Detection of regional blood perfusion changes in epileptic seizures with dynamic brain perfusion CT—A pilot study

doi:10.1016/j.eplepsyres.2006.07.017

Epilepsy Research

Volume 72, Issues 2–3, December 2006, Pages 102-110

https://doi.org/10.1016/j.eplepsyres.2006.07.017 Get rights and content

Abstract

Background and purpose

Perfusion CT (P-CT) is used for acute stroke management, not, however, for evaluating epilepsy. To test the hypothesis that P-CT may identify patients with increased regional cerebral blood flow during subtle status epilepticus (SSE), we compared P-CT in SSE to different postictal conditions.

Methods

Fifteen patients (mean age 47 years, range 21–74) underwent P-CT immediately after evaluation in our emergency room. Asymmetry indices between affected and unaffected hemispheres were calculated for regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and mean transit time (MTT). Regional perfusion changes were compared to EEG findings.

Results

Three patients in subtle status epilepticus (group 1) had increased regional perfusion with electro-clinical correlate. Six patients showed postictal slowing on EEG corresponding to an area of regional hypoperfusion (group 2). CT and EEG were normal in six patients with a first epileptic seizure (group 3). Cluster analysis of asymmetry indices separated SSE from the other two groups in all three parameters, while rCBF helped to distinguish between chronic focal epilepsies and single events.

Conclusion

Preliminary results indicate that P-CT may help to identify patients with SSE during emergency workup. This technique provides important information to neurologists or emergency physicians in the difficult clinical differential diagnosis of altered mental status due to subtle status epilepticus.

Introduction

As increased neuronal activation during a seizure might be accompanied by a relative increase in perfusion; measuring cerebral perfusion has become a widely accepted method for localizing the epileptogenic zone (Duncan, 1992). Perfusion MR imaging has been successfully used to measure ictal hyperperfusion during epilepsia partialis continua (Calistri et al., 2003) and focal status epilepticus (Flacke et al., 2000). Ictal MR perfusion studies, however, are limited due to safety aspects and patient monitoring. Interictal MRI perfusion studies demonstrated a reduction of the regional blood volume in focal epilepsies (Wu et al., 1999, Heiniger et al., 2002). With perfusion CT (P-CT), another tool is available to measure cerebral blood perfusion. Since patients presenting with altered mental status, or increased or new onset seizures undergo an emergency CT, the goal of this study was to investigate whether perfusion changes detected by CT provide additional information about the presence of clinically subtle ictal activity or postictal changes. According to the findings from MR studies (Flacke et al., 2000, Calistri et al., 2003), we hypothesized that subtle status epileticus (SSE; Treiman et al., 1984) should yield hyperperfusion of the affected areas in a P-CT study; furthermore, we wanted to test the feasibility of performing P-CT under emergency conditions.

Section snippets

Methods

The study includes a consecutive series of six women and nine men (mean age 47 years, range 21–74), who were referred to our institution's emergency room because of changes in mental status or after witnessed or presumed epileptic seizures (for details, cf. Table 1). All patients were evaluated with a non-contrast CT followed by a CT perfusion study. A contrast enhanced CT was added if an intracranial lesion was present on the non-enhanced scan. Informed consent was obtained by proxy.

Three

Hyperperfusion during subtle status epilepticus

Three patients were examined during a confusional state which, based on clinical criteria, EEG, and P-CT results could be attributed to subtle status epilepticus (Figs. 1a and b and 2). Perfusion CT revealed focal cortical hyperperfusion in all patients.

Postictal hypoperfusion in partial epilepsy

Six patients with partial epilepsy were examined during postictal state after admission. CT revealed focal hypoperfusion in all six patients.

