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Die prächirurgische Epilepsiediagnostik ist wichtig, um die korrekte Epilepsieart zu identifizieren und um den epileptischen Fokus korrekt zu lokalisieren. Die SISCOM Diagnostik ist eine Untersuchungsmethode, die bei Patient*innen mit einem negativen MRT Ergebnis und/ oder bei prä-operativen Patient*innen durchgeführt wird. Ziel: Diese Arbeit gibt einen Überblick über die SISCOM Diagnostik. Die Injektionszeit der SISCOM und der iktalen Hirnperfusionszintigraphie wird anhand der Sensitivität erforscht. Außerdem wird die SISCOM Diagnostik hinsichtlich der Sensitivität und der Spezifität bezüglich der Lokalisierung des epileptischen Fokus mit der UFH 7T MRT verglichen. Methode: Um die Forschungsfragen zu beantworten, wurde eine Literaturrecherche durchgeführt und anhand von Ein- und Ausschlusskriterien wurden insgesamt 14 Studien ausgewählt. Die Ergebnisse wurden durch deskriptive Statistik mithilfe von Grafiken dargestellt und beschrieben. Ergebnisse: Je näher der Tracer am Beginn des Anfalles appliziert wird, desto besser ist die Lokalisierung vom epileptischen Fokus. Die besten Ergebnisse liegen bei einer Injektionszeit von 45 bis 60 Sekunden mit einer Sensitivität von 90%. Automatische Injektionssysteme und manuelle Tracer Applikation wirken sich auf die Lokalisierung des epileptischen Fokus aus. Die SISCOM Diagnostik weist eine durchschnittliche Sensitivität von 57% und eine mittlere Spezifität von 48% auf. Im Vergleich dazu weist die UHF 7T MRT eine mittlere Sensitivität von 68% für die Lokalisierung des epileptischen Fokus und eine mittlere Spezifität von 38% auf. Diskussion: Die Art der fokalen Epilepsie ist ein wichtiger Faktor, der die Ergebnisse beeinflusst. TLE ist sowohl bei der SISCOM Diagnostik als auch bei der UHF 7T MRT leichter zu lokalisieren als ETLE. The presurgical epilepsy evaluation is important to identify the correct type of epilepsy and to correctly localize it. SISCOM is an examination method that is carried out on patients with a negative MRI result and/ or on presurgical patients. Aim: This work provides an overview of SISCOM. The injection time of SISCOM and ictal brain perfusion scintigraphy is explored based on sensitivity. In addition, SISCOM is compared to the UFH 7T MRI in terms of sensitivity and specificity regarding the localization of the epileptic focus. Methods: To answer the question to this thesis, research has been conducted and 14 studies have been selected on inclusion and exclusion criteria. The results were presented through descriptive statistics and visualized through tables and charts. Results: The closer the injection time is to seizure onset, the better the localization of the epileptic focus. The best results were obtained between 45 and 60 seconds with a sensitivity of 90%. The automated injection system and the manual injection influence the localization of the epileptic focus. SISCOM has an average sensitivity of 57% and specificity of 48% to localize the epileptic focus in comparison to the UHF 7T MRI with an average sensitivity of 68% and specificity of 38%. Discussion: Different focal epilepsies are an important factor which influence the results. In SISCOM as well as in UHF 7T MRI, TLE is easier to localize than ETLE.

Yoonha Hwang,1 Hwa Reung Lee,2 Hyunjin Jo,3,4 Dongyeop Kim,3,4 Eun Yeon Joo,3,4 Dae-Won Seo,3,4 Seung Bong Hong,3,4 Young-Min Shon3– 5 1Department of Neurology, The Catholic University of Korea Eunpyeong St. Mary’s Hospital, Seoul, Republic of Korea; 2Department of Neurology, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea; 3Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; 4Neuroscience Center, Samsung Medical Center, Seoul, Republic of Korea; 5Department of Medical Device Management and Research, Samsung Advanced Institute for Health Sciences & Technology (SAHIST), Sungkyunkwan University, Seoul, KoreaCorrespondence: Young-Min ShonDepartment of Neurology, Samsung Medical Center, Sungkyunkwan, University School of Medicine, 81 Irwonro, Gangnam-gu, Seoul, 06351, Republic of KoreaTel +82-2-3410-2701Fax +82-2-3410-0052Email sonogung@gmail.comBackground and Objective: Subtraction of ictal SPECT coregistered to MRI (SISCOM) provides complementary information for detecting the ictal onset zone, especially in patients with MRI-negative focal epilepsy, and provides additional useful information for predicting long-term postresection outcomes. This study sought to investigate the relationship between surgical failure and increased cerebral blood flow (CBF) pattern using SPECT in patients with mesial temporal lobe epilepsy with unilateral hippocampal sclerosis (MTLE-HS).Methods: Among 42 subjects who underwent anterior temporal lobectomy with amygdalohippocampectomy (ATL-AH) for MTLE-HS, 29 (69.0%) were seizure-free (SF group). Hyperperfusion was compared in 14 ipsilateral and contralateral brain regions in SISCOM images between the two groups.Results: The pattern of ictal hyperperfusion in temporal regions did not vary significantly between the SF and non-seizure-free (NSF) groups. However, CBF increases in the contralateral occipital area was more frequent in the NSF group than in the SF group. Furthermore, ictal hyperperfusion of the ipsilateral occipital and contralateral parietal areas tended to be more frequent in the NSF group.Conclusion: The results indicate that poor ATL-AH surgical outcome is associated with a tendency of ictal hyperperfusion of the contralateral occipital cortex based on SISCOM analysis. The pattern of early ictal CBF changes implicating the propagation from temporal to occipital cortices can be considered a marker of poor surgical outcomes of ATL-AH in MTLE-HS patients.Keywords: temporal lobe epilepsy, ictal hyperperfusion, SISCOM, contralateral occipital

