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Roberto M Lang

Publications and source records attributed to Roberto M Lang.

At least 19 recordsLinked to original sources
PubMed2006

Three-dimensional echocardiography: the benefits of the additional dimension.

Over the past 3 decades, echocardiography has become a major diagnostic tool in the arsenal of clinical cardiology for real-time imaging of cardiac dynamics. More and more, cardiologists' decisions are based on images created from ultrasound wave reflections. From the time ultrasound imaging technology provided the first insight into the human heart, our diagnostic capabilities have increased exponentially as a result of our growing knowledge and developing technology. One of the most significant developments of the last decades was the introduction of 3-dimensional (3D) imaging and its evolution from slow and labor-intense off-line reconstruction to real-time volumetric imaging. While continuing its meteoric rise instigated by constant technological refinements and continuing increase in computing power, this tool is guaranteed to be integrated in routine clinical practice. The major proven advantage of this technique is the improvement in the accuracy of the echocardiographic evaluation of cardiac chamber volumes, which is achieved by eliminating the need for geometric modeling and the errors caused by foreshortened views. Another benefit of 3D imaging is the realistic and unique comprehensive views of cardiac valves and congenital abnormalities. In addition, 3D imaging is extremely useful in the intraoperative and postoperative settings because it allows immediate feedback on the effectiveness of surgical interventions. In this article, we review the published reports that have provided the scientific basis for the clinical use of 3D ultrasound imaging of the heart and discuss its potential future applications.

Catheter Ablation↗
PubMed2006

Volumetric analysis of regional left ventricular function with real-time three-dimensional echocardiography: validation by magnetic resonance and clinical utility testing.

BACKGROUND: Quantitative information on regional left ventricular volumes from real-time three-dimensional echocardiographic (RT3DE) images has significant clinical potential but needs validation. AIM: To validate these measurements against cardiac magnetic resonance (CMR) and test the feasibility of automated detection of regional wall motion (RWM) abnormalities from RT3DE data. METHODS: RT3DE (Philips) and CMR (Siemens) images were obtained from 31 patients and analysed by using prototype software to semiautomatically calculate indices of regional left ventricular function, which were compared between RT3DE and CMR (linear regression, Bland-Altman). Additionally, CMR images were reviewed by an expert, whose RWM grades were used as a reference for automated classification of segments as normal or abnormal from RT3DE and from CMR images. For each modality, normal regional ejection fraction (REF) values were obtained from 15 patients with normal wall motion. In the remaining 16 patients, REFs were compared with thresholds that were derived from patients with normal wall motion and optimised using receiver operating characteristic analysis. RESULTS: RT3DE measurements resulted in good agreement with CMR. Regional indices calculated in patients with normal wall motion varied between segments, but overall were similar between modalities. In patients with abnormal wall motion, RWM was graded as abnormal in 74% segments. CMR and RT3DE thresholds were similar (16-segment average 55 (10)% and 56 (7)%, respectively). Automated interpretation resulted in good agreement with expert interpretation, similar for CMR and RT3DE (sensitivity 0.85, 0.84; specificity 0.81, 0.78; accuracy 0.84, 0.84, respectively). CONCLUSION: Analysis of RT3DE data provides accurate quantification of regional left ventricular function and allows semiautomated detection of RWM abnormalities, which is as accurate as the same algorithm applied to CMR images.

Algorithms↗
PubMed2006

Quantitative assessment of left ventricular size and function: side-by-side comparison of real-time three-dimensional echocardiography and computed tomography with magnetic resonance reference.

