James B. Seward

Ebstein's Anomaly:

Ebsteins anomaly, a well‐recognized congenital cardiac abnormality, involves the tricuspid valve and underlying right ventricular myocardium. The two‐dimensional diagnosis and hemodynamic characterization of this anomaly are so confident that cardiac catheterization is no longer necessary in the majority of cases. The varied anatomical abnormalities are discussed and illustrated and compared with other anomalies that should be differentiated from Ebsteins. The most diagnostic feature is an excessive downward displacement of the septal leaflet of the tricuspid valve ≥ 8 mm/m2. More importantly, in order to understand the clinical impact of Ebsteins anomaly, it is important to perform a detailed anatomical and functional echocardiographic profile. Both timing and type of surgery (i.e., repair vs replacement) can be better predicted by this type of detailed noninvasive assessment. Intraoperative and serial follow‐up are a regular part of the overall role of echocardiography in the assessment of Ebsteins anomaly. A thorough echocardiographic evaluation of Ebsteins anomaly is the best means of determining a management course for an individual patient. (ECHOCARDIOGRAPHY, Volume 10, November 1993)

Pericardiocentesis Guided by Two‐Dimensional Echocardiography

Echodirected pericardiocentesis has become the method of choice for the initial treatment of clinically significant pericardial effusions since it was introduced into the regular practice at the Mayo Medical Center in April 1980. Between April 1980 and January 1, 1994, 610 consecutive two‐dimensional (2‐D) echodirected pericardiocenteses were performed at the Mayo Clinic. There have been no deaths in the series of consecutive cases. In the first 500 consecutive cases examined in detail, there were five serious complications and 18 nonthreatening complications. Echodirected pericardiocentesis is a safe, humane, and cost‐effective means of performing a pericardial tap. Excellent results have been obtained even with a large number of physician operators. This technique is well suited to the primary care setting. Physicians performing this procedure should be familiar with reading and performing 2‐D echocardiography. Qualified physicians can be trained, fairly easily, to perform echodirected pericardiocentesis.

Rapid three-dimensional myocardial contrast echocardiography: Volumetric quantitation of nonperfused myocardium after intravenous contrast administration

Current acquisition methods for quantitative three‐dimensional myocardial contrast echocardiography require long acquisition times and therefore require the invasive administration of deposit contrast agents administered intra‐arterially or into the left atrium. This study addressed the feasibility of obtaining accurate and precise quantitative volumetric measurements of nonperfused myocardium after an intravenous bolus of echocardiographic contrast agent using a rapid three‐dimensional myocardial contrast echocardiographic acquisition technique. An open‐chest pig model of acute left anterior descending coronary artery (LAD) occlusion was used. After LAD ligature, an intravenous bolus of contrast agent was given and images were obtained over a 12‐second period using a continuously rotating transducer placed at the apical position. There was no significant microbubble destruction during the rotational acquisition period as measured by differences in mean gray scale values of apical, mid, and basal myocardial regions between the first and last image frames of acquisition. Calculated volumes of nonperfused myocardium demonstrated significant agreement and correlation (mean difference ± SD =–0.30 ± 1.71 cm3; r = 0.89; P < 0.01; y = 1.06x – 1.08) with anatomic specimens. When expressed as percent of total LV volume being nonperfused, the mean difference ± SD was 2.1 ± 3.6%, r = 0.94, P < 0.01, and y = 1.33x – 4.08. We conclude that accurate and precise measurements of nonperfused myocardium after an acute LAD coronary artery occlusion can be obtained after the intravenous bolus administration of a contrast material when a rapid 12‐second acquisition with a continuously rotating transducer is used.

Myocardial contrast echocardiography: texture analysis for identification of nonperfused versus perfused myocardium.

This study examined texture analysis for objective identification of nonperfused myocardial segments in myocardial contrast echocardiographic (MCE) images. Short‐axis MCE images from six open chest pigs after coronary artery ligation were examined. Six of 26 features (low gray level run emphasis, high gray level run emphasis, sum mean, sum variance, coefficient of variance and diagonal variance) demonstrated a significant texture value difference (P < 0.01) between the nonperfused and perfused segments with minimal statistical distribution overlap between the two groups. This study demonstrates that texture features other than mean gray level can objectively distinguish nonperfused from perfused myocardium in MCE images and may thus augment the diagnostic accuracy of current analysis techniques.