PURPOSE: Children with drug-resistant focal epilepsy have a compromised quality of life. Epilepsy surgery can control or significantly reduce the seizures. We assessed and compared the usefulness of PISCOM, a new nuclear imaging processing technique, with SISCOM and 18F-FDG PET (FDG-PET) in pre-surgical evaluation of paediatric drug-resistant focal epilepsy. METHODS: Twenty-two children with pharmcorefractory epilepsy, mainly extratemporal, who had undergone pre-surgical assessment including SISCOM and FDG-PET and with postsurgical favorable outcome (Engel class I or II) for at least two years, were included in this proof-of-concept study. All abnormalities observed in SISCOM, FDG-PET and PISCOM were compared with each other and with the known epileptogenic zone (EZ) based on surgical treatment, histopathologic and surgical outcome results. Global interobserver agreement, Cohen's Kappa coeficient and PABAK statistic were calculated for each technique. RESULTS: PISCOM concordance with the known EZ was significantly higher than SISCOM (p

Diese Arbeit befasst sich mit der Durchführung der SISCOM Diagnostik bei Patient*innen mit pharmakoresistenter fokaler Epilepsie und deren Veränderungen seit 1998. Weiters wird die Sensitivität in Bezug auf die Identifikation des epileptischen Fokus von SISCOM, einer [18F]-FDG-PET und PISCOM verglichen und das postoperative Outcome dieser drei Untersuchungsmethoden durch den Vergleich mithilfe der Engel-Klassifikation analysiert. Methode: Für die Beantwortung der zentralen Fragestellungen wurde eine Literaturrecherche durchgeführt und Studien anhand von Ein- und Ausschlusskriterien ausgewählt. Die Ergebnisse wurden durch deskriptive Statistik mithilfe von Tabellen und Diagrammen veranschaulicht und beschrieben. Ergebnisse: Veränderungen in der Durchführung der SISCOM Diagnostik zeigen sich hauptsächlich durch die Verwendung von (semi-) automatisierten Programmen zur Bildnacherarbeitung und den Einsatz von automatischen Injektionssystemen zur Tracer-Injektion bei der iktalen Hirnperfusionsszintigraphie. Automatische Injektionssysteme können den Tracer schneller nach Beginn des epileptischen Anfalles applizieren. Neue Programme zur Bilddatenverarbeitung können die SISCOM Datensätze in einer deutlich kürzeren Zeit erstellen als 1998 (3-6 Minuten vs. 40 Minuten). Die mittlere Sensitivität zur Lokalisation des epileptischen Fokus von SISCOM liegt bei 67,6% und für eine [18F]-FDG-PET bei 73,7%. Die beiden PISCOM Studien weisen eine Sensitivität von über 80% auf. In Bezug auf den postoperativen Outcome mittels Engel-Klassifikation zeigen alle ausgewählten Studien einen Anteil der günstigen Operationsergebnisse (Engel Klasse I + II) von über 60%. Die Studien verwenden SISCOM und [18F]-FDG-PET zur präoperativen Evaluierung. Für die PISCOM Diagnostik gibt es derzeit keine Studien, die den postoperativen Outcome mittels Engel-Klassifikation beschreiben. Diskussion: Diese Arbeit gibt eine Übersicht über die Durchführung der SISCOM Diagnostik und Innovationen, wie neue Programme der Bilddatenverarbeitung und automatische Injektionssysteme. Des Weiteren wird ein Überblick sowohl über die Sensitivitäten von SISCOM, [18F]-FDG-PET und PISCOM der ausgewählten Studien dargestellt als auch über den postoperativen Outcome mittels Engel-Klassifikation. Für signifikante Ergebnisse müssten Meta-Analysen mit deutlich mehr Studien durchgeführt werden. Darüber hinaus sollte die PISCOM Diagnostik zukünftig umfassend analysiert werden, um ihren Stellenwert in der Epilepsiediagnostik und Operationsplanung zu evaluieren. This thesis deals with the performance of SISCOM diagnostics in patients with pharmacoresistant focal epilepsy and its changes since 1998. Furthermore, the sensitivity regarding the identification of the epileptic focus of SISCOM, [18F]-FDG-PET and PISCOM is compared and the postoperative outcome of these three examination methods is comparatively analyzed using the Engel classification. Methods: A literature research was performed to answer the main questions, and studies were selected based on inclusion and exclusion criteria. The results were illustrated and described through descriptive statistics using tables and charts. Results: Changes in the performance of SISCOM diagnostics are mainly shown in the use of (semi-) automated programs for image post-processing and the use of automated injection systems for tracer injection in ictal brain perfusion SPECT. Automated injection systems can apply the tracer more quickly after the onset of the epileptic seizure. New image data processing programs can produce SISCOM data sets in a remarkably shorter time than in 1998 (3-6 minutes vs. 40 minutes). The mean sensitivity for localization of the epileptic focus of SISCOM is 67.6% and 73.7% for [18F]-FDG-PET. The two PISCOM studies have a sensitivity of more than 80%. Regarding postoperative outcome by Engel classification, all selected studies show a proportion of favorable surgical outcomes (Engel class I + II) above 60%. The studies use SISCOM and [18F]-FDG-PET for preoperative evaluation. For PISCOM diagnostics, there are currently no studies describing the postoperative outcome using Engel classification. Discussion: This thesis provides an overview of the performance of SISCOM diagnostics and innovations, such as new image data processing programs and automated injection systems. Furthermore, an overview of the sensitivities of SISCOM, [18F]-FDG-PET and PISCOM of the selected studies is presented as well as the postoperative outcome using Engel classification. Meta-analysis with considerably more studies would have to be performed for significant results. In addition, PISCOM should be comprehensively analyzed in the future, to evaluate its value in epilepsy diagnostics and surgery planning.

