Subfalcine herniation from complete MCA infarct, complicated by ACA infarct
Presentation
Complete left sided hemiparesis.
Patient Data
Complete right MCA territory infarct with pronounced midline shift (subfalcine herniation). The right thalamus is displaced to the left of midline (not shown). Ipsilateral distal ACA is likely to be compressed by the subfalcine herniation, resulting in infraction of the right superior frontal gyrus.
The right lateral ventricle is effaced by the mass effect with a "trapped" left lateral ventricle. Periventricular hypodensities at the trigone region of the left lateral ventricle may represent transepenedymal migration of CSF.
Apparent hyperdensities along the region of Sylvian fissure, cortical sulci and M1 segment of MCA may reflect increased cerebral pressure - the so-called "pseudosubarachnoid hemorrhage". Alternatively, the hyperdense M1 may represent an in-situ thrombus.
Case Discussion
An ACA territory infarct can occur as a complication of an MCA territory infarct - midline shift from vasogenic edema results in stretching and eventual occlusion of the anterior cerebral artery.