Case reportReversible hemispheric hypoperfusion in two cases of SMART syndrome
Section snippets
Case 1
A 52-year-old man presented with headache, dysphasia, right hemiparesis and right homonymous hemianopia. Quantitative CTP was performed using automated RAPID quantification of ‘core infarct’ (relative cerebral blood flow <30% of contralateral hemisphere) and penumbra (Tmax >6 s) with a Siemens Definition AS+ scanner (69 mm coverage with 30 acquisitions over 60 s [1].) It demonstrated large volume left hemispheric hypoperfusion (Fig. 1A) with core infarct calculated at 11 mL and penumbra >70 mL,
Case 2
A 75-year-old man developed acute-onset dysphasia, right hemianopia, hemisensory inattention and headache. Quantitative CTP (as above but with 96 mm coverage) demonstrated left hemispheric hypoperfusion, near-identical to Case 1 (Fig. 3A). CTA showed no carotid territory steno-occlusive disease. Two similar episodes occurred in the six months prior, without restricted diffusion on MRI. Four years prior, he had received radiotherapy for a single cerebral metastasis (non-small cell lung cancer).
Discussion
The precise pathophysiology of SMART syndrome is unknown; radiation-induced cortical hyperexcitability analogous to hemiplegic migraine has been proposed [4]. Our cases demonstrate that hemispheric cerebral ischaemia occurs hyper-acutely in SMART syndrome and is fully reversible. In both cases, substantial volumes of tissue reached ‘penumbral’ hypoperfusion thresholds [2], suggesting impaired cerebrovascular autoregulation as a contributor to prolonged cortical dysfunction in SMART syndrome.
Conflict of interest statement
On behalf of all authors, the corresponding author states that there is no conflict of interest.
Acknowledgements
Nil.
References (7)
- et al.
Imaging selection in ischemic stroke: feasibility of automated CT-perfusion analysis
Int J Stroke
(2015) - et al.
Hemiplegic migraine aura begins with cerebral hypoperfusion: imaging in the acute phase
Headache
(2011) - et al.
SMART: stroke-like migraine attacks after radiation therapy
Cephalalgia
(2006)