Updating of neuronavigation based on images intraoperatively acquired with a mobile computerized tomographic scanner: technical note.

Image-guided surgery based on preoperatively obtained image data is susceptible to inaccuracy resulting from intraoperative brain shift and distortion. We report a technique of updating neuronavigational data with the aid of a mobile computerized tomographic (CT) scanner. A mobile CT which is readily available in an ordinary operating room was used to acquire intraoperative images. A total of 6 - 7 titanium screws placed on the skull were used as new reference points for updating navigation. Intraoperative CT scanning was performed with a 2 mm slice thickness. After the obtained image data were transferred as Dicom files to the computer workstation of the navigation system through an Ethernet connection, navigational data were updated to registering the new reference points. Under the guidance of the updated navigation, residual lesions were explored, and further resected. Our preliminary experience in 8 patients indicates that interactive image-guidance can stably be updated based on images intraoperatively acquired with a mobile CT scanner. Comparing to intraoperative magnetic resonance imaging, this technique can simply be done in an ordinary operating room without requiring special surgical instruments, thus making it possible to update interactive image guidance on demand during an operation.