How does computer-assisted digital wall motion analysis influence observer agreement and diagnostic accuracy during stress echocardiography?

This study assessed interobserver and intraobserver variation and diagnostic accuracy during 25 dipyridamole stress echocardiography tests interpreted with different analysis systems: a) computer display of high frame rate digital cineloops (47 frames/s); b) computer display of lower frame rate digital cineloops (24 frames/s); and c) videotape recordings. The majority of the patients (84%) had documented coronary artery disease with baseline wall motion anormalities due to previous myocardial infarctions and/or coronary bypass surgery, thus comprising a population with difficult interpretation of stress echocardiography. Diagnostic accuracy was assessed using coronary angiography as reference method. Interobserver and intraobserver agreement was highest when analysis was performed from computer-displayed cineloops, 96 and 92%, respectively, compared to 84 and 80% respectively, using videotape recordings. Sensitivity for identification of coronary artery stenosis was similar using digital cineloops with high frame rate or videotape recordings (67% to 80% for both systems), and tended to be lower using cineloops with lower frame rate for analysis (53%). Inter- and intraobserver differences for wall motion score index were not significantly influenced by the analysis system. We conclude that computer assisted analysis with high frame rate of the displayed cineloops provides optimal observer agreement and diagnostic accuracy in the same range as videotape analysis in patients undergoing stress echocardiography.     

Dobutamine echocardiography: usefulness of digital image processing

The present study was undertaken in order specifically to evaluatethe usefulness of digital image processing so as to enhancethe diagnostic power of dobutamine stress echocardiography.For this purpose 44 dobutamine echocardio-graphic tests, routinelyperformed in our echo laboratory, were analysed blindly by twoobservers using traditional videotape recording and digitizedimage acquisition. The results obtained from both observers show a trend whichsuggests that the traditional videotape approach provides moretrue-positive tests than the digitized approach (27138 vs 23138and 24138 vs 22138 for the first and second observer, respectively).True-negative test detection was 6/6 with the videotape and5/6 with the digitized method for both observers. As a consequenceof the discrepancies observed between the two modalities, thevideotape indicates that it can provide higher diagnostic accuracythan the digitized approach (72 ± 9% vs 63 ± 10%).The tests results concordance (positive or negative) betweenthe two modalities of analysis was 66% for both the observers.The inter-observer agreement on the test results was 84% and80% for the videotape analysis and the digitized analysis, respectively. On the basis of the results, we consider that digitized analysisapplied to dobutamine stress echocardiography does not affordsignificant diagnostic advantages and should not be consideredas an alternative option to traditional videotape analysis.However, it may be considered an extremely useful integrativetool since it produces the on-line image evaluation more easilyand faster and allows a more practical form of stress test storage.     

Editorial note Intravenous amiodarone — a saviour?

In conclusion, the data shows that in excellent quality studies such as those obtained in vitro, 3D echocardiography is as accurate in describing the volume of the left ventricle as is angiography. When excellent quality images are obtained, the endocardial wall motion, wall thickening and thinning are better described. This, in addition to echocardiography's promise of visualizing coronary perfusion regions using contrast agents and of detecting ultrasound tissue signatures of diseased myocardium give 3D echocardiography a very bright potential in research. Since ACCURACY is of utmost importance in defining the extent of wall motion defects for evaluation of therapeutic interventions, 3D reconstruction in the short term can only be beneficial in those patients who have excellent quality studies. In the evaluation of patients with valvular disease where changes in absolute volume may herald deterioration before change in ejection fraction, 3D echocardiography may find a more immediate role. In this situation, although there is still a degree of variability, predicted volumes are as good as those predicted from any other technique.     

4D fetal echocardiography—An update

With the introduction of the electronic 4‐dimensional and spatial‐temporal image Correlation (e‐STIC), it is now possible to obtain large volume datasets of the fetal heart that are virtually free of artifact. This allows the examiner to use a number of imaging modalities when recording the volumes that include two‐dimensional real time, power and color Doppler, and B‐flow images. Once the volumes are obtained, manipulation of the volume dataset allows the examiner to recreate views of the fetal heart that enable examination of cardiac anatomy. The value of this technology is that a volume of the fetal heart can be obtained, irrespective of the position of the fetus in utero, and manipulated to render images for interpretation and diagnosis. This article presents a summary of the various imaging techniques and provides clinical examples of its application used for prenatal diagnosis of congenital heart defects and abnormal cardiac function.     

