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Susan S. Spencer - One of the best experts on this subject based on the ideXlab platform.
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7T MR spectroscopic imaging in the Localization of surgical epilepsy.
Epilepsia, 2013Co-Authors: Jullie W. Pan, Susan S. Spencer, Lawrence J Hirsch, Robert B. Duckrow, Jason L. Gerrard, Caroline Ong, Stanley R. Resor, Yan Zhang, Ognen A. C. Petroff, H. P. HetheringtonAbstract:For the neurosurgical evaluation of intractable epilepsy, Localization of Seizure onset is a critical step. Achieving Localization is commonly the result of an integrated analysis of multiple lines of evidence, including semiology, electroencephalography (EEG; scalp and intracranial), imaging, and cognitive performance. Nonetheless, the challenges of identifying Seizure onset are well known, given the varying clinical expression of different brain regions and the strong possibility for rapid Seizure propagation. It remains that identification with intracranial EEG data of Seizure onset with accuracy that is sufficient for surgery is the goal for many magnetic resonance imaging (MRI)–negative (or MRI–ambiguous) patients. Given this, a more practical goal for improving Seizure Localization would be to more accurately assess candidate regions for electrode placement. In the past, MR spectroscopy and spectroscopic imaging have been suggested to be informative for Localization (Connelly et al., 1994; Kuzniecky et al., 1997; Maudsley et al., 2010a); this is premised on the known role that N-acetyl aspartate (NAA) plays for neuronal mitochondrial function (Bates et al., 1996; Pan & Takahashi, 2005). As suggested by Connett (1988); the use of total creatine (Cr, being a key component of phosphocreatine that serves as a buffer for ATP) in the normalization of bioenergetics parameters is highly informative over a cross-section of species and within a given tissue type. Therefore, many groups have used the ratio of NAA/Cr as a normalized parameter, which we characterize as the bioenergetics of the neuronal/glial unit (“bGNU”), finding it to be informative for identifying regions of energetic and neuronal dysfunction (Suhy et al., 2000; Munoz Maniega et al., 2008; Guevara et al., 2010). However, MR spectroscopic imaging has been challenging (Goelman et al., 2007; Maudsley et al., 2010a,b) because of the need to cover wide brain territories, because available Localization may be lobar or hemispheric. In addition, studies need to be done with sufficient spatial resolution to sensitively identify dysfunctional areas, that is, to avoid extensive partial volume effects that could otherwise dilute small abnormalities. Because of these issues, it is evident that single voxel spectroscopy is not adequate for Seizure Localization. With spectroscopic imaging, the technical factors of adequate signal-to-noise (SNR), consistency of coverage, and study duration have been problematic, continuing improvements in imaging technology have been made. In this report we describe the systematic use of ultra-high field (7T) MR spectroscopic imaging to evaluate Seizure Localization in a range of temporal and neocortical Localization-related epilepsy eases. 7T is used because of the goal for high SNR in the face of relatively small voxel sizes (Vaughan et al., 2001; Inglese et al., 2006). Because of challenges intrinsic to the 7T field strength and its implementation in humans (Vaughan et al., 2001; Van de Moortele et al., 2005), this study made use of several advances in B0 shimming and radiofrequency (RF) technology to achieve consistent spectroscopic imaging performance (Avdievich et al., 2009; Hetherington et al., 2010; Pan et al., 2012a). We report on 25 patients who were included in this analysis if there was a surgical resection (rather than solely transection or device-based therapy) and there was regional overlap between the MRSI data and surgically executed plan. We assessed the concordance (complete, partial, or discordant) between the region of surgical resection and the MRSI data, and determined how this concordance related to available outcome data.
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evaluating the accuracy of perfusion metabolism spet pet ratio in Seizure Localization
European Journal of Nuclear Medicine and Molecular Imaging, 2008Co-Authors: Karen Buch, Susan S. Spencer, Hal Blumenfeld, Edward J. Novotny, I. G. ZubalAbstract:Mini-Abstract The uncoupling between brain perfusion and metabolism was evaluated as a potential tool for Seizure Localization by creating an interictal SPET divided by interictal PET functional ratio-image and by evaluating its sensitivity and specificity to areas subsequently surgically resected. The uncoupling between brain perfusion and metabolism was evaluated through the creation of a functional SPET/PET ratio-image relying on interictal single-photon emission computed tomography (SPET) and positron emission tomography (PET) scans in epilepsy patients. The uncoupling of these two physiological brain functions has been demonstrated to be a characteristic of epileptogenic tissue in temporal lobe epilepsy and could potentially serve as a diagnostic measure for Localization of Seizure onset areas in the brain. The accuracy of hemispheric Localization, sensitivity, and specificity of perfusion to metabolism ratio-images were evaluated as compared to standard methods of PET reading.
