Real-time three-dimensional stress echocardiography: a Review of current applications

Assessment of image quality in real time three-dimensional dobutamine stress echocardiography: an integrated 2D/3D approach

BACKGROUND

Three-dimensional (3D) stress echocardiography is a relatively new technique offering the potential to acquire images of the entire left ventricle from 1 or 2 transducer positions in a time-efficient manner. Relative to two-dimensional (2D) imaging, the ability to quickly acquire full volume images during peak stress with 3D echocardiography can eliminate left ventricular (LV) foreshortening while reducing inter-operator variability. Our objectives were to (1) determine the practicality of a novel integrated 2D/3D stress protocol in incorporating 3D imaging into a standard 2D stress echocardiogram and (2) to determine whether the quality of imaging using the novel 2D/3D protocol was sufficient for interpretation.

METHODS

Twenty-five patients referred for stress echocardiography underwent an integrated 2D/3D image acquisition protocol. LV segments were scored from 0 (absent or no clear endocardial visualization) to 3 (excellent/full visualization of endocardial border) with each modality. 2D segment quality scoring was compared with 3D. An integrated score was compared with either 2D or 3D imaging alone.

RESULTS

Two-dimensional and 3D imaging were optimal for differing segments and the integrated protocol was superior to either modality alone. 3D imaging was superior in visualizing the anterior and anterolateral region of the base segments, compared to 2D imaging. 3D imaging was less useful for the base, the mid-inferior, and the inferoseptal segments, thus emphasizing the need to retain 2D imaging in stress echocardiography at this time.

CONCLUSION

The integrated 2D/3D protocol approach to stress echocardiography is technically feasible and maximizes image quality of dobutamine stress echocardiography, improving patient assessment.

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.

Comparison of accuracy of mitral valve area in mitral stenosis by real-time, three-dimensional echocardiography versus two-dimensional echocardiography versus Doppler pressure half-time

Mitral valve area (MVA) in 30 patients with mitral stenosis (MS) and 34 normal controls was calculated by real-time, 3-dimensional echocardiography (RT3DE); MVA in patients with MS correlated well with the mitral area determined by 2-dimensional echocardiography (r = 0.98) and by pressure half-time (r = 0.90). MVA in normal controls on RT3DE correlated well with MVA on 2-dimensional echocardiography (r = 0.94) and pressure half-time (r = 0.91). There were significant differences between the orifice areas in patients with MS and normal controls. RT3DE can provide not only the anatomic structure of mitral valve apparatus, but also the optimal plane of the smallest mitral valve orifice, and can thus accurately measure the MVA.

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.

Three-dimensional echocardiography–guided beating-heart surgery without cardiopulmonary bypass: A feasibility study

BACKGROUND

There is no current acceptable approach for intracardiac beating-heart interventions. We have adapted real-time 3-dimensional echocardiography with specialized instrumentation to facilitate beating-heart repair of atrial septal defects and mitral valve plasty to investigate the feasibility of real-time 3-dimensional echocardiography-guided cardiac surgery.

METHODS

In experiment I a modified real-time 3-dimensional echocardiography system with x4 matrix transducer was compared with 2-dimensional echocardiography in the performance of common surgical tasks. Completion times, deviation from an ideal trajectory, and an echogenic target were measured. In experiment II porcine atrial septal defects were closed with an original semiautomatic suturing device (n = 4) and with a 5-mm endoscopic stapler and a pericardial or polytetrafluoroethylene patch (n = 4). In experiment III a pulsatile porcine mitral valve model was developed, and suture placement through the anterior and posterior mitral leaflets was performed (n = 8). During all experiments, the operator was blinded to the target and operated on only with ultrasonic guidance.

RESULTS

In experiment I, compared with 2-dimensional echocardiographic guidance, completion times improved by 21% ( P <.01) with high-trajectory accuracy, and suture deviation was significantly smaller (2-dimensional echocardiography, 5.4 +/- 2.7 mm; 3-dimensional echocardiography, 1.7 +/- 0.7 mm; P <.05) in real-time 3-dimensional echocardiography-guided tasks. In experiments II and III in both atrial septal defect closure and mitral valve plasty, real-time 3-dimensional echocardiography provided satisfactory images and sufficient anatomic detail for suturing and patch deployment. All surgical tasks were successfully performed with accuracy.

