Computer Assisted Surgery (CAS) of the head and spine interaction between neurosurgery and neuroradiology

Computed tomography and magnetic resonance imaging allow high-resolution vi sualization of morphology and are used for Computer Assisted Surgery (CAS) in the areas of the head and spine. We performed 23 spinal (metastases, screw implantations, spondylolisthesis) and 147 brain (epilepsy, abscesses, vascular malformations, metastases, pr imary brain tumors) surgical interventions. 3D MR data sets, such as MP-RAG E for T1-weighting or CISS for T2* weighting, provide high-resolution brain imaging, but also some pitfalls. Incorrect parameter choice reduces image quality. Contrast enhancement, e.g. of small vessels, is deteriorated with thin slices. Flow artifacts may pretend parenchymal lesions. Advantages are exact visualization of tumor extent allowing complete tumor resection. Fur thermore, the demonstration of tumor-vessel, and tumor-nerve relations is a n important feature. For spine surgery CT is the modality of choice. CAS is clearly superior to "conventional landmark neurosurgery": optimal cranioto my site, optimal approach to the lesion, no trial and error. Brain shift is not the problem as it was expected by theoretical considerations. The oper ation time of sophisticated epilepsy surgical interventions can be signific antly reduced.