Myocardial blood flow measurements in rats with simple pulsing contrast echocardiography

Relationship between contrast intensity and ultrasound (US) pulsing interval has been utilized to quantify myocardial blood flow (MBF) during myocardial contrast echocardiography (MCE). We tested if an MCE method employing a simple pulsing sequence during intravenous contrast infusion has the ability to quantify MBF in rats. We performed MCE in 17 rats using a 5- to 12-MHz broadband transducer during microbubble infusion via the femoral vein. Acoustic density (AD) from the anterior wall of the left ventricle imaged in the short axis plane was plotted against the frame number after shortening the pulsing interval (PI) from 1:20 to 1:1 end-systolic ECG gating. The relation between AD and frame number was fitted to a decay function. The rate of the AD decay was decreased during dipyridamole infusion, but was increased by causing coronary stenosis. The AD during long PI imaging remained unchanged during the interventions. Estimated MBF by MCE after correction by heart rate exhibited a close correlation (r = 0.83) with the present "gold standard" of colored microsphere-derived MBF. Thus, the decay rate of the contrast intensity obtained with the high-frequency transducer after abrupt shortening of PI during intravenous microbubble infusion may provide for noninvasive measurement of MBF in rats.     

Ultraharmonic myocardial contrast imaging: in vivo experimental and clinical data from a novel technique.

Myocardial contrast echocardiography (MCE) with high-mechanical-index (MI), triggered harmonic imaging is the best-established technique to date for the assessment of myocardial perfusion. A high signal-to-noise ratio, which is significantly influenced by precontrast tissue signals, is an important prerequisite. Our goal was to evaluate the efficacy of ultraharmonic MCE, a technique that rejects tissue signals by receiving signals beyond the second but below the third harmonic. Imaging was performed in 6 closed-chest dogs and in 15 healthy volunteers (11 of whom also had dipyridamole stress). Analyses of videointensity (VI) confirmed uniformly low precontrast tissue VI, a significant increase of postcontrast VI (before and after dipyridamole), and a significant decrease in VI after microbubble destruction. We conclude that ultraharmonic MCE produces low precontrast tissue signals, thus optimizing postcontrast myocardial opacification, and exhibits efficient microbubble destruction with use of multiple-frame triggering. Thus this new technique opens up a new possibility of further optimizing coronary microcirculation imaging with microbubbles.     

Potential pitfalls of visualization of myocardial perfusion by myocardial contrast echocardiography with harmonic gray scale B-mode and power Doppler imaging

OBJECTIVE: The present study compared the regional variation of myocardial signal intensity in visualizing myocardial perfusion by myocardial contrast echocardiography (MCE) between harmonic gray scale and power Doppler imaging. METHODS: MCE was performed in 12 patients by electrocardiographic (ECG)-gated intermittent triggered MCE with harmonic gray scale and power Doppler imaging following slow intravenous injection of 0.5 ml contrast agent (Optison). The interval between the ECG triggers (pulsing interval) was increased from every heart beat (1:1) to every 2 (1:2), 4 (1:4), and 8 (1:8) cardiac cycles to allow incremental microbubble (contrast agent) replenishment. The MCE images were recorded when attenuation produced by the left ventricular cavity was minimal. The background-subtracted videointensity was measured in 7 segments in an apical 4-chamber view: 3 (apical, mid, and basal) septal segments, 3 (apical, mid, and basal) lateral segments, and 1 apex segment (apical cap). RESULTS: The background-subtracted videointensity for each segment was greater with the power Doppler than the gray scale imaging (p < 0.01). With the gray scale imaging, the background-subtracted videointensity in the basal septal segment demonstrated a negative value at all pulsing intervals, and the value (-9 +/- 13) was significantly lower than that (22 +/- 20) in the apical lateral segment at a pulsing interval of 1:8 (p < 0.01). With power Doppler imaging, the background-subtracted videointensity was high even in the basal septal segment (112 +/- 33), and no significant difference was observed among each segment. CONCLUSIONS: The findings indicate that quantitative assessment of myocardial perfusion based upon background-subtracted video-intensity may be difficult in the far field with harmonic gray scale imaging although the attenuation is not apparent by visual analysis. Harmonic power Doppler is more sensitive for detecting basilar perfusion in the far field compared with harmonic gray scale imaging.     

