Usefulness of the new imaging techniques, second harmonic and contrast in endocardial border visualization. Reliability analysis in segmental contraction assessment

AIM: This study sought to determine if newer techniques significantly improve endocardial border definition in suboptimal acoustic windows, and the reproducibility of the evaluation of wall motion abnormalities according to the different techniques and degrees of expertise. METHODS: We studied a total of 20 consecutive patients with poor ultrasound window, to assess, if the use of tissue harmonic imaging (2H) or contrast with second harmonic (Levovist ; 4 g i.v.), (2HC) improves endocardial border visualization.In order to analyze inter and intraobserver reliability with the different techniques, four observers with different degrees of expertise were each asked to assess the segmental wall motion score of 31 consecutive echocardiograms. RESULTS: The quality of the image was clearly superior with 2H and 2HC compared with 2D. This difference was larger in apex and lateral endocardial border from 0.9 and 1 to 1.5 and 1.64 (p < 0.001) with 2H. 2HC was found to slightly but significantly improve the endocardial definition in apex compared with 2H (1.64 vs 1.81; p = 0.016).The percentage of segments assessed for interobserver variability significantly improve with 2H and 2HC (2D = 50%, 2H = 75% and 2HC = 95%). Interobserver agreement with the different techniques between the experienced observers did not statistically differ. The less experienced observer presented a significantly lower interobserver reliability than those with experience, and did not improve with 2H and 2HC. CONCLUSIONS: a) Native tissue harmonic imaging and second harmonic imaging with contrast (Levovist ) significantly improves endocardial border visualization; b) the newer imaging techniques significantly improve performance (percentage of evaluated segments) without decreasing reliability, and c) experience in assessing wall motion is the main factor in interobserver agreement.     

Contrast echocardiography is superior to tissue harmonics for assessment of left ventricular function in mechanically ventilated patients

BACKGROUND: Assessment of left ventricular function by echocardiography is frequently challenging in mechanically ventilated patients. We evaluated the potential value of contrast-enhanced imaging and tissue harmonic imaging over standard fundamental imaging for endocardial border detection (EBD) in these patients. METHODS AND RESULTS: Fifty patients underwent standard transthoracic 2D echocardiography and were imaged in fundamental and tissue harmonic modes and subsequently with intravenous contrast (Optison). Two echocardiographers reviewed all studies for ease of visualization of endocardial border segments and scoring of wall motion. EBD for each wall segment was graded from 1 to 4 (1 = excellent EBD). Wall motion was scored by a standard 16-segment model and 1 to 5 scale. Studies were categorized as nondiagnostic if 4 of 6 segments in the apical 4-chamber view were either poorly seen or not seen (EBD score 3 or 4). Quantification of ejection fraction was independently performed offline. Visualization of 68% of all segments improved with contrast echocardiography versus 17% improvement with tissue harmonics compared with fundamental mode. Significant improvement (poor/not seen to good/excellent) occurred in 60% of segments with contrast echocardiography versus 18% with tissue harmonics. A total of 850 segments were deemed poor/not seen, 78% of which improved to good/excellent with contrast echocardiography versus 23% with tissue harmonics. Interobserver agreement on EBD was 64% to 70%. Conversion of nondiagnostic to diagnostic studies occurred in 85% of patients with contrast echocardiography versus 15% of patients with tissue harmonics. Scoring of wall motion with fundamental mode, tissue harmonics, and contrast echocardiography was possible in 61%, 74%, and 95% of individual segments, respectively (P <.001). Wall motion scoring was altered in 17% of segments with contrast echocardiography and in 8% with tissue harmonics. Interobserver agreement on wall motion scoring was 84% to 88%. Contrast echocardiography permitted measurement of ejection fraction 45% (P =.003) more often over fundamental mode versus a 27% (P =.09) increase with tissue harmonics. CONCLUSIONS: Contrast echocardiography is superior to tissue harmonic imaging for EBD, wall motion scoring, and quantification of ejection fraction in mechanically ventilated patients.     

