Jean-Yves Gauvrit, Sabine Caron, Christian A. Taschner, Jean-Paul Lejeune, Jean-Pierre Pruvo and Xavier Leclerc
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.
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 32–78 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).
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 1 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.
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.
Christian A. Taschner, Vianney Le Thuc, Nicolas Reyns, Juergen Gieseke, Jean-Yves Gauvrit, Jean-Pierre Pruvo and Xavier Leclerc
The aim of this study was to develop an algorithm for the integration of time-resolved contrast-enhanced magnetic resonance (MR) angiography into dosimetry planning for Gamma Knife surgery (GKS) of arteriovenous malformations (AVMs) in the brain.
Twelve patients harboring brain AVMs referred for GKS underwent intraarterial digital subtraction (DS) angiography and time-resolved MR angiography while wearing an externally applied cranial stereotactic frame. Time-resolved MR angiography was performed on a 1.5-tesla MR unit (Achieva, Philips Medical Systems) using contrast-enhanced 3D fast field echo sequencing with stochastic central k-space ordering. Postprocessing with interactive data language (Research Systems, Inc.) produced hybrid data sets containing dynamic angiographic information and the MR markers necessary for stereotactic transformation. Image files were sent to the Leksell GammaPlan system (Elekta) for dosimetry planning.
Stereotactic transformation of the hybrid data sets containing the time-resolved MR angiography information with automatic detection of the MR markers was possible in all 12 cases. The stereotactic coordinates of vascular structures predefined from time-resolved MR angiography matched with DS angiography data in all cases. In 10 patients dosimetry planning could be performed based on time-resolved MR angiography data. In two patients, time-resolved MR angiography data alone were considered insufficient. The target volumes showed a notable shift of centers between modalities.
Integration of time-resolved MR angiography data into the Leksell GammaPlan system for patients with brain AVMs is feasible. The proposed algorithm seems concise and sufficiently robust for clinical application. The quality of the time-resolved MR angiography sequencing needs further improvement.