Real-time assessment of myocardial perfusion and wall motion during bicycle and treadmill exercise echocardiography: comparison with single photon emission computed tomography.

OBJECTIVES: We sought to determine the feasibility and accuracy of real-time imaging of myocardial contrast echocardiography (MCE) in detecting myocardial perfusion defects during exercise echocardiography compared with radionuclide tomography. BACKGROUND: Ultrasound imaging at a low mechanical index and frame rate (10 to 20 Hz) after intravenous injections of perfluorocarbon containing microbubbles has the potential to evaluate myocardial perfusion and wall motion (WVM) simultaneously and in real time. METHODS: One hundred consecutive patients with intermediate-to-high probability of coronary artery disease underwent treadmill (n = 50) or supine bicycle (n = 50) exercise echocardiography. Segmental perfusion with MCE and WM w ere assessed in real time before and at peak exercise using low mechanical index (0.3) and frame rates of 10 to 20 Hz after 0.3 ml bolus injections of intravenous Optison (Mallinckrodt Inc., San Diego, California). All patients had a dual isotope (rest thallium-201, stress sestamibi) study performed during the same exercise session, and 44 patients had subsequent quantitative coronary angiography. RESULTS: In the 100 patients, agreement between MCE and single photon emission computed tomography (SPECT) was 76%, while it was 88% between MCE and WM assessment. Compared with quantitative angiography, sensitivity of MCE, SPECT and WM was comparable (75%), with a specificity ranging from 81% to 100%. The combination of MCE and WM had the best balance between sensitivity and specificity (86% and 88%,respectively) with the highest accuracy (86%). CONCLUSIONS: The real-time assessment of myocardial perfusion during exercise stress echocardiography can be achieved with imaging at low mechanical index and frame rates. The combination of WM and MCE correlates well with SPECT and is a promising important addition to conventional stress echocardiography.     

Correlation between myocardial perfusion abnormalities detected with intermittent imaging using intravenous perfluorocarbon microbubbles and radioisotope imaging during high-dose dipyridamole stress echo

BACKGROUND: The clinical accuracy of myocardial contrast echocardiography (MCE) using intermittent harmonic imaging and intravenous perfluorocarbon containing microbubbles during dipyridamole stress has not been evaluated in a multicenter setting. HYPOTHESIS: The accuracy of dipyridamole stress contrast echo in the detection of coronary artery disease (CAD) using myocardial perfusion images is high in comparison with technetium-99 (99Tc) sestamibi single-photon emission computed tomography (MIBI SPECT) and increases the accuracy of wall motion data. METHODS: In 68 consecutive nonselected patients (46 men; mean age 66 years) from three different institutions in two countries. dipyridamole stress echo and SPECT with 99mTc MIBI were compared. Continuous intravenous (IV) infusion of perfluorocarbon exposed sonicated dextrose albumin (PESDA) (2-5 cc/min) was administered for baseline myocardial perfusion using triggered harmonic end systolic frames. Real-time digitized images were used for wall motion analysis. Dipyridamole was then injected in two steps: (1) 0.56 mg/kg for 3 min, (2) 0.28 mg/kg for 1 min, if the first step was negative for an inducible wall motion abnormality. After dipyridamole injection, myocardial contrast enhancement and wall motion were analyzed again by the same methodology. RESULTS: There were 35 patients with perfusion defects by SPECT. Wall motion was abnormal in 22, while MCE was abnormal in 32. Wall motion and MCE each had one false positive. The proportion of correctly assigned patients was significantly better with MCE than with wall motion (p = 0.03; chi square test). CONCLUSIONS: Myocardial contrast echocardiography, using intermittent harmonic imaging and intravenous perfluorocarbon containing microbubbles, is a very effective method for detecting coronary artery disease during dipyridamole stress echo.     