Transvascular and intracardiac two-dimensional echocardiography

Recent developments in transesophageal and catheter-based ultrasound instrumentation have allowed invasive ultrasound imaging. This experimental study presents a new application of invasive ultrasound, transvascular and intracardiac ultrasound imaging. In six pigs, we introduced a 7-mm, 5-MHz esophageal ultrasound probe into both the abdominal aorta and inferior vena cava and explored the imaging potential of this approach. Transvascular imaging from the aorta allowed visualization of the various cardiac structures, the neural canal and interspaces, and peritoneal anatomy. Advancement of the transducer to the level of the aortic valve or into the left ventricle yielded images of the cardiac valves and chambers. With transvascular imaging from the inferior and superior vena cava, the aorta, neural canal, pancreas, and liver were well visualized. Intracardiac imaging from the inferior venae cavae and various regions of the right heart, the left heart structures could be visualized. This in vivo feasibility study demonstrates the potential application of transducer-tipped catheters for transvascular and intracardiac imaging.     

Current status of stress echocardiography

Stress echocardiography is a widely applied technique for the evaluation of individuals with known or suspected coronary artery disease. The technique combines echocardiographic imaging with exercise testing or pharmacologic stress. Advances in digital image acquisition and harmonic imaging have substantially improved the quality of echocardiographic images, and have therefore increased general applicability of stress echocardiography.     

Expecting the unexpected: Echo laboratory preparedness in the time of COVID-19

COVID-19 poses a unique set of challenges to the healthcare system due to its rapid spread, intensive resource utilization, and relatively high morbidity and mortality. Healthcare workers are at especially high risk of exposure given the viruses spread through close contact. Reported cardiac complications of COVID-19 include myocarditis, acute coronary syndrome, cardiomyopathy, pericardial effusion, arrhythmia, and shock. Thus, echocardiography is integral in the timely diagnosis and clinical management of COVID-19 patients. Rush University Medical Center has been at the forefront of the COVID-19 response in Illinois with high numbers of cases reported in Chicago and surrounding areas. The echocardiography laboratory at Rush University Medical Center (RUMC) proactively took numerous steps to balance the imaging needs of a busy, nearly 700-bed academic medical center while maintaining safety.     

Simulation‐based training in echocardiography

The knowledge gained from echocardiography is paramount for the clinician in diagnosing, interpreting, and treating various forms of disease. While cardiologists traditionally have undergone training in this imaging modality during their fellowship, many other specialties are beginning to show interest as well, including intensive care, anesthesia, and primary care trainees, in both transesophageal and transthoracic echocardiography. Advances in technology have led to the development of simulation programs accessible to trainees to help gain proficiency in the nuances of obtaining quality images, in a low stress, pressure free environment, often with a functioning ultrasound probe and mannequin that can mimic many of the pathologies seen in living patients. Although there are various training simulation programs each with their own benefits and drawbacks, it is clear that these programs are a powerful tool in educating the trainee and likely will lead to improved patient outcomes.     

Real-time intracardiac two-dimensional echocardiography: an experimental study of in vivo feasibility, imaging planes, and echocardiographic anatomy

The traditional transthoracic and transesophageal echocardiographic examination have proven to be useful imaging tools for studying cardiac morphology, pathology, and function. Recently, catheter-based ultrasound transducers have been available for intravascular ultrasonic imaging. We supposed that echocardiographic examination performed from within the heart itself can provide useful information about cardiac structure and function, especially in settings where transthoracic or transesophageal echocardiography may be technically difficult to perform or poorly tolerated by the patient. To explore this concept, we performed intracardiac echocardiography in vivo in 22 dogs using both 5-MHz and 20-MHz transducers. High-quality images were obtained in all animals. Using the higher frequency transducer, detailed images with only a limited depth of field were obtained. With the 5-MHz transducer, a comprehensive cardiac examination was feasible from within the right atrium and inferior vena cava. We were able to visualize the great vessels, all cardiac valves, and cardiac chambers in a multitude of imaging planes. Alterations in ventricular function were instantly recognized. Color Doppler capabilities allowed visualization of flow abnormalities as well. We conclude that intracardiac echocardiography is feasible and could be potentially useful in certain clinical situations. With further research and development, this technique may have an important clinical impact in cardiac therapy and diagnosis.     