This study was addressed to evaluate the temporal and spatial changes in regional cerebral blood flow (rCBF) of patients with neuropsychiatric systemic lupus erythematosus (NPSLE). Our objective was to correlate the subtracted SPECT coregistered to MRI features (SISCOM) with demographic, clinical and laboratory findings to shed light upon the pathophysiological evolution of the NPSLE. Twenty-six NPSLE patients with MRI and pre and post-treatment brain SPECT with [99mTc]Tc-ECD. SISCOM features were categorized as improvement,worsening, activation and/or deactivation of rCBF findings. Patients mean age of 43.19 years and 65.38% white were evaluated. The patients mean age at onset of SLE was 26.05 and 42.29 for NPSLE. The mean time between the onset of SLE and first NPSLE symptoms was 5.57 years. The disease has already been initiated as NPSLE in 4 patients. The SLEDAI average score was 31.69 and the SLICC/ACR-DI score was 6.96. The patients underwent an average of 9.23 cyclophosphamide. The SISCOM findings showed functional and pathological states on different brain regions. The rCBF changes were not associated with index scores. There was, however, a trend towards an association between lower SLEDAI scores with improvement and higher SLEDAI with worsening in SISCOM. Also, a trend of association between lower SLICC score with improvement, and higher SLICC with worsening. The female gender was predictive of activation and worsening, separately, and deactivation and worsening in a set. Non-white patients were predictive of worsening. The seizure was predictive of deactivation separately, and deactivation and worsening in a set. Finally, normal C3 was a predictor of improvement. The present study showed dynamic brain changes in NPSLE patients. SISCOM technique showed improved rCBF in some brain areas, and worsening, activation and deactivation in anothers. There were associations between rCBF changes and gender, skin colour and complement C3, and association trends with SLEDAI and SLICC scores.

Napredak u radiologiji pružio je mogućnosti slikovnog prikaza raznih bolesti, uključujući epilepsiju. Epilepsija je bolest koja se povezuje s epileptičknim napadajima te posljedično dovodi do negativnih promjena na kognitivnoj, neurobiološkoj, psihološkoj i socijalnoj razini. S obzirom na složenost mozga kao organa, dijagnosticiranje ove bolesti zahtijeva precizne i pouzdane metode snimanja. Ističu se pretrage poput elektroencefalograma (EEG), kompjutorizirane tomografije (CT), magnetske rezonance (MR) i njenih naprednih tehnika te metode nuklearne medicine (PET, SPECT). Postoje indikacije za primjenu svake od navedenih tehnologija, međutim kada je riječ o epilepsiji MR je tada najčešći izbor snimanja mozga. Upotreba specifičnog MR protokola za epilepsiju uvelike je olakšala proces prepoznavanja i postavljanja dijagnoze ove bolesti. Protokol se sastoji od niza sekvenci koje u kombinaciji daju sliku potrebnu za uočavanje epileptogene promjene. Druge metode oslikavanja se primjenjuju kada je u pitanju hitnoća ili kada MR nalaz nije dovoljan za procjenu. To su naprednije i skuplje tehnike, ali kod određenih situacija neophodne u otkrivanju uzroka stanja u kojem se bolesnik nalazi. Postoji šest etioloških skupina uzroka te je potrebno utvrditi s kojom je povezana postojeća epilepsija. Evaluacijom slikovnog materijala može se doći do vrijednih informacija pomoću kojih se bolesniku može pružiti potrebna skrb. The development of radiology has given us the opportunity of imaging many diseases, epilepsy being one of them. This disease is associated to epileptic seizures and it can consequently lead to cognitive, neurobiological, psychological and social changes. Considering the complexity of the brain anatomy, diagnosing this type of disease requires precise and reliable imaging methods. The exams that stand out are the electroencephalogram (EEG), computed tomography (CT), magnetic resonance imaging (MRI) and its’ advanced techniques and also nuclear medicine methods (PET, SPECT). There are many indications for the use of these technologies, but when it comes to epilepsy the MRI is the most common choice for examining the brain. The use of the epilepsy dedicated protocol has helped in the process of recognizing and diagnosing this disease. The protocol consists of many sequences that, when combined, give an image that is needed for noticing the epileptogenic changes. Other forms of imaging are used when urgent or when the MR findings are not enough for the evaluation. Those methods are more advanced and expensive, but very necessary in some situations to find out the cause of the condition the patient is currently in. There are six etiologic groups of causes, and it is important to find out which one is associated to the epilepsy that the patient has. In order to give patients the care they need, it is obligatory to evaluate the images that hold the needed information.

