Real-time myocardial contrast echocardiography for assessing perfusion and function in healthy and infarcted wistar rats

Real-time myocardial contrast echocardiography (MCE) is a noninvasive perfusion imaging method, whereas technical and resolution problems impair its application in small animals. Hence, we investigated the feasibility of MCE in experimental cardiovascular set-ups involving healthy and infarcted myocardium in rats. Twenty-five male Wistar rats were examined under volatile anesthesia (2.5% isoflurane) with high-resolution conventional 2-D echocardiography (2DE) and real-time MCE (Sonos 7,500 with 15MHz-transducer, Philips Medical Systems, Andover, MA, USA) in short-axis view. Contrast agent (SonoVue, Bracco, Milan, Italy) was infused as a bolus into a sublingual vein. Background-subtracted contrast signal intensity (SI) was measured off-line in six end-systolic segments and fitted to an exponential curve (gamma variate). Derived peak SI was subsequently calculated and compared with wall motion and common functional measured quantities (left ventricular end-diastolic diameter [LVEDD], area shortening [AS]). Recordings were performed before and 14 days after left anterior descending (LAD) ligature. Infarction induced anterior wall motion abnormalities (WMA) in all animals (16 akinetic, 9 hypokinetic), increased LVEDD (9.1 +/- 0.6 vs. 7.9 +/- 0.6 mm, p < 0.001), reduced AS (36.1 +/- 10.0 vs. 59.5 +/- 4.1%, p < 0.001) and reduced anterior segmental SI (0.4 +/- 0.4 dB akinetic / 1.7 +/- 1.7 dB hypokinetic vs. 15.8 +/- 10.9 dB preinfarct, p < 0.001 / p < 0.001). Segmental SI in normokinetic segments remained unchanged. Area at risk (perfusion defect) correlated well with WMA (r = 0.838). These data confirmed high-resolution real-time MCE as a rational tool for assessing myocardial perfusion of Wistar rats. It may therefore be a useful diagnostic tool for in-vivo cardiovascular research in small animals.     

Fourier Phase Analysis Can Be Used to Objectively Analyze Real-Time Myocardial Contrast Echocardiograms

Background: Real-time myocardial contrast echocardiography (MCE) is increasingly used to assess myocardial perfusion. However, objective methods for evaluating MCE are not yet widely available. We sought to validate the ability of Fourier analysis applied to MCE to assess serial changes in microvascular perfusion during coronary occlusion and reperfusion. Methods: Six pigs underwent 45 min of left anterior descending coronary artery (LAD) occlusion followed by 120 min of reperfusion. Real time MCE was performed at baseline, during coronary occlusion, and at 5, 30, 60 and 120 min of reperfusion. Signal intensities from replenishment curves were fitted to an exponential function to obtain plateau SI (A) and the rate of SI rise (b). MCE images were mathematically transformed using a first-harmonic Fourier algorithm displaying the sequence of myocardial intensity changes as phase angles in parametric images. The phase angle difference (PD) of posterior vs. anterior region was calculated as an index of myocardial opacification heterogeneity and compared to MCE index of myocardial blood flow A×b. Results: After initial hyperemia, a progressive reduction in flow was observed during reperfusion. During LAD occlusion signal intensities were significantly reduced in anterior regions (A×b= 0.02 ± 0.01) compared to baseline (1.2 ± 0.34, p < 0.01) defining risk areas and approached higher levels postrecanalization (A×b= 1.48 ± 0.6) but gradually decreased during 120 min of reperfusion (A= 0.51 ± 0.3, p < 0.01). Similarly, profiles of phase angles in LAD perfusion territorities were consistently modified during reperfusion. The mean PD at baseline was 18°± 15°. PD decreased during coronary occlusion to –108°± 38°, increased to 29°± 19° postrecanalization but decreased to –61°± 35° after 120 min of reperfusion. PD significantly correlated with A(r= 0.8, p < 0.0001) and b(r= 0.73, p < 0.0001). Conclusions: The progressive reduction in post-ischemic microvascular perfusion was accurately detected by real-time MCE. Fourier phase imaging is feasible to quantify dynamics of myocardial opacification in a simple and objective format and is a promising approach for the interpretation of contrast echocardiograms.     