Use of echocardiography as an essential tool for targeted transcatheter biopsy of cardiac masses

Echocardiography has emerged as an essential tool to guide targeted, transcatheter biopsy of cardiac masses. Options for imaging include transthoracic or transesophageal echocardiography and intracardiac echocardiography, with appropriate use being dictated by specific patient characteristics and institutional experience. The authors present a case of three‐dimensional (3‐D) transesophageal echocardiography‐guided transcatheter biopsy of a right ventricular mass and review the current use of echocardiography to guide these procedures.     

An intensive interactive course for 3D echocardiography: is 'crop till you drop' an effective learning strategy?

BACKGROUND: Three-dimensional echocardiography (3DE) appears to show incremental benefit over two-dimensional echocardiography (2DE), but it's uptake has been slow. We tested attendees before and after an intensive interactive training course to identify its efficacy. METHODS: Attendees (n = 35, 23 cardiologists, 12 sonographers) were shown how to use 3DE review software and asked to identify the pathology of five patients (wall motion abnormality, peri-prosthetic mitral regurgitation, subaortic membrane, small ventricular septal defect, submitral stenosis) on 2D and 3D images. In the following one and a half-day interactive teaching course, brief presentations on application of 3DE for assessment of wall motion, valve and congenital abnormalities were followed by review of 3D datasets, during which the attendees made their own interpretations before being shown the optimal viewing strategy. Test cases were not discussed and the test was repeated at the end of the course. RESULTS: Most attendees (57%) had access but with little or no use of a 3DE system. Three-dimensional echocardiography had no incremental value before training. After training, overall correct responses significantly improved compared with baseline interpretation, although improvement was not the same for all diagnoses. All groups (cardiologists vs. sonographers, inexperienced vs. moderately experienced reviewers) improved similarly. CONCLUSIONS: Incorporation of 3DE into standard practice may be limited by inexperience. An interactive teaching course with rehearsal and direct mentoring appears to overcome this limitation and may improve the uptake of this technique.     

Comparison of left atrial dimensions by transesophageal and transthoracic echocardiography

Transesophageal echocardiography (TEE) is an established cardiovascular diagnostic technique. Left atrial (LA) size, as measured by transthoracic echocardiography (TTE), is associated with cardiovascular disease and is a risk factor for atrial fibrillation, stroke, death, and the success of cardioversion. Assessment of LA size has not been as well validated on TEE as on TTE. We determined LA size measurements in four standard views in 122 patients undergoing TEE and TTE at the same setting. In this study, we found that measurement of LA dimensions by TEE suffers from significant limitations in all views except the basal long-axis view (mid-esophageal level) with transducer plane at 120-150 degrees. This view had the best correlation with transthoracic LA measurements: r = 0.79 for TEE long axis (CI 0.71-0.85), P <.0001.     

Impaired left ventricular rapid filling during exercise in patients with hypertrophic cardiomyopathy

The influence of exercise on left ventricular diastolic filling was evaluated in 14 patients with hypertrophic cardiomyopathy (HCM) and 14 normal controls (NC) by dynamic exercise echocardiography. Using X-Y digitizer and computer, normalized peak rate of change of the left ventricular dimension during systole (pVs) and the rapid filling phase (pVd) were determined from the left ventricular echocardiograms at rest and during exercise when heart rate reached 100 beats/min. At rest and during exercise, pVs was significantly higher in HCM (3.2 +/- 0.4/s at rest, 4.3 +/- 1.4/s during exercise) than in NC (2.4 +/- 0.5/s at rest, 3.0 +/- 0.4s during exercise) (p less than 0.001, p less than 0.001, respectively), but pVd in HCM (4.2 +/- 1.0/s at rest, 5.8 +/- 1.0/s during exercise) was not significantly different from that in NC (4.1 +/- 1.0/s at rest, 6.0 +/- 0.7/s during exercise). The ratio of pVd to pVs (pVd/pVs) in HCM did not show significant increment during exercise (1.35 +/- 0.38 to 1.43 +/- 0.35), though that ratio in NC was significantly increased by exercise (1.67 +/- 0.22/s to 1.97 +/- 0.19/s, p less than 0.001). There was no correlation between pVd and the degree of left ventricular hypertrophy. These results suggest that diastolic reserve to exercise is depressed in HCM and that other factors besides left ventricular hypertrophy may account for diastolic abnormality.     

