Pilar Bosque‐Varela

Objective: Peri‐ictal magnetic resonance imaging (MRI) abnormalities (PMA) are increasingly recognized in patients with status epilepticus (SE), but the clinical factors influencing their occurrence and extent remain incompletely understood. We aimed to quantify PMA and investigate the associations of PMA occurrence and volume with SE duration, etiology, and mortality. Methods: In this multicenter cohort study, comprising a retrospectively identified cohort and a prospectively recruited cohort, adult patients with SE who underwent brain MRI within 48 h of SE onset were included. PMA were identified on diffusion‐weighted imaging (DWI) and quantified using an automated postprocessing pipeline to calculate total PMA volume. Multivariable regression analyses were used to examine factors associated with PMA occurrence, extent, and mortality. Results: Of 260 patients, 91 (35%) had PMA on DWI. In multivariable analyses, SE duration and etiology were independently associated with PMA occurrence and volume. SE lasting >60 min had higher odds of PMA (odds ratio [OR] = 3.90, 95% confidence interval [CI] = 1.79–8.82, p < .001) and significantly greater PMA volume, whereas acute triggering factors in patients with epilepsy were linked with lower odds (OR = .15, 95% CI = .05–.44, p < .001). PMA occurrence was associated with more than threefold higher odds of mortality (adjusted OR = 3.85, 95% CI = 1.55–10.24, p = .005). Each 10‐fold increase in PMA volume was associated with 43% higher odds of mortality (adjusted OR = 1.43, 95% CI = 1.14–1.80, p = .002). In a sensitivity analysis restricted to in‐hospital mortality, each 10‐fold increase in PMA volume was associated with 47% higher odds of mortality (adjusted OR = 1.47, 95% CI = 1.15–1.89, p = .002). Significance: PMA extent is determined by SE duration and underlying etiology. Although MRI timing relative to SE termination could not always be determined, quantitative PMA assessment provides prognostic information beyond PMA presence alone, as increasing PMA volume is associated with progressively higher mortality. These findings support quantitative PMA burden as a potential imaging biomarker of SE severity and adverse outcome.

Objective: To determine whether non‐contrast pseudo‐continuous arterial spin labeling (pCASL) detects status epilepticus (SE)–related perfusion abnormalities and shows quantitative correspondence with dynamic susceptibility contrast (DSC) perfusion magnetic resonance imaging (MRI), and to compare single‐slice and volumetric approaches for asymmetry assessment. Methods: Adult patients from a prospectively recruited single‐center SE cohort were included in this retrospective analysis when MRI was performed within 48 h after clinical SE onset and both pCASL and DSC perfusion sequences were available. Visual assessment was pCASL‐led, with corresponding DSC‐derived cerebral blood flow (CBF) and cerebral blood volume (CBV) maps subsequently evaluated. Perfusion asymmetry was quantified using mirrored contralateral reference regions. Single‐slice peak‐abnormality and volumetric segmentation approaches were applied to pCASL, DSC‐derived cerebral blood flow (CBF), and cerebral blood volume (CBV). Results: Of 982 individuals with SE, 180 underwent MRI including pCASL and DSC within 48 h. pCASL‐led assessment identified SE‐related perfusion abnormalities in 75 of 180 (42%): hyperperfusion in 65, hypoperfusion in 6, and pCASL–DSC discordance in 4. Corresponding DSC abnormalities were present in 71 of 75 (95%). Thus, quantitative asymmetry analysis was performed in 71 unilateral evaluable cases. In the hyperperfusion subgroup, pCASL asymmetry correlated significantly with DSC‐derived CBF using both volumetric and single‐slice assessment ( ρ = .558 and ρ = .571, respectively; both p < .001), and with DSC‐derived CBV ( ρ = .495 and ρ = .374, respectively; p < .001 and p = .003). Single‐slice and volumetric pCASL asymmetry showed strong correspondence ( ρ = .773, p < .001). No significant difference was observed between single‐slice and volumetric pCASL asymmetry after correction for multiple comparisons. Significance: Non‐contrast pCASL detected SE‐related peri‐ictal perfusion abnormalities and showed significant quantitative correspondence with DSC‐derived CBF and CBV in parenchymal hyperperfusion. Single‐slice pCASL asymmetry showed strong agreement with volumetric assessment, supporting its use as a pragmatic approach for clinically oriented evaluation.

