JLE

Epileptic Disorders

MENU

How to diagnose and treat post-stroke seizures and epilepsy Volume 22, numéro 3, June 2020

Figure 1

MRI findings in a 73-year-old man with status epilepticus, two years after a left middle cerebral artery ischaemic stroke with haemorrhaging. (A) FLAIR sequence showing a left temporal lobe stroke. (B) Subsequent haemorrhagic transformation of the acute ischaemic lesion (white arrow). (C) Late-onset seizures (status epilepticus), occurring after two years, are associated with DWI restriction in the left cortex in a non-vascular territory involving the frontal and parietal cortex (block white arrow); (D) complete resolution of DWI findings after two weeks.

DWI: diffusion weighted imaging; FLAIR: fluid attenuated inversion recovery.

Figure 2

Flowchart for MR signal analysis in patients with an acute seizure. We propose to start with the analysis of apparent diffusion coefficient (ADC) maps. Hypointense lesions on ADC is a reliable sign of true water restriction, which could be due to cytotoxic oedema, hypercellularity or lesions with low water content (e.g. clot, bacterial abscess) lesions. Hyperintensity on both ADC and trace images are characteristic of increased local water content, i.e. vasogenic oedema or gliosis (unless it is a T2 shine-through artefact). These lesions will show increased signal on T2/FLAIR which may or may not be enhanced on gadolinium-enhanced images. This flowchart can be meaningful if carefully analysed in combination with clinical history, patient symptoms and EEG findings. There are no hard and fast rules for differential diagnosis. A close relationship with the neuroradiologist is warranted.