title: Utility of dynamic computed tomography angiography in the preoperative evaluation of skull base tumors.
abstract: OBJECTIVE
  The anatomical complexity of skull base tumors mandates detailed preoperative planning for safe resection. In particular, the location of critical vascular and bony structures can influence the surgical approach. Traditional methods, such as MRI, MR angiography and/or venography (MRA/MRV), CT angiography and/or venography (CTA/CTV), and digital subtraction angiography, each have their limitations. One alternative that combines the benefits of both detailed anatomy compatible with intraoperative image guidance and visualization of the vascular flow is the 320-detector row dynamic volume CTA/CTV. The authors investigated this technique's impact on the surgical approach used in a series of complex intracranial tumors.
  
  
  METHODS
  All patients with complex intracranial tumors who had undergone preoperative dynamic CTA/CTV as well as MRI in the period from July 2010 to June 2012 were retrospectively reviewed. Those in whom only routine CTA/CTV sequences had been obtained were excluded. Clinical records, including imaging studies, operative reports, and hospital course, were reviewed. Ease in detecting specific major arterial and venous tributaries using dynamic CTA/CTV was graded for each case. Furthermore, 2 skull base neurosurgeons projected a desired surgical approach for each tumor based on MRI studies, independent of the CTA/CTV sequences. The projected approach was then compared with the ultimately chosen surgical approach to determine whether preoperative awareness of vasculature patterns altered the actual operative approach.
  
  
  RESULTS
  Sixty-four patients were eligible for analysis. Dynamic CTA/CTV successfully demonstrated circle of Willis arteries, major draining sinuses, and deep internal venous drainage in all cases examined. The superior petrosal sinus, vein of Labbé, tentorial veins, and middle fossa veins were also identified in a majority of cases, which played an important role in preoperative planning. Visualization of critical vascular-especially venous-anatomy influenced the surgical approach in 39% (25 of 64) of the cases.
  
  
  CONCLUSIONS
  Dynamic CTA/CTV has been applied to few neurosurgical disease pathologies to date. This noninvasive technology offers insight into vascular flow patterns as well as 3D anatomical relationships and provides thin-cut sequences for intraoperative navigation. The authors propose dynamic CTA as an addition to the preoperative planning for complex skull base tumors.
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Wenya Linda
authors.initials: WL
authors.lastname: Bi
authors.affiliation: Neuroradiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; and.
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Brown
authors.affiliation: Departments of 1 Neurosurgery and.|Department of Neurosurgery, Ain Shams University, Cairo, Egypt.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Abolfotoh
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Ossama
authors.initials: O
authors.lastname: Al-Mefty
authors.affiliation: Neuroradiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; and.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Mukundan
authors.affiliation: Departments of 1 Neurosurgery and.
authors.forename: Ian F
authors.initials: IF
authors.lastname: Dunn
mesh_terms: D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction / Q000379:methods; D002533:Cerebral Angiography / Q000379:methods*; D002536:Cerebral Arteries / Q000000981:diagnostic imaging* / Q000473:pathology; D002550:Cerebral Veins / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D010690:Phlebography / Q000379:methods; D011300:Preoperative Care / Q000379:methods*; D012039:Regional Blood Flow; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D019292:Skull Base Neoplasms / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000601:surgery; D036542:Tomography, Spiral Computed / Q000379:methods*
keywords: CTA = CT angiography; CTDIvol = volumetric CT dose index; CTV = CT venography; DLP = dose length product; DSA = digital subtraction angiography; MRA = MR angiography; MRV = MR venography; dynamic CT angiography; preoperative surgical planning; skull base surgery; skull base tumors; venous anatomy