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Biomedical subjects

Roberto M Lang

Publications and source records attributed to Roberto M Lang.

At least 91 records · Page 5Linked to original sources
PubMed2003

Unsuspected clinically important findings detected with a small portable ultrasound device in patients admitted to a general medicine service.

OBJECTIVE: We sought to determine whether physicians with training in echocardiography could successfully use a small echocardiographic device to detect occult cardiovascular disease in patients admitted to a general medical service. METHODS: In all, 103 consecutive patients had a physician-performed bedside echocardiographic examination with a small portable ultrasound device. RESULTS: Of patients, 70% did not have a clinical indication for echocardiography and of these patients, 39% had an abnormal study with the portable ultrasound device. There was a high rate of false-positive examinations, but approximately 17% of patients without a clinical indication for echocardiography had an important cardiac abnormality detected, including 10% with unsuspected left ventricular systolic dysfunction. CONCLUSIONS: Many patients on a general medical hospital ward have unsuspected, clinically important cardiac findings such as left ventricular dysfunction that can be screened for by physicians with training in echocardiography using small portable ultrasound devices.

Academic Medical Centers↗
PubMed2003

Biplane stress echocardiography using a prototype matrix-array transducer.

BACKGROUND: Rapid image acquisition after cessation of exercise is essential for accurate stress echocardiography. Recently, a prototype matrix-array transducer has been developed that allows simultaneous acquisition of 2 imaging planes (biplane [BP] imaging). METHODS: In all, 19 healthy volunteers underwent 2 separate stress echocardiographic studies. Images were acquired in traditional 2-dimensional or BP format pre-exercise and postexercise. RESULTS: Total image acquisition time for 2-dimensional stress echocardiography was 38 +/- 8 seconds versus 29 +/- 8 seconds for BP imaging (P <.05). Heart rates were acquired closer to age-predicted maximum with BP imaging in the apical 3- and 2-chamber and parasternal long- and short-axis views (82%, 75%, 70%, 70% for BP vs 76%, 72%, 68%, 66% for 2-dimensional, respectively). CONCLUSION: BP imaging using a recently developed matrix-array probe allows more rapid imaging postexercise, resulting in acquisition of poststress images at higher heart rates without compromising image quality.

Acoustics↗
PubMed2003

Dynamic three-dimensional color flow Doppler: an improved technique for the assessment of mitral regurgitation.

BACKGROUND: Prior studies have reconstructed mitral regurgitant flow in three dimensions displaying gray scale renditions of the jets, which were difficult to differentiate from surrounding cardiac structures. Recently, a color-coded display of three-dimensional (3D) regurgitant flow has been developed. However, this display was unable to integrate cardiac anatomy, thereby losing spatial information, which made it difficult to determine the jet origin and its spatial trajectory. To overcome this limitation, an improved method of 3D color reconstruction of regurgitant jets obtained from color flow Doppler using a transesophageal approach was developed to allow the combined display of both color flow and gray scale information. OBJECTIVES: To demonstrate the feasibility of 3D reconstruction of regurgitant mitral flow jets using an improved method of color encoding digital data acquired by transesophageal echocardiography (TEE). METHODS: We studied 46 patients undergoing a clinically indicated TEE study. All subjects had mitral regurgitation detected on a previous transthoracic study. Atrial fibrillation or poor image quality were not used as exclusion criteria. The 3D study was performed using a commercial ultrasound imaging system with a TEE probe (Sonos 5500, Agilent Technologies). A rotational mode of acquisition was used to collect two-dimensional (2D) color flow images at 3-degree intervals over 180 degrees. Images were processed off line using the Echo-View Software (TomTec Imaging Systems). Volume-rendered 3D color flow jets were displayed along with gray scale information of the adjacent cardiac structures. RESULTS: Mitral regurgitant flow, displayed in left atrial and two longitudinal orientations, was successfully reconstructed in all patients. The time for acquisition, post-processing, and rendering ranged between 10 and 15 minutes. There were 28 centrally directed jets and 15 eccentric lesions. Eight patients in the study had periprosthetic mitral regurgitant flow. CONCLUSIONS: Three-dimensional imaging of mitral regurgitant jets is feasible in the majority of patients. This improved technique provides additional information to that obtained from the 2D examination. Particularly, in patients with paravalvular leaks 3D color flow Doppler provides information on the origin and the extent of the dehiscence, as well as insight into the jet direction. In addition, in patients with eccentric mitral regurgitation, this new modality overcomes the inherent limitations of 2D echo Doppler by depicting the full extent of the jet trajectory.