实时心肌声学造影的仪器设置与显像效果的影响因素

目的：探讨实时心肌声学造影的仪器设置及显像效果的影响因素。方法：8只开胸充微量注射泵静脉滴注氟碳类造影剂全氟显（速度为5ml/min和10ml/min)进行实时心肌声学造影。调节仪器设置如增益,量程及深度等参数,于左室乳头肌水平短轴切面观察心肌显影的不同效果。结果：实时心肌声学造影可同时显示心肌血流灌注和室壁运动,除降低接受增益至50％,使用默认的仪器设置即可获得良好的造影效果,闪烁显像时最佳闪烁帧数为5个。结论：实时心肌声学造影易于掌握,影响因素较少,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力。     

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。     

经静脉实时心肌声学造影评价犬急性心肌梗死的实验研究

目的 研究实时心肌声学造影检出犬急性心肌梗死的效果。方法 8只开胸犬结扎第一对角支起点以下冠脉左前降支主干,分别于结扎前、结扎后1h和3h静滴全氟显（5ml/min）进行实时心肌声学造影,左室乳头肌水平短轴切面观察造影效果和室壁运动,并与病理染色比较。结果 结扎后1h及3h,实时心肌声学造均能良好显示缺血区的造影剂充盈缺损,包括缺损大小、与形态,同时清楚显示缺血区室壁运动异常。与病理染色比较,充盈缺损区大于心梗区。闪烁显像很好反映出充盈缺损区周围心肌轿流再灌注减慢。结论 与病理染色比较,充盈缺损区大于心梗区。闪烁显像很好反映出充盈缺损区周围心肌血流再灌注减慢。结论 实时心肌声学造影可同时观察心肌灌注和室壁运动,闪烁显有定量评价心肌血流灌注的潜在价值,操作简便,具有良好的应用前景。     

A comparison of video and digital data in the assessment of myocardial perfusion abnormalities by myocardial contrast echocardiography

Objective: The objective of the present study was to compare the digital and video data of myocardial contrast echocardiography (MCE) to assess altered myocardial blood flow produced by graded coronary stenoses. Methods: Three grades of left anterior descending (LAD) coronary artery stenosis and occlusion were created in eight open-chest canine models. MCE was performed with BR1 infusion by harmonic power Doppler with ECG gated intermittent triggered imaging at pulsing intervals ranging from 1:1 to 1:10. For images that were recorded simultaneously on both a videotape (video data) and an optical disk (digital data), myocardial signal intensity in the LAD region was plotted vs. pulsing intervals and was fitted to an exponential function:y=A(1 − e^−bt ), where A is the peak plateau signal intensity, and b is the rate of signal intensity rise for quantification of myocardial blood flow. Results: Both values for A and b progressively decreased with a greater level of stenosis. The correlation of A with myocardial blood flow (determined by use of fluorescent microspheres) was weak with digital data (r= 0.38, p= 0.037), and was insignificant with video data (r= 0.16, p= 0.38). The correlation of b with microsphere-derived myocardial blood flow was better than that of A with both video and digital data, and was similar between the two kinds of data (video:r= 0.69, p < 0.0001; digital:r= 0.68, p < 0.0001). Conclusions: Video and digital MCE data are equivalent in their ability to quantify altered myocardial blood flow produced by graded coronary stenoses.     

心肌造影检测冠状动脉微循环内皮损伤的初步应用研究

目的：探讨心肌超声造影（Myocardial contrast echocardiography, MCE）在检测冠心病早期冠脉微循环内皮损伤中的应用价值。资料与方法：选择冠状动脉造影（Coronary angiography, CAG）检查结果正常的患者20例为冠心病高危人群组（第2组）,另选年龄匹配的健康志愿者20例作对照组（第1组）行“声诺维”心肌造影。造影后进行4次闪烁成像,分析两组闪烁显像后心肌血流再灌注充盈曲线,获得再充盈峰值强度（PI）、达峰值强度时间（TP）以及心肌内微泡持续显影时间（T）并作定量分析。结果：第2组4次flash后的峰值强度均低于对照组（P<0.05）,达峰值强度时间（TP）以及心肌内微泡持续显影时间均明显大于对照组（P<0.05）。结论：MCE通过定量评价心肌微循环灌注可达到检测冠状动脉微循环内皮功能损伤的目的。     

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.     

