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Ictal and interictal SPECT in patients with frontal lobe epilepsy.- This paper was awarded the ADAC Prize at the Brazilian Congress of Nuclear Medicine, Recife, Brazil, December 1998.  [cached]
Wichert-Ana, Lauro.,Kato, Mery .,Terra Bustamante, Vera Cristina.,Rodrigues Velasco, Tonicarlo.
Alasbimn Journal , 1999,
Abstract: The frontal lobe seizures present variable clinical and electroencephalographic features that play some difficulties in the presurgical work-up for epilepsy. The aim of the present study is to determine the role of ictal and interictal SPECT in the localization of the epileptogenic zone in frontal lobe epilepsies. We evaluated 13 patients, 6 men and 7 women, with mean age of 16yr, and with medically intractable frontal lobe seizures. All patients were submitted to ictal SPECT and 11 also to interictal scans. Ictal SPECT studies were contributive in 54% of patients, and nonlateralized and nonlocalized, or contralateralized in the remaining patients. Interictal SPECT showed normal perfusion in 45,5% of patients, hypoperfusion localized in the suspected epileptogenic zone in 45,5%, and diffuse findings in the other 9%. We conclude that the sensitivity of ictal and interictal SPECT studies in frontal lobe epilepsies is lower than that for temporal lobe seizures, thus confirming previous data.
Perfusion Network Shift during Seizures in Medial Temporal Lobe Epilepsy  [PDF]
Karen M. Sequeira, Ali Tabesh, Rup K. Sainju, Stacia M. DeSantis, Thomas Naselaris, Jane E. Joseph, Mark A. Ahlman, Kenneth M. Spicer, Steve S. Glazier, Jonathan C. Edwards, Leonardo Bonilha
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0053204
Abstract: Background Medial temporal lobe epilepsy (MTLE) is associated with limbic atrophy involving the hippocampus, peri-hippocampal and extra-temporal structures. While MTLE is related to static structural limbic compromise, it is unknown whether the limbic system undergoes dynamic regional perfusion network alterations during seizures. In this study, we aimed to investigate state specific (i.e. ictal versus interictal) perfusional limbic networks in patients with MTLE. Methods We studied clinical information and single photon emission computed tomography (SPECT) images obtained with intravenous infusion of the radioactive tracer Technetium- Tc 99 m Hexamethylpropyleneamine Oxime (Tc-99 m HMPAO) during ictal and interictal state confirmed by video-electroencephalography (VEEG) in 20 patients with unilateral MTLE (12 left and 8 right MTLE). Pair-wise voxel-based analyses were used to define global changes in tracer between states. Regional tracer uptake was calculated and state specific adjacency matrices were constructed based on regional correlation of uptake across subjects. Graph theoretical measures were applied to investigate global and regional state specific network reconfigurations. Results A significant increase in tracer uptake was observed during the ictal state in the medial temporal region, cerebellum, thalamus, insula and putamen. From network analyses, we observed a relative decreased correlation between the epileptogenic temporal region and remaining cortex during the interictal state, followed by a surge of cross-correlated perfusion in epileptogenic temporal-limbic structures during a seizure, corresponding to local network integration. Conclusions These results suggest that MTLE is associated with a state specific perfusion and possibly functional organization consisting of a surge of limbic cross-correlated tracer uptake during a seizure, with a relative disconnection of the epileptogenic temporal lobe in the interictal period. This pattern of state specific shift in metabolic networks in MTLE may improve the understanding of epileptogenesis and neuropsychological impairments associated with MTLE.
