A 3-dimensional diagnostic imaging system for acquiring and displaying 3-dimensional images includes an ultrasound diagnostic imaging apparatus configured to display any cross section of a 3-dimensional image extracted from volume data including an affected part of a subject; a 3-dimensional medical diagnostic imaging apparatus configured to display a cross section of a 3-dimensional image extracted from volume data obtained by medical diagnostic imaging modalities other than the ultrasound diagnostic imaging apparatus, the cross section being substantially identical to the cross section displayed by the ultrasound diagnostic imaging apparatus; and an image processing/display unit configured to synchronously display substantially identical cross sections of a plurality of 3-dimensional images from both the ultrasound diagnostic imaging apparatus and the 3-dimensional medical diagnostic imaging apparatus, or to synchronously display substantially identical cross sections of a plurality of 3-dimensional images extracted from volume data obtained by the same medical diagnostic imaging modality at different times.