Spontaneous complete occlusion of middle cerebral artery aneurysm: case report

Abstract

There are few observation papers regarding the natural history of an aneurysm. We report on a case of a completely occluded middle cerebral artery (MCA) aneurysm. A 47-year-old female patient presented with a headache and was diagnosed with rupture of a right MCA aneurysm. Due to a high risk of direct neck clipping, she received conservative treatment after craniotomy and wrapping of her aneurysm. The patient's condition showed improvement, with complete occlusion of the aneurysm and considerable reduction of the aneurysm in size after approximately three years. This is a rare case of an aneurysm of MCA that showed spontaneous resolution. Finally, on the angiogram, characteristics of an aneurysm to occlude spontaneously will be presumed based on literature reviews.

Keywords: Angiography; Middle cerebral artery aneurysm; Spontaneous remission.

Fig. 1

(A) Axial computed tomography (CT) scan shows a slightly high-density intra axial mass lesion measuring approximately 2.5 cm, along the peripheral side of the right sylvian fissure. No edema was observed around the mass. There was no calcification either. (B) After contrast enhancement, the mass lesion showed significant enhancement. (C) Three-dimensional CT angiography reconstruction showing a saccular aneurysm in the right middle cerebral artery (MCA) bifurcation.

Fig. 2

(A) T2 weighted images from a brain magnetic resonance image (MRI) examination show a high signal in the aneurysm sac and a heterogeneous, peripheral low signal. (B) T1 weighted image shows a low signal in a portion close to the Circle of Willis and an iso signal far from it. (C) After contrast enhancement, strong improvement with a filling difference in the aneurysm sac is observed.

Fig. 3

Right internal carotid artery angiogram (three-dimensional subtraction image) posterior to anterior view. An aneurysm measuring 21.6 × 20.9 mm in the right MCA bifurcation is observed in a lateral direction, and an aneurysm of the right MCA bifurcation formed a broad neck along an inferior branch of M2. Several perforating branches are observed around the neck.

Fig. 4

Right internal carotid artery angiogram. Slow filling and delayed excretion pattern are noted (A, B and C).

Fig. 5

(A) MRI obtained eight months later. A target sign that appeared as a high signal, a low signal in the slightly inner portion and a high signal again in the central portion, is seen on the T1 image around the aneurysm. (B) After 19 months, the size of the aneurysm shows a considerable decrease.

Fig. 6

(A) MRI obtained three years and eight months later, showing considerable reduction in the size of the aneurysm and no trace of the mass in the sylvian fissure. (B) Three-dimensional angiography reveals an occlusion of the aneurysm and intact M2 branches.