title: Use of CT angiography in comparison with other imaging techniques for the determination of embolus and remnant size in experimental aneurysms embolized with hydrogel filaments.
abstract: OBJECTIVE
  Beam-hardening artifacts in CTA can be greatly reduced by using metal-free coils for aneurysm embolization. We compared the embolic masses and remnants of experimental rabbit aneurysms coiled with hydrogel filaments by using DSA, CTA and histology.
  
  
  METHODS
  Embolization of 12 rabbit bifurcation aneurysms was performed with detachable hydrogel filaments. Six aneurysms were embolized as completely as possible, and 6 aneurysms were embolized incompletely to intentionally leave remnants. Three aneurysms in each group underwent follow-up at 4 and 13 weeks. DSA, MRA, and CTA were performed immediately before sacrifice. The harvested aneurysms were evaluated histologically. For each imaging technique, the areas of the embolic mass and remnant were determined by using image analysis. Results were compared by using paired t tests.
  
  
  RESULTS
  CTAs were suitable for quantification of the embolus and remnant areas because only small streaking artifacts were evident. The areas of the embolus were larger on CTA compared with DSA and histologic sections. The areas of the remnant were larger on CTA and MRA compared with DSA and histologic sections. Like DSA and MRA, CTA was suitable for determining whether aneurysm retreatment was necessary, provided that loops of hydrogel filaments were not present in the parent artery.
  
  
  CONCLUSIONS
  We demonstrated that CTA is a technique with potential for surveillance of aneurysms treated with hydrogel filaments. Additional work is required to determine the accuracy of the technique compared with currently accepted imaging modalities of DSA and MRA.
authors.affiliation: Neuroscience Institute/Department of Neurology, Paracelsus Medical University, Christian Doppler Clinic, Salzburg, Austria. m.killer@salk.at
authors.forename: M
authors.initials: M
authors.lastname: Killer
authors.forename: M R
authors.initials: MR
authors.lastname: McCoy
authors.forename: M C
authors.initials: MC
authors.lastname: Vestal
authors.forename: L
authors.initials: L
authors.lastname: Weitgasser
authors.forename: G M
authors.initials: GM
authors.lastname: Cruise
mesh_terms: D000818:Animals; D002533:Cerebral Angiography / Q000379:methods*; D004621:Embolization, Therapeutic / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D020100:Hydrogels; D002532:Intracranial Aneurysm / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery*; D020766:Intracranial Embolism / Q000000981:diagnostic imaging* / Q000209:etiology / Q000517:prevention & control; D008297:Male; D008422:Materials Testing; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015607:Stents; D016896:Treatment Outcome
chemical_list: D020100:Hydrogels