Background: Despite its wide diagnostic potential, three-dimensional (3D) echocardiography is a quite rarely employed technique. The ideal method to obtain transthoracic 3D imaging is on-line 3D echocardiography, but first-generation real-time instruments had technical limitations. A new on-line 3D technology which allows true real-time volume rendering of the cardiac anatomy has been recently introduced and its feasibility and diagnostic advantages have been evaluated in the clinical setting.
Methods: The system utilizes a "matrix" transducer with a dedicated software. It allows instantaneous acquisition and rendering on-line 3D images and interactive manipulation of 3D data. Eighty-three adult patients with various cardiac pathologies underwent on-line 3D echocardiography. Long- and short-axis views of the aorta, mitral valve and left ventricle and surgical views of these structures were attempted. The duration of acquisition and reconstruction, and the quality and incremental clinical value of 3D images in comparison with two-dimensional imaging were annotated.
Results: The mean time of 3D examination was 10 +/- 5 min; the mean number of acquisitions was 10.8 per patient. The quality of the 3D images was optimal in 39%, good in 37%, sufficient in 19%, and insufficient in 5% of the patients. In all cases at least one optimal or good live 3D image was obtained from the parasternal and apical views. The reconstruction of surgical or en face views was easily and rapidly (1-2 min) achieved by two experts in 3D echocardiography. The additional clinical values of 3D vs two-dimensional imaging was demonstrated in 7 patients with mitral valve disease, 3 with aortic valve pathology, and 3 with congenital heart disease. Several on-line 3D images that have not correspondence with two-dimensional echocardiography were reconstructed, creating projections dedicated to the diagnostic goal.
Conclusions: On-line 3D echocardiography can be easily performed in adult patients and allows for unique planes and projections. The instant rendering of 3D images facilitates the recognition of cardiac structures and increases the diagnostic potential of transthoracic echocardiography.