Assessment of Myocardial Perfusion during Adenosine Stress Using Real Time Three‐Dimensional and Two‐Dimensional Myocardial Contrast Echocardiography: Comparison with Single‐Photon Emission Computed Tomography

Objectives: To evaluate diagnostic accuracy of adenosine two‐dimensional and three‐dimensional myocardial contrast echocardiography (2D‐ and 3D‐MCE) compared with single‐photon emission computed tomography (SPECT) for assessing myocardial perfusion. Methods: From January through August 2007, patients with known or suspected CAD who were referred for SPECT underwent simultaneous adenosine 2D‐MCE and 3D‐MCE (live and full volume [FV]). Perfusion and wall motion in 17 segments in the left anterior descending, left circumflex, and right coronary artery territories were analyzed. Results: We studied 30 patients: mean (SD) age, 72.6 (8.2) years; 19 (63%) men. Perfusion by SPECT was abnormal in 13 patients (43%). When comparing MCE with SPECT, sensitivity was comparable for 2D‐MCE, 92%; live 3D‐MCE, 91%; and FV 3D‐MCE, 90%. Specificity was comparable for 2D‐MCE, 75%; live 3D‐MCE, 69%; and FV 3D‐MCE, 79%. Agreement between live 3D‐MCE and 2D‐MCE was 92% (κ[SE], 0.83 [0.17]) and between FV 3D‐MCE and 2D‐MCE, 88% (κ[SE], 0.76 [0.13]). For eight patients in whom SPECT showed reversible defects, live 3D‐MCE correctly identified defects in seven (88%), whereas FV 3D‐MCE correctly identified them in five (63%) (P = 0.57). Conclusion: Myocardial perfusion assessment is feasible by 3D‐MCE with the advantage of rapid, facile acquisition and offline image manipulation. (Echocardiography 2010;27:421‐429)     

Myocardial contrast echocardiography for the detection of coronary artery stenosis: a prospective multicenter study in comparison with single-photon emission computed tomography.

OBJECTIVES: The purpose of this study was to compare myocardial contrast echocardiography (MCE) with single-photon emission computed tomography (SPECT) for the detection of significant coronary artery disease (CAD) in patients with symptoms suggestive of CAD. BACKGROUND: Single-photon emission computed tomography is a well-established method of assessing patients with CAD. Myocardial contrast echocardiography is a new technique allowing bedside assessment of myocardial perfusion. We hypothesized that MCE was comparable to SPECT in the assessment of patients with known or suspected CAD. METHODS: A total of 123 patients scheduled for coronary angiography underwent intermediate (mechanical index 0.5) triggered replenishment MCE and SPECT imaging at rest and after vasodilator stress. Coronary angiography was performed within four weeks of stress imaging. RESULTS: In total, 96 of 123 (78%) patients demonstrated CAD (stenosis >/=50%). There was no difference in the sensitivity of MCE compared with SPECT in the detection of CAD (84% vs. 82%; p = NS), and both demonstrated similar specificity (56% vs. 52%, respectively). In patients with multivessel disease, MCE and SPECT also demonstrated similar sensitivity (91% and 88%, respectively) for the detection of CAD. Agreement between MCE and SPECT for the presence or absence of CAD was 73%. CONCLUSIONS: Myocardial contrast echocardiography is comparable to SPECT in the detection of CAD not only on a patient basis but also in the localization of disease by vascular territory in a relatively high-risk population.     

Potential clinical applications of myocardial contrast echocardiography in evaluating myocardial perfusion in coronary artery disease

Myocardial contrast echocardiography (MCE) is a relatively new technique that uses microbubbles to produce myocardial opacification. Recent advances in echocardiography have resulted in improved detection of microbubbles within the myocardium allowing combined acquisition of function and perfusion data, thus making MCE suitable for bedside use. Regardless of the imaging modality chosen or the type of stress used, MCE detects changes developing in the coronary microcirculation, providing important information for the evaluation of severity of coronary artery disease and for the detection of viable myocardial tissue in acute or chronic coronary artery disease.     

Usefulness of power Doppler contrast echocardiography to identify reperfusion after acute myocardial infarction

Microvascular integrity, as seen by myocardial contrast echocardiography (MCE), assesses whether myocardium has been successfully reperfused after an acute myocardial infarction. Until now this has been demonstrated only with intracoronary injection of an ultrasound contrast agent. Power Doppler imaging is a recently developed myocardial contrast echocardiographic method that counts the contrast microbubbles destroyed by ultrasounds and displays this number in color. This study sought to evaluate whether power Doppler MCE is able to visualize myocardial reperfusion during intravenous contrast injection. Thirty patients were evaluated 2 days after their first myocardial infarction during intravenous infusion of perfluorocarbon-exposed sonicated dextrose albumin (PESDA). Coronary artery angiography and single-photon emission computed tomography (SPECT) were used as reference techniques. A 16-segment left ventricular model was used to relate perfusion to coronary artery territories. Sensitivity and specificity of power Doppler MCE for segments supplied by infarct-related arteries were 82% and 95%, respectively. Accuracy of power Doppler MCE and SPECT were similar (90% vs 92% on segmental basis and 98% vs 98% on coronary artery territory basis). Two-dimensional echocardiography was repeated after 6 weeks. Segments recovering wall motion after 6 weeks were defined as stunning myocardium. Dysfunctional but perfused myocardium at day 2 after the infarction showed a better late recovery of wall motion compared with dysfunctional but nonperfused myocardium (p <0.001). In conclusion, harmonic power Doppler imaging is a sensitive and specific method for the identification of myocardial reperfusion early after myocardial infarction. It yields prognostic information for late recovery of ventricular function differentiating stunning (dysfunctional but perfused) from necrotic myocardium (dysfunctional and nonperfused).     