BACKGROUND: Cardiac CT (CCT) and real-time 3D echocardiography (RT3DE) are being used increasingly in clinical cardiology. CCT offers superb spatial and contrast resolution, resulting in excellent endocardial definition. RT3DE has the advantages of low cost, portability, and live 3D imaging without offline reconstruction. We sought to compare both CCT and RT3DE measurements of left ventricular size and function with the standard reference technique, cardiac MR (CMR). METHODS AND RESULTS: In 31 patients, RT3DE data sets (Philips 7500) and long-axis CMR (Siemens, 1.5 T) and CCT (Toshiba, 16-slice MDCT) images were obtained on the same day without beta-blockers. All images were analyzed to obtain end-systolic and end-diastolic volumes and ejection fractions using the same rotational analysis to eliminate possible analysis-related differences. Intertechnique agreement was tested through linear regression and Bland-Altman analyses. Repeated measurements were performed to determine intraobserver and interobserver variability. Both CCT and RT3DE measurements resulted in high correlation (r2 > 0.85) compared with CMR. However, CCT significantly overestimated end-diastolic and end-systolic volumes (26 and 19 mL; P < 0.05), resulting in a small but significant bias in ejection fraction (-2.8%). RT3DE underestimated end-diastolic and end-systolic volumes only slightly (5 and 6 mL), with no significant bias in EF (0.3%; P = 0.68). The limits of agreement with CMR were comparable for the 2 techniques. The variability in the CCT measurements was roughly half of that in either RT3DE or CMR values. CONCLUSIONS: CCT provides highly reproducible measurements of left ventricular volumes, which are significantly larger than CMR values. RT3DE measurements compared more favorably with the CMR reference, albeit with higher variability.

Aged↗
PubMed2006

Recommendations for chamber quantification.

Quantification of cardiac chamber size, ventricular mass and function ranks among the most clinically important and most frequently requested tasks of echocardiography. Over the last decades, echocardiographic methods and techniques have improved and expanded dramatically, due to the introduction of higher frequency transducers, harmonic imaging, fully digital machines, left-sided contrast agents, and other technological advancements. Furthermore, echocardiography due to its portability and versatility is now used in emergency rooms, operating rooms, and intensive care units. Standardization of measurements in echocardiography has been inconsistent and less successful, compared to other imaging techniques and consequently, echocardiographic measurements are sometimes perceived as less reliable. Therefore, the American Society of Echocardiography, working together with the European Association of Echocardiography, a branch of the European Society of Cardiology, has critically reviewed the literature and updated the recommendations for quantifying cardiac chambers using echocardiography. This document reviews the technical aspects on how to perform quantitative chamber measurements of morphology and function, which is a component of every complete echocardiographic examination.

Cardiac Volume↗
PubMed2006

Clinical utility of contrast-enhanced echocardiography.

Over the past three decades, echocardiography has become a major diagnostic tool in the arsenal of clinical cardiology for real-time imaging of cardiac dynamics. More and more, cardiologists' decisions are based on images created from ultrasound wave reflections. From the time ultrasound imaging technology provided the first insight into a human heart, our diagnostic capabilities have increased exponentially as a result of our growing knowledge and developing technologies. One of the most intriguing developments that brought about a decade-long combination of expectations and disappointments was the introduction of echocardiographic contrast agents. Despite repeated waves of controversy regarding the readiness of this technology for clinical use, it has overcome multiple hurdles and currently provides useful clinical information that helps cardiologists to diagnose heart disease accurately. Since the initial reports on the use of ultrasound contrast media such as agitated saline or renografin, the major advances in the field of contrast echocardiography have included (1) the development of stable perfluorocarbon-filled microbubbles, frequently referred to as second-generation contrast agents; and (2) the development of contrast-targeted nonlinear imaging modes, such as harmonic imaging, pulse inversion, and power modulation, which allow consistent real-time visualization of these agents. These contrast agents in conjunction with the new imaging technology constitute powerful tools that improve our ability to evaluate left ventricular function and myocardial perfusion, and allow differential diagnosis of thrombi and intravascular masses. In this manuscript, we briefly review some of the literature that has provided the scientific basis for the use of echocardiographic contrast agents in the context of these important variables.

Contrast Media↗
PubMed2006

Color encoding of endocardial motion improves the interpretation of contrast-enhanced echocardiographic stress tests by less-experienced readers.

