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Biomedical subjects

Harald Becher

Publications and source records attributed to Harald Becher.

At least 19 recordsLinked to original sources
PubMed2006

Myocardial contrast echocardiography evolving as a clinically feasible technique for accurate, rapid, and safe assessment of myocardial perfusion: the evidence so far.

Intravenous myocardial contrast echocardiography (MCE) is a recently developed technique for assessment of myocardial perfusion. Up to now, many studies have demonstrated that the sensitivity and specificity of qualitative assessment of myocardial perfusion by MCE in patients with acute and chronic ischemic heart disease are comparable with other techniques such as cardiac scintigraphy and dobutamine stress echocardiography. Furthermore, quantitative parameters of myocardial perfusion derived from MCE correlate well with the current clinical standard for this purpose, positron emission tomography. Myocardial contrast echocardiography provides a promising and valuable tool for assessment of myocardial perfusion. Although MCE has been primarily performed for medical research, its implementation in routine clinical care is evolving. This article is intended to give an overview of the current status of MCE.

Acute Disease↗
PubMed2006

Analysis of myocardial perfusion or myocardial function for detection of regional myocardial abnormalities. An echocardiographic multicenter comparison study using myocardial contrast echocardiography and 2D echocardiography.

BACKGROUND: Echocardiography based myocardial perfusion imaging and regional wall motion analysis are used for evaluation of coronary artery disease and regional myocardial abnormalities. AIM: This study sought to compare myocardial contrast echocardiography (MCE) and 2D echocardiography with regard to interobserver variability and detection of regional myocardial abnormalities. METHODS: In 70 patients evenly distributed between three ejection fraction groups based on biplane cineventriculography ( > 55%, 35-55%, < 35%), unenhanced and contrast enhanced 2D echocardiography and myocardial contrast echocardiography (MCE; SonoVue; Bracco) were performed. Regional wall motion and myocardial perfusion were assessed referring to a 16 segment model. Interobserver agreement (IOA) among 2 readers was determined within each imaging modality. To define a standard of truth for the presence of segmental myocardial disease an independent expert-panel decision was obtained based on clinical data, ECG, coronary angiography and blinded information from the imaging modalities. RESULTS: Regional wall motion assessment was possible in 98.1% of segments using contrast enhanced 2D echocardiography and in 87.2% using unenhanced 2D echocardiography (p < 0.001), while perfusion assessment was possible in 90.1% of segments (p < 0.001). IOA on presence of any regional wall motion abnormality expressed as Kappa coefficient was 0.71 (95% CI 0.53-0.89) for contrast enhanced echocardiography and 0.37 (95% CI 0.14-0.59) for unenhanced echocardiography. IOA on presence of any perfusion abnormality was 0.53 (95% CI 0.34-0.73). For MCE there was high IOA for the apical segments (kappa = 0.57) and lower IOA for the basal segments (kappa=0.14), while no such gradient was found for the IOA on wall motion abnormalities. Mean accuracy to detect expert-panel defined myocardial abnormalities was 80.6% for unenhanced echocardiography, 85.0% for contrast enhanced 2D echocardiography and 80.6% for MCE. CONCLUSIONS: MCE is inferior to contrast enhanced 2D echocardiography with regard to visibility of all LV segments and appears slightly inferior with regards to IOA, while both are superior to unenhanced 2D echocardiography. The methods demonstrated high accuracy in detection of panel defined regional myocardial abnormalities.

Contrast Media↗
PubMed2006

Imaging of pericardial tumours: a case report.

BACKGROUND: Pericardial tumours are unusual and may be difficult to characterise with imaging. They manifest as large, non-contractile, solid masses within the pericardium. Presenting symptoms include heart failure, arrythmias, sudden death, cyanosis and chest pain. CASE PRESENTATION: We describe a case of massive pericardial fibroma in a 52 year old woman, who presented with palpitations only. CONCLUSION: We illustrate the different imaging modalities available to image this tumour prior to surgical resection, and indicate the strengths and weaknesses of each.

Echocardiography↗
PubMed2006

The vanishing vast ventricular thrombus.

A 54-year old man presented with multiple pulmonary emboli and an incidental finding of a huge left ventricular thrombus. Transthoracic echo images demonstrated a globally dilated heart with very poor left ventricular function. It was elected to manage the patient medically, and he was commenced on warfarin therapy, resulting in completed resolution of the thrombus over 10 weeks. No underlying cause was found and he did not experience any further embolic events. This illustrates a rare case of a large ventricular thrombus in a patient with no underlying risk factors.

