Fig. 1

Preoperative investigations. (a) Magnetic resonance imaging (MRI) on admission shows a small infarction in the left parietal lobe on diffusion-weighted imaging (DWI). (b) MR angiography on admission shows occlusion of the M2 inferior trunk of the middle cerebral artery (MCA). (c) Serial MRI shows expansion of cerebral infarction on DWI. D, E: Lateral view of right carotid angiograms. (d) In the early phase, there is an avascular area in the territory of the M2 inferior trunk. (e) In the late phase, vessels that belong to the M2 inferior trunk are represented by retrograde flow from the anterior cerebral artery. (f) Arterial spin labeling (ASL) perfusion imaging showed decreased intensity in the M2 inferior trunk of the right MCA territory