Fourier phase and amplitude analysis for automated objective evaluation of myocardial contrast echocardiograms

Aims: Objective methods for evaluating myocardial contrast echocardiography (MCE) are not yet widely available. We applied a Fourier analysis to myocardial contrast echocardiograms to identify myocardial perfusion defects. Methods: Harmonic power-Doppler contrast echocardiograms were performed in 21 patients undergoing Tl-201-SPECT imaging and in 13 controls. Images were transformed using Fourier analysis to obtain phase of the first harmonic sinusoidal curve displayed as color coded sequence of myocardial intensity changes. Means and standard deviations of regional phase angles were measured. The method was validated in an in vitro model. A contrast filled latex balloon was imaged at different gain settings mimicking defined time–intensity curves. An intraoperative porcine infarction model served to prove feasibility of Fourier transformation to analyze real-time pulse inversion contrast echocardiography. Results: In patients, phase imaging and intensity analysis showed focal areas with marked phase shifts (106 ± 90°) and heterogeneous distribution of phase angles (SD 66 ± 17°), correctly identifying 13/14 perfusion defects. The in vitro validation yielded increasing phase angles with increasing -values. This method was successfully applied to real-time MCE, identifying all infarction areas during occlusion of the left anterior descending artery. Conclusion: Phase analysis can be used to display dynamics of myocardial opacification.     

Determinants of myocardial hypoperfusion analyzed for the interventricular septum using power Doppler harmonic imaging with contrast echocardiography in humans: a methodologic approach for clinical practice.

BACKGROUND: To evaluate determinants of myocardial hypoperfusion using power Doppler harmonic imaging (PDHI) with myocardial contrast echocardiography (MCE) in clinical practice, a retrospective clinical study was performed comparing echocardiographic and angiographic data. Angiographic data of patients with a normal coronary angiogram (non-CAD) and symptomatic patients with low flow conditions caused by a stenosis of the left anterior descending coronary artery (LAD) or occlusion, or TIMI-II-flow in the LAD were compared with the PDHI data. METHODS AND RESULTS: In 32 patients, MCE was performed with a System Five Performance ultrasound system (GE Vingmed Ultrasound, Horten, Norway). Myocardial perfusion was semiquantitatively analyzed with the EchoPac 6.2b.134 software, bolus injection with Optison (0.35 mL with 5 mL saline flush), and continuous infusion with Levovist (400 mg/mL(-1); 3.5-5 mL/min(-1)) were performed (8 non-CAD patients, 8 CAD patients, respectively). After bolus injection, Doppler intensity (DI) kinetics showed a significant decrease of maximum DI wash-in rate (eg, apical septum [AS]: 4.9 +/- 3.3 vs 2.4 +/- 1.9 dB/s(-1)), of peak maximum DI (eg, AS: 25.3 +/- 6.3 vs 16.4 +/- 5.7 dB), and of DI determined 10 and 20 seconds after peak maximum DI (eg, AS: 22.1 +/- 4.9 vs 10.8 +/- 4.6 dB; AS: 20.4 +/- 5.3 vs 8.0 +/- 3.8 dB, respectively) using a trigger interval once every 3 cardiac cycles when normal perfused areas were compared with hypoperfused areas. During infusion coronary transit time (3.3 +/- 0.9 vs 7.0 +/- 3.6 seconds), maximum DI wash-in rate (eg, AS: 3.2 +/- 1.3 vs 1.3 +/- 0.8 dB/s(-1)) and DI-maximum plateau (eg, AS: 28.6 +/- 4.7 vs 18.3 +/- 6.4 dB) significantly decreased, respectively. CONCLUSION: Regional myocardial hypoperfusion at rest can be detected by using PDHI with MCE in clinical practice, according to a standardized methodologic protocol.     