Anticoagulants↗
PubMed2005

Analysis of regional left ventricular function by cineventriculography, cardiac magnetic resonance imaging, and unenhanced and contrast-enhanced echocardiography: a multicenter comparison of methods.

OBJECTIVES: To define the use of cineventriculography, cardiac magnetic resonance imaging (cMRI), and unenhanced and contrast-enhanced echocardiography for detection of left ventricular (LV) regional wall motion abnormalities (RWMA). BACKGROUND: Detection of RWMA is integral to the evaluation of LV function. METHODS: In 100 patients, cineventriculography and unenhanced and contrast-enhanced echocardiography were performed. Fifty-six of the patients underwent additional cMRI. RWMA were assessed referring to a 16-segment model for cMRI, unenhanced and contrast echocardiography. Cineventriculography was evaluated on a 7-segment model. Hypokinesia in one or more segments defined presence of RWMA. Interobserver agreement among three readers was determined within each imaging modality. Intermethod agreement between imaging modalities was analyzed. A standard of truth for the presence of RWMA was obtained by an independent expert panel decision (EPD) based on clinical data, electrocardiogram, coronary angiography, and blinded information from the imaging modalities. RESULTS: Sixty-seven patients were found to have an RWMA by EPD. Interobserver agreement expressed as kappa coefficient was 0.41 (range 0.37 to 0.44) for unenhanced echocardiography, 0.43 (range 0.29 to 0.79) for cMRT, 0.56 (range 0.44 to 0.70) for cineventriculography, and 0.77 (range 0.71 to 0.88) for contrast echocardiography. Contrast enhancement compared to unenhanced echocardiography improved agreement of echocardiography related to cMRI (kappa 0.46 vs. 0.29) and related to cineventriculography (kappa 0.59 vs. 0.28). Accuracy to detect EPD-defined RWMA was highest for contrast echocardiography, followed by cMRI, unenhanced echocardiography, and cineventriculography. CONCLUSIONS: Analysis of RWMA is characterized by considerable interobserver variability even using high-quality imaging modalities. Interobserver agreement on RWMA and accuracy to detect panel-defined RWMA is good using contrast echocardiography.

Cineradiography↗
PubMed2005

Comparison of dobutamine stress echocardiography with and without real-time perfusion imaging for detection of coronary artery disease.

In a pilot study of 27 patients, those who presented with chest pain underwent 2 dobutamine stress echocardiographic studies, 1 with high mechanical index harmonic imaging to analyze wall motion without contrast and 1 with real-time low mechanical index perfusion imaging with intravenous Optison to assess myocardial perfusion and wall motion. All patients then underwent quantitative coronary angiography. Two independent reviewers demonstrated an improvement in sensitivity when analyzing myocardial perfusion. In the 21 patients who had significant coronary stenoses, 14 had abnormal myocardial perfusion detected at peak stress and 7 had abnormal wall motion detected by standard dobutamine stress echocardiography. There was decreased specificity with perfusion imaging by 1 reviewer. The addition of real-time perfusion imaging after intravenous contrast during dobutamine stress echocardiography has the potential to improve detection of coronary artery disease.

Albumins↗
PubMed2005

Safety of contrast dobutamine stress echocardiography: a single center experience.

BACKGROUND: Contrast is increasingly being used during dobutamine stress echocardiography. However, there are few data regarding the safety of this combination. METHODS: We retrospectively analyzed 751 consecutive stress echocardiograms, 332 without contrast and 419 with contrast (299 with Sonouve, 120 with Optison). Reported side effects and physiologic data were then compared. RESULTS: There were no fatalities. The incidence of side effects was similar in the 3 groups. The Optison group had a lower diastolic blood pressure compared with the noncontrast group ( P < .05) at rest, and the Sonovue group had a higher peak heart rate compared with the noncontrast group ( P < .001). Patients receiving Optison had more premature atrial contractions ( P < .05) but there was no difference in the incidence of ventricular tachycardia, supraventricular tachycardia, or vagally mediated episodes. CONCLUSION: The use of contrast during dobutamine stress echocardiography was not associated with an increased risk of side effects.

Aged↗
PubMed2005

Can contrast dobutamine stress echocardiography be performed with standardized imaging settings for everybody?