BACKGROUND: We hypothesized that color encoding of endocardial motion could aid less-experienced readers in detection of wall-motion abnormalities at rest and stress in patients with poor acoustic windows. METHODS: Color-encoded images (color kinesis) were obtained at rest and peak dobutamine stress in 4 standard views during intravenous infusion of contrast agent in 117 patients with poorly visualized endocardium. In 101 of 117 patients (86%), in whom contrast enhancement allowed endocardial tracking, images were reviewed by two expert readers without color overlays. Each reader graded regional wall motion as normal, abnormal, or uninterpretable, and their consensus grades served as a gold standard. The same images were then reviewed and graded with and without color overlays by 3 cardiology fellows. The accuracy of the interpretation was calculated against the gold standard separately for the 3 vascular territories (left anterior descending, left circumflex, and right coronary arteries) and averaged for the 3 fellows. RESULTS: With the addition of color encoding: (1) the number of uninterpretable segments decreased by 55% at rest and 61% at peak stress; and (2) all 3 fellows reached higher levels of accuracy in all 3 vascular territories both at rest (6%-82% average) and at stress (73%-80%). CONCLUSION: The addition of color encoding of wall motion to contrast-enhanced images obtained in patients with poor acoustic windows during stress tests improves the interpretation of regional left ventricular function by less-experienced readers.

Dobutamine↗
PubMed2006

Comparison of contrast-enhanced real-time live 3-dimensional dobutamine stress echocardiography with contrast 2-dimensional echocardiography for detecting stress-induced wall-motion abnormalities.

BACKGROUND: Two-dimensional (2D) contrast-enhanced dobutamine stress echocardiography (DSE) is used clinically to diagnose stress-induced wall-motion abnormality (WMA). We hypothesized that contrast-enhanced real-time 3-dimensional (3D) DSE could improve the detection rate of WMA, because from a single full-volume acquisition, multiple segments can be visualized. METHODS: We acquired both 2D and 3D DSE in 78 patients with known or suggested coronary artery disease (mean age: 65 years; 44 men). Dobutamine was infused using a standard protocol, and atropine added, if required. For 2D DSE, the intravenous contrast agent was injected at each stage and images displayed in a quadscreen format. For 3D DSE, contrast harmonic 3D data sets (full volumes) were acquired at baseline and peak stress. Using custom software, 3 short-axis views (from apex to base) were created, and wall motion scored using a wall-motion score index using a 16-segment model. A positive stress test was defined as new or worsened WMA or fixed abnormality during stress. RESULTS: Heart rate increased from 72 +/- 13 to 133 +/- 15/min (86 +/- 11% of age-predicted). A total of 1248 segments were analyzed at each stage for both modalities. A single segment at baseline and 5 segments at peak stress could not be assessed with contrast 2D DSE. In contrast, 88 segments at baseline and 39 segments at peak stress could not be assessed with contrast 3D DSE. With 3D DSE, the majority of uninterpretable segments were in the anterior and lateral walls. Significant correlations were noted between wall-motion score index by 2D and 3D DSE at baseline (r = 0.78) and peak stress (r = 0.83). The concordance rate (positive/negative findings) between modalities was 69% (54/78) on a patient basis and 88% (206/234) on a perfusion territory basis. When using 2D DSE results as the gold standard, sensitivity and specificity for detecting WMA by 3D DSE was 58% and 75%, respectively. Sensitivity and specificity values were 67% and 94% for the right coronary artery, 53% and 81% for the left anterior descending coronary artery, and 88% and 100% for the left circumflex coronary artery territory, respectively. CONCLUSION: Contrast-enhanced 3D DSE was feasible in the majority of patients. However, the moderate concordance between both modalities was a result of: (1) difficulties in visualizing the anterolateral segments because of the relatively large imprint of the transducer; and (2) lower frame rates with 3D DSE resulting in the erroneous diagnosis of dyssynchrony.

Aged↗
PubMed2006

Three-dimensional transthoracic echocardiography to evaluate cor triatriatum in the adult.

Cor triatriatum is a rare congenital condition in which the left atrium is partitioned into two chambers by a fibrous or fibromuscular septum. The diagnosis is often made early in childhood, but can rarely be discovered later in adulthood. This delay in diagnosis is likely because of the number and size of the fenestrations in the septum. Echocardiography is the modality most often used to diagnose cor triatriatum. Generally, transesophageal echocardiography (TEE) is superior to transthoracic imaging. Three-dimensional echocardiography, however, is a modality that offers additional information not offered by 2-dimensional echocardiography. Although 3-dimensional TEE has previously been described, we report what we believe to be the first case of 3-dimensional transthoracic echocardiography used to diagnose cor triatriatum. This modality offers an advantage over TEE, as it allows the septum to be viewed easily without the risks or inconvenience of TEE.

