SIMULATION OF INTRAOPERATIVE VISUALIZATION OF CARDIAC STRUCTURES AND STUDY OF DYNAMIC SURGICAL ANATOMY WITH REAL-TIME 3-DIMENSIONAL ECHOCARDIOGRAPHY

Most prior efforts of 3-dimensional (3-D) reconstruction of echocardiographic images have focused on quantitation of ventricular size and function. The resulting images have been displayed in the wire mesh format. Recently, a method for 3-D transesophageal echocardiography using a computer-controlled probe that acquires parallel tomographic slices has been described. This technique provides dynamic 3-D volume-rendered images of the heart. This study was designed to determine if surgical visualization of intracardiac anatomy could be simulated using this imaging system. Data acquired from 8 patients with congenital and acquired heart disease were analyzed. Real-time 3-D images of the cardiac chambers and valves were obtained. Images of the cardiac pathology including fibrocalcific nodules on the aortic valve, mitral valve endocarditis, rheumatic mitral stenosis, and an ostium secundum atrial septal defect were displayed in 3 dimensions that simulated surgical exposure of these structures. These 3-D representations of cardiac anatomy were in some ways superior to standard intraoperative visualization in that they demonstrated the heart as a dynamic structure, as opposed to the empty, nonbeating heart observed while on cardiopulmonary bypass. In conclusion, 3-D images of cardiac structures as seen by the surgeon intraoperatively can be provided using a computer-driven tomographic transesophageal echocardiographic probe. This imaging system can be potentially useful in the planning and evaluation of cardiac surgery. Technical improvements such as 3-D representation of now jets, the ability to manipulate images to simulate cardiac surgery, and on line reconstruction can make this a powerful tool in the future.