Patients 4 and 6 had a pharmacoresistant partial epilepsy since childhood with a recent increase in

Discussion

This study reports the use of P-CT in the emergency assessment of patients with presumed subtle status epilepticus and compares the results to patients during their postictal state. In our series, we accurately detected subtle status epilepticus by reading P-CT during a confusional state in all three patients supporting the clinically suspected diagnosis based on neurological examination and EEG once available. Furthermore, in all three cases the regional origin of the status epilepticus was

Conclusion

Although the results presented here are based on a rather small group of patients, they are in accordance with our hypothesis that regional changes in cerebral blood flow, as detected by P-CT, may distinguish between SSE and postictal perfusion patterns. P-CT might be used as an important tool to support neurologists and emergency physicians in the clinical evaluation of patients with suspected SSE, before other neurophysiological techniques are available, and to narrow down possible etiologies

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Cited by (48)

The role of CT perfusion in the evaluation of seizures, the post-ictal state, and status epilepticus
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Rapid identification of stroke mimics, such as seizures, is a critical part of the evaluation of patients presenting with acute focal neurological deficits. The primary role of CT perfusion is in identification of patients with acute ischemic stroke who may be candidates for reperfusion therapy, but also holds promise as a modality for identifying a seizure etiology. We review the literature on this topic and attempt to define characteristic CT perfusion findings at various points along the ictal-interictal (epileptic) continuum. We suggest an approach for using CT perfusion to differentiate stroke from seizure in patients with acute onset focal neurological deficits.
Usefulness of multiparametric computerized tomography findings in the differential diagnosis of stroke mimics of epileptic origin: A preliminary study
2019, Neurologia
Tras la activación del código ictus, hasta un 30% de los pacientes presentan cuadros imitadores del ictus, siendo la epilepsia el más frecuente. Evaluamos la utilidad de la TC cerebral multiparamétrica para la diferenciación de los déficit de origen comicial versus vascular.
Estudio observacional retrospectivo con recogida prospectiva de datos. Se revisan imágenes de TC multiparamétrica de pacientes atendidos como código ictus durante un año que finalmente fueron diagnosticados de etiología comicial.
N = 11 (varones 36%, edad media 74,5 años). Tres pacientes presentaban focalidad neurológica derecha, 4 focalidad izquierda y 4 afasia aislada. El tiempo máximo desde el inicio de la clínica hasta la realización de la TC multiparamétrica fue de 8,16 h. La TC perfusión fue normal en 2 pacientes. Nueve pacientes mostraron alargamiento/acortamiento del tiempo al pico (Tmáx), siendo los mapas de flujo y volumen variables. El electroencefalograma se realizó con un tiempo máximo de evolución desde el inicio de la clínica de 47,6 h. Cuatro registros mostraron hallazgos compatibles con estatus epiléptico, 2 actividad epileptiforme focal y los 5 restantes lentificación poscrítica ipsolateral a las anomalías de la TC perfusión.
El alargamiento del tiempo al pico en una distribución cortical multilobar en ausencia de oclusión de gran vaso y con respeto de ganglios de la base ha resultado el parámetro más sensible para la diferenciación de estas entidades en nuestra serie. Consideramos que la TC cerebral multiparamétrica es una herramienta rápida, disponible y útil para el diagnóstico diferencial de síntomas neurológicos deficitarios de inicio brusco debidos a etiología comicial que son atendidos como código ictus.
Thirty percent of the patients for whom code stroke is activated have stroke mimics, the most common being epilepsy. Our purpose was to evaluate the usefulness of multiparametric CT for differentiating between seizure-related symptoms and vascular events.
We conducted a retrospective observational study; data were gathered prospectively during one year. We studied multiparametric CT images of patients admitted following code stroke activation and finally diagnosed with epilepsy.
The study included a total of 11 patients; 36% were men and mean age was 74.5 years. Three patients had right hemisphere syndrome, 4 displayed left hemisphere syndrome, and the remaining 4 had isolated aphasia. Maximum time from symptom onset to multiparametric CT study was 8.16 hours. Perfusion CT results were normal in 2 patients. Nine patients showed longer or shorter times to peak (Tmax); cerebral blood volume (CBV) and cerebral blood flow (CBF) maps varied. EEG was performed a maximum of 47.6 hours after symptom onset. Four patients showed findings compatible with status epilepticus, 2 displayed focal epileptiform activity, and 5 showed post-ictal slowing ipsilateral to perfusion CT abnormalities.
The most sensitive parameter for differentiating between stroke and epilepsy in our series was increased time to peak in multilobar cortical locations in the absence of large-vessel occlusion and basal ganglia involvement. Multiparametric CT is a fast, readily available, and useful tool for the differential diagnosis of acute-onset neurological signs of epileptic origin in patients initially attended after code stroke activation.
Most Children With Epilepsy Experience Postictal Phenomena, Often Preventing a Return to Normal Activities of Childhood
2017, Pediatric Neurology
After a seizure, individuals with epilepsy have reported diverse symptoms in the postictal period, especially motor and cognitive dysfunction. However, these phenomena have not been well characterized in children, and their impact on patient well-being is not understood. We hypothesized that in a subset of epilepsy patients, postictal symptoms would affect their ability to return to normal childhood activities.
To test our hypothesis, a survey-based approach was used to characterize the type, frequency, and duration, as well as the impact of these symptoms on the ability of these children to return to their normal activities.
