MR Imaging of Bilateral Paramedian Thalamic and Mesencephalic Infarcts. A Case Report.

We describe MR imaging of bilateral infarction of the paramedian portion of the mesencephalus and thalamus due to an occlusion of the Percheron artery. This entity is due to one of the anatomic variants of the perforating arteries supplying the thalamus and mesenchephalus. Clinically this kind of infarction presents with neurologic impairment as a disorder of consciousness, memory dysfunctions, various types of vertical gaze palsy and psychic changes, which need to be differentiated from delirium and coma. At MRI evaluation infarction of the paramedian portion of thalami and midbrain, with a "butterfly wings" pattern, was demonstrated as high signal intensity areas on FLAIR and FSE-T2W images and with diffusion restriction on DWI images.