Improvement in Endocardial Border Delineation Using Tissue Harmonic Imaging

Background and Methods: For years, tissue has been assumed to be a linear medium in diagnostic ultrasound applications; thus, no backscattered signals in the second harmonic band are expected in harmonic imaging without the injection of a contrast agent. However, it has been shown that a useful tissue image is formed even without a contrast agent. The aim of this study was to evaluate whether this tissue harmonic image provided improved visualization of endocardial borders. Fifty-six adult patients with various heart diseases were investigated using conventional two-dimensional echocardiography and tissue harmonic imaging. In 30 of these patients, the left ventricular endocardial borders were well defined in the standard parasternal and apical views using conventional two-dimensional echocardiography. In the remaining 26 patients, delineation of endocardial borders was not possible in at least two segments. The equipment used was an ATL HDI-3000 diagnostic system equipped with harmonic imaging. Results: In all 56 patients, the myocardium and valves could be imaged with tissue harmonic imaging. Harmonic recordings were sharper and contained fewer clutter artifacts than conventional recordings. Most striking was the enhancement of left ventricular endocardial borders. In the 26 patients with incomplete delineation of left ventricular endocardial borders, wall motion could be evaluated in 290 of 312 (93%) segments with tissue harmonic imaging compared with only 168 of 312 (54%) segments with conventional echocardiography (P < 0.001). Conclusions: Tissue harmonic imaging improves image quality and can be used to enhance the definition of left ventricular endocardial borders. These findings can be explained by the nonlinear propagation of ultrasound within the tissue, which results in distortion of the transmitted signal and, thus, harmonic generation.     

Power motion imaging can improve image quality in stress conditions with tachycardia

BACKGROUND: Stress echocardiographic studies are useful, but the evaluation of wall motion is sometimes suboptimal. The recently developed technique of power motion imaging can enhance mobile tissue definition. HYPOTHESIS: The study was undertaken to determine whether power motion imaging improves endocardial definition during tachycardia compared with conventional two-dimensional (2-D) imaging. METHODS: Twenty pigs were studied during pacing rates of 100, 120, and 150 beats/min. We compared power motion imaging with standard 2-D imaging using systolic thickening visualization (STV) scores (3 = excellent definition of systolic thickening approximately 0 = total lack of visualization of systolic thickening) at each heart rate. We calculated the sum of the scores of 22 left ventricular segments as the overall STV score, and also calculated the sum of the scores in 10 parasternal segments and 12 apical segments separately. RESULTS: The overall STV scores in both imaging methods were similar at 100 beats/min, but scores for power motion imaging were significantly higher than those of usual 2-D imaging at 120 and 150 beats/min. Using power motion imaging, the overall STV scores were similar as heart rate was increased; however, while using standard 2-D imaging, STV scores were significantly decreased as heart rate was increased. Findings were analyzed separately by parasternal and apical images. Especially in the parasternal images, the scores were significantly increased as heart rate was increased using power motion imaging. CONCLUSIONS: We conclude that power motion imaging improves the detection of endocardial border in stress condition with tachycardia, and thus this modality is useful for stress echocardiography.     

Head-to-head comparison of fundamental, tissue harmonic and contrast harmonic imaging with or without an air-filled contrast agent, levovist, for endocardial border delineation in patients with poor quality images.