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Evaluating the accuracy of perfusion/metabolism (SPET/PET) ratio in Seizure Localization
European journal of nuclear medicine and molecular imaging, 2007Co-Authors: Karen Buch, Susan S. Spencer, Hal Blumenfeld, Edward J. Novotny, I. G. ZubalAbstract:Mini-Abstract The uncoupling between brain perfusion and metabolism was evaluated as a potential tool for Seizure Localization by creating an interictal SPET divided by interictal PET functional ratio-image and by evaluating its sensitivity and specificity to areas subsequently surgically resected. The uncoupling between brain perfusion and metabolism was evaluated through the creation of a functional SPET/PET ratio-image relying on interictal single-photon emission computed tomography (SPET) and positron emission tomography (PET) scans in epilepsy patients. The uncoupling of these two physiological brain functions has been demonstrated to be a characteristic of epileptogenic tissue in temporal lobe epilepsy and could potentially serve as a diagnostic measure for Localization of Seizure onset areas in the brain. The accuracy of hemispheric Localization, sensitivity, and specificity of perfusion to metabolism ratio-images were evaluated as compared to standard methods of PET reading.
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Sensitivity and specificity of quantitative difference SPECT analysis in Seizure Localization.
Journal of nuclear medicine : official publication Society of Nuclear Medicine, 1999Co-Authors: Marianna V. Spanaki, Susan S. Spencer, Maria Corsi, Macmullan J, John SeibylAbstract:UNLABELLED True ictal SPECT can accurately demonstrate perfusion increases in the epileptogenic area but often requires dedicated personnel waiting at the bedside to accomplish the injection. We investigated the value of perfusion changes as measured by ictal or immediate postictal SPECT in localizing the epileptogenic region in refractory partial epilepsy. METHODS Quantitative perfusion difference images were calculated by registering, normalizing and subtracting ictal (or immediate postictal) from interictal SPECT for 53 patients with refractory epilepsy. Perfusion difference SPECT results were compared with visually interpreted SPECT, scalp electroencephalography (EEG), MRI, PET and intracranial EEG. RESULTS In 43 patients (81%), discrete areas of increased perfusion (with ictal injections) or decreased perfusion (with postictal injections) were noted. Interictal scalp EEG was localizing in 28 patients (53%), ictal scalp EEG was localizing in 35 patients (66%) and intracranial EEG was localizing in 22 patients (85%) (of 26 patients who underwent invasive study). MRI was localizing in 34 patients (64%), PET was localizing in 32 of 45 patients (71%), interictal SPECT was localizing in 26 patients (49%) and peri-ictal SPECT (visual interpretation) was localizing in 30 patients (57%). By comparison with an intracranial EEG standard of Localization, SPECT subtraction analysis had 86% sensitivity and 75% specificity. CONCLUSION Our data provide evidence that SPECT perfusion difference analysis has higher sensitivity and specificity than any other noninvasive localizing criterion and can localize epileptogenic regions with accuracy comparable with that of intracranial EEG. To obtain these results, one must apply knowledge of the timing of the ictal injection relative to Seizure occurrence.
