Introduction: MR angiography has become used regularly as a method to evaluate intracranial aneurysms after primary coiling. Digital subtraction angiography (DSA) remains the gold-standard for follow up of these patients. Our goal is to use a large database of patients that have undergone primary coiling, and follow up evaluation with DSA, MRA TOF (time of flight), MRA CE (contrast enhanced) and MPRAGE sequences to determine whether non-invasive methods can substitute DSA as follow up.

Methods: We performed a retrospective study from October 2007 through July 2013, with 54 patients (63 aneurysms). The most common aneurysm site was the anterior communicating artery (27.1%). MRAs were performed on a 3.0T scanner and filling was compared to a follow up DSA. Using Raymond criteria, aneurysm residual is categorized into 3 classes: 1) complete occlusion, 2) residual neck and 3) residual aneurysm. We calculated sensitivities and specificities for each of the MRA sequences, compared to DSA.

Results: FFollow up Digital Subtraction Angiography (DSA) demonstrated 40 (63.5%) complete occlusions (class 1), 16 (25.4%) residual necks (class 2) and 7 (11.1%) residual aneurysms (class 3). The sensitivity and specificity of MRA TOF to accurately identify class 1 aneurysm was 68% and 86%; for class 2 it was 64% and 66%; and for Class 3 it was 43% and 94%, respectively. The other sequences were similarly analyzed and yielded similar results.

Conclusions: Our study included a relatively large number of aneurysms. The specificity of all sequences (TOF, CE, and MPRAGE) to detect complete occlusion (Class 1) or residual aneurysm (Class 3) was very high, in the range 85% to 94. Sensitivity of the modalities was less robust. These findings suggest that MRA techniques are very reliable (high positive predictive value (PPV) above 0.9) at identifying patients with complete aneurysmal occlusion and may be use to follow patients after aneurysm coiling.

Patient Care: Confirmation of a viable non-invasive method to follow up these patients treated with primary coiling would significantly improve patient care by decreasing the risk of morbidity associated with conventional angiogrraphy, while still accurately assessing aneurysm occlusion.

Learning Objectives: By the conclusion of this session, participants should be able to: 1. Understand the different MRA techniques used to evaluate treated (coiled) intracranial aneurysms. 2. Discuss the accuracy of the different MRA techniques as it compares to DSA (digital subtraction angiography). 3. Understand the relevance of non-invasive techniques for evaluation of patients treated endovascularly for aneurysms.

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