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超声背向散射积分和回声强度在急性心肌梗死诊断中的应用研究
http://www.100md.com 《中华超声影像学杂志》 2000年第6期
     作者:王志刚 冉海涛 黄晶 陈庆伟 苏海兵 蒲世玉 邹建中 陈永新 何明菊

    单位:王志刚 冉海涛 苏海兵 蒲世玉 邹建中(400010 重庆医科大学附属第二医院超声科);陈庆伟 黄晶 陈永新 何明菊(心内科)

    关键词:背向散射积分;回声强度;心肌梗死

    中华超声影像学杂志000609

    【摘要】 目的 探讨心肌组织背向散射积分(IB)和回声强度(EI)是否可用于临床急性心肌梗死的诊断及其应用价值。方法 在35例急性心肌梗死患者发病2周内,用HP-5500型超声诊断仪和DFY型超声图像定量分析诊断仪,在胸骨旁左室乳头肌短轴切面,分别测量冠状动脉左前降支、左回旋支和右冠状动脉支配区域心肌组织(分别相当于左室乳头肌短轴切面上12、4、8点的位置)的IB和EI心动周期变化幅度(CVIB和CVEI)值,以CVIB和CVEI值≤同一切面三个不同部位中最高值的1/2作为诊断心肌梗死的标准,部分病例与冠脉造影结果对比。结果 用两种超声组织定征方法诊断急性心肌梗死的敏感性均为 91.43%,所确定的梗死部位与冠脉造影吻合。结论 利用IB和EI进行超声组织定征可做为临床诊断急性心肌梗死的一种无创性定性、定位新方法。
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    Clinical study of ultrasonic tissue characterization with integrated backscatter and echo intensity in the diagnosis of acute myocardial infarction

    WANG Zhigang,RAN Haitao,HUANG Jing,et al.

    (Department of Ultrasonography,the Second Hospital,Chongqing University of Medical Sciences,Chongqing 400010,China)

    【Abstract】 Objective To determine if the ultrasonic integrated backscatter and echo intensity could be used in clinical diagnosis of acute myocardial infarction (AMI).Methods Within 2 weeks after AMI, 35 patients underwent ultasonic tissue characterization from the parasternal papillary short-axis view. The cyclic variation of integrated backscatter (CVIB) and echo intensity (CVEI) of three different myocardial regions perfused by left anterior descending coronary artery, left circumflex coronary artery and right coronary artery (on the frozen frame of parasternal short-axis image,those position were approximately at the 12, 4 and 8 o'clock direction to the center of the left ventricle, respectively) were measured with HP-5500 ultrasonic system and DFY ultrasonographic quantitative analysis system. The values of CVIB and CVEI ≤half of the highest value of three different myocardial regions on a same view were defined as the criteria for diagnosing AMI, and the results from some patients were compared with that from coronary angiography. Results The sensitivity of diagnosing AMI by both ultrasonic tissue characterizations with integrated backscatter and echo intensity were 91.43%. The location of myocardial infarction detected by this technique was correspond with the damaged myocardial region determined by coronary angiography.Conclusion Ultrasonic tissue characterization with integrated backscatter and echo intensity could clinically be used as a noninvasive approache in the diagnosis of AMI.
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    【Key words】 Integrated backscatter;Echo intensity;Myocardial infarction

    超声组织定征是新近发展起来的一种无创性评估组织特性、功能和血流灌注的新方法。本研究通过射频法(背向散射积分,IB)和视频法(回声强度,EI)对急性心肌梗死患者进行超声组织定征,并对二种不同的组织定征方法进行比较,以探讨其临床应用价值。

    资 料 与 方 法

    一、实验对象

    我院1999年1月至6月收治的部分急性心肌梗死患者41例,其中6例因图像质量较差被排除。余35例中,男26例,女9例,年龄52~71岁,平均(56.8±5.4)岁。所有病例的临床症状、心电图表现和心肌酶谱检查均符合急性心肌梗死临床诊断标准。

, http://www.100md.com     二、仪器设备

    应用HP-5500型超声诊断仪,具有背向散射二维成像和相关测量分析功能。

    我院自行研制的DFY型超声图像定量分析诊断仪,具有图像存储和回声强度定量分析功能[1,2]

    三、图像获取与数据采集

    在急性心肌梗死发病2周内,获取胸骨旁左室乳头肌短轴常规切面和散射二维图像,调节图像至最佳状态,存入光盘待分析。

    分别测量冠状动脉左前降支、左回旋支和右冠状动脉支配区域心肌组织(分别相当于短轴切面12、4、8点位置[3])的IB和EI心动周期变化幅度(CVIB和CVEI值),以CVIB和CVEI≤同一切面三个不同部位中最高值的1/2作为诊断急性心肌梗死的定位、定性标准(图1~3)。
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    四、冠脉造影

    以冠脉狭窄程度≥75%为病变冠脉诊断标准。

    结 果

    一、CVIB和CVEI测值

    35例急性心肌梗死患者中,有32例在左室乳头肌短轴切面上,至少有1个部位的CVIB和CVEI值≤三个部位中最高部位测值的1/2,以此作为诊断急性心肌梗死的标准,其敏感性均为 91.43%(表1)。

    二、冠脉造影

    35例急性心肌梗死患者中,有18例做了冠脉造影检查,冠脉造影显示的病变冠脉(图4)与CVIB和CVEI降低的部位完全吻合。

    表1 35例急性心肌梗死患者中用2种
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    不同组织定征方法检查结果 参数

    阳性(例)

    阴性(例)

    敏感性(%)