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Seizure Localization and pathology following head injury in patients with uncontrolled epilepsy
Neurology, 1995Co-Authors: David Marks, Jung H. Kim, Dennis D. Spencer, Susan S. SpencerAbstract:We studied Seizure Localization and surgical pathology in 25 patients who developed intractable complex partial Seizures following head trauma. All patients underwent an extensive presurgical evaluation that included MRI, neuropsychological evaluation, and surface EEG monitoring, and 21 had intracranial EEG monitoring. Seizures were successfully localized in nine patients; all nine underwent a surgical procedure and are Seizure-free. Six of these patients had a mesial temporal lobe Seizure focus, of whom five had a pathologic diagnosis of mesial temporal sclerosis. All five patients who developed mesial temporal sclerosis sustained their head injury at or before age 5 years. The three remaining patients whose Seizures were successfully localized had neocortical foci and circumscribed radio-graphic abnormalities, which were presumed to be secondary to head trauma, and all had successful surgical resections of the epileptogenic focus. The remaining 16 patients sustained later trauma and did not have a focal MRI lesion, and their Seizures were not adequately localized. We conclude that as a group, Seizure foci secondary to head trauma are difficult to localize accurately, and this should deter surgical intervention. There was an association between early head injury (ie, at or before age 5 years) and mesial temporal sclerosis, and this association aided Seizure Localization and successful surgical intervention. Therefore, under the right circumstances, trauma can be a suitable historical element in the profile of patients in whom epilepsy surgery is successful.
David W. Loring - One of the best experts on this subject based on the ideXlab platform.
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History of neuropsychology through epilepsy eyes.
Archives of Clinical Neuropsychology, 2010Co-Authors: David W. LoringAbstract:In the 19th century, Hughlings Jackson relied on clinical history, Seizure semiology, and the neurologic examination as methods for Seizure Localization to inform the first epilepsy surgeries. In the 20th century, psychological and neuropsychological tests were first employed as both diagnostic and prognostic measures. The contemporary practice of epilepsy evaluation and management includes neuropsychology as a critical component of epilepsy care and research, and epilepsy and neuropsychology have enjoyed a very special and synergistic relationship. This paper reviews how epilepsy has shaped the practice of neuropsychology as a clinical service by asking critical questions that only neuropsychologists were in a position to answer, and how clinical care of epilepsy patients has been significantly improved based on neuropsychology's unique contributions.
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Seizure Localization in temporal lobe epilepsy: A comparison of scalp‐sphenoidal EEG and volumetric MRI
Neurology, 1993Co-Authors: Anthony M. Murro, David W. Loring, Yong D. Park, Don W. King, Brian B. Gallagher, Joseph R. Smith, Farivar Yaghmai, Victor E. Toro, Ramon Figueroa, W. LittletonAbstract:We determined the accuracy of volumetric MRI (based on identification of unilateral hippocampal atrophy) and scalp-sphenoidal EEG (based on concordant interpretations of scalp-sphenoidal ictal EEG by three independent interpreters) for Seizure focus Localization in 20 patients with temporal lobe epilepsy. All patients became Seizure-free or had rare Seizures following temporal lobectomy. Among the 20 patients, nine (45%) met both MRI and EEG Localization criteria, six (30%) met MRI Localization criteria alone, three (15%) met EEG Localization criteria alone, and two patients (10%) did not meet either Localization criteria. In the 18 patients meeting MRI or EEG Localization criteria, the predicted Localization agreed with the side of temporal lobectomy. These results suggest that a nonin-vasive approach combining MRI and EEG will correctly localize the side of Seizure onset in most patients with temporal lobe epilepsy.
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Seizure Localization in temporal lobe epilepsy a comparison of scalp sphenoidal eeg and volumetric mri
Neurology, 1993Co-Authors: Anthony M. Murro, David W. Loring, Yong D. Park, Don W. King, Brian B. Gallagher, Joseph R. Smith, Farivar Yaghmai, Victor E. Toro, Ramon Figueroa, W. LittletonAbstract:We determined the accuracy of volumetric MRI (based on identification of unilateral hippocampal atrophy) and scalp-sphenoidal EEG (based on concordant interpretations of scalp-sphenoidal ictal EEG by three independent interpreters) for Seizure focus Localization in 20 patients with temporal lobe epilepsy. All patients became Seizure-free or had rare Seizures following temporal lobectomy. Among the 20 patients, nine (45%) met both MRI and EEG Localization criteria, six (30%) met MRI Localization criteria alone, three (15%) met EEG Localization criteria alone, and two patients (10%) did not meet either Localization criteria. In the 18 patients meeting MRI or EEG Localization criteria, the predicted Localization agreed with the side of temporal lobectomy. These results suggest that a nonin-vasive approach combining MRI and EEG will correctly localize the side of Seizure onset in most patients with temporal lobe epilepsy.