Aged↗
PubMed2006

Use of real-time 3-dimensional transthoracic echocardiography in the evaluation of mitral valve disease.

Three-dimensional (3D) echocardiography (3DE) provides unique orientations of the mitral valve (MV) not obtainable by routine 2-dimensional echocardiography. However, this modality has not been adopted in routine clinical practice because of its cumbersome and time-consuming process. The recent introduction of a full matrix-array transducer has enabled online real-time 3DE (RT3DE) and rendering. This study was designed to: (1) determine the clinical use of RT3DE in patients with MV pathology and in a control group selected for their good acoustic windows (protocol I); and (2) to investigate the feasibility of imaging the MV apparatus in a large group of consecutively imaged patients to determine the acoustic window or perspective from which the MV leaflets, commissures, and orifice are best visualized (protocol II). In protocol I, 65 patients were selected based on MV pathology and good 2-dimensional echocardiography image quality. Protocol II included 150 patients who were consecutively imaged using RT3DE. Images were viewed online (protocol I) and offline on a digital review station (protocol II). RT3DE visualization of the MV apparatus was graded based on the percentage of leaflet dropout and definition. In protocol I, 78% of patients had adequate 3D MV reconstructions with complete visualization of the anterior mitral leaflet (AML) in 84% versus the posterior mitral leaflet (PML) in 77%. The mitral leaflets, commissures, and MV orifice were well seen in 98%; however, the submitral apparatus was only observed in 76% of the patients. RT3DE: (1) correctly identified the prolapsed/flailed scallop in 6 of 8 patients; (2) obtained en face orientation of the MV orifice in 9 of 11 patients with mitral stenosis, allowing accurate measurements of the orifice area and evaluation of the immediate effects of balloon mitral valvuloplasty; and (3) allowed postoperative evaluation of MV repair and the integrity of the struts of a bioprosthetic leaflet. In protocol II, 70% of patients had adequate RT3DE with complete visualization of the AML noted in 55% versus 51% for PML. The mitral leaflets, commissures, and MV orifice were observed in 69%. Irrespective of acquisition window, the AML was best seen from a ventricular perspective. In contrast, the PML was optimally examined from a parasternal window. Both the medial and lateral commissures were equally assessed from either imaging window. In conclusion, RT3DE of the MV is feasible in a large majority of patients. Using different MV acquisitions RT3DE provides important clinical information such as: (1) identification of a prolapsed/flail scallop; (2) measurement of stenotic valve areas; (3) evaluation of MV leaflet integrity postrepair; and (4) identification of a MV perforation. In general the AML is better visualized than the PML. The parasternal window is the optimal approach to visualize both AML and PMLs.

Computer Systems↗
PubMed2006

Effect of aging on twist-displacement loop by 2-dimensional speckle tracking imaging.

BACKGROUND: Newly developed 2-dimensional (2D) speckle tracking imaging provides simultaneous information on both cardiac rotation and radial displacement throughout the cardiac cycle, thus, providing the opportunity to noninvasively construct twist-displacement loops. The aim of this study was to examine the effect of aging on twist-displacement loops. METHODS: Basal and apical 2D left ventricular (LV) short-axis images with high frame rates were acquired in 59 asymptomatic healthy volunteers. Using commercially available software, LV rotation and radial displacement were obtained at each plane by 2D speckle tracking analysis. LV twist was defined as apical LV rotation relative to the base. To adjust intersubject differences in heart rate, the time sequence was normalized to the percentage of systolic and diastolic duration. Volunteers were divided into 3 groups according to age. RESULTS: Twist-displacement loops were characterized by a figure of 8 configuration. There was a linear relation between twist and displacement during systole (r = 0.97), with its slope being significantly larger in the older group compared with the young group. During early diastole, a substantial degree of untwisting developed despite a relatively small reversal of systolic radial displacement, resulting in a much steeper twist-displacement relationship observed in all groups. Subsequent diastolic expansion occurred with more gradual additional untwisting. CONCLUSION: We found that 2D speckle tracking imaging successfully provides twist-displacement loop, noninvasively. Aging affects the systolic component of the twist-displacement loop. The assessment of twist-displacement loop may be useful for evaluating LV function.