Echocardiography, Doppler, Color↗
PubMed2003

The hand-carried echocardiographic device as an aid to the physical examination.

Physical examination skills have been declining over the past several decades while technology has made diagnostic testing increasingly sophisticated. For patients with cardiovascular disease, the best approach to bedside diagnosis would be one that combines both physical examination and ready access to technology at the time of the patient encounter. Most cardiac testing is not performed at the bedside due to equipment size and time limitations for these tests. Small hand-carried echocardiographic devices are now available for rapid bedside examination. These devices compare well to full-featured systems when used in cardiology outpatient settings and in hospitalized patients who are not critically ill. Compared with physical examination by board certified cardiologists, these devices decrease diagnostic error. Early use of hand-carried echocardiographic devices after physical examination has been demonstrated to impact patient triage and treatment as well as uncover otherwise undetected cardiac disease. The degree of training required for responsible use of these devices is as yet unclear. However, organized training sessions have resulted in modest agreement with standard echocardiography and point-of-care echocardiography performed by expert echocardiographers. It is conceivable that the hand-carried echocardiographic devices will be used in medical school curriculum to enhance medical student education in the future.

Echocardiography↗
PubMed2003

Real-time three-dimensional echocardiography using a novel matrix array transducer.

Three-dimensional echocardiography has multiple advantages over two-dimensional echocardiography, such as accurate left ventricular quantification and improved spatial relationships. However, clinical use of three-dimensional echocardiography has been impeded by tedious and time-consuming methods for data acquisition and post-processing. A newly developed matrix array probe, which allows real-time three-dimensional imaging with instantaneous on-line volume-rendered reconstruction, direct manipulation of thresholding, and cut planes on the ultrasound unit may overcome the aforementioned limitations. This report will review current methods of three-dimensional data acquisition, emphasizing the real-time methods and clinical applications of the new matrix array probe.

Echocardiography, Three-Dimensional↗
PubMed2003

Use of contrast enhancement for the assessment of left ventricular function.

Endocardial visualization is essential for accurate interpretation of regional wall thickening abnormalities, which constitute the diagnostic hallmark of coronary artery disease, and for reproducible assessment of left ventricular (LV) ejection fraction. Unfortunately, in many cardiac patients, poor image quality does not allow consistent visualization, let alone automated detection, of the endocardial boundary in all segments throughout the cardiac cycle. Continuing efforts directed towards improving endocardial visualization made by both echocardiographic imaging equipment manufacturers and researchers have recently produced new objective, quantitative approaches for the assessment of global and regional LV function. Although these developments have not been integrated into routine clinical practice, they may have a positive impact on endocardial visualization and, thus, eventually improve the ability to accurately and objectively evaluate LV performance. In this review, we discuss some of the latest developments in the use of contrast for the evaluation of LV function.

Animals↗
PubMed2003

Interpretation of left ventricular wall motion during stress testing.

This article describes the obstacles to stress echocardiographic interpretation, and reviews the techniques currently available that offer a more objective approach to stress wall motion analysis than the conventional visual methodology. These techniques include Doppler-based methods, such as myocardial Doppler velocity and strain rate imaging, as well as automated border detection techniques, such as acoustic quantification and color kinesis.

Contrast Media↗
PubMed2003

Assessment of global and regional left ventricular diastolic function in hypertensive heart disease using automated border detection techniques.

Acoustic quantification (AQ) and color kinesis (CK) are techniques that involve automated detection and tracking of endocardial borders. These methods are useful for the evaluation of global and regional left ventricular (LV) systolic function and more recently have been applied to evaluating LV diastolic performance. Assessment of diastolic dysfunction in hypertensive heart disease is a relevant clinical issue in which these techniques have proven useful. The diastolic portion of left atrium and LV AQ area waveforms are frequently abnormal in patients with left ventricular hypertrophy (LVH). Left ventricular AQ curves consistently demonstrate reduced rapid filling fraction (RFF) and peak rapid filling rate (PRFR), elevated atrial filling fraction (AFF), peak atrial filling rate (PAFR), and reductions in the ratio PRFR/PAFR. Acoustic quantification complements traditional Doppler echocardiographic evaluation of global diastolic function. Many patients with significant LVH and normal Doppler diastolic parameters can be identified as having diastolic dysfunction with AQ. In addition, CK has allowed the evaluation of regional diastolic performance in hypertensive patients. Regional filling curves obtained from CK have demonstrated that endocardial diastolic motion is commonly delayed and heterogeneous in patients with LVH.