Myocardial blood flow parameters derived from contrast replenishment using harmonic power Doppler imaging are underestimated by ultrasound signal attenuation.

The effect of ultrasound signal attenuation on myocardial blood flow parameters derived from contrast replenishment was evaluated using harmonic gray-scale (HGS) and harmonic power Doppler (HPD) imaging. In vitro experiments were performed in a flow model, whereas in vivo experiments were performed in 5 open-chest dogs. In each study, intermittent HGS and HPD images were acquired at various pulsing intervals during contrast infusion. A silicone pad was interposed between the transducer and target region to simulate attenuation conditions. Baseline-subtracted HGS and HPD signal intensities were measured with and without silicone pad, and myocardial blood flow parameters A and beta were calculated using contrast replenishment. Attenuation with HGS images could be offset by baseline subtraction, as baseline images provided the reference for attenuation. However, attenuation with HPD images could not be compensated for, as baseline signal intensity was theoretically 0. In HGS mode, silicone attenuation produced no significant decreases in A and beta. In HPD mode, however, A and beta were significantly decreased by silicone attenuation (A, P <.001; beta, P <.05). Compared with nonattenuated regions, myocardial blood flow parameters in attenuated regions are underestimated when HPD imaging is used. Baseline-subtracted HGS imaging may be useful to compensate for thoracic wall attenuation.     

Impact of myocardial contrast echocardiography on vascular permeability: an in vivo dose response study of delivery mode, pressure amplitude and contrast dose

An in vivo rat model of myocardial contrast echocardiography (MCE) was defined and used to examine the dose range response of microvascular permeabilization and premature ventricular contractions (PVCs) with respect to method of imaging, peak rarefactional pressure amplitude (PRPA) and agent dose. A left ventricular short axis view was obtained on anesthetized rats at 1.7 MHz using a diagnostic ultrasound system with simultaneous ECG recording. Evans blue dye, a marker for microvascular leakage, and a bolus of Optison were injected i.v. Counts of PVCs were made from video tape during the 3 min of MCE. Hearts were excised 5 min after imaging and petechial hemorrhages, Evans blue colored area and Evans blue content were determined. No PVCs or microvascular leakage were seen in rats imaged without contrast agent followed by contrast agent injection without imaging. When PVCs were detected during MCE, petechial hemorrhages and Evans blue leakage were also found in the myocardium. Triggering 1:4 at end-systole produced the most PVCs per frame and most microvascular leakage, followed by end-systole 1:1, continuous scanning and end-diastole triggering 1:1. All effects increased with increasing Optison dosage in the range 25 to 500 microL kg(-1). Ultrasound PRPA was important, with apparent thresholds for PVCs at 1.0 MPa and for petechiae at 0.54 MPa. PVCs, petechial hemorrhages and microvascular leakage in the myocardium occur as a result of MCE in rats.     

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。     

Measurement of myocardial blood flow velocity reserve with myocardial contrast echocardiography in patients with suspected coronary artery disease: comparison with quantitative gated Technetium 99m sestamibi single photon emission computed tomography.

BACKGROUND: The ability of high and low mechanical index (MI) imaging methods during myocardial contrast echocardiography (MCE) to assess the physiologic significance of coronary stenoses were compared with technetium 99m sestamibi single photon emission computed tomography (SPECT) in patients. METHODS: Intermittent ultraharmonic imaging (high MI) and power modulation angio (low MI) were performed during continuous infusions of the echo-enhancing contrast agent, Optison, at rest and after dipyridamole stress in 39 patients. Technetium 99m sestamibi SPECT was performed simultaneously. Images from the 3 apical windows were divided into 6 walls. Myocardial blood flow (MBF) velocity and MBF velocity reserve were quantified from pulsing interval versus acoustic intensity MCE curves in each wall using postprocessed images. RESULTS: Approximately 25% of the myocardial walls could not be analyzed from MCE because of artifacts. MBF velocity and MBF derived from both MCE methods increased significantly after dipyridamole in healthy patients (n = 143 and 129 walls for high and low MI, respectively), compared with those with either reversible (n = 11 and 10 walls for high and low MI, respectively) or fixed defects (n = 18 and 14 walls for high and low MI, respectively) on SPECT. Consequently, MBF velocity and MBF reserve were significantly greater for patients with normal perfusion. Receiver operator characteristic curves obtained for MBF velocity reserve provided a sensitivity and specificity of 82% and 87%, respectively, for high MI; versus 64% and 96%, respectively, for low MI imaging after uninterpretable images were excluded from analysis. CONCLUSIONS: Both high and low MI MCE imaging techniques can be used to determine the presence of perfusion defects as identified by technetium 99m sestamibi SPECT. Low MI imaging methods have a number of drawbacks that limit its sensitivity compared with high MI techniques.     