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wada memory testing and hippocampal volume measurements in the evaluation for temporal lobectomy
Neurology, 1993Co-Authors: David W. Loring, Anthony M. Murro, Don W. King, Brian B. Gallagher, Kimford J Meador, C A Gratton, M E Nichols, Joseph R. SmithAbstract:We examined the relationship of Wada memory performance and MRI hippocampal volume measurements to laterality of ultimate Seizure Localization in 20 patients with complex partial Seizures who later underwent temporal lobectomy. Discriminant function analysis employing both Wada memory test asymmetries and hippocampal volume asymmetries correctly classified 100% of the patients into left and right temporal lobe groups. Wada memory asymmetries alone correctly classified 90% of the sample (80% of the sample when the discriminant function included all patients except the one being classified), and hippocampal volume asymmetries alone correctly classified 90% of the patients. A significant correlation was present between Wada memory asymmetries and hippocampal volume asymmetries (r = 0.78), indicating that structural evidence of reduced hippocampal volume has a functional correlate reflected by Wada memory performance. These data suggest that the combination of functional and structural measures is of value in the preoperative evaluation for epilepsy surgery.
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wada memory testing and hippocampal volume measurements in the evaluation for temporal lobectomy
International Neuropsychological Society. Annual Meeting, 1993Co-Authors: David W. Loring, Anthony M. Murro, Don W. King, Brian B. Gallagher, Kimford J Meador, C A Gratton, M E Nichols, Joseph R. SmithAbstract:We examined the relationship of Wada memory performance and MRI hippocampal volume measurements to laterality of ultimate Seizure Localization in 20 patients with complex partial Seizures who later underwent temporal lobectomy. Discriminant function analysis employing both Wada memory test asymmetries and hippocampal volume asymmetries correctly classified 100% of the patients into left and right temporal lobe groups. Wada memory asymmetries alone correctly classified 90% of the sample (80% of the sample when the discriminant function included all patients except the one being classified), and hippocampal volume asymmetries alone correctly classified 90% of the patients
Joseph R. Smith - One of the best experts on this subject based on the ideXlab platform.
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Use of scalp-sphenoidal EEG for Seizure Localization in temporal lobe epilepsy.
Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society, 1994Co-Authors: Anthony M. Murro, Yong D. Park, Don W. King, Brian B. Gallagher, Joseph R. Smith, W. LittletonAbstract:We determined the accuracy and sensitivity of scalp-sphenoidal EEG for Seizure focus Localization in 50 patients who became Seizure-free or had rare Seizures following temporal lobectomy. EEG Localization was based on concordant interpretations of scalp-sphenoidal ictal EEG by three independent interpreters. All patients became Seizure-free or had rare Seizures following temporal lobectomy. Localization from EEG disagreed with the side of surgery in only 1 (2%) of 50 patients. We identified 3 distinct patient groups with a low, moderate, and high likelihood of having a focal ictal EEG pattern during a Seizure. These groups comprised 31% (low likelihood), 44% (moderate likelihood), and 25% (high likelihood) of patients. A model based on these results suggests that with multiple ictal EEG recordings, accurate Localization from scalp-sphenoidal EEG is possible in approximately up to 65-70% of patients with temporal lobe epilepsy.
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Seizure Localization in temporal lobe epilepsy: A comparison of scalp‐sphenoidal EEG and volumetric MRI
Neurology, 1993Co-Authors: Anthony M. Murro, David W. Loring, Yong D. Park, Don W. King, Brian B. Gallagher, Joseph R. Smith, Farivar Yaghmai, Victor E. Toro, Ramon Figueroa, W. LittletonAbstract:We determined the accuracy of volumetric MRI (based on identification of unilateral hippocampal atrophy) and scalp-sphenoidal EEG (based on concordant interpretations of scalp-sphenoidal ictal EEG by three independent interpreters) for Seizure focus Localization in 20 patients with temporal lobe epilepsy. All patients became Seizure-free or had rare Seizures following temporal lobectomy. Among the 20 patients, nine (45%) met both MRI and EEG Localization criteria, six (30%) met MRI Localization criteria alone, three (15%) met EEG Localization criteria alone, and two patients (10%) did not meet either Localization criteria. In the 18 patients meeting MRI or EEG Localization criteria, the predicted Localization agreed with the side of temporal lobectomy. These results suggest that a nonin-vasive approach combining MRI and EEG will correctly localize the side of Seizure onset in most patients with temporal lobe epilepsy.
