Unenhanced Time-of-Flight MR Angiography versus Gadolinium-Enhanced Time-of-Flight MR Angiography in the Follow-Up of Coil-Embolized Aneurysms

Abstract

Background and Purpose Coil embolization of ruptured and unruptured aneurysms has emerged as a widely accepted alternative to clipping. Unfortunately, coil-embolized aneurysms need a long-term imaging follow-up to confirm the stability of the occlusion status. We investigated whether contrast-enhanced time-of-flight (ToF) magnetic resonance angiography (MRA) (gadolinium [Gd]-ToF) provides any diagnostic benefit over conventional ToF MRA (nonenhanced [NE]-ToF) in this context.

Material and Methods From October 2013 to January 2015, all patients who were regularly scheduled for their follow-up after coil embolization were examined with Gd-ToF and NE-ToF angiography. The general visibility of the occlusion result was compared between the two MRAs as well as with the last digital subtraction angiography (DSA) available. Subgroups of interest (follow-up after stent-assisted coil embolization, cases with already known aneurysm remnants) were also analyzed.

Results A total of 70 patients (44 female) harboring 74 treated aneurysms were examined. The reproducibility of the DSA result in terms of therapeutic relevance was 100%. In 10 of 74 cases (14%), the aneurysm status was more difficult to judge in the NE-ToF images (p = 0.02), and the visualization of small vessels was significantly better in the Gd-ToF (p = 0.003). NE-ToF did not fail to show any aneurysm remnants but were more difficult to depict in 35% of the cases (p = 0.09). Regarding the aneurysms that were coiled with stent assistance, there was no significant difference in terms of the visualization (p = 0.1).

Conclusion Gd-ToF angiography is in general not superior to NE- ToF for the follow-up of coil-embolized aneurysms.

Keywords

aneurysm - coil embolization - time of flight

• References

• 1 Molyneux A, Kerr R, Stratton I , et al; International Subarachnoid Aneurysm Trial (ISAT) Collaborative Group. International Subarachnoid Aneurysm Trial (ISAT) of neurosurgical clipping versus endovascular coiling in 2143 patients with ruptured intracranial aneurysms: a randomised trial. Lancet 2002; 360 (9342) 1267-1274
• 2 Molyneux AJ, Birks J, Clarke A , et al. The durability of endovascular coiling versus neurosurgical clipping of ruptured cerebral aneurysms: 18 year follow-up of the UK cohort of the International Subarachnoid Aneurysm Trial (ISAT). Lancet 2015; 385 (9969) 691-697
• 3 van Rooij WJ, Sluzewski M. Procedural morbidity and mortality of elective coil treatment of unruptured intracranial aneurysms. AJNR Am J Neuroradiol 2006; 27 (8) 1678-1680
• 4 Sluzewski M, van Rooij WJ, Slob MJ, Bescós JO, Slump CH, Wijnalda D. Relation between aneurysm volume, packing, and compaction in 145 cerebral aneurysms treated with coils. Radiology 2004; 231 (3) 653-658
• 5 Raymond J, Guilbert F, Weill A , et al. Long-term angiographic recurrences after selective endovascular treatment of aneurysms with detachable coils. Stroke 2003; 34 (6) 1398-1403
• 6 Majoie CB, Sprengers ME, van Rooij WJ , et al. MR angiography at 3T versus digital subtraction angiography in the follow-up of intracranial aneurysms treated with detachable coils. AJNR Am J Neuroradiol 2005; 26 (6) 1349-1356
• 7 Buhk JH, Kallenberg K, Mohr A, Dechent P, Knauth M. Evaluation of angiographic computed tomography in the follow-up after endovascular treatment of cerebral aneurysms—a comparative study with DSA and TOF-MRA. Eur Radiol 2009; 19 (2) 430-436
• 8 Pierot L, Portefaix C, Boulin A, Gauvrit JY. Follow-up of coiled intracranial aneurysms: comparison of 3D time-of-flight and contrast-enhanced magnetic resonance angiography at 3T in a large, prospective series. Eur Radiol 2012; 22 (10) 2255-2263
• 9 Buhk JH, Kallenberg K, Mohr A, Dechent P, Knauth M. 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. Neuroradiology 2008; 50 (10) 855-861
• 10 Yano T, Kodama T, Suzuki Y, Watanabe K. Gadolinium-enhanced 3D time-of-flight MR angiography. Experimental and clinical evaluation. Acta Radiol 1997; 38 (1) 47-54
• 11 Boulin A, Pierot L. Follow-up of intracranial aneurysms treated with detachable coils: comparison of gadolinium-enhanced 3D time-of-flight MR angiography and digital subtraction angiography. Radiology 2001; 219 (1) 108-113
• 12 Cottier JP, Bleuzen-Couthon A, Gallas S , et al. Intracranial aneurysms treated with Guglielmi detachable coils: is contrast material necessary in the follow-up with 3D time-of-flight MR angiography?. AJNR Am J Neuroradiol 2003; 24 (9) 1797-1803
• 13 Weber W, Bendszus M, Kis B, Boulanger T, Solymosi L, Kühne D. A new self-expanding nitinol stent (Enterprise) for the treatment of wide-necked intracranial aneurysms: initial clinical and angiographic results in 31 aneurysms. Neuroradiology 2007; 49 (7) 555-561
• 14 Sprengers ME, Schaafsma JD, van Rooij WJ , et al. Evaluation of the occlusion status of coiled intracranial aneurysms with MR angiography at 3T: is contrast enhancement necessary?. AJNR Am J Neuroradiol 2009; 30 (9) 1665-1671
• 15 Cho WS, Kim SS, Lee SJ, Kim SH. The effectiveness of 3T time-of-flight magnetic resonance angiography for follow-up evaluations after the stent-assisted coil embolization of cerebral aneurysms. Acta Radiol 2014; 55 (5) 604-613
• 16 Cho YD, Kim KM, Lee WJ , et al. Time-of-flight magnetic resonance angiography for follow-up of coil embolization with enterprise stent for intracranial aneurysm: usefulness of source images. Korean J Radiol 2014; 15 (1) 161-168