超声二维斑点追踪显像技术评价妊娠期糖尿病孕妇的胎儿心室力学及功能变化的研究

目的应用超声二维斑点追踪显像技术评价妊娠期糖尿病孕妇的胎儿及产后新生儿左、右心室功能和结构的变化规律和特点。方法选择深圳市南山区妇幼保健院妊娠期糖尿病孕妇(妊娠期糖尿病孕妇组,年龄21~39岁,平均年龄27.1岁;孕24~28周、32~36周;按孕周分2组)及妊娠期糖尿病产妇的新生儿(糖尿病母亲婴儿组,年龄3~25 d,平均年龄12.0 d)各20例;正常对照孕妇(正常对照孕妇组,年龄20~36岁,平均年龄25.6岁;孕24~28周、32~36周;按孕周分2组)40例及正常产妇的新生儿(正常产妇的新生儿组,年龄7~26 d,平均年龄14.0 d)20例。行超声检查,存储心尖四腔心切面,应用二维斑点追踪显像技术测量左、右心室游离壁及室间隔的基底段、中间段及心尖段心肌和心内膜下心肌及室间隔收缩期最大应变率(SRs)、舒张期最大应变率(SRd),脉冲多普勒测量二、三尖瓣口的舒张期早期峰值流速E峰、舒张晚期峰值流速A峰,计算E/A比值,超声心动图测量左、右心室及室间隔的心肌厚度。结果与对照组相比,妊娠期糖尿病孕妇组孕32~36周胎儿室间隔,左、右心室壁舒张末期厚度均较正常对照孕妇组增厚,差异有统计学意义(P0.05)。妊娠期糖尿病孕妇组胎儿心脏二、三尖瓣口血流频谱的E/A比正常对照孕妇组小,其中妊娠期糖尿病孕妇组孕32~36周胎儿及糖尿病母亲婴儿组E/A降低,差异有统计学意义(P0.05);妊娠期糖尿病孕妇组孕32~36周胎儿及糖尿病母亲婴儿组心室各段心肌SRs、SRd均减低,差异有统计学意义(P0.05);妊娠期糖尿病孕妇组孕24~28周胎儿SRs与正常对照孕妇组比较,无统计学意义(P0.05),但SRd降低,差异有统计学意义(P0.05)。结论应用二维斑点追踪显像技术可以检测妊娠期糖尿病孕妇胎儿左、右心室长轴心内膜下心肌的应变变化,可以早期发现妊娠期糖尿病孕妇胎儿及新生儿心室肌舒缩功能的减退。因此二维斑点追踪显像技术可以无创、精确地检测妊娠期糖尿病孕妇胎儿心室肌功能的变化。     

二维斑点追踪成像对心肌淀粉样变患者左心室旋转和扭转运动的初步研究

目的 应用斑点追踪成像（STI）技术测量心肌淀粉样变（CA）患者左心室短轴方向旋转和扭转角度,探讨STI评价CA患者左心室旋转和扭转运动的临床价值。方法 20例CA患者,其中男性13例,女性7例;年龄42 ～ 65岁,平均年龄54.80岁。30例健康志愿者,其中男性18例,女性12例;年龄45 ～ 62岁,平均年龄54.85岁。采集CA患者和健康志愿者的常规超声左心室短轴图像,测量二尖瓣口舒张早期血流峰速（E峰）、舒张晚期血流峰速（A峰）、收缩期S波峰值速度（Sm）、舒张早期E波峰值速度（Em）、舒张晚期A波峰值速度（Am）;采用STI测量各平面的内膜下心肌旋转（endo-rot）、外膜下心肌旋转（epi-rot）、平面旋转（bulk-rot）及跨壁扭转（mural-rot）峰值。计算左心室整体扭转（lv-tor）峰值。结果 CA组同对照组比较,E/Em明显增高（23.04 ± 6.21 vs 7.82 ± 1.19）,E波速度下降时间、Sm、Em、Am明显减低[（143.20 ± 43.32） ms vs （201.46 ± 14.99） ms,（4.68 ± 1.02） cm/s vs （7.74 ± 0.86） cm/s,（4.08 ± 1.80） cm/s vs （11.15 ± 1.44） cm/s,（4.11 ± 1.41） cm/s vs （8.23 ± 1.05） cm/s],差异具有极显著统计学意义（P 〈 0.001）; E/A增高（1.79 ± 1.54 vs 1.27 ± 1.11）,A减低[（0.51 ± 0.16） m/s vs （0.68 ± 0.06） m/s],差异具有显著统计学意义（P 〈 0.01）;E差异无统计学意义（P 〉 0.05）。CA 组各平面的endo-rot、epi-rot、bulk-rot及mural-rot峰值均显著低于对照组（P 〈 0.05）。与对照组比较,CA组lv-tor角度峰值［（5.93 ± 1.96）°］显著低于对照组［（8.75 ± 1.42）°］,差异具有极显著统计学意义（P 〈 0.001）。结论 CA患者心功能受损,左心室旋转及扭转运动发生变化,左心室短轴各平面endo-rot、epi-rot、bulk-rot、mural-rot及lv-tor角度均显著减低,示二维STI能够从短轴各平面心肌旋转和扭转运动的角度更准确及敏感反映CA患者心肌功能变化。     