OBJECTIVE: The objective was to assess a standardized imaging and contrast injection protocol for contrast-enhanced dobutamine stress echocardiography (DSE). METHODS: A total of 102 patients underwent DSE with tissue harmonic imaging and a standardized protocol with contrast power modulation. Contrast intensities in the left ventricular cavity and the myocardium were evaluated by a visual score and quantitative analysis. RESULTS: Of the contrast studies, 98% were diagnostic without modification of the settings. Excellent endocardial border definition was found in 93% of the segments with contrast versus 53% with tissue harmonic imaging (P < .05). The interobserver agreement in assessing segmental wall motion improved from 71.5% to 85.9%. There were no differences between the myocardial segments' video intensity in the four- and three-chamber views. In the two-chamber view video intensity was lower in the basal segments compared with the other segments. CONCLUSION: Power modulation contrast imaging can be applied with a completely standardized protocol for DSE in the majority of patients with excellent endocardial border definition.

Albumins↗
PubMed2005

Quantitative analysis of myocardial perfusion in rats by contrast echocardiography.

BACKGROUND: The ability to assess myocardial perfusion in small animals is important, especially to investigate models of myocardial ischemia. Myocardial perfusion is usually assessed by postmortem techniques, eliminating the possibility of follow-up. We sought to evaluate whether contrast echocardiography was able to quantify myocardial perfusion in rats. METHODS: Twenty-four rats divided in 3 groups (sham-operated, and 8 and 21 days after left anterior descending coronary artery stenosis) underwent myocardial contrast echocardiography using intermittent triggered imaging. Peak plateau intensity and slope of refilling were compared with myocardial blood flow achieved with fluorescent microspheres. RESULTS: High-quality images were easily obtained for each experiment. Close correlation was found between myocardial contrast echocardiography and myocardial blood flow, especially for measurements of peak plateau intensity x slope of refilling relative to the control area (y = 1.15 x -0.14, r = 0.86). CONCLUSION: Quantification of myocardial perfusion in rats is feasible by myocardial contrast echocardiography using intermittent triggered imaging.

Animals↗
PubMed2004

Assessment of systolic left ventricular function: a multi-centre comparison of cineventriculography, cardiac magnetic resonance imaging, unenhanced and contrast-enhanced echocardiography.

AIMS: To assess the agreement of left ventricular ejection fraction (LVEF) determinations from unenhanced echocardiography, contrast-enhanced echocardiography, magnetic resonance imaging (MRI), and cineventriculography as well as the inter-observer agreement for each method. METHODS AND RESULTS: In 120 patients, with evenly distributed EF-groups (> 55, 35-55, < 35%), cineventriculography, unenhanced echocardiography with second harmonic imaging, and contrast echocardiography at low mechanical index with iv administration of SonoVue were performed. In addition, cardiac MRI at 1.5 T using a steady-state free precession sequence was performed in a subset of 55 patients. On-site, and two blinded off-site assessments were performed for unenhanced and contrast echocardiography, cineventriculography, and MRI according to pre-defined standards. Intra-class correlation coefficients (ICCs) were determined to assess inter-observer reliability between all three readers (i.e. one on-site and two off-site). EF was 56.2 +/- 18.3% by cineventriculography, 54.1 +/- 12.9% by MRI, 50.9 +/- 15.3% by unenhanced echocardiography, and 54.6 +/- 16.8% by contrast echocardiography. Correlation on EF between cineventriculography and echocardiography increased from 0.72 with unenhanced echocardiography to 0.83 with contrast echocardiography (P < 0.05). Similarly, correlation on EF between MRI and echocardiography increased from 0.60 with unenhanced echocardiography to 0.77 with contrast echocardiography (P < 0.05). The inter-observer reliability ICC was 0.91 (95% CI 0.88-0.94) in contrast echocardiography, followed by cardiac MRI (0.86; 95% CI 0.80-0.92), cineventriculography (0.80; 95% CI 0.74-0.85), and unenhanced echocardiography (0.79; 95% CI 0.74-0.85). CONCLUSIONS: Unenhanced echocardiography resulted in slight underestimation of EF and only moderate correlation compared with cineventriculography and MRI. Contrast echocardiography resulted in more accurate EF and significantly improved correlation with cineventriculography and MRI. Contrast echocardiography significantly improved inter-observer agreement on EF compared with unenhanced echocardiography. Inter-observer reliability on EF using contrast echocardiography reaches a level comparable to MRI and is better than those obtained by cineventriculography.

Aged↗
PubMed2003

The effect of echo contrast agent on Doppler velocity measurements.