Perfusion patterns observed in Subtraction Ictal SPECT Co-registered to MRI (SISCOM) assist in focus localization and surgical planning for patients with medically intractable focal epilepsy. While the localizing value of SISCOM has been widely investigated, its relationship to the underlying electrophysiology has not been extensively studied and is therefore not well understood. In the present study, we set to investigate this relationship in a cohort of 70 consecutive patients who underwent ictal and interictal SPECT studies and subsequent stereo-electroencephalography (SEEG) monitoring for localization of the epileptogenic focus and surgical intervention. Seizures recorded during SEEG evaluation (SEEG seizures) were matched to semiologically-similar seizures during the preoperative ictal SPECT evaluation (SPECT seizures) by comparing the semiological changes in the course of each seizure. The spectral changes of the ictal SEEG with respect to interictal ones over 7 traditional frequency bands (0.1 to 150Hz) were analyzed at each SEEG site. Neurovascular (SEEG/SPECT) relations were assessed by comparing the estimated spectral power density changes of the SEEG at each site with the perfusion changes (SISCOM z-scores) estimated from the acquired SISCOM map at that site. Across patients, a significant correlation (p

Introduction: Subtraction of ictal-interictal SPECT co-registered to MRI (SISCOM) is a quantification tool that can improve the sensitivity and specificity of the epileptogenic zone (EZ) localization. Commercially available image analysis software packages for SISCOM are costly, and Statistical Parametric Mapping (SPM) could be an alternative free software for the definition of the EZ. There are only a few studies that compare SISCOM using SPM (SISCOM-SPM) with visual analysis. Aim: To compare SISCOM-SPM vs. visual analysis for localization of the EZ in patients with pharmacoresistant focal epilepsies. Materials and methods: We evaluated all our patients with focal epilepsies that underwent ictal and interictal SPECT. We defined the reference standard to locate the EZ by pathology and follow-up (in patients submitted to surgery), or seizure semiology, serial EEG, long-term video-EEG, 18F-FDG PET/CT, and MRI (in patients who were not operated). We compared the location of the EZ by visual analysis of SPECT images and by SISCOM-SPM to the reference standard and classified as concordant, discordant, or partially concordant. Results: We included 23 patients. Visual analysis was concordant with the EZ reference standard in only 13 patients (56.5%), while SISCOM-SPM was concordant in 18 cases (78.3%), providing a 21.8% increase in the location of EZ. However, this difference was not significant due to the small sample size (p = 0.0856). Conclusion: Our preliminary results demonstrate that, in clinical practice, SISCOM-SPM has the potential to add information that might help localize the EZ compared to visual analysis. SISCOM-SPM has a lower cost than other commercially available SISCOM software packages, which is an advantage for developing countries. Studies with more patients are necessary to confirm our findings.

OBJECTIVE: To assess feasibility and efficacy of subtraction ictal SPECT coregistered to MRI (SISCOM) for epilepsy localization in children who are candidates for resective surgery. METHODS: We retrospectively reviewed all patients ≤16 years with drug-resistant epilepsy screened for epilepsy surgery in the University Hospital of Leuven from January 2009 to January 2018. Fifty-eight hospitalizations for ictal SPECT and 51 SISCOM analyses in 44 patients were included. Mean age was 9.1 years. Hospitalizations for SISCOM were analyzed in terms of multiple variables affecting feasibility and efficacy. The localization of SISCOM was compared with the localization of the presumed epileptogenic zone (PEZ) as determined by video-EEG. RESULTS: SISCOM was feasible in terms of chronic medication management, rescue antiepileptic therapy during hospitalization, and operative timings. Radiotracer injection occurred within 30 seconds from seizure onset in 91.4% of the patients. ictal SPECT imaging was performed within two hours from injection in 100% of the patients (mean: 40 minutes). SISCOM was able to localize the PEZ in 51.0% (26/51) and to additionally lateralize the PEZ in 17.6% (9/51), achieving better localizations than ictal SPECT, FDG-PET, and MRI (P

PurposeWe present a modified version of the SISCOM procedure that uses interictal PET instead of interictal SPECT for seizure onset zone localization. We called this new nuclear imaging processing technique PISCOM (PET interictal subtracted ictal SPECT coregistered with MRI).MethodsWe retrospectively studied 23 patients (age range 4-61years) with medically refractory epilepsy who had undergone MRI, ictal SPECT, interictal SPECT and interictal FDG PET and who had been seizure-free for at least 2years after surgical treatment. FDG PET images were reprocessed (rFDG PET) to assimilate SPECT features for image subtraction. Interictal SPECT and rFDG PET were compared using statistical parametric mapping (SPM). PISCOM and SISCOM images were evaluated visually and using an automated volume of interest-based analysis. The results of the two studies were compared with each other and with the known surgical resection site.ResultsSPM showed no significant differences in cortical activity between SPECT and rFDG PET images. PISCOM and SISCOM showed equivalent results in 17 of 23 patients (74%). The seizure onset zone was successfully identified in 19 patients (83%) by PISCOM and in 17 (74%) by SISCOM: in 15 patients (65%) the two techniques showed concordant successful results. The volume of interest-based analysis showed no significant differences between PISCOM and SISCOM in identifying the extension of the seizure onset zone. However, PISCOM showed a lower amount of indeterminate activity due to propagation, background or artefacts.ConclusionPreliminary findings of this initial proof-of-concept study suggest that perfusion and glucose metabolism in the cerebral cortex can be correlated and that PISCOM may be a valid technique for identification of the seizure onset zone. However, further studies are needed to validate these results., This work was supported by AGAUR (Agencia de Gestio d'Ajuts Universitaris I de Recerca) 2014 SGR 279 grants.