Differentiation of Aortic Stenosis Jet From Mitral Regurgitation by Analysis of Continuous‐Wave Doppler Spectrum: Illustrative Cases

Noninvasive evaluation lacked sufficient hemodynamic information about the severity of aortic stenosis until the advent of continuouswave (CW) Doppler echocardiography. Measured Doppler maximal flow velocity can be converted to the pressure gradient with the use of the modified Bernoulli equation (pressure gradient = 4 X velocit

Absent Pulmonary Valve: Echocardiographic Features

): Published data have demonstrated an excellent correlation between gradients derived by CW Doppler echocardiography and by cardiac ~atheterization?-~ The evaluation of aortic stenosis by CW Doppler echocardiography is best done by using a nonimaging probe from multiple ultrasonic windows to record the maximum velocity jet caused by aortic valve stenosis. By using this technique, aortic velocity signals can be recorded and quantitated in nearly every ~ a t i e n t . ~ In some cases, however, confusion or misinterpretation may occur, especially in the apical position, if two highvelocity signals of mitral regurgitation and severe aortic stenosis coexist. Because both signals are systolic, move in the same direction from the same transducer position, and can be of similar magnitude, it is crucial that the two velocity jets be differentiated clearly. We present three patients in whom both mitral regurgitation and aortic stenosis velocity signals were recorded. Methods for

Differentiation of Intracardiac Tumors and Thrombi by Echocardiography Tissue Characterization: Comparison of an Artificial Neural Network and Human Observers

Congenital absence of the pulmonary valve, a rare anomaly, is characterized by absent or rudimentary pulmonary valve, often with annular stenosis, and aneurysmal dilatation of the pulmonary arteries. This defect is most commonly an accompaniment of tetralogy of Fallot but occasionally occurs alone. Four patients with this abnormality were examined by two‐dimensional echocardiography at the Mayo Clinic. Doppler echocardiography provided hemodynamic assessment of the magnitude of outflow obstruction and valve regurgitation. The two‐dimensional echocardio‐graphic and Doppler features of absent or rudimentary pulmonary valve provided diagnostic information sufficient to proceed directly to surgical correction.

Three-Dimensional Imaging Used for Virtual Dissection, Image Banking and Physical Replication of Anatomy and Physiology

The feasibility of classifying ultrasound images of intracardiac tumors and thrombi with a neural network‐based algorithm was compared with the performance of experienced echocardiographers. The neural network used statistical descriptors of the apparent echocardiographic texture of the masses, and the blinded echocardiographers were given photographic prints of enlarged regions of interest without clinical data. The network classified 66% of the images correctly and the echocardiographers, 83%. The network and echocardiographers agreed in 88% of the images. Human observers usually base their classification of intracardiac masses on clinical data. The echocardiographic texture of tumors is quantitatively different from that of thrombi. This difference can be recognized by a neural network and potentially be useful in assisting with the diagnosis when clinical clues are insufficient.

Reference Techniques for Left Ventricular Volume Measurement by Three‐Dimensional Echocardiography: Determination of Precision, Accuracy, and Feasibility

Historically, techniques of dissection have been used to aid in our understanding of human anatomy, physiology, and pathology. However, these techniques alter the structures and fine details being studied. New advances in computer technology, imaging equipment, data acquisition, processing, storage, and display now allow multidimensional imaging. Interactive computer programs can electronically display both static three‐dimensional and higher‐dimensional images that retain features such as motion, pressure, and temporal change. Multidimensional images can be reconstructed and manipulated using different holographic, stereolithographic, or interactive two‐dimensional displays. We describe the unique potential of multidimensional reconstruction, virtual dissection, and replication of cordiovascular structures using ultrasound data. Ultrasound technology has the advantage of depicting both anatomy and physiology. The ability to perform virtual dissection and surgery in the living patient without disruption of anatomy or physiology provides the clinician with a powerful new tool for diagnosis, teaching, and therapeutics.

Mitral and aortic valve thickening associated with galactosialidosis: echocardiographic features of a lysosomal storage disease.

The use of multiple in vitro reference methods to validate three‐dimensional (3‐D) echocardiographic techniques makes comparison difficult. In an attempt to establish a reference standard, we studied precision, accuracy, and feasibility of a true left ventricular (LV) volume measurement in six dog heart specimens using three techniques, called fluid, sheath, and cast. LV volumes ranged from 30 to 105 mL. Intraobserver variability was minimal in all combinations (1.26% to 2.8%) with a statistically insignificant tendency to higher values in the cast method. The cast method, however, exhibited significantly higher interobserver variability (5.78%) as compared to that ranging from 1.47% to 1.59% in the remaining two techniques. Regression analysis demonstrated high correlations among the three techniques assessed by 95% confidence limits and correlation coefficient (R2 > 0.98, P < 0.01). Mean differences among the techniques (0.12 to 1.08 mL) were not significant. The fluid technique was easy to perform. The sheath technique required some practice. The cast method was sensitive to accurate preparation of a gelatin mixture. We conclude that the fluid and sheath techniques are precise, accurate, and feasible. We recommend their use as reference standards in laboratory LV volume measurement. Validation 3‐D echocardiographic studies using either of these two techniques will be comparable. Although the accuracy of the cast technique is excellent, its lower precision makes it a second choice. It could be used in cases where an LV cavity cast is required and higher interobserver variability is acceptable.