Acquisition of 3D ultrasound images during neuronavigation

Intraoperative brain deformation is the most important cause affecting the overall accuracy of image guided neurosurgical procedures. One option for correcting this deformation is to acquire 3D ultrasound images during the operation and use these to update the information provided by the preoperatively acquired MR data. For 8 patients 3D ultrasound images have been reconstructed from a freehand sweep during neurosurgical procedures. The 3D ultrasound data have been qualitatively compared to the preoperatively acquired MR data. Before opening the dura, no brain deformation was measured. After opening the dura the maximum shift measured was 8 mm parallel to the direction of gravity and 6 nun perpendicular to this direction, showing the additional value of 3D ultrasound acquisition compared to 2D ultrasound.