Background and objectives: The aim of this study is to propose a methodology that combines non-invasive functional modalities electroencephalography (EEG) and single photon emission computed tomography (SPECT) to estimate the location of the epileptogenic zone (EZ) for the presurgical evaluation of patients with drug-resistant non-lesional epilepsy. Materials and Methods: This methodology consists of: (i) Estimation of ictal EEG source imaging (ESI), (ii) application of the subtraction of ictal and interictal SPECT co-registered with MRI (SISCOM) methodology, and (iii) estimation of ESI but using the output of the SISCOM as a priori information for the estimation of the sources. The methodology was implemented in a case series as an example of the application of this novel approach for the presurgical evaluation. A gold standard and a coincidence analysis based on measures of sensitivity and specificity were used as a preliminary assessment of the proposed methodology to localize EZ. Results: In patients with good postoperative evolution, the estimated EZ presented a spatial coincidence with the resection site represented by high values of sensitivity and specificity. For the patient with poor postoperative evolution, the methodology showed a partial incoherence between the estimated EZ and the resection site. In cases of multifocal epilepsy, the method proposed spatially extensive epileptogenic zones. Conclusions: The results of the case series provide preliminary evidence of the methodology&rsquo, s potential to epileptogenic zone localization in non-lesion drug-resistant epilepsy. The novelty of the article consists in estimating the sources of ictal EEG using SISCOM result as a prior for the inverse solution. Future studies are necessary in order to validate the described methodology. The results constitute a starting point for further studies in order to support the clinical reliability of the proposed methodology and advocate for their implementation in the presurgical evaluation of patients with intractable non-lesional epilepsy.

В статье мы рассматриваем первые результаты применения протокола SISCOM в России у пациентов с очаговой эпилепсией. Работа основана на анализе данных зарубежных исследований, а также собственном опыте применения протокола SISCOM в НМХЦ им. Н. И. Пирогова у пациентов с фармакорезистентной формой эпилепсии. По данным зарубежной литературы верификация очагов и точность определения их границ по протоколу SISCOM составляет более 85%. Наш небольшой опыт соответствует результатам зарубежных исследований. Возможность подробной оценки структуры головного мозга с совместной оценкой перфузии мозговой ткани имеет высокую прогностическую ценность для комплексного обследования пациентов с эпилепсией и предхирургической подготовки., In the article we consider the first results using SISCOM protocol in Russia in patients with focal epilepsy. This work is based on analysis of the latest data from foreign studies, as well as our own experience at the National Medical and Surgical Center named after N.I. Pirogov in patients with pharmacoresistant form of epilepsy. According to foreign literature, the verification of foci and the accuracy of determining their boundaries using the SISCOM protocol is more than 85%. Our small experience corresponds to the results of foreign research. The possibility of a detailed evaluation of the structure of the brain with a joint evaluation of perfusion of the brain tissue has a high predictive value for the comprehensive examination of patients with epilepsy and pre-surgical planing., №3 (2018)

Os equipamentos e processos utilizados em medicina nuclear devem estar inclu?dos em um programa de controle de qualidade, o que inclui uma s?rie de testes e calibra??es com periodicidade estabelecida pelas normas vigentes, baseadas nos protocolos de institui??es internacionais. Os simuladores antropom?rficos, pela sua capacidade de mimetizar situa??es real?sticas, s?o amplamente empregados para aferir dados essenciais que garantam a qualidade nos processos geradores de imagens m?dicas. O objetivo deste trabalho foi desenvolver um phantom antropom?rfico cerebral para simula??o de imagens de atividade ictal em medicina nuclear, utilizando metodologia PET com Fl?or-18 (18F). O phantom foi confeccionado em impressora industrial com tecnologia SLS (Selective Laser Sintering), de espessura de 4 mm, utilizando como mat?ria prima nylon 12. O modelo foi segmentado a partir de um estudo de resson?ncia magn?tica de um adulto normal, do sexo feminino, com 40 anos. Para a simula??o de atividade ictal foram inseridos, na regi?o correspondente ao lobo frontal direito, dois eletrodos met?licos constitu?dos de filme fino de 40 nm de prata (Ag). Para a aquisi??o das imagens, o modelo foi preenchido com ?gua destilada e com o radiois?topo 18F. As imagens foram adquiridas em equipamento de PET-CT com protocolo espec?fico para estudos cerebrais tomogr?fico e din?mico. Foram adquiridas imagens: (1) simulador sem a inser??o dos eletrodos (padr?o/basal), (2) simulador com eletrodos sem aplica??o de campo el?trico e (3) simulador com os eletrodos e aplica??o de campo el?trico. As imagens foram comparadas entre si atrav?s dos valores de SUV m?ximo e do ?ndice de capta??o. A abordagem estat?stica utilizada considerou as tr?s condi??es de imagens como grupos independentes e o teste n?o param?trico de Wilcoxon-Mann-Whitney foi aplicado. Houve diferen?a significativa entre os grupos, sendo o valor de p < 0,001 quando comparados os valores de m?dia de SUV m?ximo por corte nas situa??es basal x sem campo el?trico e basal x com campo el?trico. Na compara??o sem campo el?trico x com campo el?trico, o valor de p = 0,129 indica que a diferen?a entre os grupos n?o ? significativa. Quando avaliado o ?ndice de capta??o entre os grupos, todas as condi??es apresentaram diferen?a significativa, sendo p < 0,001 para os grupos basal x sem campo el?trico e basal x com campo el?trico, e p = 0,0123 na compara??o sem campo el?trico x com campo el?trico. As curvas TAC (time-activity-curve) foram adquiridas para demonstrar a capta??o de 18F no tempo, nas condi??es com campo el?trico e sem campo el?trico, em estudo din?mico de PET-CT. As imagens foram subtra?das atrav?s da metodologia SISCOM, utilizando a condi??o basal como refer?ncia. Os valores encontrados para p, tanto para SUV como para ?ndice de capta??o, s?o compat?veis com os achados visualizados nas imagens obtidas. Os histogramas gerados com a metodologia SISCOM demonstram que h? diferen?as entre as tr?s condi??es de imagem. As curvas TAC tra?adas correspondem ao aumento gradativo da concentra??o 18F no tempo, embora exista este aumento nas condi??es sem campo e com campo, obtivemos a maior concentra??o quando o sistema est? sob efeito do campo el?trico. O phantom antropom?rfico desenvolvido ? capaz de simular zonas an?logas ?s de imagens de atividade ictal, por?m o material utilizado como resina nos eletrodos deve ser modificado para que o produto possa ser comercializado futuramente. The equipment and processes used in nuclear medicine must be included in a quality control program that includes a series of tests and calibrations following the frequency established by current standards, which are based on international institutions protocols. The capability of anthropomorphic simulators mimic realistic situations are widely appointed to gauge essential data that guarantee the quality in medical generating processes. The purpose of this study was developing a cerebral anthropomorphic phantom for image simulation of ictal activity in nuclear medicine with 18F, PET-CT. It was made in an industrial printer with SLS (Selective Laser Sintering) technology, 4mm thick, using nylon 12. The model was segmented from a magnetic resonance study of a 40-year-old female adult. Two 40 nm thickness metal (Ag) electrodes were inserted in the right frontal lobe region to simulate ictal activity. For the images acquisition, the phantom was filled with distillated water and the 18F radioisotope. The images were acquired in PET-CT equipment with specific protocol for tomographic and dynamic cerebral studies. Images from the simulator without the insertion of the electrodes were acquired as pattern (basal), also were acquired images from the simulator with the electrodes and without electric field application, and the simulator with electric field application. The images were compared through SUV maximum values and uptake index. The non-parametric Wilcoxon-Mann-Whitney test was used as statistic approach, considering the three image conditions as independent groups. There was significant difference amongst the groups, being p < 0,001 when compared the average SUV maximum values by slices in the situations: basal x with electric field, and basal x without electric field, p = 0,129 when compared situations with electric field x without electric field, suggesting that this difference is not significant. All the groups presented significant differences for the uptake indexes obtained, being p < 0,001 in the situations basal x with electric field and basal x without electric field. The TAC (time-activity-curve) curves were obtained in A PET-CT dynamic protocol to demonstrate the 18F uptake in time, in the conditions with electric field and without electric field. The images were subtracted through SISCOM, using the basal condition as reference. The values found for p (SUV and uptake index) are compatible. The SISCOM histograms demonstrate differences for the three image comparisons. Although there are gradual raise of 18F uptake in time obtained in TAC evaluation for both with and without electric field conditions, the highest uptake visualized was when the electric field is applied. The anthropomorphic phantom developed is capable of simulating compatible zones with ictal activity, however the material used as resin in the electrodes must be modified so that the product may be commercialized in the future. Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES