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Seizure Localization in temporal lobe epilepsy a comparison of scalp sphenoidal eeg and volumetric mri
Neurology, 1993Co-Authors: Anthony M. Murro, David W. Loring, Yong D. Park, Don W. King, Brian B. Gallagher, Joseph R. Smith, Farivar Yaghmai, Victor E. Toro, Ramon Figueroa, W. LittletonAbstract:We determined the accuracy of volumetric MRI (based on identification of unilateral hippocampal atrophy) and scalp-sphenoidal EEG (based on concordant interpretations of scalp-sphenoidal ictal EEG by three independent interpreters) for Seizure focus Localization in 20 patients with temporal lobe epilepsy. All patients became Seizure-free or had rare Seizures following temporal lobectomy. Among the 20 patients, nine (45%) met both MRI and EEG Localization criteria, six (30%) met MRI Localization criteria alone, three (15%) met EEG Localization criteria alone, and two patients (10%) did not meet either Localization criteria. In the 18 patients meeting MRI or EEG Localization criteria, the predicted Localization agreed with the side of temporal lobectomy. These results suggest that a nonin-vasive approach combining MRI and EEG will correctly localize the side of Seizure onset in most patients with temporal lobe epilepsy.
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wada memory testing and hippocampal volume measurements in the evaluation for temporal lobectomy
Neurology, 1993Co-Authors: David W. Loring, Anthony M. Murro, Don W. King, Brian B. Gallagher, Kimford J Meador, C A Gratton, M E Nichols, Joseph R. SmithAbstract:We examined the relationship of Wada memory performance and MRI hippocampal volume measurements to laterality of ultimate Seizure Localization in 20 patients with complex partial Seizures who later underwent temporal lobectomy. Discriminant function analysis employing both Wada memory test asymmetries and hippocampal volume asymmetries correctly classified 100% of the patients into left and right temporal lobe groups. Wada memory asymmetries alone correctly classified 90% of the sample (80% of the sample when the discriminant function included all patients except the one being classified), and hippocampal volume asymmetries alone correctly classified 90% of the patients. A significant correlation was present between Wada memory asymmetries and hippocampal volume asymmetries (r = 0.78), indicating that structural evidence of reduced hippocampal volume has a functional correlate reflected by Wada memory performance. These data suggest that the combination of functional and structural measures is of value in the preoperative evaluation for epilepsy surgery.
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wada memory testing and hippocampal volume measurements in the evaluation for temporal lobectomy
International Neuropsychological Society. Annual Meeting, 1993Co-Authors: David W. Loring, Anthony M. Murro, Don W. King, Brian B. Gallagher, Kimford J Meador, C A Gratton, M E Nichols, Joseph R. SmithAbstract:We examined the relationship of Wada memory performance and MRI hippocampal volume measurements to laterality of ultimate Seizure Localization in 20 patients with complex partial Seizures who later underwent temporal lobectomy. Discriminant function analysis employing both Wada memory test asymmetries and hippocampal volume asymmetries correctly classified 100% of the patients into left and right temporal lobe groups. Wada memory asymmetries alone correctly classified 90% of the sample (80% of the sample when the discriminant function included all patients except the one being classified), and hippocampal volume asymmetries alone correctly classified 90% of the patients
Anthony M. Murro - One of the best experts on this subject based on the ideXlab platform.
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Use of scalp-sphenoidal EEG for Seizure Localization in temporal lobe epilepsy.
Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society, 1994Co-Authors: Anthony M. Murro, Yong D. Park, Don W. King, Brian B. Gallagher, Joseph R. Smith, W. LittletonAbstract:We determined the accuracy and sensitivity of scalp-sphenoidal EEG for Seizure focus Localization in 50 patients who became Seizure-free or had rare Seizures following temporal lobectomy. EEG Localization was based on concordant interpretations of scalp-sphenoidal ictal EEG by three independent interpreters. All patients became Seizure-free or had rare Seizures following temporal lobectomy. Localization from EEG disagreed with the side of surgery in only 1 (2%) of 50 patients. We identified 3 distinct patient groups with a low, moderate, and high likelihood of having a focal ictal EEG pattern during a Seizure. These groups comprised 31% (low likelihood), 44% (moderate likelihood), and 25% (high likelihood) of patients. A model based on these results suggests that with multiple ictal EEG recordings, accurate Localization from scalp-sphenoidal EEG is possible in approximately up to 65-70% of patients with temporal lobe epilepsy.
