case_images: PMC5234299_01
case_images: Preoperative axial (a) and mid-sagittal (b) T2-weighted images obtained on admission demonstrating a giant round mass at the frontal interhemispheric fissure, which was 39 mm in diameter. This lesion was largely thrombosed but incorporated flow void signals, which suggested a partially thrombosed aneurysm. Inflow (black arrow) and outflow (white arrowhead) arteries were located behind and at the upper surface of the aneurysm, respectively. Postoperative axial (c) and mid-sagittal (d) T2-weighted images obtained 1 year postoperatively showing significant reduction of the aneurysm
case_images: SNI-7-1069-g001.jpg
case_images: PMC5234299_01_SNI-7-1069-g001.jpg
case_images: F1
case_images: Native and contrast-enhanced magnetic resonance imaging (MRI) showed a heterogeneous round mass compressing the bilateral optic nerves and rectal gyri, which was 39 mm in maximum diameter, in the anterior interhemispheric fissure [Figure 1a and b]. Follow-up MRI 1 year after the surgery showed a significant decrease in the size of the aneurysm [Figure 1c and d].
case_images: A three-dimensional computed tomography angiogram (a) revealing a doughnut-shaped giant aneurysm at the A2 portion of the right anterior cerebral artery. The asterisk indicates intramural thrombosis. The entire schema of this case is a doughnut-shaped aneurysm (b)
case_images: SNI-7-1069-g002.jpg
case_images: PMC5234299_01_SNI-7-1069-g002.jpg
case_images: F2
case_images: A2 segment of the right anterior cerebral artery (ACA) and central thrombosis, suggesting a partially thrombosed aneurysm [Figure 2]. An outflow artery from the aneurysm arose from the top of the aneurysm under the genu of the corpus callosum, and an inflow artery was deeply located behind the aneurysm.
case_images: Preoperative right (a) and left (b) internal carotid angiograms demonstrating a giant aneurysm as a doughnut-shaped structure. Postoperative right (c) and left (d) internal carotid angiograms on the day after surgery revealing no filling of the aneurysm and right peripheral anterior cerebral arteries perfused by contralateral anterior cerebral arteries (arrowheads)
case_images: SNI-7-1069-g003.jpg
case_images: PMC5234299_01_SNI-7-1069-g003.jpg
case_images: F3
case_images: Diagnostic cerebral angiography demonstrated it as an intraluminal filling defect shaped like a doughnut, which supplied no frontal branches [Figure 3a and b].