Computational methods for wide-field reconstruction of transoesophageal echocardiographic images

Transoesophageal echocardiography imaging is limited by the proximity of the transducer to many cardiovascular structures. The location of the transducer causes these structures to appear near the apex of the backscatter image, and since the angle of the scan cannot exceed 90 degrees, much of the image information appears in a constricted area. We describe a computer-based, wide-field reconstruction technique which pieces together the picture fields from adjacent sector scans to form composite images. This description includes information regarding lessons learned, as well as technical details of the algorithms, in sufficient depth to permit reproduction of the system by interested parties. Significant aspects of wide-field image reconstruction, including computational complexity, image-pair alignment processes, requirements of alignment resolution, and image acquisition techniques, are addressed in depth. We believe that wide-field presentation of echocardiographic backscatter data enhances the utility of the transoesophageal approach, particularly when dealing with posteriorly located cardiovascular lesions.