BACKGROUND: In epilepsy patients, SISCOM or subtraction ictal single photon emission computed tomography co-registered to magnetic resonance imaging has become a routinely used, non-invasive technique to localize the ictal onset zone (IOZ). Thresholding of clusters with a predefined number of standard deviations from normality (z-score) is generally accepted to localize the IOZ. In this study, we aimed to assess the robustness of this parameter in a group of patients with well-characterized drug-resistant epilepsy in whom the exact location of the IOZ was known after successful epilepsy surgery. Eighty patients underwent preoperative SISCOM and were seizure free in a postoperative period of minimum 1 year. SISCOMs with z-threshold 2 and 1.5 were analyzed by two experienced readers separately, blinded from the clinical ground truth data. Their reported location of the IOZ was compared with the operative resection zone. Furthermore, confidence scores of the SISCOM IOZ were compared for the two thresholds. RESULTS: Visual reporting with a z-score threshold of 1.5 and 2 showed no statistically significant difference in localizing correspondence with the ground truth (70 vs. 72% respectively, p = 0.17). Interrater agreement was moderate (κ = 0.65) at the threshold of 1.5, but high (κ = 0.84) at a threshold of 2, where also reviewers were significantly more confident (p

PURPOSE: We present a modified version of the SISCOM procedure that uses interictal PET instead of interictal SPECT for seizure onset zone localization. We called this new nuclear imaging processing technique PISCOM (PET interictal subtracted ictal SPECT coregistered with MRI). METHODS: We retrospectively studied 23 patients (age range 4-61 years) with medically refractory epilepsy who had undergone MRI, ictal SPECT, interictal SPECT and interictal FDG PET and who had been seizure-free for at least 2 years after surgical treatment. FDG PET images were reprocessed (rFDG PET) to assimilate SPECT features for image subtraction. Interictal SPECT and rFDG PET were compared using statistical parametric mapping (SPM). PISCOM and SISCOM images were evaluated visually and using an automated volume of interest-based analysis. The results of the two studies were compared with each other and with the known surgical resection site. RESULTS: SPM showed no significant differences in cortical activity between SPECT and rFDG PET images. PISCOM and SISCOM showed equivalent results in 17 of 23 patients (74%). The seizure onset zone was successfully identified in 19 patients (83%) by PISCOM and in 17 (74%) by SISCOM: in 15 patients (65%) the two techniques showed concordant successful results. The volume of interest-based analysis showed no significant differences between PISCOM and SISCOM in identifying the extension of the seizure onset zone. However, PISCOM showed a lower amount of indeterminate activity due to propagation, background or artefacts. CONCLUSION: Preliminary findings of this initial proof-of-concept study suggest that perfusion and glucose metabolism in the cerebral cortex can be correlated and that PISCOM may be a valid technique for identification of the seizure onset zone. However, further studies are needed to validate these results.