Detection of coronary artery disease using real-time myocardial contrast echocardiography: a comparison with dual-isotope resting thallium-201/stress technectium-99m sestamibi single-photon emission computed tomography

Real-time myocardial contrast echocardiography (MCE) has the potential to evaluate myocardial perfusion and wall motion (WM) simultaneously. The purposes of this study were to correlate the diagnostic value of MCE with radionuclide single-photon emission computed tomography (SPECT), and to assess the sensitivity and specificity of real-time MCE in detecting coronary artery disease (CAD). Seventy patients with clinically suspected CAD underwent MCE and SPECT at baseline and after dipyridamole infusion. Segmental perfusion with MCE using low mechanical index after 0.3–0.4-ml bolus injections of perfluorocarbon exposed sonicated dextrose albumin solution was performed. All patients had a dual-isotope (rest thallium-201, stress sestamibi) study performed both at baseline and after dipyridamole infusion, and 40 patients had subsequent quantitative coronary angiography. Abnormalities were noted in 27 patients (38.6%) by MCE, in 29 patients (41.4%) by WM analysis, and in 30 patients (42.9%) by SPECT imaging. When MCE and WM analysis were combined, the agreement with SPECT imaging improved from 75.7% (Kappa = 0.50) to 82.0% (Kappa = 0.62). In 40 patients (120 territories) who underwent coronary angiography, good perfusion concordance was achieved for the left anterior descending and left circumflex arteries, and was fair for the right coronary arteries. Compared with quantitative angiography, there was no difference in sensitivity, specificity, and accuracy in detecting significant CAD among the three modalities. The combination of MCE and WM had a better sensitivity (84%), specificity (93.3%), and accuracy (87.5%) than the MCE and WM analysis alone. However, the difference did not reach statistical significance. Real-time MCE has a good agreement with SPECT imaging for detecting CAD. The combination of MCE and WM appears to have higher sensitivity, specificity, and accuracy in detecting CAD than either technique alone.     

The diagnostic value of adenosine stress-contrast echocardiography for diagnosis of coronary artery disease in hypertensive patients: comparison to Tl-201 single-photon emission computed tomography

BACKGROUND: The use of the vasodilating agent adenosine as stressor in conjunction with myocardial contrast echocardiography has not been extensively evaluated in hypertensive patients. Our aim was to evaluate the diagnostic value of adenosine myocardial contrast echocardiography (MCE) in comparison to single-photon emission computed tomography (SPECT), with reference to angiographic findings, in a hypertensive population. METHODS: Fifty hypertensive subjects, treated with standard antihypertensive treatment, were submitted to adenosine stress MCE, adenosine SPECT, and coronary angiography within a 1-month period, without any intervening events. RESULTS: Sensitivity, specificity, and accuracy were 88%, 89%, 88% for MCE and 80%, 94%, 85% for SPECT, respectively (P = not significant). In the analysis by coronary territory, it appears that MCE and SPECT are both more accurate in detecting lesions of the anterior than of the posterior coronary system, as suggested by the good concordance to angiography results in the left anterior descending artery territory (k = 0.640 and 0.671, respectively). Agreement with angiographic findings was moderate for the right coronary artery (k = 0.561 and 0.539, respectively), whereas left circumflex artery lesions were more accurately detected by MCE than by SPECT (k = 0.533 and 0.400, respectively), that is, MCE appears to be superior in the left circumflex artery territory. CONCLUSIONS: In hypertensive patients, adenosine MCE has similar overall diagnostic accuracy with SPECT for assessment of coronary artery disease but is superior in the left circumflex artery territory.     