Recent developments in tissue harmonic imaging and intravenous contrast agents have enhanced left ventricular endocardial border delineation (EBD). In a total of 48 patients with poor quality images, apical 4- and 2-chamber views were obtained with fundamental, tissue harmonic and contrast harmonic imaging with or without intravenous Levovist, an air-filled contrast agent. The left ventricle (LV) was divided into 12 segments, and the EBD of each segment was scored: (1) not visible, (2) barely visible, (3) well delineated. The EBD index (EBDI), defined as the sum of the endocardial scores divided by 12 was obtained for each patient. Of a total of 576 LV segments, 231 were scored as 1 by fundamental imaging and that number decreased to 125 segments by tissue harmonic imaging and 116 segments by fundamental imaging with Levovist. The number of segments scored as 1 decreased to 38 segments by tissue harmonic imaging with Levovist, and to 29 segments by contrast harmonic imaging with Levovist. The EBDI by fundamental imaging was 1.85+/-0.29, which improved significantly with the addition of Levovist (2.10+/-0.36, p<0.001) and was nearly identical to that by tissue harmonic imaging (2.15+/-0.32, p=NS). Tissue and contrast harmonic imaging with Levovist further enhanced the EBDI (2.43+/-0.26, 2.51+/-0.27, respectively). Levovist enhances EBD, even in the fundamental mode, to the level obtained with tissue harmonic imaging. Tissue harmonic and contrast harmonic imaging are the best modalities for enhancing EBD after Levovist injection.     

Non-contrast second harmonic imaging improves interobserver agreement and accuracy of dobutamine stress echocardiography in patients with impaired image quality

OBJECTIVE: To examine the influence of second harmonic imaging during dobutamine echocardiography on regional endocardial visibility, interobserver agreement in the interpretation of wall motion abnormalities, and diagnostic accuracy in patients with reduced image quality. DESIGN: Blinded comparison. SETTING: Tertiary care centre. PATIENTS: 103 consecutive patients with suspected coronary artery disease and impaired transthoracic image quality (>/= 2 segments with poor endocardial delineation). METHODS: Fundamental and second harmonic imaging were performed at each stage of a dobutamine stress echocardiography. Coronary angiography was undertaken within three weeks of dobutamine echocardiography in 75 patients. MAIN OUTCOME MEASURES: Evaluation of regional endocardial visibility (scoring from 0 = poor to 2 = good) and of segmental wall motion abnormalities for both modalities separately. A second blinded examiner analysed 70 studies to determine interobserver agreement. RESULTS: Mean (SD) visibility score for all segments was 1.2 (0.4) using fundamental imaging and 1.7 (0.2) using second harmonic imaging at rest (p < 0.001), and 1.1 (0.4) v 1.6 (0.3), respectively, at peak dobutamine dose (p < 0.001). The average number of segments with poor endocardial visibility was lower for second harmonic than for fundamental imaging (0.6 (1.1) v 3.8 (2.6) at rest, p < 0.001; 0.9 (1.3) v 4.3 (2.9) at peak dose, p < 0.001). Improvement was most pronounced in all lateral and anterior segments. The kappa value for identical study interpretation increased from 0. 40 to 0.69 (p < 0.05). Sensitivity for the diagnosis of coronary artery disease was 64% using fundamental imaging versus 92% using harmonic imaging (p < 0.001), while specificity remained unchanged at 75% for both imaging modalities. CONCLUSIONS: Second harmonic imaging enhances endocardial visibility during dobutamine echocardiography. Consequently, interobserver agreement on stress echocardiography interpretation and diagnostic accuracy are significantly improved compared to fundamental imaging. Thus, in difficult to image patients, dobutamine echocardiography should be performed using second harmonic imaging.     

Enhanced visualisation of the right ventricle by contrast echocardiography in congenital heart disease.

BACKGROUND: Contrast echocardiography improves endocardial border detection of the left ventricle. Whether this is also true for the right ventricle (RV) is unknown. The aim of this study is to assess whether the use of contrast (Sonovue) echocardiography has additional value in RV endocardial border visualisation (EBV), and whether it has impact on the echocardiographic judgement of RV function. METHODS: Twenty adult patients with congenital heart disease were imaged using second harmonic two-dimensional echocardiography with and without contrast. Two independent observers analysed EBV of 13 RV wall segments in each patient. EBV was graded for each wall segment from 0 to 3 ( 0 = not visible, 3 = optimal visible). RESULTS: EBV improved in all patients with contrast echocardiography compared to second harmonic imaging (mean EBV 1.00 +/- 0.77 with second harmonics, 2.13 +/- 0.75 with contrast, P < 0.0001). The benefit was most evident in the near-field images. In 55% of the patients visual estimation of RV function changed with contrast echocardiography. CONCLUSION: The use of contrast echocardiography is superior to second harmonic imaging for RV EBV. Improved EBV may allow more accurate assessment of RV dimensions and function.     

