Real time neuronavigation using 3-D ultrasound and MRI in patients with brain tumor

The loss of accuracy during neuronavigation, caused by intraoperative changes of intracranial masses after trepanation, is one of the major problems in neurosurgery. It usually affects the planning and performing of surgery as both is conventionally based on preoperative patient data sets. Thus, an online acquisition and processing of data during surgery is needed to increase navigational accuracy. Beside cost-intensive solutions like intraoperative CT or MRI scanners, an ultrasound guided navigation is applicable and demonstrates online guidance in real-time. This study describes a development to provide the best possible support for neurosurgeons intraoperatively, concerning data presentation and ergonomic aspects in the operation theatre. Patients underwent MRI examination for a conventional neuronavigation preoperatively. Intraoperatively, ultrasound volume data sets were acquired by means of a tracked ultrasound probe and related to this preoperative MRI. The intraoperative ultrasound imaging was possible in all cases whereat ultrasound images were displayed beside the corresponding MRI images. Brain shift was presentable and the possibility of online navigation with ultrasound and preoperative MRI was helpful for the surgeon.