The changes on SWI reflect the sequelae of an increase in deoxyhemoglobin in cerebral veins, resulting in blooming and prominence (not vasodilation); note how they appear normal in size on T2-weighted images.

In addition, there is mild ipsilateral arteriospasm. The vascular changes occur on the contralateral side of the hemiparesis. Speech was affected, suggesting that the main speech center is left-sided in this patient.

No features to suggest stroke and no other cause for symptoms. 

Symptoms resolved over 24 hours with no residual neurological deficit.

These are typical features of hemiplegic migraine.