Objective: Subclinical seizures (SCSs) remain an understudied aspect of presurgical evaluation in patients with drug‐resistant epilepsy (DRE), with uncertain prevalence, distribution among epilepsy types, and predictive value for surgical outcomes. This systematic review and meta‐analysis aims to explore the occurrence of SCSs, their concordance with the seizure‐onset zone (SOZ), and their association with postoperative seizure outcomes. Methods: A systematic search of Medline, Embase, and Web of Science was performed to identify studies reporting SCSs during scalp electroencephalography (EEG) monitoring or intracranial EEG (iEEG) monitoring in patients with DRE undergoing epilepsy surgery. Data on SCS prevalence, concordance with SOZ, and postoperative outcomes were extracted. Pooled proportions and odds ratios (ORs) were estimated using random‐effects generalized linear mixed models. Subgroup analyses evaluated the proportions of SCSs in temporal vs extratemporal epilepsy. Results: Thirteen studies comprising 1174 patients met the inclusion criteria. The pooled prevalence of SCSs was 32% (95% confidence interval [CI] 8–73) during scalp EEG monitoring and 50% (95% CI 38–62) during iEEG monitoring. Concordant SCSs with SOZ occurred in 37% of patients undergoing iEEG. Non‐concordant SCSs were associated with a nearly fivefold higher odds of poor postoperative seizure control (OR 4.82, 95% CI 1.80–12.96; p = 0.002). SCSs were more frequent in temporal lobe epilepsy than in extratemporal epilepsy (57% vs 44%, p = 0.046). Within temporal lobe epilepsy, the highest prevalence was observed in the mesiotemporal region (69%). Overall, the presence of SCSs alone was not associated with a poor outcome, but the spatial non‐concordance with the SOZ was highly predictive for poor seizure outcome. Significance: SCSs are common in presurgical evaluation, particularly in temporal lobe epilepsy. Although their presence alone is not prognostic, non‐concordant SCSs are associated with worse postoperative outcomes. Systematic assessment, especially using iEEG, may improve delineation of the epileptogenic zone and surgical planning in DRE.

Background and ObjectivesReliable prediction of short-term mortality in status epilepticus (SE) can contribute to guide clinical decisions. Current prognostic systems achieve only acceptable predic...

Objective: Patterns within the ictal–interictal continuum (IIC) are frequently encountered in critically ill patients undergoing continuous electroencephalographic studies and may reflect ongoing ictal activity or secondary brain injury. Peri‐ictal neuroimaging abnormalities (PNA) have been described in association with status epilepticus (SE), but their occurrence in patients with IIC across different neuroimaging modalities remains incompletely characterized. We aimed to assess the occurrence of PNA in adults with IIC across structural and functional neuroimaging techniques. Methods: We performed a systematic review and meta‐analysis following PRISMA 2020 guidelines. PubMed, Embase, and Scopus were searched up to January 2026 for studies reporting PNA in adults with IIC. Eligible modalities included magnetic resonance imaging (MRI), CT perfusion (CTP), and positron emission tomography (PET). Pooled detection rates were estimated using random‐effects generalized linear mixed models. Results: Of 8400 records identified, seven studies met the inclusion criteria. Of these, four contributed MRI data (98 patients), two—CTP data (38 patients), and two—PET data (30 patients); no SPECT study was identified. One study contributed data to two modalities. Pooled proportion of PNA was 0.41 (95% CI: 0.30–0.52; I ² = 30.4%) for MRI, 0.34 (95% CI: 0.21–0.50; I ² = 0%) for CTP, and 0.90 (95% CI: 0.73–0.97; I ² = 0%) for PET. Significance: There are currently a limited number of studies evaluating PNA in IIC. PET showed the highest pooled proportion of PNA, although these findings should be interpreted cautiously. Further studies are required to better define the neuroimaging spectrum within the IIC and to clarify its clinical and diagnostic implications.

