Developing an effective program to complete ictal SPECT in the epilepsy monitoring unit

Smith, Brien; Karvelis, Kastytis; Cronan, Susan; Porter, William C.; Smith, Leonard S.; Pantelic, Milan; Elisevich, Kost

doi:10.1016/s0920-1211(98)00097-7

Cited by 22 publications

(14 citation statements)

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“…Other series further analyzed this typical pattern by observing the relative distribution of the tracer in the different regions of the temporal lobe: mesial, lateral, and posterior regions (19). TPPs have been considered a predictor of good surgical outcome (19), and this fact has driven the efforts to optimize routines of monitoring and ictal tracer injections to improve the sensitivity of the ictal SPECT (24,25).…”

Section: Discussionmentioning

confidence: 99%

Typical and Atypical Perfusion Patterns in Periictal SPECT of Patients with Unilateral Temporal Lobe Epilepsy

Wichert‐Ana¹,

Velasco²,

Araújo³

et al. 2001

Epilepsia

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Summary:Purpose: To characterize perfusion patterns of periictal single-photon emission tomography (SPECT) in patients with unilateral temporal lobe epilepsy (TLE) and to determine their relationship to the epileptogenic zone (EZ).Methods: We studied periictal SPECT scans of 53 patients after anterior mesial temporal lobectomy who had good seizure outcome after surgery. Ictal SPECT scans were performed during video-EEG monitoring. Typical SPECT patterns consisted of ipsilateral ictal hyperperfusion or ipsilateral postictal hypoperfusion. Atypical ictal patterns included normal scans, bilateral temporal hyperperfusion, or contralateral patterns. These perfusion patterns were retrospectively analyzed searching for concordance rate with the EZ.Results: We obtained 51 ictal and two early postictal scans. In the typical group, 40 (75.4%) patients had ipsilateral ictal temporal lobe hyperperfusion, and one (1.9%) patient had ipsilateral postictal temporal lobe hypoperfusion. Twelve (22.7%) patients exhibited atypical perfusion patterns: seven (13.2%) patients had bitemporal ictal hyperperfusion (four cases showed asymmetric temporal lobe changes), four (7.6%) patients had contralateral hyperperfusion, and one (1.9%) patient had a normal SPECT scan. All four patients with bitemporal asymmetric hyperperfusions showed greater perfusion lateralized to the side of the EZ. Three of the four patients who had contralateral hyperperfusion also had a complex postictallike pattern in the ipsilateral temporal lobe consisting of anteromesial hyperperfusion with adjacent lateral hypoperfusion.Conclusions: This study analyzed typical and atypical perfusion patterns in unilateral TLE, and suggested that not only typical, but also some atypical perfusion patterns may contribute to the lateralization of EZ.

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Section: Discussionmentioning

confidence: 99%

Typical and Atypical Perfusion Patterns in Periictal SPECT of Patients with Unilateral Temporal Lobe Epilepsy

Wichert‐Ana¹,

Velasco²,

Araújo³

et al. 2001

Epilepsia

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“…Because early ictal injections give the best results, it is advisable to use a stabilized compound and to inject via an indwelling intravenous cannula in the arm that is involved less in the seizure. Smith and colleagues (7) reported ictal SPECT injections in 77% of 110 consecutive patients, with a medium injection time of 27 s. In 160 consecutive patients admitted to our video‐EEG suite, we were able to inject 80% of patients, with a median injection time of 19 s, by using an ictal SPECT setup with indwelling intravenous cannula (2). In view of the decay of the tracer, the injected dose should be adjusted.…”

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confidence: 99%

Ictal SPECT

Paesschen

2004

Epilepsia

158

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Summary:The localizing value of ictal single-photon emission computed tomography (SPECT) performed with cerebral blood flow agents in patients with epilepsy is based on cerebral metabolic and perfusion coupling. Ictal hyperperfusion is used to localize the epileptogenic zone noninvasively, and is particularly useful in magnetic resonance (MR)-negative partial epilepsy and focal cortical dysplasias. Subtraction ictal SPECT coregistered with MRI (SISCOM) improves the localization of the area of hyperperfusion. Ictal SPECT should always be interpreted in the context of a full presurgical evaluation. Early ictal SPECT injections minimize the problem of seizure propagation and of nonlocalization due to an early switch from ictal hyperperfusion to postictal hypoperfusion during brief extratemporal seizures. The degree of thresholding of SISCOM images affects the sensitivity and specificity of ictal SPECT. Ictal hypoperfusion may reflect ictal inhibition or deactivation. Postictal and interictal SPECT studies are less useful to localize the ictal-onset zone. Statistical parametric mapping analysis of groups of selected ictal-interictal difference images has the potential to demonstrate the evolution of cortical, subcortical, and cerebellar perfusion changes during a particular seizure type, to study seizure-gating mechanisms, and to provide new insights into the pathophysiology of seizures. Key Words: Ictal SPECT-SISCOMPresurgical evaluation-SPM-Epilepsy-Seizures.Ictal single-photon emission computed tomography (SPECT) has the potential to localize the ictal-onset zone accurately in a noninvasive manner. Reliably to deliver early ictal SPECT injections, detailed attention should be paid to the logistics of ictal SPECT setup. Ictal SPECT injections should be performed in the video-EEG suite, with the nursing and review station close to the rooms of the patients. Medical personnel should be educated in handling of radioactive materials and be familiar with the electroclinical features of epileptic seizures. The brainperfusion agent should be available in the room, and the injection system should allow fast ictal injections (1,2). High-resolution SPECT and magnetic resonance imaging (MRI) scanner should be available. Excellent cooperation between the neurology and nuclear medicine department is of crucial importance (3). If the implementation of ictal SPECT is too difficult, referral of selected patients for ictal SPECT should be considered.Brain 99m Tc-ECD is retained in the brain after an enzymatic conversion to ionized acid compounds and 99m Tc-HMPAO after conversion to a nondiffusible hydrophilic compound after cell uptake. These different mechanisms of brain retention could explain the differences in cerebral distribution of the two tracers (4). 99m Tc-ECD is stable 6 to 8 h, and the stabilized form of 99m Tc-HMPAO, for 4 h. 99m Tc-ECD is cleared from the body more rapidly than 99m Tc-HMPAO, and gives a higher brain-to-soft tissue activity ratio, which improves image quality (5). Lee and colleagues (6) found 99m Tc-H...

