Integration of intraoperative 3D-ultrasound in a commercial navigation system.

Study aims: The purpose of this study was the integration of three-dimensional ultrasound data into a neuronavigation system, in order to allow a guided intraoperative resection control during neurosurgical interventions.

Material and methods: A system for iterative neuronavigation based on 3D-ultrasound (US) has been developed. The main components of the system are the ultrasound device Voluson 730 (GE Healthcare) with a 5 - 9 MHz probe, the navigation system VectorVision2 (BrainLAB AG) and a standard PC with Windows XP. The ultrasound data are transferred via DICOM from the ultrasound device to an external computer, where they are processed with a C++ program for representation in the neuronavigation coordinate system. The data transfer between the navigation system and the external computer is performed via the VVLink interface from BrainLAB. The feasibility test of the system was performed with an ultrasound phantom RMI 403GS (Gammex-RMI GmbH).

Results: The error of homologous points mapping from US datasets to a CT dataset in the neuronavigation system was determined to be 1.9 +/- 0.97 mm. The maximum time required to technically integrate the ultrasound data into the navigation system was 1.5 min.

Conclusions: The developed system allows 3D-ultrasound based navigation to be carried out with a commercially available navigation system. The functionality of this system has been proven by technical tests. Recording and integration of the ultrasound data can be repeated at any time during surgery and can be used to update anatomical data and consequently for resection control. Another application is the intraoperative adaptation of preoperative datasets (MRI or CT) in order to compensate for "brain shift" during neurosurgical operations.