First true initial ictal SPECT in partial epilepsy verified by electroencephalography

Pastor, Jesús; Domínguez-Gadea, Luis; Rg, Sola; Hernando, M.D.; Ml, Meilán; E, De Dios; Jl, Martínez-Chacón; M, Martínez

doi:10.2147/ndt.s2332

Cited by 12 publications

(15 citation statements)

References 22 publications

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“…Theoretically, the most useful ictal SPECT is one that has the radioisotope injected seconds before ictal onset. This is demonstrated in few “preictal” SPECT studies that were captured either by serendipity or in special circumstances when seizures can be provoked (Hong et al., ; Pastor et al., ; Barba et al., ). These studies showed a high degree of colocalization between the area of “preictal” SPECT hyperperfusion and the corresponding epileptogenic focus.…”

Section: Discussionmentioning

confidence: 97%

“…Average injection time was 18.4 s (range 3-63 s), with the majority of patients (61.4%) having injections under 20 s. Average ictal duration was 75.6 s (range 17-260 s). With an estimated peak brain uptake of 30 s (Andersen, 1989;Kaminska et al, 2003;Dupont, 2008;Pastor et al, 2008), the majority of SPECT studies (17 of 26) occurred ictally; 6 patients had short seizures lasting <30 s. Despite expected heterogeneity of seizures in this group, we found no significant correlation between injection time (p = 0.36), or percentage of injection time over total seizure time (p = 0.39), and localization accuracy as indicated by the GEE model.…”

Section: Injection Timementioning

confidence: 99%

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Optimizing SPECT SISCOM analysis to localize seizure‐onset zone by using varying z scores

et al. 2013

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SUMMARYPurpose: Subtraction ictal single photon emission computed tomography (SPECT) co-registered to magnetic resonance imaging (MRI) (SISCOM) is a useful modality to identify epileptogenic focus. Using this technique, several studies have generally considered the area of highest ictal hyperperfusion, as outlined by thresholding the difference images with a standard z score of 2, to be highly concordant to the epileptogenic focus. In clinical practice, several factors influence ictal hyperperfusion and using different SISCOM thresholds can be helpful. We aimed to systematically evaluate the localizing value of various z scores (1, 1.5, 2, and 2.5) in a seizure-free cohort following resective epilepsy surgery, and to examine the localizing information of perfusion patterns observed at each z score. Methods: Twenty-six patients were identified as having ictal-interictal SPECT images, preoperative and postoperative MRI studies, and having remained seizure free for at least 6 months after temporal or extratemporal surgical resection. SISCOM analysis was performed using preoperative MRI studies, and then blindly reviewed for localization of hyperperfused regions. With the added information from postoperative, coregistered MRI, perfusion patterns were determined.

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Section: Discussionmentioning

confidence: 97%

Section: Injection Timementioning

confidence: 99%

Optimizing SPECT SISCOM analysis to localize seizure‐onset zone by using varying z scores

et al. 2013

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“…Consequently, SISCOM shows increases in rCBF that are associated with both the epileptic foci and the propagation areas. If the time delay between seizure onset and radiotracer injection is too long, false lateralization or localization of SISCOM due to the postictal switch phenomenon or the excitation of propagated brain region can occur (Pastor et al., 2008). Furthermore, ictal SPECT may fail to show an area of significant hyperperfusion, giving rise to false‐negative results (Newton et al., 1992).…”