Brain SPECT in mesial temporal lobe epilepsy: comparison between visual analysis and SPM
Amorim, Bárbara Juarez;Ramos, Celso Darío;Santos, Allan Oliveira dos;Lima, Mariana da Cunha Lopes de;Min, Li Li;Camargo, Edwaldo Eduardo;Cendes, Fernando;Etchebehere, Elba Cristina Sá de Camargo;
Arquivos de Neuro-Psiquiatria , 2010, DOI: 10.1590/S0004-282X2010000200001
Abstract: objective: to compare the accuracy of spm and visual analysis of brain spect in patients with mesial temporal lobe epilepsy (mtle). method: interictal and ictal spects of 22 patients with mtle were performed. visual analysis were performed in interictal (visual(inter)) and ictal (visual(ictal/inter)) studies. spm analysis consisted of comparing interictal (spm(inter)) and ictal spects (spm(ictal)) of each patient to control group and by comparing perfusion of temporal lobes in ictal and interictal studies among themselves (spm(ictal/inter)). results: for detection of the epileptogenic focus, the sensitivities were as follows: visual(inter)=68%; visual(ictal/inter)=100%; spm(inter)=45%; spm(ictal)=64% and spm(ictal/inter)=77%. spm was able to detect more areas of hyperperfusion and hypoperfusion. conclusion: spm did not improve the sensitivity to detect epileptogenic focus. however, spm detected different regions of hypoperfusion and hyperperfusion and is therefore a helpful tool for better understand pathophysiology of seizures in mtle.
First true initial ictal SPECT in partial epilepsy verified by electroencephalography  [cached]
Jesús Pastor,Luis Domínguez-Gadea,Rafael G Sola,Virgilio Hernando
Neuropsychiatric Disease and Treatment , 2008,
Abstract: Jesús Pastor1, Luis Domínguez-Gadea2, Rafael G Sola3, Virgilio Hernando3, María Luisa Meilán4, Eva De Dios4, José Luis Martínez-Chacón4, Marcos Martínez51Clinical Neurophysiology; 2Nuclear Medicine; 3Neurosurgery; 4Anaesthesiology and Reanimation; Hospital Universitario “La Princesa”, Madrid, Spain; 5Anaesthesiology and Reanimation, Cardiovascular Unit of Adults, Hospital Ramón y Cajal, Madrid, SpainAbstract: Drug-resistant epilepsy can sometimes be treated by surgery. In these cases, an accurate identification of the epileptogenic area must be addressed before resection. Ictal SPECT is one of the presurgical evaluations that can be performed, but usually, the increase in the regional cerebral perfusion observed is produced by diffusion of ictal activity. Here we describe a patient studied with v-EEG and foramen ovale electrodes that suffered a seizure after intravenous infusion of etomidate. The sequence of etomidate administration, followed by radiotracer and seizure was good enough for us to suspect that a true initial ictal SPECT was observed. We have implemented a kinetic model with four compartments, previously described (Andersen 1989), in order to estimate the fraction of hydrophilic radiotracer in the brain during the pre-ictal and ictal periods. This model has shown that the fraction of hydrophilic radiotracer during the seizure into the brain would be between 18.9% and 42.3% of total infused. We show the first true initial ictal SPECT demonstrated by bioelectrical recordings of the brain activity, obtained by a correct succession of events and compatible with theoretical data obtained from the kinetic model.Keywords: etomidate, foramen ovale electrodes, mathematical model, temporal lobe epilepsy
Avalia??o de foco epileptogênico do lobo temporal: correla??o entre SPECT ictal, ressonancia magnética e ressonancia magnética com espectroscopia de prótons
Diegues, Maria Elena Martins;Pellini, Marcos Pinto;Alves-Leon, Soniza Vieira;Domingues, Romeu C?rtes;
Radiologia Brasileira , 2004, DOI: 10.1590/S0100-39842004000100003
Abstract: the purpose of this study was to determine the degree of concordance between radiological and radioisotopic methods and, if positive, to evaluate the usefulness of ictal spect in the localization of the epileptogenic focus. ictal brain spect, magnetic resonance imaging (mri) and magnetic resonance spectroscopy (mrs) were performed on six patients with refractory temporal lobe epilepsy. ictal spect was performed after withdrawal of the anti-epileptogenic drugs during video-eeg monitoring, using 99mtc-ecd, administered to patients at the time of the ictus. mri was performed in t1, t2 and flair sequences and mrs was obtained using the press technique, with a single voxel positioned in both hippocampi. the statistical analysis included the determination of the values of kappa (k), standard error (se) and significance level (p) for the lateralization of the ictal focus. the analysis of all findings was based on eeg localization of the ictal discharge, seizure duration (109-280 s; 152 s average) and time of radiotracer injection (30-262 s; 96 s average). we obtained correlated data in four patients (67%), and values of k = 0.67, se = 0.38, and p = 0.041. we concluded that there is a concordance between ictal spect, mri and mrs data and the usefulness of the radioisotopic procedure is related to a nondiagnostic eeg and when there is a discordant or misleading diagnosis after a comparative analysis of eeg and mrs.
