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Kunz M, Karschnia P, Borggraefe I, Noachtar S, Tonn JC, Vollmar C. Seizure-free outcome and safety of repeated epilepsy surgery for persistent or recurrent seizures. J Neurosurg 2023; 138:9-18. [PMID: 35901761 DOI: 10.3171/2022.4.jns212753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 04/25/2022] [Indexed: 01/04/2023]
Abstract
OBJECTIVE Reoperation may be an option for select patients with unsatisfactory seizure control after their first epilepsy surgery. The aim of this study was to describe the seizure-free outcome and safety of repeated epilepsy surgery in our tertiary referral center. METHODS Thirty-eight patients with focal refractory epilepsy, who underwent repeated epilepsy surgeries and had a minimum follow-up time of 12 months after reoperation, were included. Systematic reevaluation, including comprehensive neuroimaging and noninvasive (n = 38) and invasive (n = 25, 66%) video-electroencephalography monitoring, was performed. Multimodal 3D resection maps were created for individual patients to allow personalized reoperation. RESULTS The median time between the first operation and reoperation was 74 months (range 5-324 months). The median age at reoperation was 34 years (range 1-74 years), and the median follow-up was 38 months (range 13-142 months). Repeat MRI after the first epilepsy surgery showed an epileptogenic lesion in 24 patients (63%). The reoperation was temporal in 18 patients (47%), extratemporal in 9 (24%), and multilobar in 11 (29%). The reoperation was left hemispheric in 24 patients (63%), close to eloquent cortex in 19 (50%), and distant from the initial resection in 8 (21%). Following reoperation, 27 patients (71%) became seizure free (Engel class I), while 11 (29%) continued to have seizures. There were trends toward better outcome in temporal lobe epilepsy and for unilobar resections adjacent to the initial surgery, but there was no difference between MRI lesional and nonlesional patients. In all subgroups, Engel class I outcome was at least 50%. Perioperative complications occurred in 4 patients (11%), with no fatalities. CONCLUSIONS Reoperation for refractory focal epilepsy is an effective and safe option in patients with persistent or recurrent seizures after initial epilepsy surgery. A thorough presurgical reevaluation is essential for favorable outcome.
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Affiliation(s)
- Mathias Kunz
- 1Department of Neurosurgery, University Hospital of the Ludwig-Maximilians-University of Munich
| | - Philipp Karschnia
- 1Department of Neurosurgery, University Hospital of the Ludwig-Maximilians-University of Munich
| | - Ingo Borggraefe
- 2Department of Pediatrics, Division of Pediatric Neurology and Developmental Medicine, University Hospital of the Ludwig-Maximilians-University of Munich; and
| | - Soheyl Noachtar
- 3Department of Neurology, Epilepsy Center, University Hospital of the Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Joerg-Christian Tonn
- 1Department of Neurosurgery, University Hospital of the Ludwig-Maximilians-University of Munich
| | - Christian Vollmar
- 3Department of Neurology, Epilepsy Center, University Hospital of the Ludwig-Maximilians-University of Munich, Munich, Germany
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Advanced Neuroimaging Approaches to Pediatric Brain Tumors. Cancers (Basel) 2022; 14:cancers14143401. [PMID: 35884462 PMCID: PMC9318188 DOI: 10.3390/cancers14143401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 07/08/2022] [Indexed: 12/10/2022] Open
Abstract
Simple Summary After leukemias, brain tumors are the most common cancers in children, and early, accurate diagnosis is critical to improve patient outcomes. Beyond the conventional imaging methods of computed tomography (CT) and magnetic resonance imaging (MRI), advanced neuroimaging techniques capable of both structural and functional imaging are moving to the forefront to improve the early detection and differential diagnosis of tumors of the central nervous system. Here, we review recent developments in neuroimaging techniques for pediatric brain tumors. Abstract Central nervous system tumors are the most common pediatric solid tumors; they are also the most lethal. Unlike adults, childhood brain tumors are mostly primary in origin and differ in type, location and molecular signature. Tumor characteristics (incidence, location, and type) vary with age. Children present with a variety of symptoms, making early accurate diagnosis challenging. Neuroimaging is key in the initial diagnosis and monitoring of pediatric brain tumors. Conventional anatomic imaging approaches (computed tomography (CT) and magnetic resonance imaging (MRI)) are useful for tumor detection but have limited utility differentiating tumor types and grades. Advanced MRI techniques (diffusion-weighed imaging, diffusion tensor imaging, functional MRI, arterial spin labeling perfusion imaging, MR spectroscopy, and MR elastography) provide additional and improved structural and functional information. Combined with positron emission tomography (PET) and single-photon emission CT (SPECT), advanced techniques provide functional information on tumor metabolism and physiology through the use of radiotracer probes. Radiomics and radiogenomics offer promising insight into the prediction of tumor subtype, post-treatment response to treatment, and prognostication. In this paper, a brief review of pediatric brain cancers, by type, is provided with a comprehensive description of advanced imaging techniques including clinical applications that are currently utilized for the assessment and evaluation of pediatric brain tumors.
