title: Three-dimensional time-of-flight MR angiography at 3 T compared to digital subtraction angiography in the follow-up of ruptured and coiled intracranial aneurysms: a prospective study.
abstract: BACKGROUND
  Since digital subtraction angiography (DSA) carries a low risk of morbidity, and is associated with patient discomfort and higher cost, our objective was to determine whether high-resolution 3-D time-of-flight MR angiography (TOF-MRA) at 3 T may replace DSA in the follow-up of patients after coiling of an intracranial aneurysm.
  
  
  METHODS
  This prospective study included 50 consecutive patients with a ruptured and subsequently coiled intracranial aneurysm. All patients were followed up at a mean of 14 months after coiling with DSA and high-resolution 3-D TOF-MRA at 3 T generating 0.02 mm3 isotropic voxels. One examiner used DSA and TOF-MR angiograms to assess the need for and risk of retreatment; these data were used to calculate intermodality agreement. Another two examiners independently assessed aneurysm occlusion by DSA and TOF-MRA according to the Raymond scale; these data were used to calculate interobserver agreement.
  
  
  RESULTS
  Discrepancies between DSA and TOF-MRA were found in three patients (intermodality agreement kappa=0.86). While DSA indicated complete aneurysm occlusion, TOF-MRA showed small neck remnants in the three patients. Coils on all DSA projections obscured these three neck remnants. Interobserver agreement was higher for DSA (kappa=0.82) than for TOF-MRA (kappa=0.68), which was in part due to the complexity of the information provided by TOF source images and reconstructions.
  
  
  CONCLUSIONS
  3-D TOF-MRA at 3 T is not only an adjunctive tool but is ready to replace DSA in the follow-up of patients with previously coiled intracranial aneurysms. Additional DSA may only be performed in complex and not clearly laid out aneurysms.
authors.affiliation: Department of Radiology, University of Bonn Medical Centre, Bonn, Germany. urbach@uni-bonn.de
authors.forename: H
authors.initials: H
authors.lastname: Urbach
authors.forename: U
authors.initials: U
authors.lastname: Dorenbeck
authors.forename: M
authors.initials: M
authors.lastname: von Falkenhausen
authors.forename: K
authors.initials: K
authors.lastname: Wilhelm
authors.forename: W
authors.initials: W
authors.lastname: Willinek
authors.forename: C
authors.initials: C
authors.lastname: Schaller
authors.forename: S
authors.initials: S
authors.lastname: Flacke
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017542:Aneurysm, Ruptured / Q000000981:diagnostic imaging* / Q000628:therapy; D015901:Angiography, Digital Subtraction; D002648:Child; D004621:Embolization, Therapeutic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000628:therapy; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D016896:Treatment Outcome