In this prospective study, data were analyzed from 208 patients seen in the pediatric neurology outpatient clinic at the Alberta Children's Hospital. We found that 86% (179 out of 208) of respondents reported postictal symptoms, with the most common symptom category being fatigue, sleepiness, and/or tiredness (90%; 161 of 179). The greatest impact resulted from weakness or being unable to move normally, which prevented 78% of those affected (71 of 91) from returning to normal activities after a seizure. Children who had focal seizures were more likely to experience postictal fatigue, sleepiness, or tiredness (P = 0.01; Bonferroni corrected), but no other postictal symptoms were significantly associated with a specific seizure type or epilepsy syndrome.
The results of this study further our understanding of the frequency, type, and duration of symptoms experienced in the postictal period and how these symptoms impact children with epilepsy. It is clear that postictal phenomena often occur after epileptic seizures and have a significant impact on the lives of children with epilepsy.
Differentiating Stroke and Seizure in Acute Setting—Perfusion Computed Tomography?
2017, Journal of Stroke and Cerebrovascular Diseases
Citation Excerpt :
In our study, PCT was conducted up to 12 hours after symptom onset; however, imaging occurred within 6-8 hours in most of the patients, which is still within the window for possible reperfusion therapies. Following Wiest et al,22 we have calculated asymmetry indices. Our study revealed that TTP only in the lateral part of the MCA territory could be a discriminating parameter.
Perfusion computed tomography (PCT) is part of acute stroke protocol in many hospitals; however, its clinical utility is still being disputed. Beyond its use in core and penumbra estimation, there is also a question about PCT role in stroke mimics diagnosis. Case series or small, retrospective studies showed equivocal results. This is the first published prospective, comparative study on PCT in differentiating stroke and seizure in acute setting.
Patients with acute focal neurologic deficits and without acute ischemic lesions on routine CT underwent PCT and electroencephalography (EEG) within 12 hours after symptom onset. Perfusion parameters were set up as asymmetry indices for corresponding regions of brain hemispheres. EEG findings were assigned to 1 of 5 classes. Neurologic examination was performed using the National Institutes of Health Stroke Scale (NIHSS). Follow-up noncontrast computed tomography was performed on the third day after symptom onset. If no CT changes appeared, magnetic resonance diffusion-weighted imaging was conducted.
Final diagnosis was hemispheric ischemic stroke in 17 patients and focal neurologic deficits in the course of seizures (post- and intraictally) in 12 patients. Those groups were significantly different only in one single PCT parameter—time to peak (TTP)—in the lateral part of the middle cerebral artery territory. Analyzed groups were not significantly different in the NIHSS scores and the EEG evaluation.
TTP may stay relatively when seizure is a cause of focal neurologic deficits, but not stroke. Further, large, prospective studies are necessary to verify the results.
Cerebral perfusion alterations in epileptic patients during peri-ictal and post-ictal phase: PASL vs DSC-MRI
2013, Magnetic Resonance Imaging
Non-invasive pulsed arterial spin labeling (PASL) MRI is a method to study brain perfusion that does not require the administration of a contrast agent, which makes it a valuable diagnostic tool as it reduces cost and side effects. The purpose of the present study was to establish the viability of PASL as an alternative to dynamic susceptibility contrast (DSC-MRI) and other perfusion imaging methods in characterizing changes in perfusion patterns caused by seizures in epileptic patients. We evaluated 19 patients with PASL. Of these, the 9 affected by high-frequency seizures were observed during the peri-ictal period (within 5 hours since the last seizure), while the 10 patients affected by low-frequency seizures were observed in the post-ictal period. For comparison, 17/19 patients were also evaluated with DSC-MRI and CBF/CBV. PASL imaging showed focal vascular changes, which allowed the classification of patients in three categories: 8 patients characterized by increased perfusion, 4 patients with normal perfusion and 7 patients with decreased perfusion. PASL perfusion imaging findings were comparable to those obtained by DSC-MRI. Since PASL is a) sensitive to vascular alterations induced by epileptic seizures, b) comparable to DSC-MRI for detecting perfusion asymmetries, c) potentially capable of detecting time-related perfusion changes, it can be recommended for repeated evaluations, to identify the epileptic focus, and in follow-up and/or therapy-response assessment.
Acute postictal confusion and violence: Two cases with unfortunate outcomes
2013, Epilepsy and Behavior Case Reports
Citation Excerpt :
In patients with TLE, it can develop after complex partial seizures with or without secondary generalization, suggesting that the temporal lobe seizure itself is a crucial requirement. Biomarkers for postictal brain dysfunction include focal and diffuse EEG slowing [7] and focal hypometabolism [8]. However, existing biomarkers do not account for the remarkable diversity of postictal behaviors.
Patients with temporal lobe epilepsy (TLE) often have a brief postictal state characterized by confusion and disorientation. Less common postictal behaviors include wandering and violence — both reactive and spontaneous. We describe two male patients with left TLE and unusual postictal states that led to unfortunate outcomes. The first patient's postictal state included an intense urge to peregrinate, as well as reactive violence. When a frightened houseguest prevented the patient from exiting his bedroom during a postictal state, the patient climbed out the window and fell to his death. The second patient's postictal state included menacing posturing, loud exclamation of guttural sounds or profanities, clapping or smacking his hands together, and punching nearby objects. During a postictal state at home, he grabbed a bat and destroyed furnishings. After he had two seizures at work followed by his typical postictal state, he was dismissed because of his perceived threat to coworkers.

