Improvement in echocardiographic evaluation of left ventricular wall motion using still-frame parametric imaging.

BACKGROUND: Conventional echocardiographic assessment of left ventricular wall motion is based on visual interpretation of dynamic images, which depends on readers' experience. We tested the feasibility of evaluating endocardial motion using still-frame parametric images. METHODS AND RESULTS: In protocol 1, integrated backscatter images were obtained in 8 anesthetized pigs at baseline, 5, and 60 seconds after left anterior descending coronary occlusion and during reperfusion. Images from 1 cardiac cycle were analyzed offline to create a parametric image of local video intensity oscillations. Ischemia-induced changes were quantified by segmenting the parametric images and calculating regional pixel-intensity profiles. In protocol 2, parametric images were obtained from contrast-enhanced echocardiograms in 30 patients (18 with wall-motion abnormalities; 12 control subjects). "Gold standard" for wall motion was determined from independent interpretations of dynamic images made by 3 experienced reviewers. Dynamic images were independently classified by 3 inexperienced and 3 intermediate-level readers. Interpretation was then repeated in combination with parametric images. Parametric images showed a bright band in the area spanned by endocardial motion, which gradually decreased in brightness and thickness in the left anterior descending territory during coronary occlusion in all animals. In patients, the agreement with the gold standard correlated with the readers' experience (68% inexperienced, 87% intermediate) and significantly improved by adding parametric images (83% and 91%, respectively). CONCLUSION: Parametric imaging provides a still-frame display of regional endocardial motion, sensitive to track ischemia-induced abnormalities. When combined with dynamic images, this technique improves the accuracy of the interpretation of wall motion, especially by less experienced echocardiographers.     

Automated interpretation of regional left ventricular wall motion from cardiac magnetic resonance images.

Magnetic resonance (MR) diagnosis of regional left ventricular (LV) dysfunction relies on visual interpretation of cine images that suffers from wide inter-observer variability, especially when performed by readers not specifically trained in the assessment of LV wall motion. Quantitative analysis tools, though widely available, are rarely used because they provide large amounts of detailed information, the interpretation of which requires additional time-consuming processing. We tested the feasibility of fast automated interpretation of regional LV function using computer analysis of this wall motion information. METHODS: Dynamic, ECG-gated, steady-state free precession short-axis images were obtained in 6-10 slices in 28 subjects (10 normal volunteers; 18 patients). Images were reviewed by an expert cardiologist who provided "gold standard" grades (normal, abnormal) for regional wall motion and, independently, by four radiologists. Same images were then analyzed using custom software. Regional fractional area changes computed in normal volunteers were used to obtain the optimal segment- and slice-specific threshold values for automated classification of regional wall motion for each patient. The levels of agreement with the "gold standard" grades were compared between the radiologists and the automated interpretation. RESULTS: While the visual interpretation required 2-5 minute per patient, the automated interpretation required < 1 sec, after endocardial border detection was complete. The automated interpretation resulted in higher sensitivity, specificity, and accuracy (84%, 77%, 79%, respectively) than the radiologists' grades (80%, 76%, 77%, respectively) and eliminated the high interobserver variability. CONCLUSION: Once the endocardial boundaries are defined, computer analysis of the regional wall motion information allows accurate, fully automated, immediate, objective and experience-independent interpretation of regional LV function.     

斑点追踪成像技术评价心室起博对左心室壁运动影响的实验研究

目的 应用斑点追踪成像技术(STI)观察评价心室起搏对左室室壁运动的影响.方法 7只成年猪在全麻成功后切开胸骨及心包,暴露出心脏.将起搏器电极放在心外膜上行左室或右室起搏,并在起搏前后采集左室中段短轴切面超声图像.用STI软件对图像进行环向应变分析并得出时间应变曲线.以QRS波作为心动周期的起点,分析起搏前后的心肌收缩起始时间、终止时间及收缩总时间占整个心动周期的比率,并了解左室壁各节段收缩协调情况.结果 与窦性心律相比,所有心室起搏心律的收缩起始时间、终止时间及收缩总时间占整个心动周期的比率均增大.心室起搏可导致室壁各节段运动明显不协调.当起搏心率＞130次/min时,在起搏心电图正常情况下,左室整体及部分节段在一个心动周期中出现一次以上的收缩或舒张运动,并出现在相邻的几个心动周期中收缩幅度变异性很大情况.结论 心室起搏可引起左室收缩延迟及时间延长,并可引起左室室壁各节段运动不协调.高频率心室起搏还可能引起左室室壁不规则运动.