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Trofimova A, Milla SS, Ryan ME, Pruthi S, Blount JP, Desai NK, Glenn OA, Islam MP, Kadom N, Mirsky DM, Myseros JS, Partap S, Radhakrishnan R, Rose E, Soares BP, Trout AT, Udayasankar UK, Whitehead MT, Karmazyn B. ACR Appropriateness Criteria® Seizures-Child. J Am Coll Radiol 2021; 18:S199-S211. [PMID: 33958113 DOI: 10.1016/j.jacr.2021.02.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 12/11/2022]
Abstract
In children, seizures represent an extremely heterogeneous group of medical conditions ranging from benign cases, such as a simple febrile seizure, to life-threatening situations, such as status epilepticus. Underlying causes of seizures also represent a wide range of pathologies from idiopathic cases, usually genetic, to a variety of acute and chronic intracranial or systemic abnormalities. This document discusses appropriate utilization of neuroimaging tests in a child with seizures. The clinical scenarios in this document take into consideration different circumstances at the time of a child's presentation including the patient's age, precipitating event (if any), and clinical and electroencephalogram findings and include neonatal seizures, simple and complex febrile seizures, post-traumatic seizures, focal seizures, primary generalized seizures in a neurologically normal child, and generalized seizures in neurologically abnormal child. This practical approach aims to guide clinicians in clinical decision-making and to help identify efficient and appropriate imaging workup. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.
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Affiliation(s)
| | - Sarah S Milla
- Emory University and Children's Healthcare of Atlanta, Atlanta, Georgia
| | - Maura E Ryan
- Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Sumit Pruthi
- Panel Chair, Vanderbilt Children's Hospital, Nashville, Tennessee
| | | | | | - Orit A Glenn
- University of California San Francisco, San Francisco, California
| | - Monica P Islam
- Nationwide Children's Hospital, Columbus, Ohio, American Academy of Neurology, Acting Director, Nationwide Children's Hospital Epilepsy Program, Director, Nationwide Children's Hospital Evoked Potential and Neurophysiologic Intraoperative Monitoring Program; Director, Nationwide Children's Hospital Tuberous Sclerosis Complex Clinic
| | - Nadja Kadom
- Emory University and Children's of Atlanta (Egleston), Atlanta, Georgia
| | | | - John S Myseros
- Children's National Hospital, Children's National Health System, Washington, District of Columbia, Neurosurgery expert, Vice Chief, Neurosurgery, Children's National Hospital
| | - Sonia Partap
- Stanford University, Stanford, California, American Academy of Pediatrics
| | | | - Emily Rose
- Keck School of Medicine of USC, Los Angeles, California, American College of Emergency Physicians
| | - Bruno P Soares
- University of Vermont Medical Center, Burlington, Vermont, Division Director, Neuroradiology, Vice Chair of Imaging Research, University of Vermont Medical Center
| | - Andrew T Trout
- Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, Officer, Joint Review Committee on Educational Programs in Nuclear Medicine Technology
| | | | | | - Boaz Karmazyn
- Specialty Chair, Riley Hospital for Children Indiana University, Indianapolis, Indiana
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Goud NS, Bhattacharya A, Joshi RK, Nagaraj C, Bharath RD, Kumar P. Carbon-11: Radiochemistry and Target-Based PET Molecular Imaging Applications in Oncology, Cardiology, and Neurology. J Med Chem 2021; 64:1223-1259. [PMID: 33499603 DOI: 10.1021/acs.jmedchem.0c01053] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The positron emission tomography (PET) molecular imaging technique has gained its universal value as a remarkable tool for medical diagnosis and biomedical research. Carbon-11 is one of the promising radiotracers that can report target-specific information related to its pharmacology and physiology to understand the disease status. Currently, many of the available carbon-11 (t1/2 = 20.4 min) PET radiotracers are heterocyclic derivatives that have been synthesized using carbon-11 inserted different functional groups obtained from primary and secondary carbon-11 precursors. A spectrum of carbon-11 PET radiotracers has been developed against many of the upregulated and emerging targets for the diagnosis, prognosis, prediction, and therapy in the fields of oncology, cardiology, and neurology. This review focuses on the carbon-11 radiochemistry and various target-specific PET molecular imaging agents used in tumor, heart, brain, and neuroinflammatory disease imaging along with its associated pathology.