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Seizure Localization in temporal lobe epilepsy: A comparison of scalp‐sphenoidal EEG and volumetric MRI
Neurology, 1993Co-Authors: Anthony M. Murro, David W. Loring, Yong D. Park, Don W. King, Brian B. Gallagher, Joseph R. Smith, Farivar Yaghmai, Victor E. Toro, Ramon Figueroa, W. LittletonAbstract:We determined the accuracy of volumetric MRI (based on identification of unilateral hippocampal atrophy) and scalp-sphenoidal EEG (based on concordant interpretations of scalp-sphenoidal ictal EEG by three independent interpreters) for Seizure focus Localization in 20 patients with temporal lobe epilepsy. All patients became Seizure-free or had rare Seizures following temporal lobectomy. Among the 20 patients, nine (45%) met both MRI and EEG Localization criteria, six (30%) met MRI Localization criteria alone, three (15%) met EEG Localization criteria alone, and two patients (10%) did not meet either Localization criteria. In the 18 patients meeting MRI or EEG Localization criteria, the predicted Localization agreed with the side of temporal lobectomy. These results suggest that a nonin-vasive approach combining MRI and EEG will correctly localize the side of Seizure onset in most patients with temporal lobe epilepsy.
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Seizure Localization in temporal lobe epilepsy a comparison of scalp sphenoidal eeg and volumetric mri
Neurology, 1993Co-Authors: Anthony M. Murro, David W. Loring, Yong D. Park, Don W. King, Brian B. Gallagher, Joseph R. Smith, Farivar Yaghmai, Victor E. Toro, Ramon Figueroa, W. LittletonAbstract:We determined the accuracy of volumetric MRI (based on identification of unilateral hippocampal atrophy) and scalp-sphenoidal EEG (based on concordant interpretations of scalp-sphenoidal ictal EEG by three independent interpreters) for Seizure focus Localization in 20 patients with temporal lobe epilepsy. All patients became Seizure-free or had rare Seizures following temporal lobectomy. Among the 20 patients, nine (45%) met both MRI and EEG Localization criteria, six (30%) met MRI Localization criteria alone, three (15%) met EEG Localization criteria alone, and two patients (10%) did not meet either Localization criteria. In the 18 patients meeting MRI or EEG Localization criteria, the predicted Localization agreed with the side of temporal lobectomy. These results suggest that a nonin-vasive approach combining MRI and EEG will correctly localize the side of Seizure onset in most patients with temporal lobe epilepsy.
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wada memory testing and hippocampal volume measurements in the evaluation for temporal lobectomy
Neurology, 1993Co-Authors: David W. Loring, Anthony M. Murro, Don W. King, Brian B. Gallagher, Kimford J Meador, C A Gratton, M E Nichols, Joseph R. SmithAbstract:We examined the relationship of Wada memory performance and MRI hippocampal volume measurements to laterality of ultimate Seizure Localization in 20 patients with complex partial Seizures who later underwent temporal lobectomy. Discriminant function analysis employing both Wada memory test asymmetries and hippocampal volume asymmetries correctly classified 100% of the patients into left and right temporal lobe groups. Wada memory asymmetries alone correctly classified 90% of the sample (80% of the sample when the discriminant function included all patients except the one being classified), and hippocampal volume asymmetries alone correctly classified 90% of the patients. A significant correlation was present between Wada memory asymmetries and hippocampal volume asymmetries (r = 0.78), indicating that structural evidence of reduced hippocampal volume has a functional correlate reflected by Wada memory performance. These data suggest that the combination of functional and structural measures is of value in the preoperative evaluation for epilepsy surgery.
