Fig. 1

a Brain computed tomography scan showing diffuse subarachnoid hemorrhage; a short streak-like high-density shadow is seen next to the M1 segment of the right middle cerebral artery. b Bone computed tomography scan with evidence of a short strip-like dense shadow in the right cerebral hemisphere. c, d Computed tomography angiography (CTA) of the head and neck shows calcified plaques with severe luminal stenosis and foreign body presence at the M1 bifurcation of the right segment of the middle. e, f Cerebral angiogram showing a foreign body penetrating the middle cerebral artery with a saccular aneurysm arising from the inferior wall, which was considered a intracranial pseudoaneurysm. The red arrow in a–f indicates a foreign body