Status epilepticus (SE) is a neurological emergency with a mortality of up to 39% in population-based studies. Animal studies suggest that, beyond a critical timepoint (t2), SE induces neuronal injury exceeding what can be expected from the underlying aetiology, but in vivo evidence in humans is scarce. Thirty-six prospectively recruited individuals with SE with a mean age of 59 years underwent serial high-resolution T1-weighted brain MRI over a mean follow-up period of 5 months and were compared with 34 individuals with drug-resistant focal epilepsy and 36 propensity-score matched healthy controls. Cortical thickness and deep grey matter volumes were estimated and harmonised to account for scanner-related effects. Longitudinal change was assessed using linear mixed-effects models adjusting for age at baseline, interscan interval and sex between groups. We further investigated the independent effects of SE duration, semiology and level of consciousness after mutual adjustment for each variable as well as aetiology, as well as longitudinal structural signatures associated with key locations of peri-ictal MRI abnormalities (PMA). SE was associated with pronounced bilateral hippocampal atrophy in comparison to normal aging and drug-resistant epilepsy, alongside volume increase in several deep grey matter nuclei as well as a trend for cortical thinning of medial brain structures. SE duration was the strongest independent driver of brain change, producing widespread cortical thinning and bilateral hippocampal atrophy. A convulsive semiology was independently associated with accelerated medial temporal cortical thinning and bilateral hippocampal volume loss when compared with non-convulsive (NCSE) and other prominent-motor SE, while reduced consciousness predicted faster thinning of medial frontoparietal cortex. PMA was associated with distinct longitudinal trajectories of subcortical volume, with pulvinar and hippocampus involvement predicting thalamic and hippocampal atrophy patterns. According to our findings, a single episode of SE was therefore associated with a measurable structural imprint in the brain that evolved over months beyond what would be expected for aetiology alone. Atrophy trajectories highlighted the vulnerability of the hippocampus and other limbic structures during the peri-ictal state. A long SE duration, together with convulsive semiology and impaired consciousness, independently amplified this damage. These findings corroborate the timepoint-based (t2) concept of SE and reinforce the clinical imperative of rapid seizure termination to contain long-term structural brain injury.

Status epilepticus (SE) is a neurologic emergency with possible long-term sequelae, including the development of epilepsy. We aimed to determine whether peri-ictal MRI abnormalities (PMA) are associated with unprovoked seizures after de novo SE. Adults without epilepsy and a first nonhypoxic SE were included from a prospective database of the Christian Doppler University Hospital, Salzburg, Austria. MRI scans performed within 48 hours of SE diagnosis were evaluated for PMA on diffusion-weighted imaging (DWI), T2-weighted fluid-attenuated inversion recovery (FLAIR), and arterial spin labeling (ASL). The outcome was unprovoked seizures, assessed by retrospective review of hospital records and telephone interviews. Cumulative risk of seizures stratified by PMA occurrence (PMA on DWI/FLAIR, hyperperfusion on ASL, no PMA) was evaluated through survival analysis. Multivariable analysis using logistic regression was conducted to assess the influence of PMA, etiology, semiology, and ictal EEG patterns on seizure occurrence. Among 135 patients included (median age 70 [interquartile range (IQR) 58-80] years and 55% female), 43 (32%) experienced seizures during a median follow-up of 23 (IQR 9-39) months. The cumulative seizure probability at 1 and 4 years was 34% (95% CI 17-47) and 61% (95% CI 37-75) in patients with PMA on DWI/FLAIR; 0% and 13% (95% CI 0-29) in patients with hyperperfusion on ASL; and 25% (95% CI 14-34) and 36% (95% CI 19-49) in those without PMA. Other SE features associated with higher seizure risk were treatment refractoriness (odds ratio [OR] 2.93, 95% CI 1.23-6.98, p = 0.02), longer SE duration (OR 1.003, 95% CI 1.001-1.004, p = 0.02), and lateralized periodic discharges on ictal EEG (OR 3.59, 95% CI 1.37-9.83, p = 0.005). In multivariable analysis, PMA on DWI/FLAIR (log-odds 1.23, 95% CI 0.13-2.33, p = 0.03) and remote etiology (log-odds 1.85, 95% CI 0.45-3.25, p = 0.009) were independently associated with increased seizure probability. PMA on DWI or FLAIR were independently linked to a cumulative seizure risk exceeding 60% after de novo SE, consistent with a diagnosis of epilepsy. The findings of our study may help guide long-term treatment decisions in patients with de novo SE.

