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The National Institutes of Health Stroke Scale (NIHSS) score is the most frequently used score worldwide for assessing the clinical severity of a stroke. Prior research suggested an association between acute symptomatic seizures after stroke and poorer outcome. We determined the frequency of acute seizures after ischemic stroke in a large population-based registry in a central European region between 2004 and 2016 and identified risk factors for acute seizures in univariate and multivariate analyses. Additionally, we determined the influence of seizures on morbidity and mortality in a matched case–control design. Our analysis of 135,117 cases demonstrated a seizure frequency of 1.3%. Seizure risk was 0.6% with an NIHSS score at admission <3 points and increased up to 7.0% with >31 score points. Seizure risk was significantly higher in the presence of acute non-neurological infections (odds ratio: 3.4; 95% confidence interval: 2.8–4.1). A lower premorbid functional level also significantly increased seizure risk (OR: 1.7; 95%CI: 1.4–2.0). Mortality in patients with acute symptomatic seizures was almost doubled when compared to controls matched for age, gender, and stroke severity. Acute symptomatic seizures increase morbidity and mortality in ischemic stroke. Their odds increase with a higher NIHSS score at admission.
Recent data have suggested that performing recanalizing therapies in ischemic stroke might lead to an increased risk of acute symptomatic seizures. This applies to both intravenous thrombolysis and mechanical thrombectomy. We therefore determined the frequency of acute symptomatic seizures attributable to these two recanalization therapies using a large, population-based stroke registry in Central Europe. We performed two matched 1:1 case–control analyses. In both analyses, patients were matched for age, stroke severity on admission and pre-stroke functional status. The first analysis compared patients treated with intravenous thrombolysis to a non-recanalization control group. To isolate the effect of mechanical thrombectomy, we compared patients with both mechanical thrombectomy and intravenous thrombolysis to those with only intravenous thrombolysis treatment in a second analysis. From 135,117 patients in the database, 13,356 patients treated with only intravenous thrombolysis, and 1013 patients treated with both intravenous thrombolysis and mechanical thrombectomy were each matched to an equivalent number of controls. Patients with intravenous thrombolysis did not suffer from clinically apparent acute symptomatic seizures significantly more often than non-recanalized patients (treatment = 199; 1.5% vs. control = 237; 1.8%, p = 0.07). Mechanical thrombectomy in addition to intravenous thrombolysis also was not associated with an increased risk of acute symptomatic seizures, as the same number of patients suffered from seizures in the treatment and control group (both n = 17; 1.7%, p = 1). In a large population-based stroke registry, the frequency of clinically apparent acute symptomatic seizures was not increased in patients who received either intravenous thrombolysis alone or in conjunction with mechanical thrombectomy.
Purpose: In the clinical routine, detection of focal cortical dysplasia (FCD) by visual inspection is challenging. Still, information about the presence and location of FCD is highly relevant for prognostication and treatment decisions. Therefore, this study aimed to develop, describe and test a method for the calculation of synthetic anatomies using multiparametric quantitative MRI (qMRI) data and surface-based analysis, which allows for an improved visualization of FCD.
Materials and Methods: Quantitative T1-, T2- and PD-maps and conventional clinical datasets of patients with FCD and epilepsy were acquired. Tissue segmentation and delineation of the border between white matter and cortex was performed. In order to detect blurring at this border, a surface-based calculation of the standard deviation of each quantitative parameter (T1, T2, and PD) was performed across the cortex and the neighboring white matter for each cortical vertex. The resulting standard deviations combined with measures of the cortical thickness were used to enhance the signal of conventional FLAIR-datasets. The resulting synthetically enhanced FLAIR-anatomies were compared with conventional MRI-data utilizing regions of interest based analysis techniques.
Results: The synthetically enhanced FLAIR-anatomies showed higher signal levels than conventional FLAIR-data at the FCD sites (p = 0.005). In addition, the enhanced FLAIR-anatomies exhibited higher signal levels at the FCD sites than in the corresponding contralateral regions (p = 0.005). However, false positive findings occurred, so careful comparison with conventional datasets is mandatory.
Conclusion: Synthetically enhanced FLAIR-anatomies resulting from surface-based multiparametric qMRI-analyses have the potential to improve the visualization of FCD and, accordingly, the treatment of the respective patients.
Cortical changes in epilepsy patients with focal cortical dysplasia: new insights with T2 mapping
(2020)
Background: In epilepsy patients with focal cortical dysplasia (FCD) as the epileptogenic focus, global cortical signal changes are generally not visible on conventional MRI. However, epileptic seizures or antiepileptic medication might affect normal-appearing cerebral cortex and lead to subtle damage. Purpose: To investigate cortical properties outside FCD regions with T2-relaxometry. Study Type: Prospective study. Subjects: Sixteen patients with epilepsy and FCD and 16 age-/sex-matched healthy controls. Field Strength/Sequence: 3T, fast spin-echo T2-mapping, fluid-attenuated inversion recovery (FLAIR), and synthetic T1-weighted magnetization-prepared rapid acquisition of gradient-echoes (MP-RAGE) datasets derived from T1-maps. Assessment: Reconstruction of the white matter and cortical surfaces based on MP-RAGE structural images was performed to extract cortical T2 values, excluding lesion areas. Three independent raters confirmed that morphological cortical/juxtacortical changes in the conventional FLAIR datasets outside the FCD areas were definitely absent for all patients. Averaged global cortical T2 values were compared between groups. Furthermore, group comparisons of regional cortical T2 values were performed using a surface-based approach. Tests for correlations with clinical parameters were carried out. Statistical Tests: General linear model analysis, permutation simulations, paired and unpaired t-tests, and Pearson correlations. Results: Cortical T2 values were increased outside FCD regions in patients (83.4 ± 2.1 msec, control group 81.4 ± 2.1 msec, P = 0.01). T2 increases were widespread, affecting mainly frontal, but also parietal and temporal regions of both hemispheres. Significant correlations were not observed (P ≥ 0.55) between cortical T2 values in the patient group and the number of seizures in the last 3 months or the number of anticonvulsive drugs in the medical history. Data Conclusion: Widespread increases in cortical T2 in FCD-associated epilepsy patients were found, suggesting that structural epilepsy in patients with FCD is not only a symptom of a focal cerebral lesion, but also leads to global cortical damage not visible on conventional MRI. Evidence Level: 21. Technical efficacy Stage: 3 J. MAGN. RESON. IMAGING 2020;52:1783–1789.