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

Abstract

Background and purpose: 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.

Materials and methods: 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.

Results: 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.

Conclusions: 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.

Fig 1.

Flow chart showing patient selection.

Fig 2.

A 64-year-old man with oculomotor nerve palsy from a partially thrombosed giant cavernous sinus aneurysm. A, Axial T2-weighted MR image at presentation shows a 30-mm right cavernous sinus aneurysm, partially thrombosed. B, Complete thrombosis of the aneurysm on an MR image 1 day after occlusion of the right ICA. C, Three months later, the aneurysm has decreased to half its initial size. D, Two and a half years after ICA occlusion, the aneurysm is completely obliterated. The patient is asymptomatic.

Fig 3.

A 10-year-old boy with symptoms of brain stem compression from a giant partially thrombosed distal vertebral aneurysm. A, Sagittal T1-weighted MR image shows a giant aneurysm with intraluminal thrombus located on the right vertebral artery compressing the brain stem. B, Right vertebral angiogram demonstrates the lumen of the aneurysm of the V4 segment distal to the PICA. C, Left vertebral angiogram shows supply of the posterior circulation with exception of the right PICA territory. D and E, Bilateral vertebral angiogram (D) and nonsubtracted image (E) after coil occlusion of the fusiform V4 aneurysm. Supply to all posterior circulation vessels is preserved. F, Sagittal T1-weighted MR image 6 months later shows reduction in aneurysm size and reduction of mass effect on the brain stem. The patient is asymptomatic.

Fig 4.

A 49-year-old man with abducens nerve palsy from a partially thrombosed PICA aneurysm projecting into the brain stem. A, Contrast-enhanced T1-weighted MR image at presentation shows a 10-mm aneurysm on the right PICA projecting into the brain stem with intraluminal thrombus. B, Left vertebral angiogram before coiling demonstrates the small aneurysm lumen. C and D, Axial T2-weighted MR image at presentation shows brain stem edema. E and F, One and a half years after selective coiling of the PICA aneurysm, the brain stem edema is resolved. The patient is asymptomatic.

Fig 5.

A 55-year-old woman with brain stem compression from a partially thrombosed PICA aneurysm. A, Axial T1-weighted MR image at presentation shows a 32-mm left PICA aneurysm with a large intraluminal thrombus. B, Left vertebral angiogram shows the small aneurysm lumen. C and D, Angiogram (C) and nonsubtracted image (D) after the second coiling show 2 separate coil meshes: The first coil mesh has migrated into the thrombus, and the second coil mesh occludes the lumen.