The ictal–interictal continuum (IIC) challenges the traditional dichotomous classification of electroencephalographic activity into ictal and interictal states and represents a major zone of diagnostic and therapeutic uncertainty in status epilepticus (SE). IIC is defined by rhythmic and periodic electroencephalographic (EEG) patterns that do not fulfill formal seizure criteria and occupies a gray zone in which the interpretation of what is ictal, treatment responsiveness, and risk of neuronal injury remains controversial. In this narrative review, we explored the boundaries between SE and the IIC, focusing on key controversies and paradoxes that emerge across electroclinical scenarios and neuroimaging findings. More specifically, we examine the time-locked electroclinical correlates and antiseizure medication responsiveness as markers of ictality, ongoing controversies in EEG-based definitions, and the role of peri-ictal neuroimaging abnormalities as complementary markers of metabolic burden. This review aims to summarize these topics and discuss key gaps for future research in the management of IIC.

Objective: Status epilepticus (SE) is the most severe expression of seizures, encompassing both SE with prominent motor symptoms and nonconvulsive SE (NCSE). Ictal–interictal continuum (IIC), an electroencephalographic phenomenon, is characterized by periodic discharges (PD), spike‐and‐waves or sharp‐and‐waves (SW), or lateralized rhythmic delta activity (LRDA). Peri‐ictal magnetic resonance imaging (MRI) abnormalities (PMA) may offer a potential surrogate marker for ictal activity, yet their association with IIC remains unclear. We aimed to investigate the occurrence of PMA in patients with SE and IIC, and to determine the relationship between IIC patterns and PMA through a latent cluster analysis (LCA). Methods: In a prospective cohort study, 223 adult patients diagnosed with SE or IIC underwent electroencephalography (EEG) and MRI within 48 h of diagnosis. Patients were stratified into two groups: the IIC group and SE group. PMA were assessed using the following MRI sequences: diffusion‐weighted imaging, fluid‐attenuated inversion recovery, and arterial spin labeling. LCA was performed to identify classes based on etiology, EEG patterns, and their localization. Results: PMA were as frequent in patients of the IIC group (23/49, 47%) as in patients of the SE group (64/149, 43%, p = .37). In the IIC group, peri‐ictal hyperperfusion was more frequently associated with lower frequency PD/SW (.5–1 Hz; 12/19, 63%), followed by LRDA (4/13, 31%) and higher frequency PD/SW (>1–2.5 Hz; 4/17, 24%). LCA revealed two classes; Class 1, characterized by nonunilateral high‐frequency PD/SW and triggering factors in epilepsy, had fewer PMA (18%) as compared to Class 2, characterized by predominantly unilateral low‐frequency PD/SW and diverse etiologies (50%; odds ratio = 5.79, p = .02). Significance: PMA occurrence in IIC aligned closely with that in SE, suggesting an overlap between IIC and SE and raising the critical question of whether patients with IIC may have NCSE. We propose an etiology‐driven approach for EEG interpretation in IIC, which may enhance diagnostic accuracy and treatment strategies.