Unexpected Cerebral Hyperperfusion after Transient Hypoperfusion Associated with Stroke-like Migraine Attacks after Radiation Therapy Syndrome.

Stroke-like migraine attacks after radiation therapy (SMART) syndrome, a delayed sequela of cranial radiotherapy encountered rarely, occurs due to transient neurological deficits coupled with migraine episodes. This case report describes an occurrence of SMART syndrome in an individual 8 years after receiving medulloblastoma treatment. The subject, a 21-year-old male, experienced abrupt aphasia and right-sided hemiparesis. Arterial spin labeling (ASL) revealed initial cerebral hypoperfusion in the left temporal and parietal regions, with no tumor resurgence or notable ischemic alterations. Two days later, the symptoms disappeared completely; nevertheless, at that time, ASL presented cerebral hyperperfusion in the same lobule. The subject experienced a pulsating headache and nausea the next day. In the context of SMART syndrome, this fluctuation in cerebral blood flow indicated by ASL is a unique finding. The significance of this case lies in the documentation of the dynamic evolution of cerebral perfusion in SMART syndrome via ASL, thereby elucidating its underlying pathophysiology. As hemiplegic migraine shows a similar cerebral perfusion pattern to SMART syndrome, we inferred an unexplored but shared pathophysiology among hemiplegic migraine and SMART syndrome. Through this successful capture of these distinct cerebral blood flow alterations, from hypoperfusion to hyperperfusion, our understanding of the pathophysiological intricacies inherent to SMART syndrome will be enhanced.