Adult↗
PubMed2006

Quantification of regional left ventricular wall motion from real-time 3-dimensional echocardiography in patients with poor acoustic windows: effects of contrast enhancement tested against cardiac magnetic resonance.

OBJECTIVE: Regional left ventricular function can be assessed by real-time 3-dimensional echocardiography (RT3DE) in patients with good image quality. Our goals were to: (1) test the feasibility of RT3DE quantification of regional wall motion (RWM) in patients with poor acoustic windows who require contrast for endocardial visualization; and (2) validate these measurements against cardiac magnetic resonance (CMR) reference. METHODS: RT3DE datasets and CMR images were obtained in 24 patients. In 16 of 24 patients with suboptimal endocardial definition, RT3DE imaging was repeated with intravenous contrast and triggering at end systole and end diastole. RT3DE datasets were analyzed using custom software designed to semiautomatically detect and segment the endocardial surface and calculate RWM values. CMR images were analyzed using commercial software to obtain reference values for RWM. RESULTS: In 8 of 24 patients with good endocardial definition, RT3DE values of RWM correlated well with CMR (r = 0.73) with a small bias (-1.0 mm). In the remaining 16 patients, analysis of nonenhanced RT3DE datasets yielded lower correlation with CMR (r = 0.61) and a slightly greater bias (-1.5 mm). The agreement with CMR improved significantly (r = 0.76, bias -1.1 mm) with contrast enhancement. CONCLUSIONS: The agreement between RT3DE and CMR values of RWM is directly related to RT3DE image quality. In patients with poor acoustic windows, dual-triggered contrast enhancement improves the accuracy of RWM quantification to a level similar to that noted in patients with good images without contrast.

Computer Systems↗
PubMed2006

Age-related changes in left ventricular twist assessed by two-dimensional speckle-tracking imaging.

The aim of this study was to determine the normal value of left ventricular (LV) twist, and to examine the effects of aging on LV twist by newly developed 2-dimensional ultrasound speckle-tracking imaging. We acquired basal and apical LV short-axis second harmonic images in 118 healthy volunteers. Using commercially available 2-dimensional strain software, time-domain speckle tracking was performed, and mean value of LV rotation obtained at each plane. LV twist was defined as apical rotation relative to the base. Adequate data were obtained in 113 volunteers. During systole, the LV performs a wringing motion with a counterclockwise rotation at the apex and a clockwise rotation at the base. The mean value of peak twist was 7.7 +/- 3.5 degrees. Immediately after end systole, rapid untwisting develops. Different LV twist profiles are noted according to age. Peak LV twist was significantly higher, and the rate of LV untwisting significantly reduced and delayed, with advancing age. LV twist can be measured noninvasively by 2-dimensional ultrasound speckle-tracking imaging. The observed reduced and delayed diastolic untwisting with aging may contribute toward the tendency of diastolic dysfunction. This novel method allows the detailed study of diastolic function in various cardiovascular diseases.

Adult↗
PubMed2006

Computerized evaluation of echocardiographic stress tests in patients with poorly visualized endocardium using analysis of color-encoded contrast-enhanced images.