Detection of left ventricular endocardial border with tissue harmonic imaging

BACKGROUND: Ultrasonic wave propagation in human tissues is not linear. As a consequence, harmonic waves, whose frequency is a multiple (harmonic) of the emitted frequency, are generated. Tissue Harmonic Imaging (THI) processes only the second harmonic frequency in order to improve the signal-to-noise ratio of the received signal. The study was aimed at investigating the impact of THI on the detection of the Left Ventricular (LV) endocardial border. Attention was paid to determine which LV walls were analysed more clearly with THI rather than with conventional Fundamental Frequency Imaging (FFI). METHODS: We compared the FFI and the THI visualization of the 16 LV segments and of the 6 LV walls in 30 consecutive patients by scoring the images as bad, sufficient or good. The equipment used was a GE Vingmed System Five (Orten, Norway). RESULTS: Images were good in 85% of segments explored with THI, whereas FFI provided good images in 47% of segments (p<0.001). From the apical window, visualization of the apex, lateral wall and anterior wall significantly improved with THI; using the parasternal approach, imaging of posterior wall was definitely better with THI than with FFI. CONCLUSIONS: THI enhances both endocardial visualization and global image quality. Tech-nical development, however, increases the diagnostic possibilities of echocardiography but does not substitute the operator's experience.     

Comparison of native and contrast-enhanced harmonic echocardiography for visualization of left ventricular endocardial border

Our study was designed to compare the utility of fundamental and second harmonic imaging (SH) for visualization of the left ventricular (LV) endocardial border. SH is a new imaging modality using nonlinear acoustic response, which may provide better endocardial border delineation. Standard apical views were studied in 42 patients using fundamental frequency (FF), SH without contrast (1.6- to 1.8-MHz and 2.1- to 2.5-MHz transmission frequencies), and SH after an intravenous injection of 2.5 g of Levovist. The quality of endocardial delineation in 16 standard segments was scored from 0 to 2. The endocardial visualization index was calculated as a mean of the scores. SH with and without contrast significantly improved LV endocardial border detection (endocardial visualization index 1.25+/-0.53, 1.64+/-0.67, 1.55+/-0.69, and 1.73+/-0.28 for fundamental, lower, and higher frequency harmonic and contrast-harmonic mode, respectively, p <0.005). Improvement was found in all LV segments. The number of invisible segments decreased from 142 (FF) to 54, 112, and 61 (in lower, higher, and contrast SH mode, respectively, p <0.001). Endocardial delineation in the apical segments using SH was optimal after contrast injection. In the basal LV area, contrast-enhanced images were less informative because of signal attenuation. Thus, SH significantly improves visualization of the LV endocardial border. Contrast enhancement with Levovist improves imaging of the apical segments but has no additional advantage in the basal segments. SH emerges as first-line modality for studies of LV function.     

Verbesserung der Endokarderkennung mittels modifizierter transthorakaler Echokardiographie unter Verwendung der zweiten harmonischen Schwingungen (Tissue Harmonic Imaging)

In human tissue sound propagation is not linear resulting in a modification of the ultrasound waves. Therefore the received ultrasound frequencies are not just the transmitted frequencies of the transducer, but contain additional harmonic frequencies. These frequencies were not used by standard echocardiography. Harmonic imaging processes the second harmonic frequency. Distortion of the transmitted beam by shallow surface layers or reverberations between the skin surface and ribs impair image quality in conventional 2-dimensional echocardiography. Since harmonic components develop with propagation distance, the reverberations are almost entirely made up of ultrasound energy at the fundamental frequency. The exclusive processing of the second harmonic frequency provides an impressive improvement in image quality of 2-dimensional echocardiograms. Noise and clutter artifacts are reduced and endocardial borders are enhanced. Commercially available imagers provide tissue harmonic imaging using transmit frequencies from 1.7 to 2.1 MHz and second harmonic frequencies between 3.4 and 4.2 MHz. Several clinical studies have shown that harmonic imaging was superior to standard echocardiography in the assessment of left ventricular (LV) wall motion by LV wall motion analysis. In patients with poor acoustic windows the number of myocardial segments which could be evaluated was significantly higher using harmonic imaging than standard echocardiography. Tissue harmonic imaging particularly improves the delineation of the anterior wall using the 2-chamber view and the lateral wall using the 4-chamber view. CONCLUSION: Harmonic imaging is a clinically relevant improvement of echocardiography. We suggest that this new technology should be the method of choice in the evaluation of LV function.     

