Spontaneous Complete Occlusion of Middle Cerebral Artery Aneurysm: Case Report
A 46-year-old female patient visited the hospital, complaining of a headache. No abnormal findings were observed on the first neurologic examination, while other medical examinations also showed normal findings. Findings on brain computed tomography (CT) examination showed a slightly high-density intra axial mass lesion measuring approximately 2.5 cm lateral sides on the right sylvian fissure. It showed no edema around the mass, iso-density and strong enhancement without calcification inside (). According to findings on a three-dimensional CT angiogram (3-D CTA) examination, the mass was diagnosed as a saccular aneurysm in the right MCA bifurcation (). T2 weighted images from a brain magnetic resonance image (MRI) examination showed a high signal in the aneurysm and a heterogeneous peripheral low signal. At the back of the aneurysm sac, M2 branches were advanced and deviated toward the medial side. A T1 weighted image showed a low signal in a part close to the Circle of Willis and an iso signal far from it. Like the CT image, it showed a slightly low signal with dense contrast enhancement and difference in filling in the aneurysm sac (). In addition, SAH was not found on the CT examination; however, a small amount of SAH was noted around the aneurysm and along the sylvian fissure. In the right internal carotid artery (ICA) angiogram (three-dimension subtraction image) posterior to anterior view, an aneurysm measuring 21.6 × 20.9 mm in the right MCA bifurcation was observed in a lateral direction. It formed a broad neck along an inferior branch of M2 and several perforating branches were observed around the neck (). It is specific in the angiogram that the filling of the aneurysm in the early arterial phage was not partially performed. Filling of the aneurysm in the later arterial phage was completed, without excretion up to the capillary phage. This is referred to as a slow filling and delayed excretion (). The patient underwent surgery after approximately ten days. Direct clipping in the operation field was difficult; therefore, the operation was completed after wrapping the ruptured portion using surgical glue. The patient was discharged from the hospital without complications. According to findings on the MRI examination performed approximately months after discharge, a target sign that appeared as a high signal, and a low signal in a slightly inner portion and a high signal again in a central portion, was seen around the aneurysm on the T1 image (). An examination after 19 months showed that the size of the aneurysm had decreased considerably (). Finally, according to findings on the angiogram and MRI examination (which were performed after three years and eight months), there was no trace of the mass in the sylvian fissure due to the considerable reduction in the size of the aneurysm and almost everything in the M2 branch was intact ().