Non-invasive detection of coronary artery stenosis: a comparison among power-Doppler contrast echo, 99Tc-Sestamibi SPECT and echo wall-motion analysis

BACKGROUND: Power-Doppler imaging is a recently developed method for myocardial contrast echocardiography (MCE). It can selectively evaluate the signal coming from an ultrasound contrast agent, allowing myocardial perfusion studies. OBJECTIVE: To compare the ability of power-Doppler MCE with stress-echo wall-motion and nuclear scan imaging (SPECT) to assess myocardial ischaemia during pharmacological stress, using coronary angiography as reference. METHODS: In 25 patients the three non-invasive imaging modalities were acquired during a single dipyridamole stress test (so as to avoid stress variations). Power-Doppler MCE was acquired using continuous intravenous infusion of Levovist. Echo wall-motion was acquired too. At peak stress 99Tc-Sestamibi was injected; stress SPECT images were acquired 30 min after injection. RESULTS: Power-Doppler MCE and SPECT showed 84% concordance (21 of 25 patients; kappa=0.67) for detection of ischaemia. Concordance based on coronary artery territories for normal perfusion versus fixed defects versus reversible defects was 92% (69 of 75; kappa=0.81), with 100% for left anterior descending, 92% for right coronary artery and 84% for circumflex. Power-Doppler MCE had lower sensitivity than SPECT (89 versus 100%) but higher specificity (100 versus 88%) for identification of stenotic (> or = 70%) coronary arteries as assessed by angiography. Echo wall-motion analysis showed the lowest sensitivity (68%) with 100% specificity. Accuracy was 94% for both power-Doppler MCE and SPECT, and 83% for wall-motion analysis. CONCLUSION: Power-Doppler MCE is a sensitive and specific method for identification of myocardial perfusion during pharmacological stress. Accuracy of power-Doppler MCE for stenotic coronary arteries appears to be slightly higher than stress-echo wall-motion and similar to SPECT.     

The value of myocardial contrast echocardiography compared with SPECT in detecting myocardial perfusion abnormalities in patients with anterior acute myocardial infarction

BACKGROUND: Microvasculature damage after myocardial infarction (MI), known as "no-reflow" phenomenon, may occur in some patients with acute MI in spite of invasive treatment and opened infarct-related coronary artery. There are several non-invasive and invasive methods used for the coronary flow assessment at the tissue level. AIM: To compare the value of intravenous contrast echocardiography (MCE) in detecting myocardial perfusion defects in patients with acute MI with (99m)Tc MIBI SPECT study. METHODS: Sixteen patients (11 males, 5 females, mean age 55.4+/-10.2 years) underwent primary coronary angioplasty or facilitated angioplasty (with reduced dose of a fibrinolytic drug and glycoprotein IIb/IIIa inhibitor) (PCI) for acute anterior MI. TIMI grade flow, TIMI Myocardial Perfusion Grade (TMPG), corrected TIMI frame count (cTFC), wall motion score index (WMSI) and segmental perfusion by myocardial contrast echocardiography (MCE) were estimated in real time before and immediately after PCI. MCE was repeated on the third day after PCI. All patients underwent (99m)Tc MIBI SPECT study (SPECT) while at rest on the third day after PCI. The area at risk was defined as the number of segments with no perfusion before angioplasty. Reflow was defined as an increase in contrast score in the same segments after angioplasty. RESULTS: Baseline MCE showed 95 segments with perfusion defects. Immediately after PCI, 77 segments were found with perfusion defect; in 10 patients improvement of myocardial perfusion was observed whereas in 6 patients perfusion defect remained unchanged. On the third day further improvement was observed in 8 patients. The number of segments with perfusion defect decreased to 53. SPECT detected perfusion defect in 54 segments. The agreement between MCE and SPECT for detecting perfusion abnormality was 98% (kappa 0.94). CONCLUSIONS: MCE is a safe technique for detecting myocardial perfusion in patients with acute MI. MCE proves that both primary and facilitated angioplasty improve myocardial perfusion in two thirds of patients with acute MI. Serial MCE allows identification of patients with both early and late improvement of myocardial perfusion. There is a very strong correlation between MCE and SPECT in the assessment of perfusion defects.     