Quantitative evaluation of regional endocardial visualisation with second harmonic imaging and contrast left ventricular opacification in heart failure patients.

AIMS: Wall motion score index (WMSI) is an important prognostic indicator in heart failure (HF) patients but requires endocardial visualisation. This study evaluated the role tissue harmonic imaging (THI) and contrast opacification (LVO) for improving endocardial visualisation and the determination of WMSI in HF patients. METHODS AND RESULTS: Thirty-one HF patients and 30 controls underwent apical echocardiography with fundamental imaging (FUND), THI and THI with contrast agent (Levovist). Visualisation and motion were graded in the six segments from each of the apical two and four chamber views. Both THI and LVO reduced the percentage of non-visualised segments (FUND 13.6%, THI 5.6%, LVO 2.8%, p=0.01) in the controls, but in HF patients, only THI improved visualisation (% segments not visualised FUND 9.7%, THI 3.5%, LVO 4.8%, p=0.06). The anterior and lateral walls were the least well visualised with FUND, but improved with LVO (anterior p=0.0026, lateral p=0.0003). No improvement was seen in the inferior wall (p=0.30) or septum (p=0.2). WMSI was similar by all methods and negatively correlated with ejection fraction (FUND r=-0.69, THI r=-0.74, LVO r=-0.77, all p<0.001). CONCLUSION: THI improved endocardial visualisation in all subjects and LVO offered additional benefit in the controls, but not in HF patients. Regional endocardial visualisation was inconsistent. Thus, both patient factors and wall segment site need to be considered when using contrast agents for endocardial visualisation.     

Contrast and harmonic imaging improves accuracy and efficiency of novice readers for dobutamine stress echocardiography

BACKGROUND: Newer contrast agents as well as tissue harmonic imaging enhance left ventricular (LV) endocardial border delineation, and therefore, improve LV wall-motion analysis. Interpretation of dobutamine stress echocardiography is observer-dependent and requires experience. This study was performed to evaluate whether these new imaging modalities would improve endocardial visualization and enhance accuracy and efficiency of the inexperienced reader interpreting dobutamine stress echocardiography. METHODS AND RESULTS: Twenty-nine consecutive patients with known or suspected coronary artery disease underwent dobutamine stress echocardiography. Both fundamental (2.5 MHZ) and harmonic (1.7 and 3.5 MHZ) mode images were obtained in four standard views at rest and at peak stress during a standard dobutamine infusion stress protocol. Following the noncontrast images, Optison was administered intravenously in bolus (0.5-3.0 ml), and fundamental and harmonic images were obtained. The dobutamine echocardiography studies were reviewed by one experienced and one inexperienced echocardiographer. LV segments were graded for image quality and function. Time for interpretation also was recorded. Contrast with harmonic imaging improved the diagnostic concordance of the novice reader to the expert reader by 7.1%, 7.5%, and 12.6% (P < 0.001) as compared with harmonic imaging, fundamental imaging, and fundamental imaging with contrast, respectively. For the novice reader, reading time was reduced by 47%, 55%, and 58% (P < 0.005) as compared with the time needed for fundamental, fundamental contrast, and harmonic modes, respectively. With harmonic imaging, the image quality score was 4.6% higher (P < 0.001) than for fundamental imaging. Image quality scores were not significantly different for noncontrast and contrast images. CONCLUSION: Harmonic imaging with contrast significantly improves the accuracy and efficiency of the novice dobutamine stress echocardiography reader. The use of harmonic imaging reduces the frequency of nondiagnostic wall segments.     