心肌造影超心动图与低剂量多巴酚丁胺负荷超声心动图识别心肌梗死后存活心肌的对比研究

目的：比较心肌造影超声心动图（MCE）与低剂量多巴酚丁胺负荷超声心动图（LDDSE）评价25例心肌梗死后心肌存活性。方法：MCE采用谐频频率1．8－3．6MHz的能量多普勒模式,按1：4的比例于收缩末期触发的方式提取图像。利声显浓度为300mg/ml,采用微量输液泵于患者左肘静脉内持续输注4分钟（2ml/min）,MCE心肌灌注结果进行半定量评价：0为无显影作用,0．5为部分或不均匀显影作用,1为完全及均匀显影作用;MCE定义心肌存活性为显影作用≥0．5分,无显影作用表示无心肌存活性。LDDSE输注剂量分别为5、10、20μg/kg/min,每期3min,采用16节段划分法在每个节段的心肌搏幅进行记分：正常运动＝1分,低动力＝2分,无动力＝3分,矛盾运动＝4分。LDDSE是计分减少≥1分定义为收缩功能储备。结果：（1）MCE前后及LDDSE前与5、10μg/（kg/min）,患者血压和心率改变无明显差异;（2）总共44个梗死节段中,MCE评价存活为28节段,不存活为16节段,LDDSE评价存活为23节段,不存活19节段（与MCE相比,LDDSE的敏感性与特异性为92％、84％）;（3）MCE与LDDSE评价心肌存活性的观察一致率为87％（Kappa:0.77)。结论：MCE与LDDSE均为评价心肌存活性的好方法。     

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.     

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.     

Quantification of myocardial blood flow and assessment of its transmural distribution with real-time power modulation myocardial contrast echocardiography.

BACKGROUND: The purpose of this study was to examine the ability of real-time myocardial contrast echocardiography (MCE) with power modulation to quantitate myocardial blood flow (MBF) and to assess its transmural distribution in open-chest dogs undergoing partial or total coronary stenoses. METHODS AND RESULTS: MBF was measured in 12 dogs instrumented with a cuff occluder around the left anterior descending coronary artery at rest, during partial coronary stenosis (during infusion of adenosine), and during coronary occlusion. The MCE-derived rate of microbubble velocity, beta, and myocardial blood volume, A, were obtained by curve fitting of videointensity versus time plots, after the transient destruction of microbubbles by high-energy ultrasound. The data were compared with MBF measured with radiolabeled microspheres. Significant correlations were found between radiolabeled microsphere-derived MBF and both beta (r = 0.93) and the product of A x beta (r = 0.91). MCE beta reserve also correlated well with microsphere-derived flow reserve. Comparing endocardial/epicardial MCE ratios and microsphere-derived MBF ratios, significant correlation was also found between endomicropsheres/epimicrospheres MBF ratio and both endo/epi beta (r = 0.90) and endo/epi A x beta (r = 0.88). CONCLUSIONS: Real-time power modulation MCE allows for an accurate quantification of MBF and of its transmural distribution in open-chest dogs undergoing partial or total coronary stenoses.     

Contrast advanced dynamic flow imaging and contrast pulse subtraction imaging: Preliminary results in hepatic tumors

Purpose

To investigate the usefulness of contrast advanced dynamic flow imaging and contrast pulse subtraction imaging in the intranodular hemodynamics of hepatic tumors.