术中冠脉血流显像技术评价急性心肌梗死犬心肌血流灌注的研究

目的探讨术中冠脉血流显像（CFI）技术观察急性心肌梗死犬心肌血流灌注的应用价值。方法18只健康开胸杂种犬于前降支分出第一对角支后约1 cm处结扎3小时建立急性心肌梗死模型。分别于结扎前、结扎3小时后应用i13L高频探头观察前降支远端及前壁心尖段心肌内血流灌注程度、血流方向,并测量心肌内冠脉血流速度,同时在以上观察时点经股静脉匀速推注造影剂（C3F8）行心肌声学造影（MCE）检查对照。结果18只犬均成功建立急性心肌梗死模型。结扎前降支3 h后,根据MCE显示前壁心尖段有无造影剂充填分为无侧支循环形成组（A组）和侧支循环形成不充分组（B组）,A组10只犬中,CFI显示60%（6/10）未见血流信号显示,40%（4/10）前壁心尖段内仅见星点状血流信号。B组7只犬中,CFI则均显示有少量血流信号,与基础状态相比,舒张期峰值血流速度（D-Vmax）、收缩期峰值血流速度（S- Vmax）及D-Vmax/S-Vmax比值均明显降低（P〈0.05）。另有1只犬MCE显示前壁心尖段造影剂充填良好,CFI亦显示丰富的血流信号,舒张期峰值血流速度（0.65 m/s）快于基础状态峰值血流速度（0.28 m/s）。结论术中冠脉血流显像技术能直观、无创、敏感地显示心肌血流灌注状态,与MCE比较,能更敏感的反映心肌血流灌注。     

能量多普勒造影技术在经静脉心肌声学造影研究中的临床初步应用

目的：观察能量多普勒造影技术（ＰＣＩ）行静脉心肌声学造影（ＭＣＥ）的效果。方法：利用ＰＣＩ技术观察６例非特异性胸痛患者及３例陈旧性心肌梗塞患者的经静脉心肌声学造影效果。其中,心肌梗塞患者在ＭＣＥ后一周内行核素检查。结果：６例非特异性胸痛患者均未见节段室壁运动异常,在声学造影剂注射后见全部心肌组织均匀显影 ３例陈旧性心肌梗塞患者则见梗塞相应部位室壁运动异常,且声学造影检查发现该部位多普勒能量信号缺失     

Real-time myocardial blood flow imaging in normal human beings with the use of myocardial contrast echocardiography.

Triggered myocardial contrast echocardiography (MCE) has been used successfully to quantify myocardial blood flow and assess coronary stenosis in animal models, but practical considerations have limited its broad clinical use. Real-time MCE may have practical advantages to assess perfusion and real time myocardial blood flow in human beings. We compared real-time MCE with triggered imaging in 23 normal human volunteers by using an investigational ultrasound contrast agent (DMP-115) and a commercially available ultrasound platform (Acuson Sequoia). Peak myocardial opacification (reflecting myocardial blood volume) after contrast infusion was quantified digitally in gray scale units (GU). In 13 subjects, myocardial blood flow reserve was assessed during dipyridamole infusion with the use of intermittent destruction-replenishment techniques. Real-time MCE resulted in a 30- to 45-GU increase from baseline compared with a 20- to 70-GU increase with triggered imaging. Real-time MCE showed no statistical difference in opacification (P = .131 by analysis of variance) among any of the myocardial regions of interest. Triggered imaging resulted in heterogeneous opacification among the regions of interest (P < .05 by analysis of variance). Dipyridamole did not significantly change peak myocardial opacification (myocardial blood volume) for either technique. Quantification of flow reserve revealed that myocardial blood flow reserve for the dipyridamole group was 3.6 +/- 0.4 (mean +/- 1 standard error of the mean). Real-time MCE is feasible in normal human volunteers and provides homogenous opacification of the myocardium. Furthermore, quantification of myocardial blood flow with real-time MCE in normal human beings produces results that are consistent with the known physiology of the coronary microcirculation.     

实时心肌声学造影评价正常犬心肌血流灌注的实验研究

目的：应用实时心肌声学造影评价正常犬的心肌血流灌注。方法：8只开胸犬以微量注射泵静脉滴注全氟显（速度为5ml/min和10ml/min）进行实时心肌声学造影。乳头肌水平短轴切面观察左室各壁的造影效果和室壁运动。以闪烁显像观察左室各壁的再注情况。结果：实时心肌声学造影良好地显示了犬正常心肌的血流灌注特点,包括色彩、亮度与灌注时间,同时各室壁节段运动显示良好,回放测量与M型测值无明显差异,闪烁显像准确反映了心肌血流灌注的速度。结论：实时心肌声学造影可同时观察心肌灌注和室壁运动,“闪烁”显像具有定量评价心肌血流灌注的潜在价值,具有良好的应用前景。     