The hazards of lack of co-registration of ictal brain SPECT with MRI: A case report of sinusitis mimicking a brainstem seizure focus
Tracy Butler, Lawrence J Hirsch, Jan Claassen
BMC Medical Physics , 2004, DOI: 10.1186/1471-2385-4-2
Abstract: A young woman with encephalitis and refractory seizures underwent brain SPECT during a period of frequent seizure-like episodes, and during a seizure-free period. A focal area of increased radiotracer uptake present only when she was experiencing frequent seizure-like episodes was originally localized to the brainstem, but with later computerized co-registration of SPECT to MRI, was found to lie outside the brain, in the region of the sphenoid sinus.Low-resolution SPECT images present difficulties in interpretation, which can be overcome through co-registration to higher-resolution structural images.Radiotracers used for brain single photon emitted computed tomography (SPECT) pass the blood-brain barrier and bind intracellularly on their first pass through the circulation, providing a "snapshot" of cerebral perfusion at a particular timepoint. When injected during a focal epileptic seizure, an area of significantly increased radiotracer uptake typically corresponds to the region of maximal abnormal activity, often the seizure focus. This ictal pattern of cerebral blood flow can be compared to an interictal/baseline pattern obtained when the patient is not having a seizure, to provide unique information about the nature and location of a patient's epileptic focus, which can be used to guide therapy [See [1] for a review of the use of SPECT in epilepsy].A previously-healthy young woman developed behavioral changes followed by seizures and refractory status epilepticus. She was diagnosed with encephalitis and treated with antiviral and multiple antiepileptic agents. She required nasotracheal intubation and mechanical ventilation for respiratory support. She experienced persistent episodes of facial twitching resembling seizures. These episodes were not however associated with an ictal EEG pattern on continuous video/EEG monitoring. To clarify the nature of these episodes, 99mTc-HMPAO was injected during a period of frequent twitching. Brain SPECT showed a prominent foc
Ictal ECG changes in temporal lobe epilepsy
Li, L.M.;Roche, J.;Sander, J.W.A.S.;
Arquivos de Neuro-Psiquiatria , 1995, DOI: 10.1590/S0004-282X1995000400012
Abstract: changes in cardiac rhythm may occur during epileptic seizures and this has been suggested as a possible mechanism for sudden unexpected death amongst patients with chronic epilepsy (sudep). we have studied ecg changes during 61 complex partial seizures of temporal lobe origin in 20 patients. tachycardia was observed in 24/61 (39%) and bradycardia in 3/61 (5%). the mean and median tachycardia rate was 139 and 140 beats/min (range 120-180). the longest r-r interval observed was 9 seconds. no difference was found in regard to the lateralisation of seizures and cardiac arrhytmia. one of the patients with bradycardia was fitted with a demand cardiac pacemaker, which appeared to decrease the number of his falls. in conclusion, ictal cardiac changes which may be seen in temporal lobe epilepsy (tle) are sinus tachycardia and occasionally sinus bradycardia. patients presenting vague complains suggestive of either tle or cardiac dysrhythmia, simultaneous monitoring with eeg/ecg is required, and if the episodes are frequent, video-eeg should be considered. further studies on this subject are warranted as this may shed some light on possible mechanisms for sudep.
Epistaxis during a generalized seizure leading to an atypical ictal SPECT finding at the skull base
Wichert-Ana, Lauro;Ferruzzi, Emerson Henklain;Alexandre Jr, Veriano;Velasco, Tonicarlo Rodrigues;Bianchin, Marino Muxfeldt;Terra-Bustamante, Vera Cristina;Kato, Mery;Santos, Antonio Carlos;Azevedo-Marques, Paulo Mazzoncini de;Oliveira, Lucas Ferrari de;Sakamoto, Américo Ceiki;
Journal of Epilepsy and Clinical Neurophysiology , 2006, DOI: 10.1590/S1676-26492006000700007
Abstract: 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.
