Partially thrombosed intracranial aneurysms presenting with mass effect: long-term clinical and imaging follow-up after endovascular treatment

Partially thrombosed aneurysms as a distinct entity form a diverse collection of complex aneurysms characterized by organized intraluminal thrombus and solid mass. Endovascular treatment options are PVO or selective coil occlusion of the remaining lumen. We present long-term clinical and angiographic results of endovascular treatment of unruptured partially thrombosed aneurysms that presented with symptoms of mass effect. Between 1994 and 2008, 30 partially thrombosed aneurysms were treated by selective coiling and 26 by PVO. Of 56 aneurysms, 53 (95%) were large or giant. Neurologic recovery during a mean clinical follow-up of 42.7 months was established. Evolution of aneurysm size during a mean follow-up of 26.6 months in 46 patients was assessed with MR imaging. Seventeen of 56 patients (30%) fully recovered, 22 patients (39%) partially recovered, 11 patients (20%) were unchanged, and 6 patients (11%) died. Complete recovery more often occurred after PVO than after coiling (12 of 26 versus 5 of 30, P = .02). Aneurysm size reduction occurred more often after PVO (17 of 18 versus 2 of 28, P < .001). Five aneurysms continued to grow after coiling, resulting in death in 3. During follow-up, 27 additional treatments were performed in 19 patients, all treated with coiling. In partially thrombosed aneurysms presenting with mass effect, the results of PVO are much better than those of selective coiling. After coiling, additional treatments are often needed, and some aneurysms keep growing. When PVO is not tolerated or not possible, surgical options should be considered before proceeding with coiling