Neuroimaging studies in preclinical research are an essential prerequisite for the development of drugs and biomarkers for human step. Being able to superimpose the functional and biological information provided by imaging techniques such as PET and SPECT on high-resolution anatomical images such as MRI, is of great help. However, few, complex and very expensive for small animal specific algorithms have been implemented, as opposed to those made for humans. This greatly hinders the work of researchers without technical training. In this project a graphical interface that facilitates the work of these professionals is proposed. To do so will start out the functions globally validated of SPM, written in MATLAB code. We will adapt it for use with rodents, and add the functionalities requested and that are not implemented in the SPM, as is the quantification and fusion of both images. SISCOM method for detecting epileptic foci will also be implemented as a collaborative group request. As a general conclusion, it has been found that the software made meets the specific needs of the center, thus facilitating the work of the image quantification. Los estudios de neuroimagen en preclínica son un paso previo e indispensable para el desarrollo de fármacos y biomarcadores para humanos. Poder superponer la información funcional y biológica proporcionada por técnicas de imagen como el PET y el SPECT sobre imágenes anatómicas de alta resolución como la RM, supone una gran ayuda. Sin embargo, son pocos, complejos y muy caros los algoritmos específicos para pequeño animal que se han implementado en contraposición a los realizados para humanos. Eso dificulta enormemente el trabajo de los investigadores sin formación técnica. En este proyecto se propone una interfaz gráfica que facilite el trabajo de estos profesionales. Para ello partiremos de las funciones validadas a nivel mundial del SPM, escrito en código MATLAB, lo adaptaremos al uso con roedores, y añadiremos las funcionalidades solicitadas y que no están implementadas en el SPM, como es la cuantificación y fusión de ambas imágenes. También se implementará el método SISCOM para la detección de focos epilépticos como petición de un grupo colaborador. Como conclusión general, se ha podido comprobar que el software realizado cumple con las necesidades específicas del centro, facilitando así el trabajo de la cuantificación de las imágenes Els estudis de neuroimatge en preclínica són un pas previ i indispensable per al desenvolupament de fàrmacs i biomarcadors per a humans. Poder superposar la informació funcional i biològica proporcionada per tècniques d'imatge com el PET i el SPECT sobre imatges anatòmiques d'alta resolució com la RM, suposa una gran ajuda. No obstant això, són pocs, complexos i molt cars els algoritmes específics per petit animal que s'han implementat en contraposició als realitzats per a humans. Això dificulta enormement el treball dels investigaors sense formació tècnica. En aquest projecte es proposa una interfície gràfica que faciliti la feina d'aquests professionals. Per a això partirem de les funcions validades a nivell mundial de l'SPM, escrit en codi MATLAB, l'adaptarem a l'ús amb rosegadors, i afegirem les funcionalitats sol?licitades i que no estan implementades en l'SPM, com és la quantificació i fusió de les dues imatges. També s'implementarà el mètode SISCOM per a la detecció de focus epilèptics com a petició d'un grup col?laborador. Com a conclusió general, s'ha pogut comprovar que el software realitzat compleix amb les necessitats específiques del centre, facilitant així el treball de la cuantifició de les imatges.

Subtraction of Ictal SPECT Co-registered to MRI (SISCOM) is an imaging technique used to localize the epileptogenic focus in patients with intractable partial epilepsy. The aim of this study was to determine the accuracy of registration algorithms involved in SISCOM analysis using FocusDET, a new user-friendly application. To this end, Monte Carlo simulation was employed to generate realistic SPECT studies. Simulated sinograms were reconstructed by using the Filtered BackProjection (FBP) algorithm and an Ordered Subsets Expectation Maximization (OSEM) reconstruction method that included compensation for all degradations. Registration errors in SPECT-SPECT and SPECT-MRI registration were evaluated by comparing the theoretical and actual transforms. Patient studies with well-localized epilepsy were also included in the registration assessment. Global registration errors including SPECT-SPECT and SPECT-MRI registration errors were less than 1.2 mm on average, exceeding the voxel size (3.32 mm) of SPECT studies in no case. Although images reconstructed using OSEM led to lower registration errors than images reconstructed with FBP, differences after using OSEM or FBP in reconstruction were less than 0.2 mm on average. This indicates that correction for degradations does not play a major role in the SISCOM process, thereby facilitating the application of the methodology in centers where OSEM is not implemented with correction of all degradations. These findings together with those obtained by clinicians from patients via MRI, interictal and ictal SPECT and video-EEG, show that FocusDET is a robust application for performing SISCOM analysis in clinical practice.

Purpose We employed the results of imaging modalities from pediatric patients who received successful epilepsy surgery to determine the accuracy of each imaging tool in identifying epileptic zones in youngsters. Methods All Engel class I pediatric patients who received epilepsy surgery between October 2003 and April 2008 were selected. Their pathology, EEG, MRI, PET, and subtraction ictal SPECT coregistered to MRI (SISCOM) results were compared for accuracy in locating the epileptic foci, defined as "area that resulted in seizure ablation after resection". Results Forty-two patients were enrolled (23 temporal lobectomy, 19 extratemporal resections). MRI showed concordance in 84.2% of extratemporal cases, all of which had precise localization of lesions. In temporal cases, lateralization was 91.3% and localization was 82.6%. PET showed a concordance rate of 95.5% and localization was 72.7% for temporal lesions. For extratemporal lesions, concordance was only 68.4%. SISCOM showed concordance in 100% of temporal and 92.3% of extratemporal cases, with localization in 66.7% of temporal and 84.6% of extratemporal cases. Most temporal lobe cases had hippocampal sclerosis, and cortical dysplasia was observed in extratemporal cases. Discussion MRI was invariably reliable in all cases. PET results were as reliable in lateralizing the temporal epileptic area, while its efficacy was lower for extratemporal cases. SISCOM effectively localized lesions in extratemporal cases, but its efficacy was lower in temporal lesions. In cases of conflicting pre-surgical results, MRI, with supplementary data from PET, helped to establish correct decisions in temporal epilepsies, while utilization of SISCOM and MRI data is advised for extratemporal cases.