Abstract：

Objective To assess the change of left ventricular wall motion at ventricular pacing(VP)by using global circumferential strain (GCS) and segmental circumferential strain of speckle tracking imaging(STI). Methods Seven adult pigs were sedated,followed by median sternotomy and opening of the pericardium. Temporary pacing leads were placed on the right ventricular (RV) epicardium and LV epicardium for RV or LV pacing. A LV short axis view at the mid-level LV was acquired at sinus and VP rhythm. Analysis of circumferential strain by STI was performed offline. The onset of QRS wave was used to characterize the beginning of the cardiac cycle, and the ratio of beginning systolic time, end systolic time and total systolic time to cardiac cycle dyssynchrony was analyzed at sinus and VP rhythm. Results Compared with sinus rhythm,in VP rhythm all of the ratio of the beginning systolic time,end systolic time and total systolic time to cardiac cycle were increased (all P ＜0.05), and the construction of six segments were dyssynchrony,even segmental paradoxical movement. At VP ≥130 beats/min,both LV global and LV segments sometimes showed irregular motion while the EKG remained normal, which included: ( 1 ) multiple construction and diastole in one heart cycle; (2) A large variability of construction amplitude in several consecutive cardiac cycles. Conclusions VP can lead to several kinds of disturbance of left ventricular wall motion, including delay and lengthening of LV systole, dyssynchrony, and irregularity of systole and diastole.     

Systolic outward motion of the left ventricular apical wall as detected by magnetic resonance tagging in patients with apical hypertrophic cardiomyopathy.

Patients with apical hypertrophic cardiomyopathy (APH) associated with paradoxic jet flow (ie, diastolic flow away from the apex) may gradually develop an apical aneurysm, which often leads to arrhythmia and mural thrombus formation. We observed systolic outward motion of the left ventricular apical myocardium in patients with APH using a magnetic resonance tagging procedure and examined the relationship of the outward motion to echocardiographic and scintigraphic findings and to cardiac events. Systolic displacement of the myocardial tags of the apical region perpendicular to the long axis in the 4-chamber view was recorded in 31 patients with APH. Of these patients, 14 showed no outward movement of tags (group A), and 17 showed outward movement (group B). In group B, apical hypertrophy was more severe (35 +/- 7 mm vs. 29 +/- 6 mm, p < 0.05), paradoxic jet flow was more frequent (64% vs. 14%, p < 0.05) and the defect score in I-123-beta-methyliodophenylpentadecanoic acid scintigraphy was higher (2.1 +/- 0.7 vs. 1.3 +/- 0.7, p < 0.01). During a mean follow-up period of 55 months, only 1 patient experienced paroxysmal atrial fibrillation in group A. In group B, 1 patient died suddenly, 1 was admitted to hospital because of congestive heart failure, 2 developed angina pectoris, 2 exhibited non-sustained ventricular tachycardia, and 1 showed multifocal premature ventricular contraction; in these 7 patients the outward movement was greater than in the 10 patients in Group B who had no cardiac events (1.00 +/- 0.59 vs. 0.52 +/- 0.40, p < 0.05). Hence, our results show that outward tag displacement is frequently associated with severe apical hypertrophy, paradoxic jet flow, apical ischemia, and cardiac events. The tagging method may be useful in assessing the severity of APH and predicting the occurrence of cardiac events at an early stage.     

Objective assessment of left ventricular wall motion from contrast-enhanced power modulation images.

