Comparison of Statistical Parametric Mapping and SPECT Difference Imaging in Patients with Temporal Lobe Epilepsy

Chang, David J.; Zubal, I. George; Gottschalk, Chris; Necochea, Alejandro; Stokking, Rik; Studholme, Colin; Corsi, María; Slawski, Jessica; Spencer, Susan S.; Blumenfeld, Hal

doi:10.1046/j.1528-1157.2002.21601.x

Cited by 95 publications

(80 citation statements)

References 16 publications

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“…For example, neuroimaging studies in humans have shown decreased cerebral blood flow (CBF) in frontal and parietal cortex during these events [18,51,59] as well as with interictal discharges [39] causing deactivation in bilateral posterior cingulate during interictal spikes [37].…”

Section: Default Mode Network Involvement In Complex Partial Seizuresmentioning

confidence: 99%

The Default Mode Network and Altered Consciousness in Epilepsy

Danielson

Guo

Blumenfeld

2011

Behavioural Neurology

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141

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Abstract. The default mode network has been hypothesized based on the observation that specific regions of the brain are consistently activated during the resting state and deactivated during engagement with task. The primary nodes of this network, which typically include the precuneus/posterior cingulate, the medial frontal and lateral parietal cortices, are thought to be involved in introspective and social cognitive functions. Interestingly, this same network has been shown to be selectively impaired during epileptic seizures associated with loss of consciousness. Using a wide range of neuroimaging and electrophysiological modalities, decreased activity in the default mode network has been confirmed during complex partial, generalized tonic-clonic, and absence seizures. In this review we will discuss these three seizure types and will focus on possible mechanisms by which decreased default mode network activity occurs. Although the specific mechanisms of onset and propagation differ considerably across these seizure types, we propose that the resulting loss of consciousness in all three types of seizures is due to active inhibition of subcortical arousal systems that normally maintain default mode network activity in the awake state. Further, we suggest that these findings support a general "network inhibition hypothesis," by which active inhibition of arousal systems by seizures in certain cortical regions leads to cortical deactivation in other cortical areas. This may represent a push-pull mechanism similar to that seen operating between cortical networks under normal conditions.

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Section: Default Mode Network Involvement In Complex Partial Seizuresmentioning

confidence: 99%

The Default Mode Network and Altered Consciousness in Epilepsy

Danielson

Guo

Blumenfeld

2011

Behavioural Neurology

Self Cite

141

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“…In addition to visual inspection, BSI is also suitable for statistical analysis. Statistical analysis of BSI has been used to analyze the regions of the brain that show diff e rences in perfusion in pathologies such as Alzheimer's disease 4 , systemic lupus erythematosus 5 and in the evaluation of epileptic foci in BSI [6][7][8] .…”

Section: Resumo -Objetivo: Investigar O Padrão De Anormalidades Perfumentioning

confidence: 99%

Statistical voxel-wise analysis of ictal SPECT reveals pattern of abnormal perfusion in patients with temporal lobe epilepsy

Amorim

Etchebehere

Camargo

et al. 2005

Arq. Neuro-Psiquiatr.

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-O b j e c t i v e :To investigate the pattern of perfusion abnormalities in ictal and interictal brain perfusion SPECT images (BSI) from patients with temporal lobe epilepsy (TLE). Method: It was acquired interictal and ictal BSI from 24 patients with re f r a c t o ryTLE. BSIs were analyzed by visual inspection and statistical parametric mapping (SPM2). Statistical analysis compared the patients group to a control gro u p of 50 volunteers. The images from patients with left-TLE were left-right flipped. Results: It was not obs e rved significant perfusional diff e rences in interictal scans with SPM. Ictal BSI in SPM analysis revealed hyp e r p e rfusion within ipsilateral temporal lobe (epileptogenic focus) and also contralateral parieto-occipital region, ipsilateral posterior cingulate gyrus, occipital lobes and ipsilateral basal ganglia. Ictal BSI also showed areas of hypoperf u s i o n . Conclusion: In a group analysis of ictal BSI of patients with TLE, voxelwise analysis detects a network of distant regions of perfusional alteration which may play active role in seizure genesis and propagation.KEY WORDS: brain perfusion, SPECT, SPM, seizures, epilepsy.Análise estatística baseada em voxel do SPECT ictal revela um padrão de alteração perf u s i o n a l em pacientes com epilepsia de lobo temporal RESUMO -Objetivo: Investigar o padrão de anormalidades perfusionais no SPECT de perfusão cere b r a l (SPC) ictal e interictal na epilepsia de lobo temporal (ELT ) . Método: Foram realizados SPCs ictal e interictal de 24 pacientes com ELT que foram analisados visualmente e com o statistical parametric mapping (SPM2). A análise estatística comparou o grupo de pacientes versus um grupo controle de 50 voluntários. Resultados: Na análise do SPM não foram observadas diferenças significativas no grupo de SPC interictal. No grupo de SPC ictal o SPM revelou hiperperfusão no lobo temporal ipsilateral (foco epileptogênico) e também na região parieto-occipital contralateral, porção posterior do cíngulo ipsilateral, lobos occipitais e núcleos da base ipsilateral. O SPC ictal também mostrou áreas de hipoperf u s ã o . Conclusão: Em uma análise de grupo do SPC ictal de pacientes com ELT, a análise baseada em voxel detecta uma rede de alteração perfusional em regiões distantes que pode ter uma função ativa na origem e propagação das crises. PALAVRAS-CHAVE: Perfusão cerebral, SPECT, SPM, crises epilépticas, epilepsia.Epilepsy affects 0.5 to 1% of the world populat i o n 1 . Anti-epileptic drugs successfully control seiz u res in most patients with epilepsy. Surgical tre a tment of epilepsy is a therapeutic option for those patients who do not achieve a seizure -f ree status with medication and have a focal brain lesion accounting for the origin of seizures. Medial temporal lobe epilepsy (TLE) is both the most fre q u e n t f o rmof epilepsy as well as the form that accounts for the majority of epilepsy patients submitted to s u rg e ry, which is perf o rmed by hippocampal removal. Histological analysis of the specimen re s ...

