Association of ictal imaging changes in status epilepticus and neurological deterioration

Abstract

Objective: In patients with status epilepticus (SE), the clinical significance of ictal changes on magnetic resonance imaging (MRI) is insufficiently understood. We here studied whether the presence of ictal MRI changes was associated with neurological deterioration at discharge.

Methods: The retrospective cohort comprised all identifiable patients treated at Odense University Hospital in the period 2008-2017. All amenable MRIs were systemically screened for ictal changes. Patient demographics, electroencephalography, seizure characteristics, treatment, and SE duration were assessed. Neurological status was estimated before and after SE. The predefined endpoint was the association of neurological deterioration and ictal MRI changes.

Results: Of 261 eligible patients, 101 received at least one MRI during SE or within 7 days after cessation; 43.6% (44/101) had SE due to non- or less brain-damaging etiologies. Patients who received MRI had a longer duration of SE, less frequently had a history of epilepsy, and were more likely to have SE due to unknown causes. Basic characteristics (including electroencephalographic features defined by the Salzburg criteria) did not differ between patients with (n = 20) and without (n = 81) ictal MRI changes. Timing of MRI was important; postictal changes were rare within the first 24 h and hardly seen >5 days after cessation of SE. Ictal MRI changes were associated with a higher risk of neurological deterioration at discharge irrespective of etiology. Furthermore, they were associated with a longer duration of SE and higher long-term mortality that reached statistical significance in patients with non- or less brain-damaging etiologies.

Significance: In this retrospective cohort, ictal changes on MRI were associated with a higher risk of neurological deterioration at discharge and, possibly, with a longer duration of SE and poorer survival.

Keywords: DWI; duration; ictal MRI changes; imaging; long-term outcome; status epilepticus.

FIGURE 1

STROBE (Strengthening the Reporting of Observational Studies in Epidemiology)‐compliant flowchart for patient screening and identification. DWI, diffusion‐weighted imaging; EEG, electroencephalography; FLAIR, fluid‐attenuated inversion recovery; ICD, International Classification of Diseases; MRI, magnetic resonance imaging; SE, status epilepticus.

FIGURE 2

Neurological deterioration and survival. (A) Neurological deterioration in patients with status epilepticus (SE) with and without ictal magnetic resonance imaging (MRI) changes (p = .07, chi‐squared test; the group with National Institutes of Health Stroke Scale [NIHSS] score > 10 includes patients who died in‐hospital). (B) Survival of patients with and without ictal MRI changes (log‐rank test). (C) Neurological deterioration in patients with SE due to non‐ or less brain‐damaging etiologies depending on the presence or absence of ictal MRI changes (p = .005, chi‐squared test; the group with NIHSS > 10 includes patients who died in‐hospital). (D) Survival of patients with SE due to non‐ or less brain‐damaging etiologies and the presence or absence of ictal MRI changes (log‐rank test).

FIGURE 3

Duration and time of magnetic resonance imaging (MRI) under status epilepticus (SE). (A) Association of ictal MRI changes and the duration of SE in patients with SE of all etiologies and (B) in patients with SE due to non‐brain‐damaging etiologies (Whitney–Mann test). (C) Timing of MRI relative to the cessation of SE and the presence or absence of ictal MRI changes. (D) Association of timing of MRI, change of National Institutes of Health Stroke Scale (NIHSS) score, and ictal MRI changes. *Indicates individual patients (outlayers).