Role of Single Photon Emission Computed Tomography in Epilepsy  [PDF]
Sita Jayalakshmi,Pushpalatha Sudhakar,Manas Panigrahi
International Journal of Molecular Imaging , 2011, DOI: 10.1155/2011/803920
Abstract: Molecular imaging with ictal single photon emission computed tomography (SPECT) is an established functional imaging modality for the presurgical evaluation of patients with refractory partial onset seizures. SPECT coregistered on to the MRI has greater sensitivity to identify the ictal onset zone. Ictal SPECT should always be interpreted in the context of other presurgical investigations. Ictal SPECT is sensitive method for the lateralization of TLE, but ictal SPECT is more sensitive when MRI is normal. Ictal SPECT and interictal PET are complementary to each other in lateralizing the side in patients with TLE and normal MRI. In extratemporal epilepsy, ictal SPECT will guide the placement of surface grid and depth electrodes. 1. Introduction Molecular imaging with ictal and interictal single photon emission computed tomography (SPECT) is an established functional imaging modality for the presurgical evaluation of patients with refractory partial onset seizures. Ictal SPECT has the potential to localize the ictal onset zone noninvasively and accurately and provides complementary data during multimodality evaluation of the epileptogenic zone. Ictal SPECT is more sensitive than structural imaging [1] but gives little indication about the underlying pathology. SPECT co-registered on to the MRI has greater sensitivity to identify the ictal onset zone. It is usually assumed that the largest and most intense ictal hyperperfusion region is the ictal onset zone. Ictal SPECT injection should be performed in the video EEG unit by trained technicians. The dye should be injected fast [2, 3]. High resolution SPECT and MRI scanner are important with a need for good cooperation between neurology and nuclear medicine departments for a successful programme to be implemented. 2. Brain Perfusion Tracers The brain perfusion tracers that cross the blood brain barrier with a long retention time in the brain are 99mtechnetium (99m TC-labeled agents). The two commonly used tracers are 99mhexamethylene propylene amino (99mTC-HMPAO) and 99mTC-ethyl cysteinate dimer (99mTC-ECD). 99mTC-ECD is stable 6 to 8 hours and 99mTC-HMPAO for 4 hours. 99mTC-ECD is cleared from the body more rapidly than 99m TC HMPAO and gives a higher brain to soft tissue activity ratio, and this improves the image quality [4] D.S.Lee et al. found that 99mTC-HMPAO ictal SPECT was superior to 99mTC-ECD ictal SPECT for localization of epileptogenic zone [5]. Early ictal injection is an important criterion for best results and is associated with high concordance with other studies [6]. S. K. Lee et al. reported
Imaging Lung Function in Mice Using SPECT/CT and Per-Voxel Analysis  [PDF]
Brian N. Jobse, Rod G. Rhem, Cory A. J. R. McCurry, Iris Q. Wang, N. Renée Labiris
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0042187
Abstract: Chronic lung disease is a major worldwide health concern but better tools are required to understand the underlying pathologies. Ventilation/perfusion (V/Q) single photon emission computed tomography (SPECT) with per-voxel analysis allows for non-invasive measurement of regional lung function. A clinically adapted V/Q methodology was used in healthy mice to investigate V/Q relationships. Twelve week-old mice were imaged to describe normal lung function while 36 week-old mice were imaged to determine how age affects V/Q. Mice were ventilated with Technegas? and injected with 99mTc-macroaggregated albumin to trace ventilation and perfusion, respectively. For both processes, SPECT and CT images were acquired, co-registered, and quantitatively analyzed. On a per-voxel basis, ventilation and perfusion were moderately correlated (R = 0.58±0.03) in 12 week old animals and a mean log(V/Q) ratio of ?0.07±0.01 and standard deviation of 0.36±0.02 were found, defining the extent of V/Q matching. In contrast, 36 week old animals had significantly increased levels of V/Q mismatching throughout the periphery of the lung. Measures of V/Q were consistent across healthy animals and differences were observed with age demonstrating the capability of this technique in quantifying lung function. Per-voxel analysis and the ability to non-invasively assess lung function will aid in the investigation of chronic lung disease models and drug efficacy studies.
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