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wada memory testing and hippocampal volume measurements in the evaluation for temporal lobectomy
International Neuropsychological Society. Annual Meeting, 1993Co-Authors: David W. Loring, Anthony M. Murro, Don W. King, Brian B. Gallagher, Kimford J Meador, C A Gratton, M E Nichols, Joseph R. SmithAbstract:We examined the relationship of Wada memory performance and MRI hippocampal volume measurements to laterality of ultimate Seizure Localization in 20 patients with complex partial Seizures who later underwent temporal lobectomy. Discriminant function analysis employing both Wada memory test asymmetries and hippocampal volume asymmetries correctly classified 100% of the patients into left and right temporal lobe groups. Wada memory asymmetries alone correctly classified 90% of the sample (80% of the sample when the discriminant function included all patients except the one being classified), and hippocampal volume asymmetries alone correctly classified 90% of the patients
Hal Blumenfeld - One of the best experts on this subject based on the ideXlab platform.
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Seizure Localization using three dimensional surface projections of intracranial eeg power
NeuroImage, 2013Co-Authors: Mark W Youngblood, Dennis D. Spencer, Pue Farooque, Stephen Jhun, William C Chen, Irina I Goncharova, Kenneth P Vives, Hitten P Zaveri, Lawrence J Hirsch, Hal BlumenfeldAbstract:Abstract Intracranial EEG (icEEG) provides a critical road map for epilepsy surgery but it has become increasingly difficult to interpret as technology has allowed the number of icEEG channels to grow. Borrowing methods from neuroimaging, we aimed to simplify data analysis and increase consistency between reviewers by using 3D surface projections of intracranial EEG poweR (3D-SPIER). We analyzed 139 Seizures from 48 intractable epilepsy patients (28 temporal and 20 extratemporal) who had icEEG recordings, epilepsy surgery, and at least one year of post-surgical follow-up. We coregistered and plotted icEEG β frequency band signal power over time onto MRI-based surface renderings for each patient, to create color 3D-SPIER movies. Two independent reviewers interpreted the icEEG data using visual analysis vs. 3D-SPIER, blinded to any clinical information. Overall agreement rates between 3D-SPIER and icEEG visual analysis or surgery were about 90% for side of Seizure onset, 80% for lobe, and just under 80% for sublobar Localization. These agreement rates were improved when flexible thresholds or frequency ranges were allowed for 3D-SPIER, especially for sublobar Localization. Interestingly, agreement was better for patients with good surgical outcome than for patients with poor outcome. Localization using 3D-SPIER was measurably faster and considered qualitatively easier to interpret than visual analysis. These findings suggest that 3D-SPIER could be an improved diagnostic method for presurgical Seizure Localization in patients with intractable epilepsy and may also be useful for mapping normal brain function.
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New open‐source ictal SPECT analysis method implemented in BioImage Suite
Epilepsia, 2010Co-Authors: Dustin Scheinost, Thomas Z. Teisseyre, Marcello Distasio, Matthew N. Desalvo, Xenophon Papademetris, Hal BlumenfeldAbstract:Ictal single photon emission computed tomography (SPECT) is a powerful tool for noninvasive Seizure Localization, but it has been underutilized because of practical challenges, including difficulty in implementing ictal-interictal SPECT difference analysis. We previously validated a freely available utility for this purpose, ictal-interictal subtraction analysis by statistical parametric mapping (SPM) (ISAS). To further simplify and improve the difference imaging technique, we now compare a new algorithm, ISAS BioImage Suite (see http://spect.yale.edu and http://bioimagesuite.org), to the original ISAS method in 13 patients with known Seizure Localization. We found that ISAS BioImage Suite was in agreement with the original algorithm in all cases for which ISAS correctly identified a single unambiguous region of Seizure onset. We also tested for possible effects of scan-order bias in the control group used for the analysis and found no significant effect on the results. These findings establish a simple, validated and objective method for analyzing ictal-interictal SPECT difference images for use in the care of patients with epilepsy.