The purpose of this investigation was to determine the effect of echo contrast agents on spectral Doppler velocity measurements. SH U 508A was administered by IV injection in 15 patients. The transmitral flow velocity was measured at the E- and A-wave peaks before the start and at the peak of the contrast effect. The Doppler velocity was determined from the Doppler video spectral display and from power spectral analysis of the audio Doppler signal. The Doppler signal intensity was also measured. The Doppler signal intensity increased 17.4 +/- 3.5 dB (p < 0.0001) following echo contrast injection. This was associated with a significant increase in the spectral peak velocity as determined from either the video display or audio analysis. (p < 0.0001). The velocity corresponding to the audio power peak frequency (the modal velocity) did not change significantly (p = NS) and was independent of Doppler signal strength.

Adult↗
PubMed2003

Echoscintigraphy: a new imaging modality for the reduction of color blooming and acoustic shadowing in contrast sonography.

The purpose of this study was to develop and evaluate a new imaging modality (echoscintigraphy) to reduce color blooming and acoustic shadowing in contrast sonography. After injection of various amounts (700 to 40,000 bubbles/mL) of the echo contrast agent SH-U 563A into a flow phantom, artificial vessels were insonated in the intermittent harmonic-power Doppler imaging (H-PDI) mode. The receive gain was varied from 50% to 75%. The cross-sectional area (CSA) of the tube was assessed using a new summation algorithm (echoscintigraphy) and a conventional single-frame analysis (S-FA) of the H-PDI-signals. Echoscintigraphy is based on the recording and summation of low-intensity signals that are emitted during the ultrasound (US)-induced destruction of microbubbles. Application of the summation algorithm at low-contrast concentration allowed a gain-independent automatic calculation of the CSA at medium and high gain settings. Using the S-FA method, the assessment of the vessel diameter and the CSA was gain-dependent and allowed correct measurements only from 60% to 65% gain. At a high receive-gain and high contrast concentration, S-FA resulted in an overestimation of the CSA up to 35.5%. Echoscintigraphy allows correct display of contrast-filled vessels over a wide range of gain settings at low contrast concentrations, where S-FA does not adequately display echo contrast. Thus, echoscintigraphy minimizes artefacts resulting from color blooming and acoustic shadowing.

Algorithms↗
PubMed2002

[Contrast echocardiography: clinical applications and future prospects].

BACKGROUND: Contrast echocardiography has been used as a clinical method for more than 20 years. Using conventional ultrasound techniques the clinical use of contrast was limited. Now the development of "contrast specific" imaging modalities has increased the indications for contrast echocardiography. CONTRAST AGENTS: For clinical use two classes of contrast agents are available: 1. "right heart" contrast media (Echovist, agitated solutions), which do not cross the pulmonary vascular bed following intravenous injection and which can be used with conventional (fundamental) imaging methods, 2. "left heart" contrast media (Levovist, Optison, SonoVue) which need "contrast specific" imaging modalities for optimal use. INDICATIONS: Despite of the developments in Doppler methods and transesophageal echocardiography "right heart" contrast media still are needed in some patients with atrial and pulmonary shunts, complex congenital heart disease, noisy Doppler recordings of tricuspid regurgitation. For "left heart" contrast media improvement of endocardial border definition is the most important indication, which has been validated in a series of well performed studies. Therefore contrast enhanced recordings are recommended in the clinical echo laboratory when unenhanced recordings are suboptimal. Coronary flow reserve of the LAD can be measured using contrast enhanced Doppler echocardiography. All contrast specific imaging modalities provide assessment of myocardial perfusion. The previously used imaging modalities (Harmonic B mode, Pulse Inversion and Harmonic Power Doppler) did not provide sufficient myocardial contrast signals using real-time imaging. Although intermittent imaging resulted in good myocardial opacification, this modality did not gain wider clinical acceptance. NEW TECHNOLOGIES: Using new contrast specific imaging technologies like Power Pulse Inversion, Power Modulation and Coherent Imaging myocardial perfusion can be evaluated in "real-time". Thus simultaneous assessment of left ventricular wall motion and myocardial perfusion became a reality and facilitated the data acquisition. New ultrasound contrast media like SonoVue can be used for all imaging modalities. Recent studies have demonstrated that the information derived from myocardial contrast echocardiography provides clinically relevant information on top of the findings obtained from conventional left ventricular wall motion analysis.

Contrast Media↗