Registration of 3d Ultrasound Images to Surface Models of the Heart

Ultrasound images of the heart are obtained by a probe placed on the patient's chest. The resultant image is a triangular plane with its base in the middle of the body and the tip close to the probe on the chest. Thus, image planes with a different orientation (e.g. parallel to the surface of the body) are impossible to obtain. The aim of current 3D ultrasound of the heart is to provide the physician with diagnostically important views that are impossible to gain with standard 2D ultrasound devices. These imaging planes are calculated from 3D data sets generated by rotating a standard ultrasound probe around its center axis. Imaging planes obtained from a 3D data set are independent of the probe position. The disadvantage is that the physician evaluating such an image off-line has to orient himself in this volume without knowing the exact position of the plane in respect to the diagnostic relevant views. He needs a geometrical reference scenario as guidance. In the CardiAssist project (Berlage & Grunst, 1995), we have supplemented the ultrasound image by a surface model of the heart (see Fig. 1). This scenario not only serves as an orientation during diagnosis (Berlage et al., 1996), but also for training purposes and teleconsultation (Berlage, 1996).