Intracranial aneurysms treated with Guglielmi detachable coils: long-term imaging follow-up with contrast-enhanced magnetic resonance angiography

Object. The aim of this study was to assess the long-term results of intracranial aneurysms treated with Guglielmi detachable coils (GDCs) with the aid of contrast-enhanced magnetic resonance (MR) angiography. Methods. Between January 1998 and August 2001, 92 patients with 92 aneurysms treated by endovascular coiling with GDCs underwent contrast-enhanced MR angiography. These patients underwent long-term follow-up (range 3278 months, mean 42.1 +/- 11.9 months [standard deviation]) after endovascular treatment. All images were compared with digital subtraction angiograms and contrast-enhanced MR angiograms that had been obtained during the short-term follow-up (range 5-25 months, mean 13 +/- 5.1 months after treatment). The MR angiograms were analyzed independently by 2 senior radiologists. Findings were assigned to 1 of 3 categories: complete obliteration (Class 1), residual neck (Class 2), or residual aneurysm (Class 3). Results. Of 92 contrast-enhanced MR angiograms obtained at the long-term follow-up, complete obliteration of the aneurysm was noted in 57 patients (Class 1), a residual neck was seen in 22 (Class 2), and a residual aneurysm was observed in 13 (Class 3). One patient experienced aneurysm rehemorrhaging during the follow-up period. The comparison of short- and long-term follow-up angiograms demonstrated a change in aneurysm classification in 7 patients (7.6%), including 4 that progressed from Class I to Class 2 and 3 from Class 2 to Class 3. However, 4 (14.2%) of the 28 long-term recurrences were not detected on the short-term control images. Conclusions. Long-term follow-up with contrast-enhanced MR angiography after selective embolization of intracranial aneurysms can identify late aneurysm recanalization that is undetected at short-term follow-up.