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evaluating the accuracy of perfusion metabolism spet pet ratio in Seizure Localization
European Journal of Nuclear Medicine and Molecular Imaging, 2008Co-Authors: Karen Buch, Susan S. Spencer, Hal Blumenfeld, Edward J. Novotny, I. G. ZubalAbstract:Mini-Abstract The uncoupling between brain perfusion and metabolism was evaluated as a potential tool for Seizure Localization by creating an interictal SPET divided by interictal PET functional ratio-image and by evaluating its sensitivity and specificity to areas subsequently surgically resected. The uncoupling between brain perfusion and metabolism was evaluated through the creation of a functional SPET/PET ratio-image relying on interictal single-photon emission computed tomography (SPET) and positron emission tomography (PET) scans in epilepsy patients. The uncoupling of these two physiological brain functions has been demonstrated to be a characteristic of epileptogenic tissue in temporal lobe epilepsy and could potentially serve as a diagnostic measure for Localization of Seizure onset areas in the brain. The accuracy of hemispheric Localization, sensitivity, and specificity of perfusion to metabolism ratio-images were evaluated as compared to standard methods of PET reading.
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Evaluating the accuracy of perfusion/metabolism (SPET/PET) ratio in Seizure Localization
European Journal of Nuclear Medicine and Molecular Imaging, 2008Co-Authors: Karen Buch, Hal Blumenfeld, S. Spencer, E. Novotny, I. G. ZubalAbstract:Mini-Abstract The uncoupling between brain perfusion and metabolism was evaluated as a potential tool for Seizure Localization by creating an interictal SPET divided by interictal PET functional ratio-image and by evaluating its sensitivity and specificity to areas subsequently surgically resected. The uncoupling between brain perfusion and metabolism was evaluated through the creation of a functional SPET/PET ratio-image relying on interictal single-photon emission computed tomography (SPET) and positron emission tomography (PET) scans in epilepsy patients. The uncoupling of these two physiological brain functions has been demonstrated to be a characteristic of epileptogenic tissue in temporal lobe epilepsy and could potentially serve as a diagnostic measure for Localization of Seizure onset areas in the brain. The accuracy of hemispheric Localization, sensitivity, and specificity of perfusion to metabolism ratio-images were evaluated as compared to standard methods of PET reading. Methods Interictal HMPAO-SPET and FDG-PET scans were obtained from 21 patients who then went on to remain Seizure free for a minimum of 1 year post surgical resection. Using Statistical Parametric Mapping (SPM2), the SPET and PET scans were spatially registered and spatially normalized to a standard template (geometric warping). A functional image was created by calculating the ratio of perfusion to metabolism. Discrete areas of uncoupling in the ratio-images were selected, quantified, and compared to visually interpreted PET readings as well as the actual site of subsequent surgical resection. Localization was determined by comparing the hemispheric location of these areas to sites of surgical resection. Sensitivity and specificity of ratio-images and PET readings were calculated by dividing the brains into four sections per hemisphere. Results When compared to known sites of successful surgical resection, the pre-surgical visually interpreted PET readings had a correct hemispheric Localization in 69.6% of cases, while the regions of uncoupling selected in the pre-surgical ratio-images had a correct hemispheric Localization of 82.6%. In addition, the regional sensitivity of visually interpreted PET readings was 63.0% with a specificity of 95.7%, while the sensitivity of the ratio-images was 68.0% with a specificity of 96.0%. Conclusion Compared to the PET readings, the ratio-images yielded similar sensitivity and specificity measures, but had an improved hemispheric Localization. Hence, ratio-images may be a valuable diagnostic tool in the hemispheric Localization, which could enhance the use of PET readings alone.
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Evaluating the accuracy of perfusion/metabolism (SPET/PET) ratio in Seizure Localization
European journal of nuclear medicine and molecular imaging, 2007Co-Authors: Karen Buch, Susan S. Spencer, Hal Blumenfeld, Edward J. Novotny, I. G. ZubalAbstract:Mini-Abstract The uncoupling between brain perfusion and metabolism was evaluated as a potential tool for Seizure Localization by creating an interictal SPET divided by interictal PET functional ratio-image and by evaluating its sensitivity and specificity to areas subsequently surgically resected. The uncoupling between brain perfusion and metabolism was evaluated through the creation of a functional SPET/PET ratio-image relying on interictal single-photon emission computed tomography (SPET) and positron emission tomography (PET) scans in epilepsy patients. The uncoupling of these two physiological brain functions has been demonstrated to be a characteristic of epileptogenic tissue in temporal lobe epilepsy and could potentially serve as a diagnostic measure for Localization of Seizure onset areas in the brain. The accuracy of hemispheric Localization, sensitivity, and specificity of perfusion to metabolism ratio-images were evaluated as compared to standard methods of PET reading.