Comparison of low-mechanical index pulse sequence schemes for detecting myocardial perfusion abnormalities during vasodilator stress echocardiography

Myocardial contrast echocardiography has the potential to accurately detect functionally significant coronary artery disease during pharmacologic stress testing. Different low-mechanical index modalities, including triggering replenishment imaging (TRI) and real-time imaging (RTI), are currently used to identify myocardial perfusion defects. We compared the ability of TRI with that of RTI for detecting and localizing perfusion abnormalities. Thirty-six patients (62 +/- 14 years old, 15 men) underwent single-photon emission computed tomography (SPECT) with technetium-99m sestamibi and myocardial contrast echocardiography at baseline and after infusion of 0.56 mg/kg of dipyridamole. Sixteen of these patients also underwent quantitative angiography. Contrast-enhanced images were obtained in 4-, 3-, and 2-chamber views after intravenous bolus injections of lipid-encapsulated microbubbles (0.1 ml of Definity). A myocardial perfusion defect was defined by myocardial contrast echocardiography as a delay of >2 seconds in contrast replenishment after high-mechanical index flash impulse. The myocardial segments were divided into 3 major coronary territories. There was agreement in detecting perfusion defects between SPECT and TRI in 26 patients (72%, kappa = 0.46) and between SPECT and RTI in 27 patients (75%, kappa = 0.50). Agreements between myocardial contrast echocardiography and SPECT for localizing coronary territories with perfusion defects were 81% for TRI (kappa = 0.43) and 85% for RTI (kappa = 0.61). Accuracy of RTI for detecting >50% diameter stenoses by quantitative angiography was 79%, that of TRI was 71%, and that of SPECT was 65%. These data indicate that the different low-mechanical index imaging schemes are equivalent to radionuclide SPECT in accurately detecting diseased coronary artery territories during vasodilator stress.     

Intravenous myocardial contrast echocardiography for the diagnosis of coronary artery disease

PURPOSE OF REVIEW: Myocardial contrast echocardiography is a recently developed technique that permits the noninvasive assessment of myocardial perfusion. Myocardial contrast enhancement from microbubbles characteristically reflects the myocardial blood volume. The analysis of microbubble kinetics using quantitative myocardial contrast echocardiography permits the evaluation of myocardial blood flow both at rest and during pharmacological stress. RECENT FINDINGS: Myocardial contrast echocardiography has been shown to have good concordance with single photon emission computed tomography for the localization of perfusion abnormalities. As a result of its better spatial resolution and the fact that it tracks myocardial blood flow changes, it seems to have higher sensitivity for the detection of angiographically significant coronary artery disease, while maintaining similar specificity to single photon emission computed tomography. Low mechanical index imaging techniques (real-time myocardial contrast echocardiography) have the advantage of permitting simultaneous analysis of wall motion and perfusion, which is particularly important during dobutamine stress. Myocardial perfusion analysis using real-time myocardial contrast echocardiography has been shown to have higher sensitivity and diagnostic accuracy than wall motion analysis for the detection of coronary artery disease. Quantitative myocardial contrast echocardiography seems to overcome the expertise requirements for appropriate interpretation of myocardial perfusion images, and may have been demonstrated to be an accurate supplemental technique for estimating the severity of coronary artery disease. SUMMARY: Recent technological advances have positioned myocardial contrast echocardiography as a safe and feasible technique for the evaluation of myocardial perfusion. The analysis of myocardial perfusion using myocardial contrast echocardiography has higher diagnostic accuracy than wall motion analysis for detecting coronary artery disease.     

Identification of Hibernating Myocardium: Comparative Accuracy of Myocardial Contrast Echocardiography,Rest-Redistribution Thallium-201 Tomography and Dobutamine Echocardiography