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Affiliation(s)
- Nerella Sridhar Goud
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Ahana Bhattacharya
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Raman Kumar Joshi
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Chandana Nagaraj
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Rose Dawn Bharath
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
| | - Pardeep Kumar
- Department of Neuroimaging and Interventional Radiology (NIIR), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru 560 029, India
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Automated production of 1-(2-[ 18F]fluoroethyl)-l-tryptophan for imaging of tryptophan metabolism. Appl Radiat Isot 2020; 156:109022. [PMID: 32056678 DOI: 10.1016/j.apradiso.2019.109022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/18/2019] [Accepted: 12/05/2019] [Indexed: 11/23/2022]
Abstract
Automated production of an fluorine-18 labeled tryptophan analogue, 1-(2-[18F]fluoroethyl)-l-tryptophan (1-L-[18F]FETrp) in a current Good Manufacturing Practice facility was achieved. 1-L-[18F]FETrp was produced by a one-pot, two-step strategy with an overall synthesis time of approximately 100 min, a radiochemical yield of 20 ± 5% (decay corrected), radiochemical purity and enantiomeric excess over 90%, and a molar activity of 103 ± 15 GBq/μmol at the end of synthesis (EOS). The dose mass of 1-L-FETrp in four consecutive batches was less than 5 μg. The radiopharmaceutical product met all quality control criteria for clinical use.
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Juhász C, John F. Utility of MRI, PET, and ictal SPECT in presurgical evaluation of non-lesional pediatric epilepsy. Seizure 2019; 77:15-28. [PMID: 31122814 DOI: 10.1016/j.seizure.2019.05.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 02/12/2019] [Accepted: 05/10/2019] [Indexed: 12/12/2022] Open
Abstract
Children with epilepsy and normal structural MRI pose a particular challenge in localization of epileptic foci for surgical resection. Many of these patients have subtle structural lesions such as mild cortical dysplasia that can be missed by conventional MRI but may become detectable by optimized and advanced MRI acquisitions and post-processing. Specificity of objective analytic techniques such as voxel-based morphometry remains an issue. Combination of MRI with functional imaging approaches can improve the accuracy of detecting epileptogenic brain regions. Analysis of glucose positron emission tomography (PET) combined with high-resolution MRI can optimize detection of hypometabolic cortex associated with subtle cortical malformations and can also enhance presurgical evaluation in children with epileptic spasms. Additional PET tracers may detect subtle epileptogenic lesions and cortex with enhanced specificity in carefully selected subgroups with various etiologies; e.g., increased tryptophan uptake can identify epileptogenic cortical dysplasia in the interictal state. Subtraction ictal SPECT can be also useful to delineate ictal foci in those with non-localizing PET or after failed surgical resection. Presurgical delineation of language and motor cortex and the corresponding white matter tracts is increasingly reliable by functional MRI and DTI techniques; with careful preparation, these can be useful even in young and sedated children. While evidence-based pediatric guidelines are still lacking, the data accumulated in the last decade strongly indicate that multimodal imaging with combined analysis of MRI, PET, and/or ictal SPECT data can optimize the detection of subtle epileptogenic lesions and facilitate seizure-free outcome while minimizing the postsurgical functional deficit in children with normal conventional MRI.
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Affiliation(s)
- Csaba Juhász
- Department of Pediatrics, Wayne State University, PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, 3901 Beaubien St., Detroit, Michigan, 48201, USA; Departments of Neurology and Neurosurgery, Wayne State University, 4201 St. Antoine St., Detroit, Michigan, 48201, USA.
| | - Flóra John
- Department of Pediatrics, Wayne State University, PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, 3901 Beaubien St., Detroit, Michigan, 48201, USA; Department of Neurology, University of Pécs, H-7623, Rét u. 2., Pécs, Hungary.
