Erschienen in:
Open Access
01.10.2008 | Interventional Neuroradiology
No advantage of time-of-flight magnetic resonance angiography at 3 Tesla compared to 1.5 Tesla in the follow-up after endovascular treatment of cerebral aneurysms
verfasst von:
Jan-Hendrik Buhk, Kai Kallenberg, Alexander Mohr, Peter Dechent, Michael Knauth
Erschienen in:
Neuroradiology
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Ausgabe 10/2008
Abstract
Introduction
Long-term follow-up after coil embolization of intracranial aneurysms is mandatory to monitor coil compacting and aneurysm recurrence. Most centers perform one digital subtraction angiography (DSA) on follow-up continuing with time-of-flight magnetic resonance angiography (TOF–MRA). This study explores the diagnostic value of TOF–MRA at 1.5 T versus 3 T compared to DSA.
Materials and methods
In 18 patients with 20 aneurysms treated with coil embolization, TOF–MRA at 1.5 and 3 T were performed the day before follow-up DSA, the latter serving as reference. Optimized diagnostic protocols were applied (1.5 T: 0.78 × 0.55 × 0.8 mm, voxel size; acquisition time (TA), 6.37 min; 3 T: 0.56 × 0.45 × 0.65 mm, voxel size; TA, 3.12 min). Three independent neuroradiologists experienced in neuroendovascular therapy rated the occlusion rate (“complete occlusion” vs. “residual neck” vs. “residual aneurysm”) and compared the two methods subjectively. Weighted κ statistics were calculated to assess the level of interobserver agreement.
Results
Compared to DSA, TOF–MRA was more sensitive in detecting neck remnants, with a slight advantage at 3 T. Regarding artifact load, there are advantages at 1.5 T. Ratings of the occlusion rate correlated highly between all observers (r > 0.85, p < 0.001, respectively). Interobserver agreement was high in all cases (к
w ≈ 0.8, respectively).
Conclusion
TOF–MRA is a reliable tool for follow-up imaging of cerebral aneurysms after endovascular treatment. Our study shows no advantage of TOF–MRA at 3 T over 1.5 T, when comparable measurement protocols are applied. TOF–MRA at 1.5 T therefore provides appropriate information regarding a therapeutic decision.