Assessment of resting perfusion defects in patients with acute myocardial infarction: comparison of myocardial contrast echocardiography, combined first-pass/delayed contrast-enhanced magnetic resonance imaging and 99mTC-sestamibi SPECT

Background Information on the accuracy of both magnetic resonance imaging (MRI) and myocardial contrast echocardiography (MCE) for the identification of perfusion defects in patients with acute myocardial infarction is limited. We evaluated the accuracy of MRI and MCE, using Single Photon Emission Computed Tomography (SPECT) imaging as reference technique.Methods Fourteen consecutive patients underwent MCE, MRI and ^99mTc-MIBI SPECT after acute myocardial infarction to assess myocardial perfusion. MCE was performed by Harmonic Power Angio Mode, with end-systolic triggering 1:4, using i.v. injection of Levovist^®. First-pass and delayed enhancement MRI was obtained after i.v administration of Gadolinium-DTPA. At MCE, homogeneous perfusion was considered as normal and absent or “patchy” perfusion as abnormal. At MRI, homogenous contrast enhancement was defined as normal whereas hypoenhancement at first-pass followed by hyperenhancement or persisting hypoenhancement in delayed images was defined as abnormal.Results At MCE 153 (68%) of segments were suitable for analysis compared to 220 (98%) segments at MRI (p<0.001). Sensitivity, specificity and accuracy of MCE for segmental perfusion defects in these 153 segments were 83, 73 and 77%, respectively. Sensitivity, specificity and accuracy of MRI were 63, 82, and 77%, respectively. MCE and MRI showed a moderate agreement with SPECT (k: 0.52 and 0.46, respectively). The agreement between MCE and MRI was better (k: 0.67) that the one of each technique with SPECT.Conclusion MCE and MRI may be clinically useful in the assessment of perfusion defects in patients with acute myocardial infarction, even thought MCE imaging may be difficult to obtain in a considerable proportion of segments when the Intermittent Harmonic Angio Mode is used.     

Real-time myocardial contrast echocardiography for pharmacologic stress testing: is quantitative estimation of myocardial blood flow reserve necessary?

BACKGROUND: Little is known about the diagnostic accuracy of quantitative real-time myocardial contrast echocardiography (MCE) as an adjunct to stress testing. This study was performed to evaluate the agreement between MCE and technetium 99m-sestamibi single photon emission computed tomography (SPECT) for detection of perfusion defects and to investigate whether quantitative assessment of myocardial perfusion can increase the diagnostic value of MCE. METHODS: MCE was performed at rest and during peak adenosine stress in 50 unselected patients undergoing SPECT imaging. Concordance between the 2 methods was assessed using kappa statistics. MCE images were analyzed quantitatively, measuring peak intensity (A) and maximal rise of signal intensity (beta). Myocardial blood flow reserve was estimated by calculating the ratios of A(adenosine)/A(baseline) (A reserve), beta(adenosine)/beta(baseline) (beta reserve), and A x beta(adenosine)/A x beta(baseline) (A x beta reserve). RESULTS: Visual analysis of MCE agreed well with SPECT (kappa = 0.67) with sensitivity of 64%, specificity of 97%, and overall accuracy of 87%. Quantitative analysis showed that peak signal intensity A significantly increased under adenosine stress in SPECT-normal segments (2.6 +/- 1.9 vs 3.0 +/- 1.6 dB, P <.0001), tendencially decreased in reversible (3.0 +/- 2.0 vs 2.4 +/- 1.2 dB, P =.07) and remained unchanged in fixed (0.9 +/- 0.9 vs 0.8 +/- 0.9 dB) defects. beta Increased markedly under adenosine in normal segments (0.4 +/- 0.4 vs 1.4 +/- 1.3, P <.0001) but not in segments with reversible or fixed defects. Receiver operating characteristic showed that beta reserve and A x beta reserve, but not A reserve, are sensitive parameters for detecting perfusion defects with areas under the curve of 0.84, 0.85, and 0.61, respectively. Cut-off values of 1.9 and 2.3, respectively, for beta and A x beta reserve yielded sensitivity rates of 79% and 80%, specificity rates of 75% and 78%, and overall accuracy rates of 76% and 79%, respectively. CONCLUSION: Quantitative estimation of myocardial blood flow reserve by MCE parameters corresponds to the evaluation of myocardial perfusion by nuclear imaging and can increase the sensitivity but not the overall accuracy of contrast echocardiography.     