Diagnostic accuracy and cost-effectiveness of contrast echocardiography on evaluation of cardiac function in technically very difficult patients in the intensive care unit

Echocardiographic assessment of cardiac function can be quite difficult in the intensive care unit and may require transesophageal echocardiography (TEE). We therefore compared harmonic imaging alone or in combination with contrast to TEE in 32 consecutive patients in the intensive care units who were considered technically very difficult (> or =50% of the 16 segments not visualized from any view). Excellent or adequate endocardial visualization was achieved in 13% of segments with fundamental imaging, 34% with harmonic imaging, and 87% with contrast (p < 0.0001); the latter success rate was similar to TEE (87% vs 90%; p = NS). When TEE was used as the standard, agreement in exact interpretation of wall motion increased from 48% for fundamental imaging to 58% with harmonic imaging, and reached 70% with contrast (p <0.0001). Contrast had the best sensitivity (89%) for detecting wall motion abnormalities. Estimation of ejection fraction was possible in 31% with fundamental imaging, 50% with harmonic imaging, and in 97% with contrast. Ejection fraction quantitated by contrast enhancement correlated best with TEE (r = 0.91). Cost-effectiveness analysis revealed that contrast echo was cost-effective compared with TEE in determining regional and global ventricular function, with a cost saving of 3% and 17%, respectively. Thus, contrast echocardiography provides an accurate, safe, and cost-effective alternative to TEE for evaluating ventricular function in technically very difficult studies.     

Use of harmonic echocardiographic contrast imaging and intravenous bolus of Levovist for evaluation of the left ventricle

Harmonic imaging is a new imaging modality using nonlinear acoustic response, which is particularly sensitive for the particles of contrast agents. Our study was designed to compare the potential of harmonic echocardiographic imaging of the left ventricle using a contrast agent, Levovist to improve the detection of endocardium in patients with suboptimal image quality. 40 patients were studied using standard transthoracic apical views of the left ventricle patients using fundamental frequency and second harmonic frequency after and intravenous injection of 2.5 g Levovist. The quality of endocardial delineation in 16 standard segments was scored from 0 to 2. Endocardial visualization index was calculated as a mean of the scores to express overall diagnostic quality. Harmonic imaging with contrast significantly improved left ventricular endocardial border detection (endocardial visualization index at baseline 1.24 +/- 0.41, with contrast 1.63 +/- 0.38; p < 0.001). The improvement was qualitatively observed in all parts of the left ventricle: in apex (2.4 +/- 0.8), in the middle part (2.5 +/- 0.9) and slightly less in the basal part (2.1 +/- 1.1) as scored on a 0-3 scale. The number of invisible segments decreased from 124 (fundamental) to 50 in contrast harmonic mode. The persistence of the contrast enhancement, prolonged in harmonic as compared to fundamental imaging (284 +/- 136s vs 117 +/- 87s; p < 0.001) enabled convenient recording of all necessary views. Harmonic imaging after an intravenous injection of Levovist significantly improves the visualization of left ventricular endocardial border. Prolonged contrast effect after a single bolus enhances the pertinence of the method in clinical practice.     

Power Doppler Imaging as a Basis for Automated Endocardial Border Detection During Left Ventricular Contrast Enhancement