SummaryA 27-year-old man had complex partial seizures and a dysembryoplastic neuroepithelial tumor (DNT) in the left inferior-basal temporal region. The patient's seizures consisted of incomprehensible speech, staring, unresponsiveness, fumbling and then looking around. For the brain SPECT study, radiotracer was injected during the preictal (11s prior to seizure onset), ictal (at 25s out of 47s seizure duration) and interictal periods. Interictal SPECT was subtracted from preictal or ictal-injection SPECTs and then the subtracted SPECTs were overlaid on the patient's MRI (SISCOM). SISCOM with preictal-injection SPECT showed hyperperfusion at the brain lesion, whereas SISCOM with ictal-injection SPECT showed hyperperfusion at the ipsilateral amygdala-hippocampus and hypoperfusion around the tumor lesion. After the DNT and nearby temporal lobe tissues were resected with preservation of amygdala-hippocampus, the patient became seizure free without complaint of subjective postsurgical memory decline. In this patient, SISCOM with preictal injection of radiotracer localized an epileptogenic zone, whereas SISCOM with the ictal injection showed hyperperfusion at the symptomatogenic zone.

INTRODUCTION: Generalized tonic-clonic seizures (GTCS) are among the most dramatic types of epileptic seizures and may be accompanied by rising blood pressure and pulse rate, physical injuries from falling, muscular convulsions, tongue biting, or aspiration pneumonia. Epistaxis is an uncommon complication of generalized seizures and investigations should exclude local or systemic disorders. OBJECTIVE: We aim to report a 29-year-old male patient with medically intractable right temporal lobe epilepsy whose ictal SPECT showed a conspicuous high extracerebral accumulation of the tracer at the skull base. METHODS: The tracer 99mTc-ECD was injected during a GTCS complicated by simultaneous epistaxis during a long term video-electroencephalographic monitoring. RESULTS: Initially, SPECT images showed an unexpected hot spot at the skull base suggesting pharyngeal or pituitary tumors. Clinical history disclosed chronic sinusitis and rare episodes of epistaxis. White and red cells blood count, platelet count, serum biochemistry, coagulation tests, and rest arterial blood pressure were normal. Computed tomography and MRI excluded sinusoidal expansive or vascular lesions, head trauma, fractures or acute infections. Subtracted SPECT disclosed a focal high concentration of the radiotracer within the left sphenoid sinus, probably related to the nose bleeding. CONCLUSION: This is a singular case of a brain SPECT artifact secondary to a nasal bleeding during a generalized seizure that was misinterpreted as neoplastic disease. Also, this case raises concerns about the pathophysiological relationship among epileptic seizures, nasal bleedings and chronic sinusitis.

We investigated the diagnostic performance of 18F-FDG PET and ictal (99m)Tc-HMPAO SPET in pediatric temporal lobe epilepsy (TLE). Twenty-one pediatric TLE patients were enrolled in this study. Their diagnoses were confirmed by histology and post-surgical outcome (Engel class I or II). The patients' ages were 18 or younger (15+/-3 years). Of the 21 patients, 21 patients underwent 18F-FDG PET scan and 15 underwent ictal (99m)Tc-HMPAO SPET. Preoperative PET and/or ictal SPET images were reviewed by simple visual assessment and by statistical parametric mapping (SPM). Asymmetric indices (AI) were calculated using statistical probabilistic anatomical map (SPAM) on 18F-FDG PET. In nine patients who underwent both ictal and interictal SPET, SISCOM (subtraction ictal SPET coregistered to MR template) was performed. PET correctly localized epileptogenic zones in 20 of 21 (95%) by visual assessment. SPM analysis of PET correctly localized epileptogenic zones in 18 of 21 (86%). Ictal SPET correctly localized epileptogenic zones in 12 of 15 (80%) by visual assessment. SPM analysis of ictal SPET correctly localized epileptogenic zones in 12 of 15 (80%). SISCOM correctly localized 8 of 9 (89%), which was equal to that of visual assessment of ictal SPET. The AIs of the temporal lobes by PET were -15+/-8.4 in the left and 9.9+/-8.9 in the right TLE (normal control: -2.9+/-2.8), and correctly localized epileptogenic zones in all cases. As is found in adult TLE, PET and ictal SPET efficiently localized epileptogenic zones in pediatric TLE. SPM analysis of PET or ictal SPET could be used as an aid to visual assessment. Moreover, SISCOM was equal visual assessment of ictal SPET images in terms of lesion localizations.

The correlation of data from several proveniences in Epilepsy has registered some progresses in the detection of the Epileptogenic focus/zone. The subtraction of SPECT co-registered to MRI (SISCOM) has been assuming as a valiant technique, localising the lesion area for surgical recession through a good location of theEpiletogenic zone. In this paper we present the automation and improvement performed to the Epilepsy SISCOM protocol used at the Neurophysiology Department of Santo António GeneralHospital that was previously too complex, not allowing an autonomous use by the clinician responsible to perform it., A correlação de dados de diversas proveniências em Epilepsia tem registado alguns avanços na detecção do foco/zona Epileptogénica. A subtracção de SPECT co-registado com IRM (SISCOM) tem-se assumido como uma valorosa técnica, localizando a área lesional para recessão cirúrgica através de uma boa localização da zona Epileptogénica. Neste trabalho apresentamos a automatização e optimização do protocolo de realização da SISCOM em Epilepsia do serviço de Neurofisiologia do Hospital Geral de Santo António que era demasiado complexo, não permitindo uma utilização autónoma aos clínicos deste serviço.