Section: Discussionmentioning

confidence: 99%

Repeated ictal SPECT in partial epilepsy patients: SISCOM analysis

Lee

Joo

Park³

et al. 2011

Epilepsia

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SUMMARYPurpose: Ictal single-photon emission computerized tomography (SPECT) is often nonlocalized in patients with partial epilepsy. We repeated ictal SPECT in patients with partial epilepsy whose first ictal SPECT was nonlocalized. We also performed subtraction ictal SPECT coregistered to magnetic resonance imaging (MRI) (SISCOM) to test the localizability of ictal SPECT. Methods: We recruited 69 patients with partial epilepsy (33 male and 36 female, mean plus or minus standard deviation age 29.5 ± 12.2 years), who had a repeated ictal SPECT. Ictal-interictal SPECT subtractions were performed, and the subtracted SPECTs were coregistered with their brain MRI studies. SISCOM results were considered to be localizing when the results were concordant with the final location of the epileptic focus, as determined by the presurgical evaluation. We compared seizure duration, tracer injection time, interictal and ictal scalp electroencephalography (EEG) patterns, presence and time of secondary generalization, and epilepsy classification between the localized and nonlocalized SISCOM groups. Key Findings: The SISCOM results of the second ictal SPECT were localized in 43 (62.3%) patients and nonlocalized in 26 (37.7%) patients. In the second ictal SPECT, the radiotracer injection time was significantly shorter in the localized group (25.1 ± 8.9 s), as compared to the nonlocalized group (49.2 ± 55.8 s) (p = 0.008). Furthermore, the radiotracer injection time of the second ictal SPECT was significantly shorter than the first ictal SPECT, only in the localized group (36.8 ± 23.8 s in the first and 25.1 ± 8.9 s in the second ictal SPECT in the localized group, p = 0.004). The percent injection time ([(tracer injection time)seizure onset time)/total seizure duration] · 100%) in the second SPECT was significantly shorter in the localized group, as compared to the nonlocalized group (37.9 ± 23.0% in the localized group and 72.3 ± 46.2% in the nonlocalized group, p < 0.001). The localized ictal EEG patterns at the time of injection were more frequent in the localized SISCOM group. The secondary generalization of seizures at the time of injection was more frequent in nonlocalized groups. Significance: Repeated ictal SPECT with SISCOM analysis is helpful for localizing an epileptic focus in patients with partial epilepsy who have a nonlocalized first ictal SPECT. The most important factor for increasing the localizability of repeated ictal SPECT is early injection time and a localizing ictal EEG pattern at the time of radiotracer injection.

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“…However, SPECT injection was performed without depth electrode or subdural grid electroencephalographic recording, and several of our patients were injected during the expression of the specified semiology. Taking into account a 30 s transit time for 99m Tc‐HMPAO injection to reach the brain and that brain uptake reaches maximum within 1 min after injection (Andersen, 1989; Pastor et al., 2008), it is, therefore, possible that some of the perfusion changes may be postictal. Future study of patients with same semiology injected 30 s prior to manifestation of the semiologic features with seizure lasting a minute or more will be needed to confirm our findings.…”

Section: Discussionmentioning

confidence: 99%

Brain activation patterns of versive, hypermotor, and bilateral asymmetric tonic seizures

et al. 2010

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SUMMARYPurpose: Patients who have seizure onset from different brain regions can produce seizures that appear clinically indistinguishable from one another. These clinically stereotypic manifestations reflect epileptic activation of specific networks. Several studies have shown that ictal perfusion single photon emission computed tomography (SPECT) can reveal propagated ictal activity. We hypothesize that the pattern of hyperperfusion may reflect neuronal networks that generated specific ictal symptomatology. Methods: All patients were identified who were injected with 99m Tc-hexamethyl-propylene-amine-oxime (HMPAO) during versive seizures (n = 5), bilateral asymmetric tonic seizures (BATS; n = 5), and hypermotor seizures (n = 7) in the presurgical epilepsy evaluation between 2001 and 2005. The SPECT ictal-interictal difference image pairs of each subgroup were compared with image pairs of 14 controls using statistical parametric mapping (SPM 2) to identify regions of significant hyperperfusion. Hyperperfused regions with corrected cluster-level significance p < 0.05 were considered significant. Results: We have identified a distinct ictal perfusion pattern in each subgroup. In versive seizure subgroup, prominent hyperperfusion was present in the frontal eye field opposite to the direction of head version. In addition, there was associated caudate and crossed cerebellar hyperperfusion. The BATS subgroup showed pronounced hyperperfusion supplementary sensorimotor area ipsilateral to the epileptogenic region, bilateral basal ganglia, and contralateral cerebellar hemisphere. The hypermotor seizure subgroup demonstrated two clusters of significant hyperperfusion: one involving bilateral frontomesial regions, cingulate gyri, and caudate nuclei, and another involving ipsilateral anteromesial temporal structures, frontoorbital region, insula, and basal ganglia. Discussion: We have identified distinct hyperperfusion patterns for specific ictal symptomatology. Our findings provide further insight into understanding the anatomic basis of seizure semiology.

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First true initial ictal SPECT in partial epilepsy verified by electroencephalography

Cited by 12 publications

References 22 publications

Optimizing SPECT SISCOM analysis to localize seizure‐onset zone by using varying z scores

Optimizing SPECT SISCOM analysis to localize seizure‐onset zone by using varying z scores

Repeated ictal SPECT in partial epilepsy patients: SISCOM analysis

Brain activation patterns of versive, hypermotor, and bilateral asymmetric tonic seizures

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