There is no method to objectively evaluate left ventricular (LV) function from contrast-enhanced images. We tested the feasibility of evaluating regional LV function by using power modulation imaging. In protocol 1, 9 anesthetized closed-chest pigs were studied. Images were obtained during contrast infusion at baseline, during LAD occlusion and reperfusion. In protocol 2, images were obtained in 20 patients (14 wall-motion abnormalities; 6 controls) during contrast enhancement. Off-line, frame-by-frame, semiautomated endocardial border detection was followed by color encoding of endocardial motion, followed by segmentation and calculation of regional fractional area changes. In all animals, coronary occlusions resulted in hypokinesis and decreased fractional area changes in LAD-related segments only, which were reversed during reperfusion. In patients, wall-motion analysis was in agreement with an expert reader of dynamic images in 92.5% segments, with interobserver variability of 12.5%. Color encoding of endocardial motion from contrast-enhanced power modulation images allows accurate quantitative assessment of regional LV function.     

Three-dimensional echocardiographic assessment of left ventricular wall motion abnormalities in mouse myocardial infarction.

We applied 3-dimensional echocardiographic reconstruction to assess left ventricular (LV) volumes, function, and the extent of wall motion abnormalities in a murine model of myocardial infarction (MI). Consecutive parasternal short-axis planes were obtained at 1-mm intervals with a 13-MHz linear array probe. End-diastolic and end-systolic LV volumes were calculated by Simpson's rule, and the ejection fraction and cardiac output were derived. Echocardiography-derived cardiac output was validated by an aortic flow probe in 6 mice. Echocardiography was then performed in 9 mice before and after the left anterior descending coronary artery was ligated. Wall motion was assessed, and the ratio of the abnormally to normally contracting myocardium was calculated. After MI occurred, LV end-diastolic volume and LV end-systolic volume increased (33 +/- 10 vs 24 +/- 6 microL, P <.05 and 24 +/- 9 vs 10 +/- 4 microL, P <.001), whereas cardiac output decreased (4.2 +/- 1.5 mL/min vs 6.6 +/- 2.3 mL/min, P <.01). Forty percent of the myocardium was normokinetic, 24% was hypokinetic, and 36% was akinetic. Echocardiography can measure LV volumes and regional and global function in a murine model of myocardial infarction, thereby providing the potential to quantitate and compare the responses of various transgenic mice to MI and its therapies.     

二维斑点追踪成像对冠心病左室心肌局部收缩功能异常的研究

目的 运用二维斑点追踪成像（STI）测量正常人及心绞痛、心肌梗死患者左心室各节段的二维应变值,探讨二维斑点追踪技术对节段性心肌缺血的临床价值.方法 心绞痛患者73例,心肌梗死患者67例,健康对照组50例,分别采集其左心室长轴和短轴方向的二维动态图像,测量心肌收缩期峰值的纵向应变、径向应变和圆周应变.结果 对照组应变曲线排列规律,纵向应变由基底部到心尖部递增;同一水平室间隔周向应变较高;径向应变在同一水平不同节段分布较一致.心绞痛组、心肌梗死组缺血室壁节段纵向应变、径向应变和圆周应变减低,应变曲线紊乱;心绞痛组纵向应变、径向应变较对照组减低（P〈0.05）,心肌梗死组纵向应变、径向应变和圆周应变较对照组和心绞痛组均减低（P〈0.05）.结论 STI能够准确测量左室心肌节段的二维应变值,定量评价心肌缺血程度,纵向应变和径向应变是冠心病早期心肌缺血的敏感指标.     

Right ventricular wall motion abnormalities found in healthy subjects by cardiovascular magnetic resonance imaging and characterized with a new segmental model.