Multiplane/3D transesophageal echocardiography monitoring to improve the safety and outcome of complex transvenous lead extractions

Both transesophageal echocardiography (TEE) and intracardiac echocardiography have been used to assist transvenous lead extractions. The clinical utility of continuous echocardiographic monitoring during the procedure is still debated, with different reports supporting opposite findings. In cases where the procedure is expected to be difficult, we propose adding a continuous TEE monitoring using a static 3D/multiplane probe in mid‐esophageal position, with digital remote manipulation of the field of view. This approach may improve the chances of a successful extraction, increase safety, or even guide the entire intervention. We present here a short case series where continuous monitoring by TEE played an important role.     

Three-dimensional color Doppler transpharyngeal echocardiographic reconstruction of the left common,internal, and external carotid arteries

To our knowledge, we report the first cases of successful three-dimensional reconstruction of the left common, internal, and external carotid arteries using color Doppler transpharyngeal echocardiography.     

Can Hospital Rounds With Pocket Ultrasound By Cardiologists Reduce Standard Echocardiography?

Background

Frequently, hospitalized patients are referred for transthoracic echocardiograms. The availability of a pocket mobile echocardiography device that can be incorporated on bedside rounds by cardiologists may be a useful and frugal alternative.

Methods

This was a cross-sectional study designed to compare the accuracy of pocket mobile echocardiography images with those acquired by transthoracic echocardiography in a sample of hospitalized patients. Each patient referred for echocardiography underwent pocket mobile echocardiography acquisition and interpretation by a senior cardiology fellow with level II training in echocardiography. Subsequently, transthoracic echocardiography was performed by skilled ultrasonographers and interpreted by experienced echocardiographers. Both groups were blinded to the results of the alternative imaging modality. Visualizability and accuracy for all key echocardiographic parameters (ejection fraction, wall motion abnormalities, left ventricular end-diastolic dimension, inferior vena cava size, aortic and mitral valve pathology, and pericardial effusion) were determined and compared between imaging modalities.

Results

A total of 240 hospitalized patients underwent echocardiography with pocket mobile echocardiography and transthoracic echocardiography. The mean age was 71 ± 17 years. Pocket mobile echocardiography imaging time was 6.3 ± 1.5 minutes. Sensitivity of pocket mobile echocardiography varied by parameter and was highest for aortic stenosis (97%) and lowest for aortic insufficiency (76%). Specificity also varied by parameter and was highest for mitral regurgitation (100%) and lowest for left ventricular ejection fraction (92%). Equivalence testing revealed the pocket mobile echocardiography outcomes to be significantly equivalent to the transthoracic echocardiography outcomes with no discernible differences in image quality between pocket mobile echocardiography and transthoracic echocardiography (P = 7.22 × 10⁻⁷). All outcomes remain significant after correcting for multiple testing using the false discovery rate.

Conclusions

The results from rapid bedside pocket mobile echocardiography examinations performed by experienced cardiology fellows compared favorably with those from formal transthoracic echocardiography studies. For hospitalized patients, this finding could shift the burden of performing and interpreting the echocardiogram to the examining physician and reduce the number and cost associated with formal echocardiography studies.     

Biplane transesophageal echocardiography utilizing transverse and sagittal imaging planes: technique, echo-anatomic correlations, and display approaches

The recent development of biplane transesophageal probes equipped with both transverse plane and sagittal plane imaging transducers allows a more complete examination of cardiac and aortic anatomy than is possible with conventional single plane transesophageal instruments. While the imaging planes used in transverse plane transesophageal imaging have been standardized, several different approaches have been suggested for the orientation and display of the newer sagittal plane images. An accepted display convention for the transverse and sagittal plane images would ease interpretation of the multiple complex images obtained during the biplane transesophageal examination. In this article, the different transverse plane and sagittal plane echocardiographic images that may be acquired during the biplane transesophageal examination are described and correlated with cardiac anatomy. A method for image display orientation is suggested that is most consistent with that previously used for the single plane transesophageal examination.