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^☆: The content was presented at the XXX Congress of the European Society of Neuroradiology, Barcelona, September 17, 2005.

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Detection of regional blood perfusion changes in epileptic seizures with dynamic brain perfusion CT—A pilot study☆

Abstract

Background and purpose

Methods

Results

Conclusion

Introduction

Section snippets

Methods

Hyperperfusion during subtle status epilepticus

Postictal hypoperfusion in partial epilepsy

Discussion

Conclusion

Ictal SPECT perfusion reflects the activation of the symptomatogenic cortex in spontaneous and electrically-induced non-habitual focal epileptic seizures: correlation with subdural EEG recordings

Epileptic Disord.

Visualisation of evolving status epilepticus with diffusion and perfusion imaging

AJNR Am. J. Neuroradiol.

Coupling of the cortical hemodynamic response to cortical and thalamic neuronal activity

Proc. Natl. Acad. Sci.

Epilepsy, cerebral blood flow, and cerebral metabolic rate

Cerebrovasc. Brain Metab. Rev.

Focal status epilepticus: follow up by perfusion- and diffusion MRI

Eur. Radiol.

A proposed diagnostic scheme for people with epileptic seizures and with epilepsy: report of the ILAE task force on classification and terminology.

Epilepsia

Reversible changes in echo planar perfusion- and diffusion-weighted MRI in status epileticus

Neuroradiology

Diffusion and perfusion MRI for the localisation of epileptogenic foci in drug-resistant epilepsy

Neuroradiology

Opposite ictal perfusion patterns of subtracted SPECT hyperperfusion and hypoperfusion

Brain

Use of CT perfusion to differentiate between brain tumor and cerebral infarction

Cerebrovasc. Dis.