Evaluation of a new ultrasound contrast agent (AI-700) using two-dimensional and three-dimensional imaging during acute ischemia.

BACKGROUND: A new intravenous contrast agent, AI-700, was evaluated to determine whether a bolus injection could be used to detect myocardial perfusion abnormalities during acute ischemia by using 2-dimensional (2D) and 3-dimensional (3D) myocardial contrast echocardiography. METHODS: 2D MCE was performed in 14 closed-chest dogs during coronary occlusion by using both continuous and triggered gray scale harmonic imaging and triggered power Doppler imaging. 3D MCE (open-chest) and nuclear perfusion imaging were performed in 10 of the 14 dogs. Postmortem triphenyl tetrazolium chloride (TTC) staining was performed to verify infarction. RESULTS: Thirteen of the 14 dogs had infarct by TTC; all 10 that had nuclear imaging showed a perfusion defect. Of the 13 dogs that had infarction, perfusion defects were detected in all (13 of 13) by gray scale harmonic imaging (sensitivity = 100%), and in 11 of 13 by power Doppler imaging (sensitivity = 85%). All 10 dogs that had nuclear imaging showed perfusion defects by gray scale harmonic imaging (sensitivity = 100%) and 8 of 10 by power Doppler imaging (sensitivity = 80%). The perfusion defect size, derived from 3D imaging (25% +/- 12%) correlated well with that from nuclear imaging (24% +/- 12%) (y = 0.9x + 3.8, r = 0.96, mean difference = 1.3% +/- 2.6%). The perfusion defect mass by 3D (22 +/- 14 g) also correlated well with the infarct mass by TTC staining (24 +/- 16 g) (y = 0.8x + 2.9, r = 0.89, P <.001, mean difference = -2.8 +/- 7.6 g). CONCLUSION: After a single bolus of AI-700, both 2D and 3D MCE could accurately detect perfusion defects representing the area at risk of infarction during acute ischemia compared with nuclear imaging and predicted the size of infarction as verified by TTC staining.     

一种新的心肌声学造影技术:持续静脉滴注声振微泡的心肌声学造影方法研究

目的;探讨持续静脉滴注法行心肌声学造影的安全性及有效性。方法：经犬外周静脉持续注微泡造影剂动态观察心肌显效果及其对血流动力学的影响。结果：２ｍｌ／ｍｉｎ和６ｍｌ／ｍｉｎ滴注组分别于滴注后约７２．７秒和１９．９秒心肌开始显影,持续到滴注停止后约半分钟心肌显影消退。前降支套扎及再灌注过程中可观察到局部心肌声学造影充填,缺损、再充填的动态演变。全部造影过程中无血流动力学及心电图变化。结论：持续静脉滴注法     

谐波、超谐波心肌声学造影技术评价犬急性心肌梗死

目的探讨谐波(HA)和超谐波(UH)两种心肌声学造影技术评价心肌梗死的准确性。方法10条常规开胸犬动物模型,在基础状态、结扎冠状动脉左前降支1h后,分别应用HA和UH技术采集心肌声学造影图像,目测观察充盈缺损的范围,定量计算充盈缺损的面积,并与应用TTC染色测量的梗死心肌面积对比。结果TTC染色显示心肌梗死HA面积百分率为15.8%±2.4%,应用两种心肌声学造影模式计算的充盈缺损面积与解剖学梗死心肌面积高度相似,应用HA模式为15.5%±2.9%,应用UH模式为15.5%±3.0%。两种心肌声学造影模式检测急性心肌梗死HA的敏感性、特异性及诊断准确率分别为:在HA模式为88%、100%、94%;在UH模式为100%、75%、88%。结论两种心肌声学造影技术在诊断急性心肌梗死中均具有高度的准确性。     

实时心肌造影评价急性心肌梗死患者应用冠状动脉远端保护装置后心肌灌注的初步探讨

目的：对急性心梗应用远端保护装置术后患者进行实时心肌造影检查,初步探讨患者术后心肌血流灌注恢复情况。材料与方法：急性心肌梗死入院并行急诊介入治疗联合应用冠脉远端保护装置术后患者3例应用SonoVue造影剂进行经静脉实时心肌造影检查。结果：患者均无任何不适。梗死相关节段室壁的功能和心肌灌注均得到了不同程度的恢复。结论：联合使用远端保护装置,可有效改善心肌灌注。     

The impact of emission power on the destruction of echo contrast agents and on the origin of tissue harmonic signals using power pulse-inversion imaging.