Materials and Methods

Ten patients underwent contrast advanced dynamic flow imaging and contrast pulse subtraction imaging using Levovist^®, a microbubble contrast agent. Fourteen hepatic tumor nodules were studied: 9 were hepatocellular carcinoma, 1 metastasis, 1 hemangioma, 1 adenomatous hyperplasia, and 2 metastatic lymph nodes of hepatocellular carcinoma. Real-time scanning of contrast advanced dynamic flow imaging and intermittent interval-delay scanning of contrast pulse subtraction imaging were carried out in the early arterial phase, the late vascular phase, and the postvascular phase. The results obtained from contrast advanced dynamic flow imaging and contrast pulse subtraction imaging were compared with those obtained by precontrast power Doppler imaging and three-phase dynamic CT, respectively.

Results

The rate of detection of intranodular vascularity by contrast advanced dynamic flow imaging (93%) or contrast pulse subtraction imaging (93%) was significantly higher than that of precontrast power Doppler imaging (29%) and was as high as that of dynamic CT. Characteristic intranodular hemodynamics were detected in hepatocellular carcinoma, metastasis, hemangioma, and adenomatous hyperplasia with typical appearance of an intranodular blood vessel image in the early arterial phase, a parenchymal stain image in the late vascular phase, and a perfusion defect image in the post-vascular phase.

Conclusion

Contrast advanced dynamic flow imaging and contrast pulse subtraction imaging clearly show the intranodular hemodynamics in hepatic tumors.     

心肌声学造影在肥厚型梗阻性心肌病无水乙醇化学消融术中的应用

目的评价心肌声学造影(MCE)在经皮经冠状动脉心肌化学消融术(PTSMA)治疗肥厚型梗阻性心肌病的应用价值。方法 22例肥厚型梗阻性心肌病患者,术前超声观察二尖瓣前叶收缩期前向运动(SAM征)与室间隔接触点,脉冲多普勒测量左室流出道流速加速点,相应水平肥厚的室间隔确定为梗阻相关心肌(靶域)。术中行冠状动脉超声造影,根据室间隔支发出部位拟定消融血管;行MCE,若心肌显影范围与梗阻心肌范围吻合则确定该室间隔支为支配靶域的消融血管(靶血管),注入无水乙醇行PTSMA治疗。结果 22例患者术中,19例MCE心肌显影部位与术前靶域相吻合,直接行PTSMA治疗;2例MCE显示心肌显影区域小于靶域,更换靶血管后行PTSMA治疗;1例MCE显示非靶域显影而放弃消融治疗。21例患者术后即刻静息左室流出道压差(LVOTPG)下降达50%以上。PTSMA术后1、3、12个月IVST、LVOTG较术前减小(P0.05)。术后1个月SAM评分、二尖瓣反流评分较术前减小(P0.05),术后3个月、1年与术后1个月差异无统计学意义。结论 MCE在PTSMA术中能引导定位定量消融心肌,减少盲目消融导致的非靶域心肌损伤。     

Adenosine myocardial contrast echo in intermediate severity coronary stenoses: a prospective two-center study

Background We sought to evaluate the role of adenosine myocardial contrast echocardiography (MCE) for the determination of functional relevance of coronary stenoses with intermediate angiographic severity and compared the results to single photon imaging (SPECT). We hypothezised that sole assessment of myocardial blood volume changes during adenosine on MCE would indicate functional stensosis relevance when accompanied by increased myocardial oxygen consumption (MVO2). Methods Fifty-seven patients with ≥1 coronary stenosis underwent adenosine MCE (ultraharmonic imaging) and exercise SPECT. On MCE, myocardial blood volume was assessed and constant or increased myocardial opacification during adenosine coupled with increased MVO2 was defined as normal and decreased opacification as abnormal. Results Rate–pressure product significantly increased during adenosine in all patients due to reflex tachycardia following mild hypotension, indicative of increased MVO2. Concordance between MCE and SPECT for the detection of reversible myocardial perfusion defects was 89% (κ = 0.83). Comparison of regions between rest and during adenosine as opposed to comparison to remote regions of the same stage was important for accurate assessment because concordance betweenn MCE and SPECT was less on separate assessment at rest (73%, κ = 0.40) compared to stress (91%, κ = 0.81, P < 0.05) mainly due to territories scored normal on SPECT and abnormal on MCE. Conclusions Assessment of myocardial blood volume changes during adenosine using MCE can be used for the determination of the functional relevance of coronary stenoses of intermediate angiographic severity if MVO2 is increased during adenosine.