Diastole↗
PubMed2003

Accuracy of mitral valve area measurements using transthoracic rapid freehand 3-dimensional scanning: comparison with noninvasive and invasive methods.

OBJECTIVE: The feasibility and accuracy of direct transthoracic 3-dimensional (3D) mitral valve area (MVA) measurements obtained using freehand scanning was investigated in patients with mitral stenosis. METHODS: A total of 30 patients (26 women, 4 men; aged 55 +/- 13 years) underwent a 2-dimensional (2D) and Doppler study 1 hour before percutaneous balloon mitral valvuloplasty. Transthoracic freehand data were acquired using a magnetic receiver attached to a broadband transducer, gated to electrocardiography and respiration. Volumetric MVA measurements from the left ventricle and left atrium were obtained and compared with MVA measurements derived from 2D planimetry, pressure half-time, and proximal isovelocity surface area. Invasive Gorlin MVA measurements were the gold standard for comparison. RESULTS: In all, 29 patients (97%) had 3D data allowing MVA measurements. Direct 3D measurements from the left ventricle had the least bias (0.06 +/- 0.19 cm(2)) and tightest limits of agreement (-0.44 to 0.32) compared with left atrium measurements (0.17 +/- 0.25 cm(2) and -0.67 to 0.33, respectively). The proximal isovelocity surface area method (bias: 0.09 +/- 0.34 cm(2)) was the most accurate of all 2D methods followed by pressure half-time (0.17 +/- 0.36 cm(2)) and planimetry (0.21 +/- 0.29 cm(2)). CONCLUSION: Direct 3D MVA measurements from the left ventricle using transthoracic freehand scanning are more accurate than traditional 2D methods.

Adult↗
PubMed2003

Simultaneous real-time echocardiographic imaging of myocardial perfusion and regional function using color-encoded, contrast-enhanced power modulation.

We hypothesized that color-encoded, contrast-enhanced, power modulation imaging could allow simultaneous quantification of myocardial perfusion and regional left ventricular function. We studied 12 anesthetized, closed-chest pigs at baseline, during acute ischemia, and during reperfusion, and 8 patients after acute myocardial infarction. Color kinesis was used to color encode endocardial motion during real-time contrast perfusion imaging with high-energy ultrasound pulses. Wall motion was assessed by calculating regional fractional area changes. Translation-free perfusion analysis was performed in automatically identified myocardial regions of interest. Steady-state intensity and postimpulse rate of contrast replenishment were calculated. In all animals, ischemia caused reversible changes in the images and the perfusion- and function-calculated indices. A significant decrease in pixel intensity (14%) and contrast replenishment rate (66%) in left anterior descending coronary artery segments, in agreement with fluorescent microspheres measurements, coincided with a decrease in fractional area change (34%). For patients, respective perfusion and function indices were 61%, 51%, and 58% lower in segments where perfusion defects, regional wall-motion abnormalities, or both were noted in gray scale images. Color-encoded, contrast-enhanced power modulation allows simultaneous real-time imaging and quantitative analysis of myocardial perfusion and regional left ventricular function.

Animals↗
PubMed2003

Normal values of left ventricular systolic and diastolic function derived from signal-averaged acoustic quantification waveforms: a multicenter study.

Automated border-detection techniques such as acoustic quantification have proven accurate and useful for quantifying left ventricular (LV) function. We acquired LV acoustic quantification waveforms from the parasternal short-axis window in 140 healthy patients in the age range of 16 to 78 years. Signal-averaged waveforms were analyzed for parameters of systolic and diastolic performance. The average fractional area change was 54 +/- 12%, and there were no significant changes in LV systolic function in the age range studied. There were significant changes in diastolic parameters with aging. The percentage of contribution to total LV filling occurring during atrial filling nearly tripled during the 6 decades studied, from 13% in the youngest cohort to 36% in the eighth decade of life. This study provides normal reference values for systolic and diastolic parameters of LV function determined from signal-averaged acoustic quantification waveforms acquired from the parasternal short-axis view in adult and adolescent patients over a wide age range.

Adolescent↗
PubMed2003

Quantification of regional myocardial perfusion using semiautomated translation-free analysis of contrast-enhanced power modulation images.

