SMART syndrome, an acronym for stroke-like migraine attacks after radiation therapy, is an uncommon delayed complication of cerebral radiation therapy.
Patients usually present years after radiation therapy (6-30 years in a case series) with seizures and subacute stroke-like episodes with symptoms such as hemiplegia, aphasia, and hemianopia 6. These episodes have been associated with headaches and are often preceded by a migraine-like aura 1-2.
MRI is the modality of choice to investigate SMART syndrome.
Features of laminar necrosis in the involved territory, such as cortical calcifications, can be seen following the initial episode.
The hallmark of SMART syndrome is prominent unilateral gyral enhancement with mild mass effect, usually in an area included in the radiation ports. It is also observed as cortical thickening (hyperintense in T2 and FLAIR) with or without diffusion restriction. In one case series, features of cortical laminar necrosis were present in ~27% of patients and manifested as early as 17 days following the initial event.
- T1: hyperintense signal within the cortex can be seen if associated with cortical laminar necrosis
- T2/FLAIR: hyperintense signal, often with cortical thickening
- DWI: diffusion restriction is variably seen
- SWI: foci of susceptibility artifacts may be seen, thought to be related to cavernous malformations induced by remote radiotherapy
- T1C+ (Gd): prominent unilateral gyriform enhancement (cortical and leptomeningeal)
Treatment and prognosis
Typically, the condition is self-limiting and gradually resolves over the course of several weeks 4. However, in one case series, incomplete recovery was noted in ~45% of subjects 6.
- nonconvulsive status epilepticus and repeated partial seizures: may demonstrate similar imaging and clinical features
- peri-ictal pseudoprogression: similar to nonconvulsive status epilepticus and repeated partial seizures, but occurring in patients with brain tumours 6,7
- subacute cerebral infarction
- posterior reversible encephalopathy syndrome (PRES)
- 1. Caplan LR. Caplan's Stroke, A Clinical Approach. Saunders. (2009) ISBN:1416047212. Read it at Google Books - Find it at Amazon
- 2. Bartleson JD, Krecke KN, O'neill BP et-al. Reversible, strokelike migraine attacks in patients with previous radiation therapy. Neuro-oncology. 2003;5 (2): 121-7. doi:10.1215/S1522-8517-02-00040-6 - Free text at pubmed - Pubmed citation
- 3. Kerklaan JP, Lycklama á nijeholt GJ, Wiggenraad RG et-al. SMART syndrome: a late reversible complication after radiation therapy for brain tumours. J. Neurol. 2011;258 (6): 1098-104. doi:10.1007/s00415-010-5892-x - Free text at pubmed - Pubmed citation
- 4. Bradshaw J, Chen L, Saling M et-al. Neurocognitive recovery in SMART syndrome: a case report. Cephalalgia. 2011;31 (3): 372-6. doi:10.1177/0333102410388436 - Pubmed citation
- 5. Khanipour Roshan S, Salmela MB, McKinney AM. Susceptibility-weighted imaging in stroke-like migraine attacks after radiation therapy syndrome. Neuroradiology 2015;57(11):1103-9. doi: 10.1007/s00234-015-1567-8. Epub 2015 Aug 5. http://www.ncbi.nlm.nih.gov/pubmed/26242361
- 6. Black DF, Morris JM, Lindell EP, Krecke KN, Worrell GA, Bartleson JD, Lachance DH. Stroke-like migraine attacks after radiation therapy (SMART) syndrome is not always completely reversible: a case series. (2013) AJNR. American journal of neuroradiology. 34 (12): 2298-303. doi:10.3174/ajnr.A3602 - Pubmed
- 7. Rheims S, Ricard D, van den Bent M, Taillandier L, Bourg V, Désestret V, Cartalat-Carel S, Hermier M, Monjour A, Delattre JY, Sanson M, Honnorat J, Ducray F. Peri-ictal pseudoprogression in patients with brain tumor. (2011) Neuro-oncology. 13 (7): 775-82. doi:10.1093/neuonc/nor082 - Pubmed