title: Combined x-ray and magnetic resonance imaging facility: application to image-guided stereotactic and functional neurosurgery.
abstract: OBJECTIVE
  To assess the feasibility of a hybrid imaging setup combining x-ray and magnetic resonance imaging (MRI) in the setting of both stereotactic and functional neurosurgery.
  
  
  METHODS
  A combined x-ray and MRI scanning facility with a trolley system for a fast patient transfer between both modalities was installed in a neurosurgical setting. A registration algorithm for fusion of MRI scans and x-ray images was derived for augmentation of fluoroscopic x-ray projection images with MRI scan data, such as anatomic structures and planned probe trajectories. Phantom measurements were obtained between both modalities for estimation of registration accuracy. Practical application of our system in stereotactic and functional neurosurgery was tested in brachytherapy, deep brain stimulation, and motor cortex stimulation.
  
  
  RESULTS
  Phantom measurements yielded a mean spatial deviation of 0.7 +/- 0.3 mm with a maximum deviation of 1.1 mm for MRI scans versus x-rays. Augmentation of x-ray images with MRI scan data allowed intraoperative verification of the planned trajectory and target in three types of neurosurgical procedures: positioning iodine seeds in brachytherapy in one case with cerebellar metastasis, placement of electrodes for deep brain stimulation in two cases of advanced Parkinson's disease, and placement of an epidural grid for motor cortex stimulation in two cases of intractable pain.
  
  
  CONCLUSIONS
  Combined x-ray and MRI-guided stereotactic and functional neurosurgery is feasible. Augmentation of x-ray projection images with MRI scan data, such as planned probe trajectories and MRI scan segmented anatomic structures may be beneficial for probe guidance in stereotactic and functional neurosurgery.
authors.affiliation: Department of Stereotactic and Functional Neurosurgery, University of Cologne, Cologne, Germany. stefan.hunsche@uk-koeln.de
authors.forename: Stefan
authors.initials: S
authors.lastname: Hunsche
authors.forename: Dieter
authors.initials: D
authors.lastname: Sauner
authors.forename: Mohammad
authors.initials: M
authors.lastname: Maarouf
authors.forename: Klaus
authors.initials: K
authors.lastname: Lackner
authors.forename: Volker
authors.initials: V
authors.lastname: Sturm
authors.forename: Harald
authors.initials: H
authors.lastname: Treuer
mesh_terms: D001918:Brachytherapy; D001932:Brain Neoplasms / Q000532:radiotherapy* / Q000556:secondary / Q000601:surgery; D002138:Calibration; D046690:Deep Brain Stimulation / Q000295:instrumentation / Q000379:methods; D005240:Feasibility Studies; D005471:Fluoroscopy / Q000295:instrumentation*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008962:Models, Theoretical; D009044:Motor Cortex / Q000601:surgery; D019635:Neurosurgical Procedures / Q000295:instrumentation* / Q000379:methods; D010148:Intractable Pain / Q000601:surgery / Q000628:therapy; D010300:Parkinson Disease / Q000601:surgery / Q000628:therapy*; D019047:Phantoms, Imaging; D013238:Stereotaxic Techniques / Q000295:instrumentation*