Quantitative analysis of myocardial perfusion is currently based on manual tracing and frame-by-frame realignment of regions of interest. We developed a technique for semiautomated identification of myocardial regions from power modulation images as a potential tool for quantification of myocardial contrast enhancement. This approach was tested in 13 anesthetized pigs during continuous intravenous infusion of contrast at baseline, left anterior descending coronary artery occlusion, and reperfusion. Regional pixel intensity was calculated for each consecutive end-systolic frame after a high-energy ultrasound impulse, and fitted with an exponential function. Perfusion defects caused by occlusion of left anterior descending coronary artery were confirmed by a significant decrease in both postimpulse steady-state intensity and the initial rate of contrast replenishment (P <.05), which were reversed with reperfusion. Automated measurements of myocardial intensity correlated highly with conventional manual tracing (r = 0.90 to 0.97), and resulted in improved signal-to-noise ratios. This technique allows translation-free quantification of regional myocardial perfusion, without the need for manual tracing.

Algorithms↗
PubMed2003

Innovations in transesophageal echocardiographic imaging.

Over the last three decades, the continuing development of transesophageal echocardiography (TEE) has represented a major advance in our ability to visualize cardiovascular structures with ultrasound. TEE serves as a valuable complement to transthoracic echocardiography (TTE) by allowing: images to be obtained with less attenuation from structures such as the lung, muscle, bone, and soft tissue; high resolution visualization of structures not well seen by TTE, such as left atrial appendage, descending thoracic aorta, and prosthetic heart valves; and assessment of hemodynamics and flow disorders in greater detail. This article provides a brief overview of current as well as emerging clinical applications of transesophageal echocardiography.

Cardiovascular Diseases↗
PubMed2003

Expanding the differential diagnosis of hemoptysis: mycotic aortic aneurysms.

The differential diagnosis of hemoptysis includes a wide spectrum of infectious, autoimmune, and neoplastic diseases as well as chest trauma. The clinical presentation of a mycotic aortic aneurysm is often nonspecific, but mortality is high, especially after aneurysmal rupture. A high index of suspicion is warranted in any patient presenting with hemoptysis and a recent past history of subacute bacterial endocarditis, intravascular interventions, known aortic aneurysm, and/or immunocompromised state. A case report is presented of a patient with an ascending aortic mycotic aneurysm eroding into the adjacent lung, leading to chest pain, dyspnea, and hemoptysis. This case report provides an important lesson of the need to expand the differential

Aged↗
PubMed2002

The role of contrast enhancement in echocardiographic assessment of left ventricular function.

With or without contrast, echocardiographic evaluation of left ventricular (LV) function is qualitative, subjective, and experience dependent, because it is mostly based on visual interpretation of gray-scale 2-dimensional images or, at best, relies on tedious and time-consuming manual tracing of the endocardial boundaries. Adequate endocardial visualization is essential for accurate interpretation of regional wall thickening abnormalities, which constitute the diagnostic hallmark of coronary artery disease, and for reproducible assessment of LV ejection fraction. Studies performed in the last decade have estimated the number of patients with suboptimal endocardial delineation by fundamental imaging at 30%. These studies have highlighted the problem of variable image quality as a major limitation of transthoracic echocardiography because failure to adequately visualize a segment, either at rest or during stress, may compromise the ability of this technique to identify areas of dysfunctional myocardium. Several remedies based on different technologic and methodologic approaches have been tested over the years with variable success. In this review we discuss the most recent techniques that have had a positive impact on endocardial visualization, as well as the potential benefits of these approaches.

Contrast Media↗
PubMed2002

Objective assessment of left ventricular wall motion from contrast-enhanced power modulation images.

There is no method to objectively evaluate left ventricular (LV) function from contrast-enhanced images. We tested the feasibility of evaluating regional LV function by using power modulation imaging. In protocol 1, 9 anesthetized closed-chest pigs were studied. Images were obtained during contrast infusion at baseline, during LAD occlusion and reperfusion. In protocol 2, images were obtained in 20 patients (14 wall-motion abnormalities; 6 controls) during contrast enhancement. Off-line, frame-by-frame, semiautomated endocardial border detection was followed by color encoding of endocardial motion, followed by segmentation and calculation of regional fractional area changes. In all animals, coronary occlusions resulted in hypokinesis and decreased fractional area changes in LAD-related segments only, which were reversed during reperfusion. In patients, wall-motion analysis was in agreement with an expert reader of dynamic images in 92.5% segments, with interobserver variability of 12.5%. Color encoding of endocardial motion from contrast-enhanced power modulation images allows accurate quantitative assessment of regional LV function.

Aged↗
PubMed2002

Papillary fibroelastoma of the aortic valve.

We hereby report the case of a patient with a papillary fibroelastoma involving the right coronary cusp of the aortic valve that was diagnosed with the use of transesophageal echocardiography after workup for recurrent transient ischemic attacks.

Aortic Valve↗