AIM: To evaluate right ventricular wall motion abnormalities in healthy subjects using a new segmental model for the right ventricle. METHODS AND RESULTS: 29 healthy subjects (9 female, 20 male, mean age 48.9+/-15 years) underwent cardiovascular magnetic resonance imaging (CMR; 1.5-Tesla Sonata, Siemens, Erlangen, Germany) for the evaluation of cardiac function and right ventricular wall motion. A steady-state free precession gradient-echo sequence (TrueFISP) was used. Right ventricular wall motion was analyzed, and the site of areas of disordered motion was classified according to the new segmental model. Such areas were seen in 27 (93.1%) of the 29 subjects. Dyskinesia was found in 22 subjects (75.9%), hypokinesia in 11 (37.9%), and bulging in 8 (27.6%). The number of wall motion abnormalities diagnosed was significantly higher in the transverse plane (86.2%) than in the short-axis plane (13.8%) and the horizontal longitudinal plane (41.4%; p = 0.000). CONCLUSION: Right ventricular wall motion abnormalities are one of the criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy. However, our findings indicate that they may also be seen around the insertion of the moderator band in healthy subjects, so that the significance of their presence at this site in patients undergoing diagnostic investigations for this disease should be interpreted with caution.     

Mitral annulus motion compared with wall motion scoring index in the assessment of left ventricular ejection fraction.

The biplane disc summation method is the recommended echocardiographic procedure to determine left ventricular (LV) ejection fraction (EF). Assessment of mitral annulus motion (MAM) or wall motion scoring index (WMI) has been reported to be less dependent on image quality compared with the recommended method, and proposed as a surrogate to the disc summation method in calculation of LVEF. We aimed to compare MAM and WMI in the echocardiographic assessment of LVEF. In a randomly selected population-based sample of 75-year-old men and women in sinus rhythm (n = 409) MAM, as measured by M-mode, was compared with WMI, calculated as the mean value of wall motion scoring in 9 LV segments. LVEF, as measured by the biplane disc summation method was used as reference. The limits of agreement (mean difference +/- 1.96 SD) between LVEF and corresponding MAM values were -18 to +13 LVEF%, and between LVEF and corresponding WMI values were -12 to +13 LVEF%. The areas under the receiver operating characteristic curves for MAM and WMI to predict a LVEF < 50% were 0.892 and 0.998, respectively (95% confidence interval of the difference 0.062-0.149). The corresponding areas for MAM and WMI to predict a LVEF < 40% were 0.955 and 0.998, respectively (95% confidence interval of the difference 0.017-0.069). In conclusion, the ability of WMI to estimate LVEF was more favorable than MAM in this population-based sample of 75-year-old participants. The findings suggest that the WMI is preferable to MAM in estimating LVEF.     

Value of gadolinium-enhanced magnetic resonance imaging in patients with Tako-Tsubo-like left ventricular dysfunction.

We present gadolinium-enhanced cardiac magnetic resonance imaging (CMRI) in Tako-Tsubo-like left ventricular dysfunction showing the findings in acute phase and in follow-up. Gadolinium-enhanced CMRI allows to distinguish between myocardial infarction and other myocardial alterations, e.g., myocarditis. CMRI may thus permit to non-invasively identify patients with Tako-Tsubo syndrome by ruling out myocardial infarction or myocarditis in the setting of wall motion abnormalities (WMA).     

Quantification of regional left ventricular wall motion in newborns by color kinesis.

BACKGROUND: Normal values for regional left ventricular wall motion, although documented in adults, have not been reported in healthy newborns. METHODS: This study prospectively evaluated global and segmental systolic and diastolic cardiac function by color kinesis in clinically asymptomatic healthy newborns. RESULTS: Eighty-eight asymptomatic infants who were less than 48 hours old were studied. Systolic and diastolic parameters of global and regional left ventricular function are reported as means +/- SD, medians, 5th and 95th percentiles to establish the normative values for newborns. The reported fractional area changes during systole and diastole are similar to the reported normal values for older subjects. Higher body surface area significantly correlated with an increased peak velocity during systole, and fractional area changes during filling of the lateral wall. CONCLUSIONS: Our report of left ventricular regional wall-motion characteristics of healthy newborns, as evaluated by color kinesis, may help in the objective evaluation and management of newborns suspected to have global or segmental ventricular dysfunction.     

