Clinical use of Real-time three-dimensional echocardiography in pediatric cardiology

The use of echocardiography in congenital heart surgery and intervention

Echocardiography has revolutionized the management of pediatric and adult heart disease, especially in the diagnosis of congenital heart defects. Although the early methods of echocardiography (M-mode and Doppler imaging) were limited in their ability to define the defect in question, the advent of 2D, and now 3D, imaging have clearly equaled or surpassed traditional methods of diagnosis (e.g., noninvasively obtained plain chest radiographs and electrocardiograms) and invasive tests (e.g., cardiac catheterization and angiography). Confidence in the images obtained using echocardiography has continued to increase, with many patients referred for corrective or palliative surgery on the basis of echocardiographic imaging alone. Echocardiography has eliminated the need, decreased the frequency, or improved the timing or performance of invasive studies in other patients. Specifically, it is used to definitively diagnose a cardiac defect and any associated lesions. It will also provide quantitative information for the assessment of the hemodynamic severity of the lesion. This review outlines the manner in which echocardiography is used to plan and guide congenital heart surgery or intervention, along with some of the advantages and disadvantages (pitfalls) of which to be aware. The use of echocardiography within the cardiac catheterization or surgical theater, as well as in the intensive care unit, is discussed, as is the use of echocardiography as a means of monitoring recovery and follow-up following cardiac surgery. Finally, the authors discuss who is best qualified or suited to perform these tests.

Usefulness of 3D reconstructed computed tomography imaging for double outlet right ventricle

BACKGROUND/PURPOSE

To evaluate the value of 3D reconstructed computed tomography (CT) imaging for patients with double outlet right ventricle (DORV).

METHODS

CT images were obtained preoperatively from 17 patients who ranged in age from 5 days to 5 years. Reconstructed 3D images were created using gradient-shading surface rendering, which allowed partial subtraction of the anterior sections of the virtual heart to view the interior. Interpretations of CT, echocardiography and cine-cardioangiography were compared and verified from surgical findings, autopsy, and consensus upon review of all imaging and diagnostic tests.

RESULTS

Three subaortic, seven subpulmonary, six non-committed, and one double-committed subtypes of ventricular septal defect (VSD) were observed. The 3D electron beam CT images provided good delineation of the spatial relationship inside the heart. The range of diagnostic accuracy for all VSD types in DORV was 88-100% for 3D CT, 71-94% for echocardiography, and 60-100% for cine-cardioangiography. In comparison, 3D CT offered better diagnostic accuracy for all variants of DORV.

CONCLUSION

3D constructed CT imaging is a good modality for differentiating VSD type in DORV. It allowed us to directly evaluate the inside of cardiac chambers for the right ventricular outlet, great arterial root, and determine the VSD relationships.

Three-Dimensional Echocardiography in Congenital Heart Disease

Matrix array technology has brought three-dimensional echocardiography into the clinical practice of cardiology. Arguably, this advancement is most notable in the field of pediatric cardiology. Full-volume acquisitions now can be undertaken in the youngest of infants with excellent image quality. This article illustrates the clinical application of three-dimensional echocardiography in congenital heart disease.

Real-Time 3-Dimensional Echocardiography: A Review of the Development of the Technology and Its Clinical Application

Real-time 3-dimensional echocardiography (RT3DE) is a new imaging technique that can provide accurate, important, and additional information concerning cardiovascular morphology, pathology, and function. This article will review the development of the technology of RT3DE and its clinical application. As the technique continues to evolve, RT3DE is bound to play an increasingly important role in the diagnosis, prognosis, and treatment of patients with various forms of cardiovascular disease.

Three- and four-dimensional freehand fetal echocardiography: a feasibility study using a hand-held Doppler probe for cardiac gating

OBJECTIVE

To evaluate the clinical feasibility of the signal from a hand-held Doppler probe as a real-time tracking signal for dynamic three-dimensional (3D) (so-called four-dimensional (4D)) fetal echocardiography in a random patient cohort.

METHODS

Seventy fetuses, with and without congenital heart disease, at various gestational ages (mean, 25 weeks; range, 18-38 weeks) were investigated using freehand 3D echocardiography. Time gating was achieved concurrently by obtaining a Doppler signal of the fetal heart without further signal averaging. In 10 fetuses, Doppler gating was compared to cardiotocogram (CTG)-gated 3D echo using signal averaging. Gray-scale and color Doppler dynamic 3D displays and multiplanar views were assessed according to their ability to accurately depict cardiac gating and cardiac morphology.

