title: Preoperative magnetic resonance and intraoperative ultrasound fusion imaging for real-time neuronavigation in brain tumor surgery.
abstract: OBJECTIVE
  Brain shift and tissue deformation during surgery for intracranial lesions are the main actual limitations of neuro-navigation (NN), which currently relies mainly on preoperative imaging. Ultrasound (US), being a real-time imaging modality, is becoming progressively more widespread during neurosurgical procedures, but most neurosurgeons, trained on axial computed tomography (CT) and magnetic resonance imaging (MRI) slices, lack specific US training and have difficulties recognizing anatomic structures with the same confidence as in preoperative imaging. Therefore real-time intraoperative fusion imaging (FI) between preoperative imaging and intraoperative ultrasound (ioUS) for virtual navigation (VN) is highly desirable. We describe our procedure for real-time navigation during surgery for different cerebral lesions.
  
  
  METHODS
  We performed fusion imaging with virtual navigation for patients undergoing surgery for brain lesion removal using an ultrasound-based real-time neuro-navigation system that fuses intraoperative cerebral ultrasound with preoperative MRI and simultaneously displays an MRI slice coplanar to an ioUS image.
  
  
  RESULTS
  58 patients underwent surgery at our institution for intracranial lesion removal with image guidance using a US system equipped with fusion imaging for neuro-navigation. In all cases the initial (external) registration error obtained by the corresponding anatomical landmark procedure was below 2 mm and the craniotomy was correctly placed. The transdural window gave satisfactory US image quality and the lesion was always detectable and measurable on both axes. Brain shift/deformation correction has been successfully employed in 42 cases to restore the co-registration during surgery. The accuracy of ioUS/MRI fusion/overlapping was confirmed intraoperatively under direct visualization of anatomic landmarks and the error was < 3 mm in all cases (100 %).
  
  
  CONCLUSIONS
  Neuro-navigation using intraoperative US integrated with preoperative MRI is reliable, accurate and user-friendly. Moreover, the adjustments are very helpful in correcting brain shift and tissue distortion. This integrated system allows true real-time feedback during surgery and is less expensive and time-consuming than other intraoperative imaging techniques, offering high precision and orientation.
authors.affiliation: Neurosurgery, Fondazione IRCCS Istituto Neurologico C. Besta, Milano, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Prada
authors.affiliation: Neurosurgery, Fondazione IRCCS Istituto Neurologico C. Besta, Milano, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Del Bene
authors.affiliation: Neurosurgery, Fondazione IRCCS Istituto Neurologico C. Besta, Milano, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Mattei
authors.affiliation: Research and Development, Esaote S. p. a., Genova, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Lodigiani
authors.affiliation: Research and Development, Esaote S. p. a., Genova, Italy.
authors.forename: S
authors.initials: S
authors.lastname: DeBeni
authors.affiliation: Research and Development, MedCom, Darmstadt, Germany.
authors.forename: V
authors.initials: V
authors.lastname: Kolev
authors.affiliation: Neurosurgery, Fondazione IRCCS Istituto Neurologico C. Besta, Milano, Italy.
authors.forename: I
authors.initials: I
authors.lastname: Vetrano
authors.affiliation: Interventional Oncology, A. O. Circolo, Busto Arsizio, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Solbiati
authors.affiliation: Research and Development, MedCom, Darmstadt, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Sakas
authors.affiliation: Neurosurgery, Fondazione IRCCS Istituto Neurologico C. Besta, Milano, Italy.
authors.forename: F
authors.initials: F
authors.lastname: DiMeco
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000556:secondary / Q000601:surgery*; D002540:Cerebral Cortex / Q000473:pathology / Q000601:surgery; D002648:Child; D003399:Craniotomy / Q000295:instrumentation / Q000379:methods; D004867:Equipment Design; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods*; D007431:Intraoperative Complications / Q000175:diagnosis* / Q000601:surgery*; D007432:Intraoperative Period; D053783:Magnetic Resonance Imaging, Interventional / Q000295:instrumentation* / Q000379:methods*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000295:instrumentation* / Q000379:methods*; D038361:Neuronavigation / Q000295:instrumentation* / Q000379:methods*; D011300:Preoperative Care; D012680:Sensitivity and Specificity; D018084:Ultrasonography, Interventional / Q000295:instrumentation* / Q000379:methods*; D014584:User-Computer Interface