CONCLUSIONS

Real-time 3-dimensional echocardiography provides adequate imaging and anatomic detail to act as a sole guide for surgical task performance. These initial experiments demonstrate the feasibility of beating-heart direct or patch closure of atrial septal defects and mitral valve plasty without cardiopulmonary bypass.

Three-dimensional echocardiography–guided atrial septectomy: An experimental study

OBJECTIVES

The surgical feasibility of beating-heart atrial septectomy under the guidance of two different types of real-time 3-dimensional echocardiography systems was examined.

METHODS

A modified real-time 3-dimensional echocardiography system with a x4 matrix transducer (Sonos 7500; Philips Medical Systems, Andover, Mass) or a mechanical 1-dimensional array transducer (SSD-5500; Aloka Co, Ltd, Tokyo, Japan) was used. Small porcine atrial septal defects (n = 8) were enlarged with a Kerrison bone punch in the tank model. In the animal studies, small atrial septal defects (n = 8) were enlarged with the same device through a transatrial port. In both experiments, the area of the atrial septal defect measured by real-time 3-dimensional echocardiography was compared with the area measured directly.

RESULTS

Real-time 3-dimensional echocardiography provided satisfactory images and sufficient anatomic detail for the atrial septectomy in both experimental settings. All the atrial septal defects were successfully enlarged; an increase of as much as 293% of the preoperative atrial septal defect area was achieved in the tank experiment, and an increase of as great as 449% of the preoperative area was achieved in the animal experiment. The size of the atrial shunt was increased significantly after the atrial septectomy relative to that before the surgery (P <.0001). The percentage enlargement of the atrial septal defect measured by real-time 3-dimensional echocardiography was strongly correlated with that measured directly (both r(2) = 0.997, P <.0001) Bland-Altman analysis showed close agreement between the results obtained by the two measurement methods in both models.

CONCLUSIONS

Real-time 3-dimensional echocardiography provides satisfactory images and sufficient anatomic detail for atrial septectomy. This experiment demonstrates the surgical feasibility of a beating-heart intracardiac procedure such as atrial septectomy under real-time 3-dimensional echocardiographic guidance.

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.

Beating atrial septal defect closure monitored by epicardial real-time three-dimensional echocardiography without cardiopulmonary bypass

BACKGROUND

We assessed the feasibility of beating atrial septal defect (ASD) closure monitored by real-time 3D echocardiography (RT3DE).

METHODS AND RESULTS

RT3DE was developed with prototype ultrasound equipment consisting of a high-speed 3D rendering unit with a frame rate of 5 to 10 frames/s. We also developed a prototype semiautomatic suture device and suture cutting system. In the experiment, 12 mongrel dogs were anesthetized, and after median sternotomy, the echo probe was applied directly to the surface of the right atrium. Three surgical maneuvers (balloon atrial septectomy, enlargement of the ASD, and ASD closure) were performed through the atrial port inserted into the right atrial appendage. The heart was then excised, and the area of the ASD measured by RT3DE was compared with its area measured directly. The ASD was successfully closed in all experimental animals except the first 2. Examination of the excised heart showed that none of the sutures were loose. The mean area of the ASD was 82.5+/-38.6 mm(2) when measured by RT3DE and 81.6+/-38.2 mm(2) when measured directly, and there was a significant correlation between the areas measured by RT3DE and those measured directly (echo measurements=1.007xdirect measurements+0.337; P<0.0001). A Bland-Altman analysis revealed close agreement between the results obtained by the 2 methods (7.807 mm(2) upper and -6.024 mm(2) lower limit of agreement).

CONCLUSIONS

Introduction of RT3DE, a semiautomatic suture device, and a suture cutting system made beating ASD closure without cardiopulmonary bypass possible.