Echocardiographic evaluation of left ventricular (LV) systolic function relies on endocardial visualization, which can be improved when necessary using contrast enhancement. However, there is no method to automatically detect the endocardial boundary from contrast-enhanced images. We hypothesized that this could be achieved using harmonic power Doppler imaging. Twenty-two patients were studied in two protocols: (1) 11 patients with poorly visualized endocardium (> 3 contiguous segments not visualized) and (2) 11 consecutive patients referred for dobutamine stress echocardiography who were studied at rest and at peak dobutamine infusion. Patients were imaged in the apical four-chamber view using harmonic power Doppler mode (HP SONOS 5500) during LV contrast enhancement (Optison or Definity DMP115). Digital images were analyzed using custom software designed to automatically extract the endocardial boundary from power Doppler color overlays. LV cavity area was automatically measured frame-by-frame throughout the cardiac cycle, and fractional area change calculated and compared with those obtained by manually tracing the endocardial boundary in end-systolic and end-diastolic gray scale images. Successful border detection and tracking throughout the cardiac cycle was possible in 9 of 11 patients with poor endocardial definition and in 10 of 11 unselected patients undergoing dobutamine stress testing. Fractional area change obtained from power Doppler images correlated well with manually traced area changes (  r = 0.82 and r = 0.97  , in protocols 1 and 2, respectively). Harmonic power Doppler imaging with contrast may provide a simple method for semi-automated border detection and thus facilitate the objective evaluation of LV function both at rest and under conditions of stress testing. This methodology may prove to be particularly useful in patients with poorly visualized endocardium.     

For left ventricular opacification and endocardial border definition: is it really important which contrast agent we use, or is it the imaging modality we choose?

AIMS: The purpose of this study was to prospectively compare the effect of three imaging modalities (fundamental, harmonics, and power harmonics) on left ventricular opacification and endocardial border definition with two different echo agents, Optison and Albunex. METHODS: A total of 84 patients who had suboptimal transthoracic images were studied with echo contrast agents Albunex (n=41) and Optison (n=43). Each contrast agent was examined with three different imaging modalities, fundamental, harmonics and power harmonics, respectively. Left ventricular opacification was obtained by videodensitometric analysis. Percentage of endocardial border visualization was determined by indexing circumference of visualized endocardium to total circumference. Variables were compared with respect to three imaging modalities between two different echo agents. RESULTS: Higher videointensities and higher percentages of endocardial visualization were achieved with Optison compared to Albunex with fundamental and harmonics. However, there was no significant difference between Optison and Albunex with respect to LV opacification and border visualization by power harmonics. CONCLUSION: These results indicate that left ventricular opacification and endocardial border visualization is significantly improved by using power harmonic imaging as compared to harmonics or fundamental imaging following both echo contrast agents. Furthermore, although Optison is clearly superior to Albunex in opacifying left ventricle, power harmonic imaging compensates for the less robust agent.     

Usefulness of contrast echocardiography with harmonic imaging in a patient with hypertrophic cardiomyopathy and midventricular obstruction

Echocardiography is routinely used for the evaluation of cardiac function. Definition of the endocardial border is essential for the assessment of global and regional left ventricular contractility. This is sometimes difficult due to an inadequate acoustic window. New echocardiographic techniques may be useful to accurate and noninvasively diagnose certain conditions which may otherwise remain undiagnosed with traditional techniques.We present a case of a patient diagnosed with segmental wall motion abnormalities (lateral and apical hypokinesis) by conventional echocardiography. The use of harmonic imaging with contrast changed the initial diagnosis and the patient was diagnosed with severe hypertrophic cardiomyopathy with midventricular obstruction, without segmental wall motion abnormalities.     

Comparison of tissue harmonic imaging and standard imaging in echocardiography based on 4 different emission frequencies

Harmonic imaging is an innovative technique which is now available in most of the echographic equipment currently on the market. The use of echographic contrast agents led to the introduction of this particular technology, which has largely superseded the former method. In everyday medical practice, it seems to provide a better definition of endocardial contours. In this article, the authors have described a prospective study including 32 patients with an average age of 64 years (+/- 5 years). The aim was to compare imaging quality obtained by 2 acquisition frequencies for standard imaging with that procured by harmonic imaging (emission and reception frequency, 2.5 and 3.3 MHz respectively for the former technique; emission and reception frequency, 1.7 and 2.2 MHz respectively for the latter). The overall scores given by 2 different examiners for emission and reception frequency were as follows: 3.28 and 3.15 for 2.5 MHz, 2.84 and 2.56 for 3.3 MHz regarding the standard technique; 2.56 and 3.031 for 1.7 MHz and 2.56 and 2.063 for 2.2 MHz for the harmonic imaging technique. The superior performance of tissue harmonic imaging has been confirmed in the endocardial study of the left ventricular segments and in the analysis of the mitral valve. This study shows that harmonic imaging, a technique which was easy to use in the present study, provides a means of obtaining an average level of ultrasound imaging that facilitates the interpretation of the clinical picture.     

