title: Intraoperative ultrasound in pediatric brain tumors: does the surgeon get it right?
abstract: OBJECTIVE
  Intraoperative ultrasound (iUS) is a valuable tool-inexpensive, adds minimal surgical time, and involves minimal risk. The diagnostic predictive value of iUS is not fully characterized in Pediatric Neurosurgery. Our objective is to determine if surgeon-completed iUS has good concordance with post-operative MRI in estimating extent of surgical resection (EOR) of pediatric brain tumors.
  
  
  METHODS
  We reviewed charts of all pediatric brain tumor resections (single institution 2006-2013). Those with iUS and postoperative imaging (<1 week) were included. The surgeon's estimation of the EOR based on iUS and the post-operative neuroimaging results (gold standard) were collected, as well as information about the patients/tumors.
  
  
  RESULTS
  Two hundred two resections were reviewed and 58 cases were included. Twenty-six of the excluded cases utilized iUS but did not have EOR indicated. The concordance of interpretation between iUS and post-operative MRI was 98.3%. Of 43 cases where iUS suggested gross total resection, 42 were confirmed on MRI (negative predictive value (NPV), 98%). All 15 cases where iUS suggested subtotal resection were confirmed on MRI (positive predictive value (PPV), 100 %). Agreement between iUS and post-operative imaging had an overall Kappa score of 0.956, signifying almost perfect agreement.
  
  
  CONCLUSIONS
  The results from this study suggest that iUS is reliable with both residual tumor (PPV-100%) and when it suggests no residual (NPV-98%) in tumors that are easily identifiable on iUS. However, tumors that were difficult to visualize on iUS were potentially excluded, and therefore, these results should not be extrapolated for all brain tumor types.
authors.affiliation: Division of Neurosurgery, Department of Surgery, University of British Columbia and BC Children's Hospital, Vancouver, British Columbia, Canada. ash.singhal@cw.bc.ca.|Division of Pediatric Neurosurgery, B.C. Children's Hospital, 4480 Oak Street, Room K3-159, Vancouver, BC, V6H 3V4, Canada. ash.singhal@cw.bc.ca.
authors.forename: Ash
authors.initials: A
authors.lastname: Singhal
authors.affiliation: Division of Neurosurgery, Department of Surgery, University of British Columbia and BC Children's Hospital, Vancouver, British Columbia, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Ross Hengel
authors.affiliation: Division of Neurosurgery, Department of Surgery, University of British Columbia and BC Children's Hospital, Vancouver, British Columbia, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Steinbok
authors.affiliation: Division of Neurosurgery, Department of Surgery, University of British Columbia and BC Children's Hospital, Vancouver, British Columbia, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Doug Cochrane
mesh_terms: D000293:Adolescent; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D016343:Monitoring, Intraoperative / Q000379:methods*; D019635:Neurosurgical Procedures / Q000379:methods*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography; D055815:Young Adult
keywords: Brain tumors; EOR; Extent of resection; Intraoperative ultrasound; Pediatric; Post-operative MR; iUS