Objectives. We sought to evaluate the comparative accuracy of myocardial contrast echocardiography (MCE), quantitative rest-redistribution thallium-201 (Tl-201) tomography and low and high dose (up to 40 μg/kg body weight per min) dobutamine echocardiography (DE) in identifying myocardial hibernation.Background. Myocardial contrast echocardiography can assess myocardial perfusion and may therefore be useful in predicting myocardial hibernation. However, its accuracy in comparison to myocardial perfusion scintigraphy and to that of high dose DE remains to be investigated.Methods. Eighteen patients (aged [±SD] 57 ± 10 years) with stable coronary artery disease and ventricular dysfunction underwent the above three modalities before coronary revascularization. Myocardial contrast echocardiography was achieved with intracoronary Albunex. Rest echocardiographic and Tl-201 studies were repeated ≥6 weeks after revascularization.Results. Of 109 revascularized segments with severe dysfunction, 46 (42%) improved. Left ventricular ejection fraction increased from 38 ± 14% to 45 ± 13% at follow-up (p = 0.003). Rest Tl-201 uptake and the ratio of peak contrast intensity of dysfunctional to normal segments with MCE were higher (p < 0.01) in segments that recovered function compared with those that did not. Myocardial contrast echocardiography, thallium scintigraphy and any contractile reserve during DE had a similar sensitivity (89% to 91%) with a lower specificity (43% to 66%) for recovery of function. A biphasic response during DE was the most specific (83%) and the least sensitive (68%) (p < 0.01). The best concordance with MCE was Tl-201 (80%, kappa 0.57). Changes in ejection fraction after revascularization related significantly to the number of viable dysfunctional segments by all modalities (r = 0.54 to 0.65).Conclusions. In myocardial hibernation, methods evaluating rest perfusion (MCE, Tl-201) or any contractile reserve have a similar high sensitivity but a low specificity for predicting recovery of function. A limited contractile reserve (biphasic response) increases the specificity of DE. Importantly, the three techniques identified all patients who had significant improvement in global ventricular function.(J Am Coll Cardiol 1997;29:985–93)© 1997 by the American College of Cardiology     

Real-time myocardial contrast echocardiography for the detection of stress-induced myocardial ischemia. Comparison with 99mTc-sestamibi single photon emission computed tomography

BACKGROUND: Real-time contrast echocardiography (MCE) is a new promising technique for assessing myocardial perfusion. The purpose of this study was to test whether realtime MCE can be used to detect functionally significant coronary artery stenosis in patients with known or suspected coronary artery disease. Myocardial contrast echocardiographic studies were compared with nearly simultaneous 99mTc-sestamibi single photon emission computed tomography (SPECT) as a clinical standard reference to evaluate regional myocardial perfusion defects. METHODS: Real-time MCE based on continuous infusion of Optison (8-10 ml/h) was performed in 66 patients during standard 99mTc-SPECT dipyridamole (0.56 mg/kg x 4 min) stress testing. Images were obtained in apical 4- and 2-chamber views, each divided into 6 segments. Tracer uptake and myocardial opacification were visually analyzed for each segment by two pairs of blinded observers and graded as normal, mildly reduced, severely reduced, or absent. In 792 myocardial segments, myocardial opacification by MCE was uninterpretable in 143 (18%) segments and tracer uptake by SPECT was not clearly defined in 92 (12%) segments. Interobserver variability for MCE was good with concordance rates of 83% (kappa=0.72) for rest- and 86% (kappa=0.76) for stress images. Overall concordance between MCE and SPECT was good (83%, kappa=0.63) at a segmental level. In the diagnosis of fixed and reversible defects, and of normal perfusion, concordance rates were 73, 65 and 83%, respectively. When analysis was performed at the regional level, we found comparable levels of concordance rates for LAD (83%, kappa=0.59), LCX (86%, kappa=0.64) and RCA (80%, kappa=0.68) perfusion territories. CONCLUSIONS: These findings suggest that realtime MCE is a clinically acceptable method to evaluate myocardial perfusion defects during dipyridamole stress testing.     

Comparison between contrast echocardiography and magnetic resonance imaging to predict improvement of myocardial function after primary coronary intervention

The relative merits of myocardial contrast echocardiography (MCE) and magnetic resonance imaging (MRI) to predict myocardial function improvement after percutaneous coronary intervention have not been evaluated until now. We studied 35 consecutive patients with acute myocardial infarction who underwent percutaneous coronary intervention using MCE and MRI and first-pass imaging for evaluation of myocardial perfusion. Delayed-enhanced MRI was included as another method to differentiate viable from infarcted tissue. MCE was performed by power modulation and intravenous Sonovue. A 16-segment model of the left ventricle was used to analyze all myocardial contrast echocardiograms and magnetic resonance images. At 60 days of follow-up, MCE showed improvement of function in 115 of 192 (60%) dysfunctional segments. The sensitivity, specificity, and accuracy for the prediction of functional improvement were comparable among MCE (87%, 90%, and 88%), first-pass MRI (87%, 60%, and 79%), and delayed-enhancement MRI (75%, 100%, and 82%, respectively, all p = NS). In conclusion, MCE and MRI allowed for prediction of myocardial function improvement after percutaneous coronary intervention. MCE had a comparable accuracy and, as a bedside technique, may be an alternative tool in the acute phase of acute myocardial infarction.     