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“…9 A similar approach subsequently was developed and evaluated by others using control data from pairs of SPECT scans of each of 7 nonneurologic patients, but their method was not compared with other more established methods such as SISCOM. 10 The aim of this study was to objectively compare our new method of SPM analysis of ictal-interictal difference data (statistical ictal SPECT coregistered to MRI [STATISCOM]) with SISCOM by using the same raw SPECT data from each patient.…”

Section: Discussionmentioning

confidence: 99%

Ictal SPECT statistical parametric mapping in temporal lobe epilepsy surgery

et al. 2010

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Objective: Although subtraction ictal SPECT coregistered to MRI (SISCOM) is clinically useful in epilepsy surgery evaluation, it does not determine whether the ictal-interictal subtraction difference is statistically different from the expected random variation between 2 SPECT studies. We developed a statistical parametric mapping and MRI voxel-based method of analyzing ictalinterictal SPECT difference data (statistical ictal SPECT coregistered to MRI [STATISCOM]) and compared it with SISCOM. Methods:Two serial SPECT studies were performed in 11 healthy volunteers without epilepsy (control subjects) to measure random variation between serial studies from individuals. STATISCOM and SISCOM images from 87 consecutive patients who had ictal SPECT studies and subsequent temporal lobectomy were assessed by reviewers blinded to clinical data and outcome. Results:Interobserver agreement between blinded reviewers was higher for STATISCOM images than for SISCOM images ( ϭ 0.81 vs ϭ 0.36). STATISCOM identified a hyperperfusion focus in 84% of patients, SISCOM in 66% (p Ͻ 0.05). STATISCOM correctly localized the temporal lobe epilepsy (TLE) subtypes (mesial vs lateral neocortical) in 68% of patients compared with 24% by SISCOM (p ϭ 0.02); subgroup analysis of patients without lesions (as determined by MRI) showed superiority of STATISCOM (80% vs 47%; p ϭ 0.04). Moreover, the probability of seizure-free outcome was higher when STATISCOM correctly localized the TLE subtype than when it was indeterminate (81% vs 53%; p ϭ 0.03). Conclusion:Statistical ictal SPECT coregistered to MRI (STATISCOM) was superior to subtraction ictal SPECT coregistered to MRI for seizure localization before temporal lobe epilepsy (TLE) surgery. STATISCOM localization to the correct TLE subtype was prognostically important for postsurgical seizure freedom. Neurology ® 2010;74:70 -76 GLOSSARY CI ϭ confidence interval; ECD ϭ ethyl cysteinate dimer; HMPAO ϭ hexamethyl propylene-amine-oxime; SISCOM ϭ subtraction ictal SPECT coregistered to MRI; SPM ϭ statistical parametric mapping; STATISCOM ϭ statistical ictal SPECT coregistered to MRI; TLE ϭ temporal lobe epilepsy.Early methods of ictal SPECT interpretation relied on a visual comparison of ictal and interictal SPECT images to detect focal hyperperfusion changes (these represented potential sites of ictal hyperperfusion).1 SPECT imaging subsequently was improved by subtraction ictal SPECT with coregistration on MRI (SISCOM).2-5 With SISCOM, ictal SPECT data are subtracted from interictal SPECT data, 6,7 and the "difference image," which shows the focus of altered perfusion, is coregistered with the patient's MRI for anatomic correlation. A recent study that compared several functional imaging modalities showed that positive SISCOM has the greatest association with seizure-free outcome after focal epilepsy surgery. 8Despite the validation of its clinical usefulness, SISCOM detection of abnormal perfusion is based a priori on a defined threshold of perfusion changes, and it does not account for the...

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Comparison of Statistical Parametric Mapping and SPECT Difference Imaging in Patients with Temporal Lobe Epilepsy

Cited by 95 publications

References 16 publications

The Default Mode Network and Altered Consciousness in Epilepsy

The Default Mode Network and Altered Consciousness in Epilepsy

Statistical voxel-wise analysis of ictal SPECT reveals pattern of abnormal perfusion in patients with temporal lobe epilepsy

Ictal SPECT statistical parametric mapping in temporal lobe epilepsy surgery

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