Registration Accuracy Using the Main Portal-vein Branch as Vascular Landmark Acquired by Intraoperative Ultrasound for 3D-Navigated Liver Resection

Abstract

Introduction: The accuracy of image registration for 3D-navigated liver resection is crucial. Registration with intraoperative ultrasound (IOUS) using the right or left main portal-vein branch (PV) as landmark has the potential to optimize the accuracy and reduce errors compared to traditional liver surface landmark acquisition. Aim of this study was to analyze the IOUS registration accuracy regarding the distance to the portal vein branches and compare the use of a commercial vs. an semi-automatic in-house 3d-liver model.MethodsImage analysis of the intraoperative use of the IOUS registration process in patients who underwent 3D-navigated combined liver resection/thermal ablation. Results: 108 measurements were performed. Accuracy defined by the mean registration error was 0.75cm±0.48cm, using the left portal vein branch it was 0.65cm± 0.40cm, the right branch 0.95cm±0.54cm(p=0.001). Correlation between distance to the acquired portal vein branch landmarks and the resulting registration error was low (r2=0.36) showing a high accuracy in a distance up to 6cm to the PV. Registration error comparing the commercial 3D-liver model vs. the semi-automatic in-house 3D-liver model was not different (0.91±0.51 vs 0.99±0.58,p=0.64) Conclusion: IOUS registration algorithm shows a high accuracy in a distance up to 6cm to the region of interest in the left liver lobe using in-house 3D-image reconstruction. Accuracy in the right liver lobe was lower.