Long-term prospective follow-up of intracranial aneurysms treated with endovascular coiling using contrast-enhanced MR angiography

Abstract

Background and purpose: Catheter angiography has been the criterion standard for follow-up evaluation of coiled intracranial aneurysms. In our center, CE-MRA has been used to evaluate aneurysm recanalization. Our aim was to investigate the feasibility and usefulness of a CE-MRA protocol for following patients with intracranial aneurysms treated with endovascular coiling.

Materials and methods: From September 2003 to December 2006, 134 aneurysms were treated by endovascular coiling in 124 patients by using detachable coils. These patients were followed with CE-MRA at 3 months, 15 months, and 3 and 5 years. MRAs were analyzed by 2 interventional neuroradiologists. Findings were assigned to 3 categories: complete obliteration (class 1), residual neck (class 2), and residual aneurysm (class 3).

Results: Initially, CE-MRA demonstrated 67 (50%) complete obliterations (class 1), 57 (41.79%) residual necks (class 2), and 8 (5.97%) residual aneurysms (class 3). No patient experienced rebleed during the follow-up period. A total of 214 patient-years of follow-up were obtained (range, 0-53 months). Two (1.49%) patients died after the follow-up, and 11 (8.21%) patients were lost to follow-up. On follow-up, 76 (56.72%) patients showed stable results. Fifty-six (41.79%) aneurysms showed change in their obliteration pattern. Of these 56, 47 demonstrated recanalization and 9 (6.72%) showed further obliteration. Most of the aneurysms that showed change in their obliteration remained stable on follow-up. Only 11 (8.21% of the total and 23.4% of those who showed recanalization) patients underwent recoiling or clipping.

Conclusions: CE-MRA can be used in routine practice to follow-up aneurysm recanalization noninvasively. CE-MRA permits close-interval follow-up and may show more filling of the aneurysm neck or sac than DSA.

Fig 1.

A, CE-MRA shows large recurrent class 3 aneurysm (arrow). B, Anteroposterior angiogram of the left ICA injection shows only minimal filling of the coiled aneurysm (arrow). C, Anteroposterior angiogram of the left ICA injection after recoiling (arrow) by using two 5 mm × 20 cm and 1 each of 4 mm ×10 cm, 3 mm× 8 cm, and 2 mm × 6 cm coils. This shows the helmet effect of coils, which obscures the filling of the coiled aneurysm on the conventional angiogram.

Fig 2.

A and D, Axial base image of the CT angiography (A) performed at presentation of the patient shows an AcomA aneurysm, which is further confirmed on the subsequent conventional angiogram (D). B and E, The base image (B) and the MIP image (E) on CE-MRA performed 3 months after coiling show no evidence of residual filling. C and F, The base image (C) and the MIP image (F) on CE-MRA performed at 20 months' follow-up show a small amount of residual filling of the aneurysm near the neck, which can be more confidently seen compared with the base image of the initial CT angiogram (A).