Comparative accuracy of real-time myocardial contrast perfusion imaging and wall motion analysis during dobutamine stress echocardiography for the diagnosis of coronary artery disease

OBJECTIVE: This study sought to compare the accuracy of myocardial contrast echocardiography (MCE) and wall motion analysis (WMA) during submaximal and peak dobutamine stress echocardiography (DSE) for the diagnosis of coronary artery disease (CAD). BACKGROUND: The relative merits of MCE and WMA for the detection of CAD during DSE have not been studied in a large number of patients. METHODS: We studied 170 patients who underwent dobutamine (up to 50 microg/kg/min)-atropine stress testing and coronary angiography. The WMA and MCE (using repeated boluses of Optison [Mallinckrodt, St. Louis, Missouri] or Definity [Bristol-Myers Squibb, New York, New York]) were performed at rest, at intermediate stress (65% to 75% of maximal heart rate), and at peak stress. The diagnosis of CAD (>/=50% stenosis in >/=1 coronary artery) was based on reversible wall motion and perfusion abnormalities. RESULTS: Coronary artery disease was detected in 127 (75%) patients. Sensitivity of MCE was higher than that of WMA at maximal stress (91% vs. 70%; p = 0.001) and at intermediate stress (84% vs. 20%; p = 0.0001). Specificity was lower for MCE compared with WMA (51% vs. 74%; p = 0.01). Overall accuracy was higher for MCE than for WMA (81% vs. 71%; p = 0.01). Sensitivity for detection of CAD based on abnormalities in >/=2 vascular regions was higher for MCE than for WMA (67% vs. 28%; p < 0.01). CONCLUSIONS: The majority of inducible perfusion abnormalities occur at an intermediate phase of the stress test, without wall motion abnormalities. Myocardial contrast echocardiography provides better sensitivity than WMA, particularly in patients with submaximal stress and in identifying patients with multivessel CAD.     

NC100100, a new echo contrast agent for the assessment of myocardial perfusion--safety and comparison with technetium-99m sestamibi single-photon emission computed tomography in a randomized multicenter study

BACKGROUND AND HYPOTHESIS: Myocardial contrast echocardiography using second-generation agents has been proposed to study myocardial perfusion. A placebo-controlled, multicenter trial was conducted to evaluate the safety, optimal dose, and imaging mode for NC100100, a novel intravenous second-generation echo contrast agent, and to compare this technique with technetium-99m sestamibi (MIBI) single-photon emission computed tomography (SPECT). METHODS: In a placebo-controlled, multicenter trial, 203 patients with myocardial infarction > 5 days and < 1 year previously underwent rest SPECT and MCE. Fundamental and harmonic imaging modes combined with continuous and electrocardiogram-- (ECG) triggered intermittent imaging were used. Six dose groups (0.030, 0.100, and 0.300 microliter particles/kg body weight for fundamental imaging; and 0.006, 0.030, and 0.150 microliter particles/kg body weight for harmonic imaging) were tested. A saline group was also included. Safety was followed for 72 h after contrast injection. Myocardial perfusion by MCE was compared with myocardial rest perfusion imaging using MIBI as a tracer. RESULTS: NC100100 was well tolerated. No serious adverse events or deaths occurred. No clinically relevant changes in vital signs, laboratory parameters, and ECG recordings were noted. There was no significant difference between adverse events in the NC100100 (25.7%) and in the placebo group (17.9%, p = 0.3). Intermittent harmonic imaging using the intermediate dose was superior to all other modalities, allowing the assessment of perfusion in 76% of all segments. Eighty segments (96%) with normal perfusion by SPECT imaging also showed myocardial perfusion with MCE. However, a substantial percentage of segments (61-80%) with perfusion defects by SPECT imaging also showed opacification by MCE. This resulted in an overall agreement of 66-81% and a high specificity (80-96%), but in low sensitivity (20-39%) of MCE for the detection of perfusion defects. CONCLUSION: NC100100 is safe in patients with myocardial infarction. Intermittent harmonic imaging with a dose of 0.03 microliter particles/kg body weight can be proposed as the best imaging protocol. Myocardial contrast echocardiography with NC 100100 provides perfusion information in approximately 76% of segments and results in myocardial opacification in the vast majority of segments with normal perfusion as assessed by SPECT. Although the discrepancies between MCE and SPECT with regard to the definition of perfusion defects requires further investigation, MCE with NC 100100 is a promising technique for the noninvasive assessment of myocardial perfusion.     