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“…It also increases the risk of contamination. 10 It is clear that multidisciplinary cooperation is required for this type of endeavor, 10 and that has been achieved in our center. Moreover, the layout of the unit has contributed to the successful…”

Section: Discussionmentioning

confidence: 96%

“…Our mean time for injection after the onset of the clinical seizure indicates a very efficient and effective protocol. In some centers, the personnel that perform the ictal injection are EEG technologists, 10 dedicated research fellows, 11 and even epileptologists. 12 In our center, the advantage of having the nurse deliver the radiopharmaceutical resides in the fact that they are familiar with the patient's events and they have a greater experience in the management of intravenous administration of medications.…”

Section: A B Cmentioning

confidence: 99%

Evaluating the Development of a SPECT Protocol in a Canadian Epilepsy Unit

Burneo

Vezina²,

Romsa³

et al. 2007

Can. j. neurol. sci.

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Studies on the epidemiology of intractable epilepsy in the Canadian population are not available. 1 However, extrapolating from studies done in the United States (US), the incidence is of approximately 6/100,000 patients per year, translating to about 17,000 new cases destined to meet criteria of intractability annually. 2 This group accounts for over 50% of the total cost of epilepsy. 3 For many of these patients, epilepsy surgery offers the only opportunity to become completely or nearly free of seizures. The role of surgery for intractable epilepsy is rapidly changing. No longer an intervention of last resort, surgical therapy is often an earlier option to be considered because it may achieve seizure-free outcomes in patients otherwise intractable. 4 A standard presurgical evaluation of a patient with intractable epilepsy consists of a video-EEG study performed in an epilepsy ABSTRACT: Background: Functional neuroimaging can address some challenges of seizure localization, and sometimes preclude the need for EEG recording using intracranial electrodes. Ictal Single Photon Emission Computed Tomography (SPECT) has developed into an important tool in the presurgical evaluation of patients with medically-intractable localization-related epilepsy. The purpose of the study was to determine whether the development of a programme using trained nurses to perform ictal injections enabled a more efficient delivery of radiopharmaceuticals and therefore a greater sensitivity and specificity of outcome. Methods: In our epilepsy unit, nursing staff inject 99m Tc-HMPAO at bedside, during or at seizure onset. Brain SPECT is performed later on a gamma camera. Results: Since the implementation of the new protocol (February 2005), 57 scans have been performed: 22 ictal and 35 interictal. Latency of ictal injection was found to be 5-40 seconds (mean 19.7 sec, standard deviation (SD) 10.4). Only 20% of reconstituted radiopharmaceutical vials were not used. Contamination rate was nil. Sixty three percent of SPECT studies were concordant with standard presurgical evaluation. Conclusion: The latency of injections and the percentage of unused vials indicated an efficient and effective protocol compared to the literature. Our results show that ictal SPECT can be a safe, noninvasive procedure performed on a routine basis in the epilepsy unit when appropriately trained support staff are incorporated into a structured multidisciplinary programme. RÉSUMÉ: Évaluation du développement d'un protocole de TEMP dans une unité d'épilepsie au Canada.Contexte : La neuroimagerie fonctionnelle peut permettre de relever certains défis que pose la localisation des crises convulsives et obvier à la nécessité de recourir à l'enregistrement ÉEG effectué au moyen d'électrodes intracrâniennes. La TEMP ictale est devenue un outil important dans l'évaluation préchirurgicale de patients ayant une épilepsie localisée, réfractaire au traitement médical. Le but de cette étude était de déterminer si le développement d'un programme d'injection ictale par des infirm...

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Developing an effective program to complete ictal SPECT in the epilepsy monitoring unit

Cited by 22 publications

References 23 publications

Typical and Atypical Perfusion Patterns in Periictal SPECT of Patients with Unilateral Temporal Lobe Epilepsy

Typical and Atypical Perfusion Patterns in Periictal SPECT of Patients with Unilateral Temporal Lobe Epilepsy

Ictal SPECT

Evaluating the Development of a SPECT Protocol in a Canadian Epilepsy Unit

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