Intraoperative imaging using a mobile computed tomography scanner

Objective: The radicality of tumour removal in patients suffering from glioma is discussed to be an important factor for longer survival times. Therefore intraoperative imaging modalities like magnetic resonance imaging (MRI), computed tomography (CT) and ultrasound (US) are tested in many neurosurgical facilities for clinical use. In our department a mobile CT for intraoperative applications is used for this purpose since 1999. The handling and useful application of the mobile CT scanner as well as results without intraoperative imaging are discussed. Material and Methods: 470 CT scans with the mobile CT were accomplished, including 270 cases of neuronavigation planning, 76 cases of intraoperative scans, 48 cases of postoperative scans, 69 CT scans for stereotactic biopsy planning and control as well as 3 cases of emergency scanning in trauma patients and 4 spine applications. The results of the intraoperative CT scans are compared with those of the postoperative MRI scans. Additionally 87 patients with glioma were evaluated. These patients underwent surgery without intraoperative imaging. Results: In 27 out of 43 patients with glioma residual tumour was detected with intraoperative CT. In 13 cases the surgery was resumed to complete resection, in 14 cases the operation was not continued due to close vicinity to eloquent areas or difficulties in image interpretation. In 44 cases the results of intraoperative CT and postoperative MRI were compared. In 6 cases the MRI demonstrated residual tumour in contrast to the results of the CT scans. In 3 cases the tumour removal could have been more complete (6.8%). In 87 cases glioma surgery was performed without intraoperative CT. In 6 cases a more complete tumour removal could have been performed (6.9%) according to the results of postoperative MRI. Conclusion: Intraoperative imaging with a mobile CT scanner is a good method for detection of residual tumour. The CT scanner can be integrated in an operative setting without problems. Although intraoperative imaging can be helpful in some selected cases, most of the neurosurgical procedures can be well performed with proper neuronavigation planning.