The purpose of this study was to determine the impact of emission power on ultrasound (US)-induced destruction of echocontrast microbubbles during real-time power pulse inversion imaging (PPI) in myocardial contrast echocardiography (MCE) and to evaluate the magnitude of noncontrast PPI signals arising from myocardial tissue at variable emission power to define the cut-off emission power for optimal MCE using low power technologies. In vitro studies were performed in a flow phantom using Optison, Definity and AFO 150. PPI signal intensity during real-time imaging at 27 Hz was compared with intermittent imaging at 0.1 Hz to evaluate bubble destruction at variable emission power (MI: 0.09 to 1.3). In healthy volunteers, PPI signal intensities during constant infusion of Optison(R) was studied in real-time PPI 22 HZ and during intermittent imaging triggered end-systolic frames every, every 3rd and every 5th cardiac cycle. In addition, the impact of emission power on nonlinear PPI signals from myocardial structures was studied. In vitro, there was a 40% decrease of real-time PPI signal intensity for Optison and AFO 150 at lowest emission power (0.09), whereas no signal loss was observed for Definity. Increase of emission power resulted in a faster decay for Optison(R) and AFO 150 as compared to Definity. In vivo, real-time PPI during continuous infusion of Optison(R) resulted in a 40% decrease of myocardial signal intensity as compared to intermittent imaging every 5th cardiac cycle, even at lowest possible emission power (mechanical index = 0.09). There was a strong positive relationship between MI and noncontrast myocardial PPI signals in all myocardial segments. PPI signal intensity was found to be lower than 1 dB only for extremely low emission power (MI < 0.2). Destruction of microbubbles during real-time imaging by use of PPI at low emission power varies considerably for different echo contrast agents. However, bubble destruction and the onset of tissue harmonic signals focus the use of real-time perfusion imaging to very low emission power.     

应用对比脉冲系列成像技术以SonoVue进行心肌造影的初步临床观察

目的本研究旨在应用对比脉冲系列成像(CPS)超声造影技术,采用经静脉注射SonVue后,观察心肌显影效果,并与患者的冠脉造影结果进行对比研究,评估其有效性和安全性。方法对25例经冠状动脉造影检查的患者,在CPS超声心肌造影的成像技术条件下,经静脉注射SonVue2ml,,进行超声心肌造影。并与冠状动脉造影对比分析。结果本组显示,大多数冠脉3支病变的患者显示心肌灌注明显下降,单支或双支病变的患者则表现为相应冠脉供血区心肌灌注下降。在肥厚型心肌病和酒精性心肌病的患者,尽管冠状动脉造影正常,但心肌灌注明显延迟。结论本研究结果提示,应用CPS造影成像技术,所用超声强度机械指数较低,静脉注射超声造影剂SonVue剂量小,即能达到满意的心肌显影效果,本组患者中未发现明显副作用。     

Relationship between function and perfusion early after acute myocardial infarction

To assess the relationship between baseline left ventricle function, functional reserve and resting myocardial perfusion in patients with acute myocardial infarction (AMI). After AMI the presence of dysfunctioning but viable myocardium plays a determinant role in clinical outcome. Regional ventricular function was evaluated by echocardiography both in resting conditions and during dobutamine infusion (10 g/kg/min). Perfusion was assessed by magnetic resonance imaging in a single slice approach where the first pass of an intravenously injected bolus of gadolinium-based contrast agent was followed through six regions of interest within the myocardium. In each patient a region with normal function was used as reference and the cross-correlation coefficient (CCC), which described the myocardial perfusion relatively to the reference region (CCC = 1 means equivalent perfusion), was obtained for the other five myocardial regions. Twenty-two patients were enrolled into the study. Sixty-one segments had normal function and normal perfusion (CCC = 0.92 ± 0.23). The perfusion deficit was more marked in the 29 regions with resting akinesia–dyskinesia than in the 20 hypokinetic regions (CCC = 0.71 ± 0.45 vs. 0.84 ± 0.23; p < 0.05). Out of the 29 regions with resting akinesia–dyskinesia the 13 segments which showed functional improvement following dobutamine had a higher resting perfusion than the 16 segments which were unresponsive to dobutamine (CCC = 0.83 ± 0.32 vs. 0.61 ± 0.52, p < 0.05). Similarly, out of the 20 regions with resting hypokinesia the 11 segments having functional reserve showed an higher resting perfusion than the segments which did not (0.96 ± 0.21 vs. 0.69 ± 0.19; p < 0.05). Early after AMI, the perfusion deficit reflects the severity of the mechanical dysfunction. In regions with baseline dyssynergy resting perfusion is, in general, higher when contractile reserve can be elicited by stress-echo.     

