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A female 60-year-old long-term survivor of high-grade glioma presented with progressive migraine-like left-sided cephalgia and expressive aphasia for three days. Ten years ago, a left temporo-occipital IDH-wildtype glioblastoma was treated with radiochemotherapy per EORTC 26981/22981 (TMZ/RT → TMZ; 60 Gy in 30 fractions) resulting in complete remission on follow-up imaging (A). On admission, repetitive EEG was negative for patterns on the ictal-interictal continuum. Brain MRI revealed faint gyriform contrast-enhancement (arrowheads) and enlarged vessels (arrows) in gadolinium-enhanced T1-weighted imaging, left temporo-occipital edema adjacent to radiation-induced white matter-hyperintensity on T2-weighted imaging with corresponding diffusion restriction, and temporo-occipital elevation of the left cortical blood volume (CBV) of the previously irradiated left temporo-occipital brain region in comparison to the contralateral hemisphere in perfusion MRI sequences (5.6 mL/100 g vs. 3.1 mL/100 g; B). [18F]fluorethyltyrosine ([18F]FET)-PET detected corresponding gyral tracer uptake with moderate signal intensity and increasing time-activity-curves, not typical for tumor recurrence (C) [1]. Diagnosis of stroke-like migraine attacks after radiation therapy (SMART) syndrome was given [2]. Under supportive therapy, symptoms and imaging abnormalities fully resolved within 6 weeks (D). ([18F]FET)-PET 1 year after symptoms showed complete regression of the gyral tracer uptake. SMART syndrome represents a rare, delayed complication of brain-directed radiotherapy involving impaired cerebrovascular autoregulation [3]. Symptoms are characteristically transient in nature, and diagnosis rests upon distinct clinico-radiographic findings as well as exclusion of differentials. To our knowledge, this is the first case demonstrating [18F]FET-PET imaging in a patient with ongoing SMART syndrome, which could potentially improve diagnostic accuracy by exclusion of important differentials such as tumor recurrence.

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