Usefulness of silent magnetic resonance angiography for intracranial aneurysms treated with a flow re-direction endoluminal device

Purpose Flow re-direction endoluminal device (FRED) is a novel dual-layer flow-diverting stent to treat cerebral aneurysms with high obliteration rates, however, it induces inevitable metal-related artifacts. We compared silent magnetic resonance angiography (MRA), a new MRA method using ultra-short time of echo and arterial spin-labeling, with conventional time-of-flight (TOF)-MRA for imaging aneurysms treated using FRED. Methods Between May 2020 and September 2022, 16 patients with unruptured internal carotid aneurysms treated using FRED simultaneously underwent silent MRA and TOF-MRA after treatment, with 36 follow-up sessions in total. Two observers independently graded the quality of intra-aneurysmal flow and stented parent arteries under both types of MRA from 1 (not visible) to 4 (nearly equal to digital subtraction angiography [DSA]), with reference to DSA images as a standard criterion. Results The mean scores for intra-aneurysmal flow and stented parent arteries were significantly better for silent MRA (3.93 +/- 0.21 and 3.82 +/- 0.32, respectively) than for TOF-MRA (2.08 +/- 0.99 and 1.92 +/- 0.79, respectively) (P < 0.01). Intermodality agreements for intra-aneurysmal flow and stented parent arteries were 0.87 and 0.90, respectively. Conclusion Silent MRA is superior to TOF-MRA for assessing patients treated with FRED, with potential as an alternative imaging modality to DSA.