Ultrasound assessment of ovarian tumors--comparison between transvaginal 3D technique and conventional 2-dimensional vaginal ultrasonography

Abstract

Three-dimensional (3D) ultrasound is capable of visualising all three orthogonal planes simultaneously. With the stored volumetric data, imaging planes can be reconstructed that are not visible when using standard vaginosonographic procedures. In patients with ovarian tumours, diagnosis and the appropriate therapeutic approach depend to a crucial degree upon the results of sonographic investigations, which therefore need very exact diagnostic data. Two-dimensional (2D) vaginosonography can only yield sagittal and frontal sections of the lesser pelvis; 3D volume scanning, however, visualises all three perpendicular planes simultaneously on a monitor screen. In cystic tumours of the ovary, conspicuous parietal structures can be specifically localised and rendered three-dimensionally in the surface mode. Such imaging capabilities create new perspectives in assessing ovarian tumours. Within the framework of a prospective study at the Gynecological Clinic of the University of Mainz, we compared the sonographic findings obtained for 45 patients with ovarian tumours using 2D and 3D vaginosonography. After the transvaginal application of conventional 2D vaginosonography, the tumours were examined by means of 3D sonography. The use of 3D volume scanning was advantageous because we could image specifically targeted planes and reconstruct image planes that cannot be shown using standard vaginosonography. In addition, the volumetric technique allows 3D surface reconstruction of conspicuous parietal structures from a wide variety of different perspectives. These advantages allow one to better assess the grading of tumours especially of those that are cystic. Problems associated with the application of this transvaginal 3D technique module orientation within a given volume, the overlapping of sonographic planes, increase the time required for surface calculations and increased data storage capacity. Transvaginal 3D sonography represents a new technique of imaging. Owing to its ability to register all three imaging planes simultaneously as well as to visualise surfaces three-dimensionally, this technique opens up new sonomorphologic possibilities in the evaluation of ovarian tumours.