Left ventricular endocardial and epicardial border length delineation with perflutren contrast during transthoracic echocardiography

Objective: Precise estimation of wall motion abnormalities during routine echocardiography rests on optimal endocardial border visualization. Endocardial “dropout” may result in the misinterpretation of regional wall motion. Left ventricular opacification (LVO) with intravenous contrast improves the visualization of the left ventricular endocardial border length (EnBL). The purpose of this study was to determine if contrast also improves the visualization of the epicardial border length (EpBL) in addition to the EnBL. Method: This is a single center retrospective observational study. From 200 consecutive patients referred to the Echocardiography Laboratory for the assessment and evaluation of coronary artery disease, 73 patients who received contrast were enrolled. All the images were standardized using offline software. The visualized segments of the epicardium and endocardium were measured in diastole and systole, without and with contrast‐enhancement and these segments were summed to provide the total visualized EnBL and EpBL. Results: Contrast enhanced imaging improved EnBL by 65% and 45% in end‐diastolic and end‐systolic views, respectively. Similarly, EpBL was improved by 61% and 57% in end‐diastolic and end‐systolic views, respectively (all P values <0.05). Conclusion: Contrast LVO improves the EnBL as previously reported. Additionally, based upon the blinded review of 1,752 regional myocardial wall segments, this study is the first to suggest that contrast also enhances the visualization of the EpBL. This finding has direct clinical implications as the improvement in both EnBL and EpBL with contrast may assist in evaluation of regional left ventricular wall thickening which is a critical parameter used to assess for myocardial ischemia. (Echocardiography 2011;28:761‐766)     

Endocardial border delineation during dobutamine infusion using contrast echocardiography

BACKGROUND: A significant percentage of pharmacologic stress echocardiograms produce suboptimal images despite the use of second harmonic imaging. Intravenous continuous infusion of myocardial ultrasound contrast may enhance endocardial border delineation during dobutamine-atropine stress echocardiography (DASE), improving wall-motion analysis. PATIENTS AND METHODS: We prospectively studied 68 patients (41 males and 27 females), mean age 58 years, with DASE during intravenous infusion of contrast using second harmonic imaging. Dobutamine was infused in scalar doses of 5 microg/kg/min to 40 microg/kg/min, and atropine was administered in doses of up to 1 mg. We diluted 0.1 mL of perfluorocarbon-exposed sonicated dextrose albumin (PESDA) microbubbles into 80 mL of saline solution, which was used for continuous intravenous infusion. Blinded reviewers used a 16-segment model at rest and peak DASE to analyze segmental wall delineation in two sets of images for each patient, with and without contrast. An endocardial delineation score of 0-3 (nondelineated to excellent delineation) was given to each segment. An endocardial delineation score index (EDSI), the number of endocardial delineation scores for each set of images divided by 16, was created. RESULTS: The analysis of the mean EDSI for the 2176 segments was 1.46 (+/- 0.43) at rest and 1.30 (+/- 0.48) at peak for noncontrast images and 2.22 (+/- 0.52) and 2.29 (+/- 0.52) for contrast images. Complete left ventricle opacification was obtained in all patients, with a mean dose of 4 mL/min, although in 15 (22%) patients, signs of apical bubble destruction occurred. There were 1768 (81%) of 2176 segments delineated without contrast enhancement and 2057 (95%) of 2176 with enhancement (P < 0.05). CONCLUSION: Continuous infusion of myocardial ultrasound contrast improves endocardial border delineation using second harmonic imaging in patients undergoing DASE.