Comparison of myocardial contrast echocardiography with NC100100 and (99m)Tc sestamibi SPECT for detection of resting myocardial perfusion abnormalities in patients with previous myocardial infarction

OBJECTIVE—To determine whether myocardial contrast echocardiography (MCE) following intravenous injection of perfluorocarbon microbubbles permits identification of resting myocardial perfusion abnormalities in patients who have had a previous myocardial infarction.
PATIENTS AND INTERVENTIONS—22 patients (mean (SD) age 66 (11) years) underwent MCE after intravenous injection of NC100100, a novel perfluorocarbon containing contrast agent, and resting ^99mTc sestamibi single photon emission computed tomography (SPECT). With both methods, myocardial perfusion was graded semiquantitatively as 1 = normal, 0.5 = mild defect, and 0 = severe defect.
RESULTS—Among the 203 normally contracting segments, 151 (74%) were normally perfused by SPECT and 145 (71%) by MCE. With SPECT, abnormal tracer uptake was mainly found among normally contracting segments from the inferior wall. By contrast, with MCE poor myocardial opacification was noted essentially among the normally contracting segments from the anterior and lateral walls. Of the 142 dysfunctional segments, 87 (61%) showed perfusion defects by SPECT, and 94 (66%) by MCE. With both methods, perfusion abnormalities were seen more frequently among akinetic than hypokinetic segments. MCE correctly identified 81/139 segments that exhibited a perfusion defect by SPECT (58%), and 135/206 segments that were normally perfused by SPECT (66%). Exclusion of segments with attenuation artefacts (defined as abnormal myocardial opacification or sestamibi uptake but normal contraction) by either MCE or SPECT improved both the sensitivity (76%) and the specificity (83%) of the detection of SPECT perfusion defects by MCE.
CONCLUSIONS—The data suggest that MCE allows identification of myocardial perfusion abnormalities in patients who have had a previous myocardial infarction, provided that regional wall motion is simultaneously taken into account.


Keywords: myocardial contrast echocardiography; NC100100; single photon emission computed tomography; perfusion     

Detection of coronary artery disease with a continuous infusion of definity ultrasound contrast during adenosine stress real time perfusion echocardiography

BACKGROUND: Myocardial perfusion imaging during adenosine stress is an accurate method of detecting physiologically relevant coronary artery disease. METHODS: Real time perfusion echocardiography (RTPE) was compared to nuclear scintigraphy (rest Thallium, stress Sestamibi) in 40 patients with intermediate to high pretest probability. RTPE was performed with a continuous infusion of intravenous microbubbles (Definity; Bristol Myers Squibb) and intermittent high mechanical index impulses, with visual examination of both the replenishment rate and plateau intensity of contrast. RESULTS: Of the 119 coronary artery territories compared, SPECT and RTPE were in agreement in 105 (88% agreement; kappa 0.67). In patients who went on to quantitative coronary arteriography (QCA), there were three who had normal appearing radionuclide SPECT during adenosine, but subendocardial perfusion defects with RTPE. In all three cases, QCA confirmed the presence of a >50% diameter stenosis in the abnormal territory. CONCLUSIONS: We conclude from this study that adenosine stress imaging with RTPE is an accurate method of detecting coronary artery disease. The higher resolution of RTPE may identify subendocardial defects that would otherwise have gone undetected with radionuclide imaging.     

Limitations and potential clinical application on contrast echocardiography

Myocardial contrast echocardiography (MCE) is a relatively simple myocardial perfusion imaging technique which should be used in different clinical settings. The ability of MCE to provide a comprehensive assessment of cardiac structure, function, and perfusion is likely to make it the technique of choice for non-invasive cardiac imaging.Contrast agents are encapsulated microbubbles (MB) filled with either air or high-molecular-weight gas. They are innocuous, biologically inert and when administered intravasculary, the sound backscatter from the blood poll is enhanced because MB have the enormous reflective ability due to a large acoustic impedance mismatch between the bubble gas and surrounding blood.MCE is an ideal imaging tool for the assessment of left heart contrast and the myocardial microcirculation. MCE detects contrast MB at the capillary level within the myocardium and, thus, has the potential to assess tissue viability and the duration of the contrast effect. MCE was equivalent to SPECT for the detection of CAD with a tendency toward higher sensitivity of MCE compared with SPECT in microvascular disease and CAD. MCE is also a bedside technique that can be used early in patients presenting with acute heart failure to rapidly assess LV function (regional and global) and perfusion (rest and stress).