Three-dimensional navigated laparoscopic ultrasonography: First experiences with a new minimally invasive diagnostic device

Background: A three-dimensional (3D) display of diagnostic imaging methods is technically feasible and increasingly important. However, the technical integration of laparoscopic ultrasound and 3D image reconstruction has not yet been realized. For this purpose, an electromagnetic navigation system was integrated into the tip of a conventional laparoscopic ultrasound probe. This first experience with a certified prototype of a navigated 3D laparoscopic ultrasound probe is reported. Methods: Navigated 3D laparoscopic ultrasound was compared with the imaging data of 3D-navigated transcutaneous ultrasound and 3D computed tomography (CT) scan. The 3D CT scan served as the "gold standard". Clinical applicability, imaging quality, diagnostic potential, and accuracy in volumetric assessment of various well-defined hepatic lesions were analyzed. Results: Navigated 3D laparoscopic ultrasound facilitates exact definition of tumor location and margins. As compared with the "gold standard" of the 3D CT scan, 3D laparoscopic ultrasound has a mild tendency to underestimate the volume of the region of interest (ROI) (δ 3.1%). A comparison of 3D laparoscopy and transcutaneous 3D ultrasonography clearly demonstrated that the former is more accurate for volumetric assessment of the ROI. Conclusions: Three-dimensional laparoscopic ultrasound imaging with a navigated probe is technically feasible. The technique facilitates detailed ultrasound evaluation of laparoscopic procedures involving visual, in-depth, and volumetric perception of complex liver pathologies. Navigated 3D laparoscopic ultrasound may have the potential to improve the significance of laparoscopic ultrasonography, and additionally to become a valuable technology for planning and improving interventions guided by laparoscopic ultrasound.