Previous extensions of two-dimensional ultrasonic imaging to three dimensions used lattice diagrams which give measurement information, but no anatomic detail. The authors conducted three sets of experiments to test the hypothesis that complete acoustic backscatter data should be retained to produce useful information about heart structure and function. First, in vitro compound B-scans were taken under ideal conditions; second, in vitro rotating conventional sector scans were taken to test clinically applicable methods; and third, clinical in vivo rotating conventional sector scans were taken of a human volunteer. It is concluded that the resulting images show details of cardiac anatomy and have great clinical promise. Interactive analysis and surface and volume displays give context and perspective information which should improve diagnostic accuracy, communication with noncardiologists and yield more precise measurements of anatomical structure and function. >