二维斑点追踪技术评价冠心病患者心肌功能的研究

目的：应用二维斑点追踪成像（ speckle tracking imaging, STI）技术对常规方法显示室壁运动正常的冠心病患者进行定量分析,探讨STI技术用于诊断冠心病的临床应用价值。方法采集经冠状动脉造影证实的50例冠心病和40例对照组患者的心尖长轴、四腔和两腔观的二维灰阶动态图像,测量比较两组各节段纵向收缩期峰值应变（ global longitudinal systolic peak strain, GLPS）及整体纵向平均应变（ GLPS?Avg）,应用受试者工作特征曲线（ receiver operating characteristic curve, ROC曲线）评价GLPS?Avg对筛选冠心病的敏感性和特异性。结果冠心病组各节段心肌的GLPS均明显低于对照组,差异性具统计学意义（P＜0?05）。 GLPS?Avg 冠心病组（－15?79％±3?35％）绝对值低于正常组（－19?02％±2?78％）的绝对值,有统计学差异（P＜0?05）。 ROC曲线显示以GLPS?Avg－17?7％作为筛选冠心病的截断值,其诊断敏感性为77?5％,特异性为60?0％,AUC＝0?777。结论 STI作为早期诊断冠心病的指标是可行的。     

超声斑点追踪成像技术在右心功能评估中的研究进展

一直以来,右心室被认为在心功能构成中并未发挥主要作用.随着对右心室结构和功能研究的深入,人们逐渐意识到右心室形态与功能在临床与预后评价中的重要作用,各种用于整体评估右心室功能的成像技术不断得到发展.随着超声心动图技术的发展,斑点追踪成像(STI)技术在右心室功能评估中得到了广泛应用,为不同临床条件下右心室功能评估与研究,以及为与右心室功能相关的心肺疾病诊断与预后评价提供了简单且实用的新方法.对STI技术在右心室功能评估中的原理、方法和意义,以及其在临床应用中的问题作一综述.     

不同β-肾上腺素能受体对低氧应激大鼠心脏舒缩功能的影响

目的:探讨不同β-肾上腺素能受体(β-adrenergic receptor,β-AR)在急性低氧应激中对大鼠左、右心室舒缩功能的影响。方法:健康雄性SD大鼠随机分为4组(n=7):对照组(control group)、非选择性β-肾上腺素能受体阻断剂普萘洛尔组(propranolol group)、选择性β_1-肾上腺素能受体阻断剂阿替洛尔组(atenolol group)和选择性β2-肾上腺素能受体阻断剂ICI 118,551组(ICI 118,551 group),各组大鼠分别在常氧(西宁,海拔2 260 m,20.9% O_2,79.1% N_2)和急性低氧(15.0% O_2,85.0% N_2)通气的状态下进行实验,监测各组大鼠心率(heart rate,HR)、左心室收缩压(left ventricular systolic pressure,LVSP)、右心室收缩压(right ventricular systolic pressure,RVSP)及左、右心室内压最大上升和下降速率(±dp/dt_(max))等心功能指标变化;同时,比较低氧通气前后动脉血气的变化。结果:常氧下,propranolol组、atenolol组与ICI 118,551组LVSP和左心室±dp/dt_(max)较给药前降低,同时propranolol组与atenolol组RVSP和右心室±dp/dt_(max)较给药前明显降低(P0.05)。低氧通气5 min后,各组大鼠与常氧组相比动脉血氧分压(PaO_2)、LVSP和左心室±dp/dt_(max)均降低(P0.05);但右心室±dp/dt_(max)明显升高(P0.05);且低氧条件下control组心功能指标的变化程度均比propranolol组和atenolol组明显。结论:低氧应激时心脏β_1-AR的激活可能是心脏发挥代偿调节的重要方式,但右心室通过紧张源性扩张代偿表现出的右心舒缩功能增强对低氧下机体循环血流量的维持更为重要。     