AIMS: We hypothesized that real-time color encoding of contrast-enhanced images would allow objective detection of stress-induced wall motion abnormalities (WMA). METHODS: We studied 117 patients with poorly visualized endocardium undergoing dobutamine stress tests. Color-encoded images (Philips, color kinesis) were obtained at rest and peak stress in four standard views during i.v. infusion of Definity. Images were reviewed without color overlays by two expert readers, who graded regional wall motion as normal or abnormal. In 101/117 patients (86%), in whom contrast enhancement allowed endocardial tracking, regional fractional area changes were calculated from the color overlays, and thresholds for calling a stress-induced WMA were optimized in a randomly selected subgroup of 34 patients (ROC analysis) to achieve maximum agreement with expert grades. This computerized detection of stress-induced WMA was then tested prospectively in the remaining 67 patients, using the expert grades as a "gold standard". RESULTS: 20/67 patients had resting WMA and 13/67 patients developed WMA at peak stress. The automated technique detected stress-induced WMA in at least one vascular territory with a sensitivity, specificity and accuracy of 0.80, 0.65 and 0.69, while the level of agreement between the two experts was 0.62, 0.91 and 0.85, respectively. CONCLUSION: Analysis of color-encoded, contrast-enhanced images allows objective, accurate, automated detection of stress-induced WMA in patients with poor acoustic windows.

Cardiotonic Agents↗
PubMed2006

Overestimation of postischemic myocardial stunning on gated SPECT imaging: correlation with echocardiography.

BACKGROUND: Postischemic global and regional left ventricular (LV) dysfunction on stress-gated single photon emission computed tomography (SPECT) imaging is attributed widely to myocardial stunning. We sought to determine the specificity of gated SPECT for the detection of myocardial stunning after ischemic stress. METHODS AND RESULTS: Twenty-seven patients with an ischemic response to stress on dual-isotope exercise SPECT were enrolled prospectively. Transthoracic echocardiography was performed just before stress gated SPECT for assessment of regional wall motion and quantitative LV ejection fraction (LVEF). The 17 myocardial segments for each patient were scored for myocardial perfusion by stress gated SPECT, and regional wall motion by stress gated SPECT and echo. Of the 459 myocardial segments, 41% had perfusion defects, 15% had stress gated SPECT regional wall motion abnormality, 4.8% had poststress echo regional wall motion abnormality, and 3.9% had baseline regional wall motion abnormality. Overall, a stress gated SPECT regional wall motion abnormality had a sensitivity of 100% and a specificity of 89%. Among reversible perfusion defects of moderate severity or more, a stress gated SPECT regional wall motion abnormality had a specificity of 41% and a positive predictive value of 8%. Stress gated SPECT LVEF was similar to poststress echo LVEF for all patients, but significantly lower in patients with reversible perfusion defects of moderate severity or more. CONCLUSION: Post-stress gated SPECT imaging overestimates global and regional myocardial stunning. Caution should be exercised in interpreting poststress global or regional LV function on stress gated SPECT in scans with reversible ischemia.

Echocardiography↗
PubMed2006

Automated interpretation of regional left ventricular wall motion from cardiac magnetic resonance images.

UNLABELLED: Magnetic resonance (MR) diagnosis of regional left ventricular (LV) dysfunction relies on visual interpretation of cine images that suffers from wide inter-observer variability, especially when performed by readers not specifically trained in the assessment of LV wall motion. Quantitative analysis tools, though widely available, are rarely used because they provide large amounts of detailed information, the interpretation of which requires additional time-consuming processing. We tested the feasibility of fast automated interpretation of regional LV function using computer analysis of this wall motion information. METHODS: Dynamic, ECG-gated, steady-state free precession short-axis images were obtained in 6-10 slices in 28 subjects (10 normal volunteers; 18 patients). Images were reviewed by an expert cardiologist who provided "gold standard" grades (normal, abnormal) for regional wall motion and, independently, by four radiologists. Same images were then analyzed using custom software. Regional fractional area changes computed in normal volunteers were used to obtain the optimal segment- and slice-specific threshold values for automated classification of regional wall motion for each patient. The levels of agreement with the "gold standard" grades were compared between the radiologists and the automated interpretation. RESULTS: While the visual interpretation required 2-5 minute per patient, the automated interpretation required < 1 sec, after endocardial border detection was complete. The automated interpretation resulted in higher sensitivity, specificity, and accuracy (84%, 77%, 79%, respectively) than the radiologists' grades (80%, 76%, 77%, respectively) and eliminated the high interobserver variability. CONCLUSION: Once the endocardial boundaries are defined, computer analysis of the regional wall motion information allows accurate, fully automated, immediate, objective and experience-independent interpretation of regional LV function.

Automation↗