    CVIB

    32

    3

    91.43

    CVEI

    32

    3

    91.43

    讨 论
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    心肌组织IB和EI随心动周期而变化,其心动周期变化幅度与局部心肌组织的收缩功能密切相关;心肌缺血或梗死时,CVIB和CVEI降低,由此可区别正常与缺血或梗死心肌组织[4-8]。目前已有利用IB技术对冠心病等进行超声组织定征的报道[9,10]

    但是,由于不同部位心肌组织CVIB和CVEI值存在差异,且测值亦受仪器设置、分辨力和操作者熟练程度的影响[11-14],目前尚无判断正常、异常的统一标准,给临床广泛应用造成困难。

    图1 急性心肌梗死患者,男,67岁,背向散射积分检测图。为了便于显示,图中基线分别作了调整。由上至下分别为右冠状动脉、冠状动脉左前降支和左回旋支供血区心肌组织IB值心动周期变化曲线,其CVIB值分别为 2.1 dB、6.3 dB和 6.5 dB
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    图2 回声强度定量分析法检测图,为同一病例心室收缩末期,图中方框为取样容积,取样部位为冠状动脉左回旋支支配区域。图左下为取样容积内心肌组织的回声强度最大、最小及均值,均值为 28.66 dB。图右下为显示回声强度的三维图像

    图3 同一病例舒张末期相同部位心肌组织回声强度均值为 33.66 dB,其CVEI值=5.0 dB

    图4 同一病例冠脉造影示右冠状动脉严重狭窄 本研究结果显示,以胸骨旁左室乳头肌短轴切面为标准切面,分别测量冠状动脉左前降支、左回旋支和右冠状动脉支配区域心肌组织(分别相当于短轴切面上12、4、8点的位置)的CVIB和CVEI值,以CVIB和CVEI≤同一切面三个不同部位中最高部位值的1/2,作为诊断心肌梗死的标准,其敏感性均为 91.43%。其中18例经冠脉造影证实,其病变冠脉与采用超声组织定征方法所确定的部位完全吻合。我们认为,利用IB和EI进行超声组织定征可作为临床诊断急性心肌梗死的一种新的无创性定性、定位检测方法,二种方法无显著性差异[8]
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    CVIB和CVEI测值的精确性依赖于高质量的清晰图像,而冠心病患者往往体型较胖,图像质量欠佳。本研究观察了41例急性心肌梗死患者,其中有6例因图像质量较差而无法进行CVIB和CVEI分析,其超声组织定征在这方面的应用范围受到一定限制,对心内膜下心肌梗死欠敏感。本组35例患者中,采用超声组织定征方法漏诊的3例即是临床确诊的下壁心内膜下心肌梗死。虽然有报道,心内膜下心肌梗死时,病变部位心室壁中线至心内膜下心肌组织的CVIB值明显降低,出现心室壁CVIB值梯度,但实际测量较困难,重复性较差。

    资助项目:重庆市重点科技攻关项目[渝科委计(1997)22号41)]

    参 考 文 献

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    2,王志刚,蒲世玉,于成银,等.风心病二尖瓣病变声像图回声强度定量及病理改变研究.中国超声医学杂志,1998,14(3):19-22.
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    3,Lung-Chun Lin, Chau-Chung Wu,Yi-Lwun Ho, et al. Ultrasonic tissue characterization for coronary care unit patient with acutc myocardial infarction.Ultrasound in Med & Biol,1998,24:187-196.

    4,Madaras EI,Barzilai B,Perez JE,et al.Changes in myocardial backscatter throughout the cardiac cycle. Ultrasonic Imaging,1983, 5:229-239.

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    6,Naito J, Masuyams T, Mano T, et al. Influence of preload, afterload, and contractility on myocardial ultrasonic tissue characterization with integrated backscatter. Ultrasound in Med & Biol,1996,22:305-312.

    7,Rijsterborch H,Van Der Steen, Krams, et al. The relationship between myocardial integrated backscatter, perfusion pressure and wall thickness during isvolumic contraction: an isolated pig heart study.Ultrasound in Med & Biol,1996,22:43-52.
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    8,冉海涛,王志刚,邹建中,等.超声背向散射积分和回声强度定量在急性心肌缺血与再灌注过程中的变化及其与心肌收缩力的关系.中国超声医学杂志,1999,15:885-888.

    9,Naito J,Masuyama T,Tanouchi J, et al.Analysis of transmural trend of myocardial integrated ultrasonic backscatter for the differentiation of hypertrophic cardiomyopathy and ventricular hypertrophy due to hypertension. J Am Coll Cardiol,1994,24:517-524.

    10,Saeian K,Rhyne TL,Sagar KB.Ultrasonic tissue characterization for diagnosis of acute myocardial infarction in the coronary care unit. Am J Cardiol,1994,74:1211-1215.
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    11,Wear KA, Milunski MR, Wickline SA, et al. The effects of frequency on the magnitude of cycleic variation of backscatter in dogs and implications for promt detection of acute myocardial ischemia.IEEE Trans,1991,UFFC-38:498-502.

    12,Van der stten AFW,Rijsterborch H,Mastik F, et al. Influence of attenuation on measurements of ultrasonic myocardial integrated backcatter during cardiac cycle (an in vitro study). Ultrasound in Med & Biol,1991,17:869-877.
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    13,Hall CF, Verdonk ED, Wickline SA, et al. Anisotropy of the apparent frequency dependence of backscatter in formalin fixed human myocardium. J Acoustic Soc Am,1997,101:563-568.

    14,Takahiro OTA, Damian M Craig, Joseph Kisslo. Influence of ultrasonic machine settings, transducer frequency and placement of region of interest on the measurement of integrated backscatter and cyclic variation. Ultrasound in Med & Biol,1997,23:1059-1070.

    (收稿日期:1999-08-02), 百拇医药