组斑块回声性质特征 病例组颈动脉斑块以混合回声(45%)和弱回声(36%)为主，强回声和低回声分别仅占9%和10%。 4.3两组斑块回声性质特征比较 病例组的混合性回声斑块(45%)和弱回声斑块(36%)明显多于对照组的混合性回声斑块(巧%)和弱回声斑块(8%)，而低回声斑块(10%)和强回声斑块(9%)明显少于对照组的低回声斑块(26%)和强回声斑块(51%)，差别有统计学意义，P<0.01。 5.应用背向散射积分技术对颈动脉斑块定量组织定征 5.1不同回声斑块IBS比较 斑块强回声(42.00土5.76曲)、低回声(33.01土4.51曲)、弱回声(28.13*4.46db)、管腔血液回声( 20.87士3.78db)之间分别两两比较，均有显著性差别，而且强回声高于低回声，低回声高于弱回声，弱回声高于管腔血液回声更多还原

【Abstract】 The cerebral infarction has become the third lethal reason secondary to cardiac diseases and tumors. The examination of carotid arteries can be used to e-valuate the pathologic circumstances of intercerebral arteries. It is important to determine the risk of cerebral ischemia caused by carotid plaque, which can provide a feasible reference index for therapy. Endothelial dysfunction exists in the patients of atherosclerosis. We can use color Doppler ultrasound to evaluate the artery endothelial function.It is difficult to characterize the components of plaque by using conventional 2DE techniques. IBS is a new ultrasonic technique for tissue characterization. This study was designed to quantitate the carotid plaque of patients with cerebral ischemia and infarction using IBS. Therefore, we can get a useful parameter for the risk of carotid plaque in cerebral ischemic diseases.Material136 adults were enrolled in this study. 76 patients （men 47,women 29,average age 62yrs） , 60 control subjects （ men 35, women 25, average age 59yrs）.Data was acquired by using Philips Sonos 5500 ultrasonic system equipped with IBS analysis software with a 7.5 MHz linear - array transducer.Methods1. 2DE imagingAll the objects in this study lay in the supine position, The carotid arteries were examined bilaterally in the area of common carotid artery （ CCA） the carotid bifurcation （ BIF） internal carotid artery （ICA） and external carotid artery （ECA）. The diameters of all the arteries and the intima - media thickness （IMT） of the CCA were measured.2. Definition the plaquesIMT^l. 20mm or 0. 5mm thicker than the place of neighbour it, or 1. 5 times more than the place of neighbour it, or blood defect in some place of lumen of blood vessel by color imaging, the area of defect was more than 10mm2.3. Determining the rate of stricture of arteryComputing the rate of stricture of artery: the rate of stricture of artery = （1 - A/N） x 100%. A was area of narrow plaque, N was normal area of lumen.4. Color Doppler flow imagingCombined 2DE imaging with color Doppler flow imaging,it was determined to fillness in lumen with blood flow.5. The measurement of spetral DopplerPeak systolic velocity （ S ） mean velocity （ N ） end - diastolic velocity （D） pulsatility index （PI） resistance index （RI） were measured using spectral Doppler.6. The detection on plaques by IBS technichIntergrated backscatter system was preset and data was acquired: After swithing on AD - IBS procedure, we acquired digital integrated backscatter image sequences of the CCA lumen and the parts of weak echo low echo and high density echo according to machine settings mentioned above.7. The examination of vascular endothelial function by ultrasound8. Statistical analysisData was analyzed by SPSS （vertion11.0） software. P<0.05 was considered statistically significance.ResultsThe value of IMT in CCA（ 1.17 +0.24mm） in patients was higher than that（0.77 ±0.17mm） in the control group. The results indicated that the diameters of CCA（8.44 ± 1.16mm） ICA（6.65 ± 1.04mm） ECA（5.58 ±0.90mm） and BIF（10.45 ± 1.47mm） respectively were wider than those of CCA （7.91 ±0. 88mm） ICA（5. 85 ± 0. 65mm） ECA （4. 95 ± 0. 64mm）^BIF（9. 68 ± 1. 01mm） in the control group. The value of PI in CCA （1. 86 ±0.41） ICA（ 1. 17±0.37）ECA （2.57±0.92） and the RI in CCA （0.78 ±0.01） ICA（0. 64 ±0.01） ECA（0.84 ±0.01） in patients respectively were higher than those of PI in CCA（ 1.46 ±0.40） ICA（ 1.00 ±0.32）,ECA （1.95±0.47） and RI in CCA（₀.72±0.11） ICA （0.60±0.11）, ECA （0.80±0.01） . The rest parameters had not statistical significance.49 subjects of 76 patients had carotid atherosclerotic plaques. The incidence rate was 64% , while it was 36% in control group. The incidence rate of plaque were much higher than that in control group, and the occurrence rate （37.9% ）of stenosis of the artery in patient group were much higher than that （11.1% ） in control group.In the patient group the number of the plaque in ICA was the most, a更多还原