PMC9560543_01
Initial computed tomography shows subarachnoid hemorrhage (SAH) and hematoma in the left temporal lobe (A). Three-dimensional (3D) -rotation angiography of left internal carotid artery (ICA) (B), conventional left ICA angiography (C), and vascular structure schema (D) shows three consecutive aneurysms at the left M1 segment, A1-M1 anastomosis (arrowheads), and M1-M2 anastomosis (arrows). The most distal aneurysm is a ruptured cerebral aneurysm with a bleb (asterisk).
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A computed tomography (CT) scan of the head revealed a subarachnoid hemorrhage (SAH) with an intracerebral hematoma (Fig. 1A). Thin anastomotic vessels were also observed at M1 and M2 (Fig. 1B-D).
Clipping of a ruptured aneurysm was performed by securing the internal carotid artery (star) via a sub frontal approach. The anastomosis between the left M1 and M2 was confirmed during the operation (arrows).
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The vessels that anastomosed M1 and M2 were observed visually during the procedure (Fig. 2).
Superselective angiography performed by inserting a microcatheter into M1 shows three consecutive aneurysms, and the most distal aneurysm has lost its bleb due to clipping (asterisk). (A) Conventional left internal carotid artery (ICA) angiography (B) and vascular structure schema (C) visualized superselective balloon test occlusion performed by occluding the same site (shaded area), which reveals a slight stump (arrow) but no aneurysms. The distal left M2 was perfused by the A1-M1 anastomosis. Three-dimensional-rotation angiogram of the left ICA after endovascular treatment (D) shows that the blood flow to the aneurysms had completely disappeared. Furthermore, LSA branching from A1-M1 anastomosis (arrows) is preserved.
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When the microcatheter was engaged in the M1 for ssBTO, the blood flow in the MCA was completely discontinued (Fig. 3A). An angiography during ssBTO showed no retrograde perfusion of the aneurysm, and the area distal to M2 was visualized from the blood vessels anastomosing the anterior cerebral artery (ACA) and MCA (Fig. 3B). PAO was performed at this site (Fig. 3C, D). Postoperative head MRI showed no cerebral infarction and no new neurological findings.