RESULTS

In 68/70 fetuses, valid Doppler-based trigger signals were obtained. Correct cardiac gating was achieved in 231/275 (84%) 4D datasets. Doppler tracing of the fetal heart allowed beat-to-beat triggering without the necessity for signal averaging. Doppler gating detected rapid changes in the fetal heart rate more reliably than CTG gating, but was more sensitive to acoustic interference between the gating and echo-transducer when color-coded Doppler imaging was used. Image quality was highly dependent on random motion and the acoustic window. A total of 171/231 (74%) correctly gated datasets successfully demonstrated clinically useful 4D images of the fetal heart. The reconstruction of 3D and multiplanar views provided additional views not obtainable by two-dimensional imaging.

CONCLUSION

These results show that a hand-held Doppler probe can be used as a reliable online gating source for 4D fetal echocardiography.

Real-time 3-dimensional echocardiography in assessing atrial and ventricular septal defects: an echocardiographic-surgical correlative study

OBJECTIVE

The aim of this study is to explore the feasibility and the value of real-time 3-dimensional echocardiography (RT3DE) in quantitative evaluation of the size of atrial septal defect (ASD) and ventricular septal defect (VSD) and to correlate with the surgical findings.

METHODS

Thirty eight patients with ASD and/or VSD were examined with RT3DE. Three-dimensional image data-base was post-processed using 3D work-station. The results were compared with the results measured by 2-dimensional echocardiography and surgical findings.

RESULTS

RT3DE produced novel views of congenital septal defects and improved quantification of the size of the defect. The sizes obtained from 3DE have better correlation with surgical findings than diameter measured by 2-dimensional echocardiography (r = 0.69 vs r = 0.92).

CONCLUSIONS

RT3DE offers additional special information in congenital heart disease without extending examining time, permits quantitative recording of septal defect dynamics, and enhances the understanding of complex cardiac anatomy and elucidation of the disease mechanism. It is a potentially valuable clinical tool for diagnosing and managing patients with congenital heart disease.

Dynamic free-hand three-dimensional fetal echocardiography gated by cardiotocography

OBJECTIVE

To evaluate the clinical feasibility of conventional cardiotocography (CTG) as a cardiac cycle triggering signal for three-dimensional (3D) fetal echocardiography.

METHOD

Free-hand 3D echocardiography was performed on a total of 25 fetuses with and without congenital heart disease at various gestational ages (mean, 29 weeks; range, 19-35 weeks). Simultaneously, online CTG was used for time gating. Gray-scale and color Doppler dynamic 3D displays, as well as multiplanar views, were assessed for their ability to depict the cardiac morphology and correct cardiac gating.

RESULTS

Valid CTG-based trigger signals could be obtained in 24 of the 25 fetuses. Correct cardiac gating was achieved in 101 of the 111 (91%) 3D datasets. Color Doppler imaging of blood flow in four dimensions was possible in 34 of 36 (94%) datasets. Reconstructed 3D and multiplanar views provided additional views not available in two-dimensional (2D) imaging. Acoustic interference between the CTG transducer and echotransducer could be reduced by the use of a high-frequency echotransducer, second-harmonic frequency imaging and appropriate positioning of the two transducers. Imaging quality was highly dependent on the quality of 2D images and random motion artifacts.

CONCLUSIONS

CTG can be used as an online gating source for dynamic 3D fetal echocardiography.

Spatio-temporal image correlation (STIC): new technology for evaluation of the fetal heart

Spatio-temporal image correlation (STIC) is a new approach for clinical assessment of the fetal heart. It offers an easy to use technique to acquire data from the fetal heart and to aid in visualization with both two-dimensional and three-dimensional (3D) cine sequences. The acquisition is performed in two steps: first, images are acquired by a single, automatic volume sweep. Second, the system analyzes the image data according to their spatial and temporal domain and processes an online dynamic 3D image sequence that is displayed in a multiplanar reformatted cross-sectional display and/or a surface rendered display. The examiner can navigate within the heart, re-slice, and produce all of the standard image planes necessary for a comprehensive diagnosis. The advantages of STIC for use in evaluation of the fetal heart are as follows: the technique delivers a temporal resolution which corresponds to a B-mode frame rate of approximately 80 frames/s; it provides the examiner with an unlimited number of images for review; it allows for correlation between image planes that are perpendicular to the main image acquisition plane; it may shorten the evaluation time when complex heart defects are suspected; it enables the reconstruction of a 3D rendered image that contains depth and volume which may provide additional information that is not available from the thin multiplanar image slices (e.g. for pulmonary veins, septal thickness); it lends itself to storage and review of volume data by the examiner or by experts at a remote site; it provides the examiner with the ability to review all images in a looped cine sequence.

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.