心肌灌注造影在多巴酚丁胺负荷前后早期诊断冠心病的临床研究

目的探讨心肌灌注造影(MCE)技术在大剂量多巴酚丁胺负荷前后早期诊断冠心病的价值.方法 对临床疑为冠心病患者38例,进行大剂量多巴酚丁胺负荷超声心动图试验,分别在静息状态和多巴酚丁胺负荷超声心动图试验终止时即刻行MCE检查.以冠状动脉造影为金标准将大剂量多巴酚丁胺负荷超声心动图前后心肌灌注状态目测法对冠心病的检出率进行比较.结果 多巴酚丁胺负荷超声心动图检查的38例患者中,9例(24%,9/38)达到峰值负荷水平,22例(58%,22/38)达到中级负荷水平.其中通过冠状动脉造影诊断的27例冠心病患者在多巴酚丁胺负荷前后,通过心肌灌注状态目测法诊断心肌缺血患者的例数分别为10例(37%,10/27)及24例(89%,24/27,χ2=15.565,P＜0.01).结论 大剂量多巴酚丁胺负荷超声心动图结合MCE可提高缺血心肌的检出率,发现隐匿性心肌缺血,为临床无创性诊断早期冠心病患者提供新方法.     

利声显经静脉心肌声学造影评价心肌梗死后患者的心肌灌注

目的 心肌造影超声心动图（MCE）采用触发谐频能量多普勒显像模式并用静脉持续输液利声显,观察心肌梗死后患者的心肌灌注情况,方法,使用谐频频率1．8－3．6MHZ的能量多普勒模式,于心电图T波终末处,按1：4心动周期进行触发,利声显浓度为300mg/ml,采用微量输液泵将所配心肌造影剂于患者左肘静脉内持续输注4 min(2ml/min),25例心肌梗死后患者的血压和心率变化并对心肌灌注情况进行半定量分析。结果 （1）MCE前后,患者血压和心率改变无明显差异;（2）触发谐频能量多普勒显像模式并用静脉持续输液min的心肌显影效果,而后方衰减可以避免。结论 触发谐频能量多普显像并用静脉持续输注利声显,可以产生较好的心肌灌注显像效果。     

多巴酚丁胺负荷超声心动图结合心肌灌注造影早期诊断冠心病的价值

目的 探讨大剂量多巴酚丁胺负荷超声心动图(DSE)结合心肌灌注造影(MCE)技术早期诊 断冠心病的价值。方法 对临床可疑冠心病的38例患者进行大剂量多巴酚丁胺负荷试验,分别在静息状态和试验终止的即刻实行MCE检查。并在静息状态及各级负荷状态下观察室壁运动(WM)情况;对每次MEC后各心肌节段灌注状态进行评估。大剂量DSE时,以冠状动脉造影为金标准比较WM目测法和心 肌灌注状态目测法诊断冠心病的敏感性和特异性。结果 DSE时,9例(24％)患者达到峰值负荷水平,22 例(58％)达到中级负荷水平。DSE终止时,通过心肌灌注状态目测法及WM目测法诊断有心肌缺血患者 的例数分别为24例(89％)及15例(52％)(P＜0.01)。同时,通过上述两组方法评估心肌缺血,并根据相应缺血心肌节段所对应冠脉分支准确判断病变血管的敏感性分别为71％及41％(P ＜0.01)。结论 大剂量DSE结合心肌灌注造影可以提高检出缺血心肌的敏感性,发现隐匿性心肌缺血,为临床诊断早期冠心 病患者提供了无创性新方法。