【作者】 王晓光；

【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， 2002， 硕士

【摘要】 前言 高血压是常见的心血管疾病，长期周围血管阻力升高，心肌细胞肥大，间质纤维增生，使左心室肥厚扩大。原发性高血压无彻底治疗史的几何构型的最高风险发生在左室向心性肥厚病人，中等风险发生在向心性重构和离心性肥厚病人，正常左室构型病人的风险性最低。预防和改善心肌重构是高血压病治疗的重要目标。 传统二维超声心动图通过观察心腔大小、室壁厚度、室壁运动和室壁回声的异常变化，可以了解心脏大体结构及功能状态，但是无法确定心肌组织病理改变。超声心肌背向散射技术是通过心肌声学特性的改变来判断心肌细微组织病理变化的方法，可以利用组织声学特征来研究组织的物理特征。本研究应用超声心动图测得不同左室构型心肌背向散射参数变化，探讨不同构型左室心肌的细微组织病理改变而引起的心肌声学特性的变化。 实验材料 原发性高血压病患者146例，男95例，女51例，平均年龄51.6±12.3岁。收缩压≥140mmHg和/或舒张压≥90mmHg。根据左心室重量指数(LVMI)和左心室室壁相对厚度(RWT)值将高血压病人分成四组：左室正常组(组1)，向心性重构组(组2)，向心性肥厚组(组3)和离心性肥厚组(组4)。对照组32例正常人，男22例，女10例，平均年龄52.2±10.3岁，血压＜140/90mmHg。 使用仪器为HP-Sonos 5500型超声诊断仪，配有声学定量分析系统软件，相控阵探头频率为2．0－4．OMHz。 实验方法 1．H维数据采集：在标准的胸骨旁左室长轴切面，测量舒张末期室间隔厚度、左室后壁厚度和左室内径（LVID）等。用Penn公式计算左心室重量（LVM）及 LVMI。 2．背向散射积分OBS）仪器设置与图像采集：调节总增益、深度人GC曲线及TGC曲线并保持不变。于胸骨旁左室长轴切面，选取最佳图像存盘，以备分析。 3．IBS的测定：分别测量室间隔和左室后壁的心肌IBS、校正IBS厂BS％X背向散射积分周期变化幅度（CVIB）和跨壁梯度（TGIB）。 4．数据的统计分析：数据以均值土标准差（mean。SD）表示。使用 t检验和方差分析，并进行相关分析，P＜0．05时有统计学意义。 结 果 一、正常人组和高血压病人在年龄、性别、体表面积和身体重量指数方面无显著差异。和正常人比较，高血压病人有显著升高的收缩期和舒张期血压。室壁厚度、左室重量和左室重量指数。 H、左心室构型：高血压病组共146例，l组的例，2组18例，3组 20例，4组 44例。LVMI以组 3（17．13 75．皿4m勺最大，其次为组 4（156．41。44．15牙m‘）及组 2（103．07。10．80吵m’）。m叮以组3最大（o．53。0．08），其次为组2（0．旭do．M）P＜0．of）。LVID以组 4（5．76．50 cm）最大，其次为组 3（5．of t0．71 Cm），（P＜0．01）。体循环血管阻力最高者为组 2O．68 t ·2·0＊0 kPa·s／l），其次为组 3（4．23 ti．36 kPa·s／l）、组二（4．02。二．58 kPa·s／l），三者与对照组（3．51。0．82 kPa·s／l）比较差异有显著性意义门叨＊U。 三、背向散射积分分析：高血压正常构型组与正常人对照组比较，室间隔与左室后壁的＊S％，CVIB及TGIB间均无统计学差异。高血压四组之间比较：IBS％：室间隔及左室后壁部位，以组3（分别为53．6。9．8和52．8。8．3）为最高，其次为组2（分别为49＊。7．2和姐．6。9．o）、组4（分别为49．0。7．7和48．9土8．2），组1（分别为42．3 L 8．4和41．8。9．二）最小，2、3、4组与1组比较均存在统计学差异（均为P＜0．01八C＊：室间隔及后壁以组3（分别为5．4n．gdB和6．9。2．3dB）最低，其次为组4（分另为5．7L二．7dB和7．O。2．6dB）＼组2（分别为6．2。o．gdB和7．8t3．ldB），组互（分别为6．8。2．0 dB和8．3z2．5 dB）最大，3人组与1组比较均存在统计学差异（均为P＜O．05＊＊＊ f左室后壁组3（o．9＊0·sdB）和组2（O．8z0．6dB）与组二（0．4504＊）和组4（o．5。0．3＊）间比较有显著性差异（P＜O．05）。 室间隔的IBS％与室间隔厚度对对室壁厚度及LVMI呈弱相关（分别为r＝0·＊，r＝0·＊，r＝0．36，P＜0．01）。 讨 论 高血压是常见的心血管疾病，左室为适应动脉高压而使心肌显示出几何重构。本研究各型所占比例左室正常型 43．8％、向心性重构型u．3％、向心性肥厚型13．7％和离心性肥厚型30％，离心性肥厚较向心性肥厚更为常见，向心性重构也占一定的比例。向心性左心室肥厚者具有各组中最高的血压水平，其各种原因的死亡率均较高，心血管事件最多。 近年发展起来的超声组织定征技术可以对心肌细胞成分进行 ·3· ／定量的评估。心肌超声背向散射积分正常情况下表现出一种随心动更多还原