Quality evaluation of ultrasound imaging in the carotid artery based on normalization and speckle reduction filtering

Image quality is important when evaluating ultrasound images of the carotid for the assessment of the degree of atherosclerotic disease, or when transferring images through a telemedicine channel, and/or in other image processing tasks. The objective of this study was to investigate the usefulness of image quality evaluation based on image quality metrics and visual perception, in ultrasound imaging of the carotid artery after normalization and speckle reduction filtering. Image quality was evaluated based on statistical and texture features, image quality evaluation metrics, and visual perception evaluation made by two experts. These were computed on 80 longitudinal ultrasound images of the carotid bifurcation recorded from two different ultrasound scanners, the HDI ATL-3000 and the HDI ATL-5000 scanner, before (NF) and after (DS) speckle reduction filtering, after normalization (N), and after normalization and speckle reduction filtering (NDS). The results of this study showed that: (1) the normalized speckle reduction, NDS, images were rated visually better on both scanners; (2) the NDS images showed better statistical and texture analysis results on both scanners; (3) better image quality evaluation results were obtained between the original (NF) and normalized (N) images, i.e. NF–N, for both scanners, followed by the NF–DS images for the ATL HDI-5000 scanner and the NF–DS on the HDI ATL-3000 scanner; (4) the ATL HDI-5000 scanner images have considerable higher entropy than the ATL HDI-3000 scanner and thus more information content. However, based on the visual evaluation by the two experts, both scanners were rated similarly. The above findings are also in agreement with the visual perception evaluation, carried out by the two vascular experts. The results of this study showed that ultrasound image normalization and speckle reduction filtering are important preprocessing steps favoring image quality, and should be further investigated.     

Experimental acute hypoxia in healthy subjects: evaluation of systolic and diastolic function of the left ventricle at rest and during exercise using echocardiography

To clarify whether or not systolic and diastolic function of the human left ventricle (LV) were decreased during acute hypoxia, at rest and with exercise, 14 healthy male volunteers [age 25.9 (SD 3.0) years, height 182.9 (SD 7.1) cm, body mass 75.9 (SD 6.9)kg] were examined using M-mode and 2D-mode echocardiography to determine the systolic LV function as well as Doppler-echocardiography for the assessment of diastolic LV function on 2 separate test days. In random order, the subjects breathed either air on 1 day (N) or a gas mixture with reduced oxygen content on the other (H; oxygen fraction in inspired gas 0.14). Measurements on either day were made at rest, several times during incremental cycle exercise in a supine position (6-min increments of 50 W, maximal load 150 W) and in 6th min of recovery. Corresponding measurements during N and H were compared statistically. Arterial O₂ tension (P _aO₂) was normal on N-day. All subjects showed a marked acute hypoxia at rest [P _aO₂, 54.5 (SD 4.6) mmHg], during exercise and recovery on H-day. The latter was associated with tachycardia compared to N-day. All echocardiographic measurements at rest were within the limits of normal values on both test days. Ejection time, end-systolic and end-diastolic left ventricular dimensions as well as the thickness of left posterior wall and of interventricular septum showed no statistically significant influence of H either at rest or during exercise. Stroke volume and cardiac output were always higher on H-day, which could be attributed to a slight reduction in end-systolic volume with unaffected end-diastolic volume as well as to increased heart rates. Among the indices of systolic LV function the fractions of thickening in the left ventricular posterior wall and interventricular septum showed no differences between H and N at rest or during exercise. However, fibre shortening, ejection fraction and mean circumferential fibre shortening were increased on H-day on all occasions. The mitral-valve-Doppler ratio, the index of diastolic LV function, was decreased with H at rest, showed a more pronounced reduction during exercise and was still lower in 6th min of recovery compared to N-day. It was concluded that with acute hypoxia of the severity applied in this study left ventricular systolic function in our healthy subjects showed a pronounced improvement and left ventricular diastolic function was reduced, both at rest and with exercise.