组织多普勒成像技术评估慢性房颤患者左室壁运动

目的 应用组织多普勒成像技术（DTI）探讨慢性房颤患者的室壁运动特点,为临床诊治提供重要的信息,方法,将研究分为三组,A组为18例正常对照,B组为15例心房大小正常的房颤患者,C组为16例心房扩大的房颤患者,所有患者均无严重瓣膜病或节段性室壁运动异常,采用HP SONOS 5500超声显像仪和脉冲DTI,分别在心尖四腔心切面和胸骨旁长轴切面测定左室侧壁和后壁收缩期峰值速度（VS）,舒张期峰值速度（VE）,心电图QRS波起始至收缩期峰值速度的平均时间T1,心电图QRS波起始至舒张期峰值速度的平均时间T2,平均心率为R－R,结果 （1）A组正常人均有舒张早期和晚期两个波峰（E峰和A峰）,B组和C组房颤患者均只有一个舒张期波峰（E峰）,（2）A组与B组这间的DTI测值差异均无显著性意义（均为P＞0．05）,（3）C组左室侧的VS显著小于A组（P＜0．05）,C组左室后壁的VS,VE均显著大于A组（P均＜0．05）,C组侧壁的T1／（R－R）^1/2,Ts/(R-R)1/2显著高于A组（P均＜0．05）,C组后壁的T1／（R－R）^1/2,T2/(R-R)^1/2与A组比较差异无显著性意义（P均＞0．05）,结论 左房增大的房颤患者左室壁在长轴方向收缩活动减弱,舒张期峰值速度延迟,在短轴方向舒缝活动增强,DTI技术能精确地定量分析房颤患者的室壁活动,可成为评价房颤患者心肌舒缩功能的无创伤性新方法。     

Evaluation of left ventricular torsion by cardiovascular magnetic resonance

Recently there has been considerable interest in LV torsion and its relationship with symptomatic and pre-symptomatic disease processes. Torsion gives useful additional information about myocardial tissue performance in both systolic and diastolic function. CMR assessment of LV torsion is simply and efficiently performed. However, there is currently a wide variation in the reporting of torsional motion and the procedures used for its calculation. For example, torsion has been presented as twist (degrees), twist per length (degrees/mm), shear angle (degrees), and shear strain (dimensionless). This paper reviews current clinical applications and shows how torsion can give insights into LV mechanics and the influence of LV geometry and myocyte fiber architecture on cardiac function. Finally, it provides recommendations for CMR measurement protocols, attempts to stimulate standardization of torsion calculation, and suggests areas of useful future research.     

解剖M型超声技术检测左心室室壁运动的准确性

目的评价解剖M型超声技术检测左室壁运动的准确性。方法两个月内两次测量30例行冠状动脉造影患者的左室短轴二尖瓣水平观和乳头肌水平观的6个节段以及心尖四腔观的4个节段的室壁收缩快速射血期最大厚度、舒张期末厚度和收缩期增厚率。结果两次测量结果显示,左室壁所有各节段的收缩快速射血期最大厚度、舒张期末厚度和室壁收缩期增厚率的平均值均没有显著统计学差异(p>0.05)。结论解剖M型超声技术测定左室壁各节段的收缩期增厚率等指标时有较好的可重复性,因此有可能用于准确定量分析左室壁节段性运动。     

CT冠状静脉成像与室壁运动评价用于心脏再同步化治疗

心脏再同步化治疗（CRT）在心力衰竭合并心室电-机械失同步的治疗中取得了令人满意的成就，但部分患者对CRT低反应或无反应。将左心室起搏电极置于心室最延迟收缩区域的冠状静脉属支内可避开瘢痕负荷过重区域，提高CRT应答率，最大限度提高临床获益。CRT术前较全面获取冠状静脉解剖及延迟收缩的心肌节段等信息，对确定左心室起搏电极植入部位有重要意义。本文针对CT冠状静脉成像及室壁运动评价用于CRT的进展进行综述。