【Abstract】 PrefaceHypertension is one of the commonest cardiovascular diseases. The left ventricle ( LV) of hypertension patients is generally thought to adapt to sustained arterial hypertension by developing hypertrophy and remodeling. The prognosis is related to LV pattern and left ventricular mass index (LVMI) . The highest risk occurred in those with concentric hypertrophy and the lowest risk occurred in those with normal left ventricular geometry; the risk was intermediate for patients with concentric remodeling and eccentric hypertrophy. To prevent and improve ventricular remodeling was an important target.Although conventional echocardiography is particularly useful in providing fundamental information about heart structure, morphology and function by observing the size of heart chambers and the thickness, echo level or moving of LV wall, it cant evaluate myocardial pathologic changes. Ultrasonic myocardial integrated backscatter technology can detect physical and pathologic changes of myocardial tissue according to myocardial tissue acoustic characterization. Ultrasonic tissue characterization consists of the identification of the abnormalities in the physical or physiological state of biological structures based on analyzing interactions between ultrasound and tissue. In this study weevaluate the clinical application of ultrasonic backscatter parameters to assessment of the lesion of myocardium in patients with hypertension by different LV remodeling.MaterialsDate were obtained from 146 patients (males 95,females 51 ,age 51. 6 ± 12.3 years) with essential hypertension. Hypertensive patients had systolic blood pressure ( BP) > 160 mmHg or diastolic BP ^ 95 mmHg. Patients were divided into four groups, according to the values of LVMI and relative wall thickness ( RWT) : Normal LV( group 1) , concentric remodeling ( group 2 ) , concentric hypertrophy ( group 3 ) and eccentric hypertrophy ( group 4). A control group of 32 normal subjects (males 22,females 10,age 52. 2 ± 10. 3 years) who had BP < 140/90 mmHg was also studied.For all patients, echocardiography measures were performed with the instrument of Hewlett-Packard Sonos-5500 with IBS analysis software with a 2 ~ 4 MHz phased array transducer.MethodsTwb-dimensional images were obtained in the parasternal left ventricle long-axis views in both patients and control subjects. Left ventricular end-diastolic diameters (LVID) and wall thickness were measured. Left ventricular mass(LVM) and LVMI were calculated by the Pennfc formula.Integrated backscatter system preset and data acquisition; Switching on AD-IBS procedure, we preset the instrument settings of gain,depth, LGC and TGC. We respectively acquired digital integrated backscatter (IBS) image sequences of the ventricular septum and the LV posterior wall from the parasternal long-axis view.Statistical analysis. All data presented as mean value ± SD. Data acquired was analyzed by EXCELL 2000 and SPSS 8.0 software.Results1. Clinical and echocardiographic characteristics of normal and hypertensive subjects. There were no statistical differences in age, gender, body surface area or body mass index between hypertensive and normal subjects either in the entire study group. Compared with the normal subjects, hypertensive patients had significantly higher systolic and diastolic blood pressure, LV wall thickness, LVM and LVMI.2. Patterns of left ventricular geometry. Of the 146 hypertensive patients,64 were in group 1,18 were in group 2,20 were in group 3 and 44 were in group 4. While LVMI was the highest in group 3 (176.13 ±75. 00 g/m2) and also high in group 4 (156.41 ±44.15 g/ m2) and group 2 (103. 07 ± 10. 80 g/m2). RWT was the highest in group 3(0.53 ±0.08) and also high in group 2(0.48 ±0.04 ) (P < 0.01). LVID was the highest in group 4(5.76 ±0.50 cm) and also high in group 3(5. 01 ±0.71cm) (P<0.01). Total peripheral resistance was the highest in group 2(4.68 ±0. 60 kPa ?s/1) and high in group 3 (4. 23 ±1. 36 kPa ?s/1) and group 1 (4更多还原