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Krucoff MO, Chan AY, Harward SC, Rahimpour S, Rolston JD, Muh C, Englot DJ. Rates and predictors of success and failure in repeat epilepsy surgery: A meta-analysis and systematic review. Epilepsia 2017; 58:2133-2142. [PMID: 28994113 DOI: 10.1111/epi.13920] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2017] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Medically refractory epilepsy is a debilitating disorder that is particularly challenging to treat in patients who have already failed a surgical resection. Evidence regarding outcomes of further epilepsy surgery is limited to small case series and reviews. Therefore, our group performed the first quantitative meta-analysis of the literature from the past 30 years to assess for rates and predictors of successful reoperations. METHODS A PubMed search was conducted for studies reporting outcomes of repeat epilepsy surgery. Studies were excluded if they reported fewer than five eligible patients or had average follow-ups < 1 year, and patients were excluded from analysis if they received a nonresective intervention. Outcomes were stratified by each variable of interest, and quantitative meta-analysis was performed to generate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS Seven hundred eighty-two patients who received repeat resective epilepsy surgery from 36 studies were included. Engel I outcome was observed in 47% (n = 369) of patients. Significant predictors of seizure freedom included congruent over noncongruent electrophysiology data (OR = 3.6, 95% CI = 1.6-8.2), lesional over nonlesional epilepsy (OR = 3.2, 95% CI = 1.9-5.3), and surgical limitations over disease-related factors associated with failure of the first surgery (OR = 2.6, 95% CI = 1.3-5.3). Among patients with at least one of these predictors, seizure freedom was achieved in 58%. Conversely, the use of invasive monitoring was associated with worse outcome (OR = 0.4, 95% CI = 0.2-0.9). Temporal lobe over extratemporal/multilobe resection (OR = 1.5, 95% CI = 0.8-3.0) and abnormal over normal preoperative magnetic resonance imaging (OR = 1.9, 95% CI = 0.6-5.4) showed nonsignificant trends toward seizure freedom. SIGNIFICANCE This analysis supports considering further resection in patients with intractable epilepsy who continue to have debilitating seizures after an initial surgery, especially in the context of factors predictive of a favorable outcome.
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Affiliation(s)
- Max O Krucoff
- Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, U.S.A
| | - Alvin Y Chan
- Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A
| | - Stephen C Harward
- Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, U.S.A
| | - Shervin Rahimpour
- Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, U.S.A
| | - John D Rolston
- Department of Neurosurgery, University of Utah, Salt Lake City, Utah, U.S.A
| | - Carrie Muh
- Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, U.S.A
| | - Dario J Englot
- Department of Neurosurgery, Vanderbilt University Medical Center, Nashville, Tennessee, U.S.A
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El Tahry R, Wang IZ. Failed epilepsy surgery: is this the end? Acta Neurol Belg 2017; 117:433-440. [PMID: 28303525 DOI: 10.1007/s13760-017-0769-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 03/07/2017] [Indexed: 12/14/2022]
Abstract
Resective epilepsy surgery can lead to sustained seizure control in 70-80% of patients evaluated for epilepsy surgery, indicating that up to 30% of patients still have recurrent seizures after surgery. Definitions of failed epilepsy surgery vary amongst studies. This review focuses on seizure outcome predictors after reoperation, possible mechanisms of failure and best management for this difficult patient population.
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Affiliation(s)
- Riëm El Tahry
- Department of Neurology, Center for Refractory Epilepsy, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Av. Hippocrate 10, 1200, Brussels, Belgium.
- Department of Pneumology, Sleep Laboratory, Cliniques Universitaires Saint Luc, Université Catholique de Louvain, Av Hippocrate 10, 1200, Brussels, Belgium.
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Abstract
Positron emission tomography (PET) is a neuroimaging method that offers insights into the molecular functioning of a human brain. It has been widely used to study metabolic and neurotransmitter abnormalities in people with epilepsy. This article reviews the development of several PET radioligands and their application in studying the molecular mechanisms of epilepsy. Over the last decade, tracers binding to serotonin and γ-aminobutyric acid (GABA) receptors have been used to delineate the location of the epileptic focus. PET studies have examined the role of opioids, cannabinoids, acetylcholine, and dopamine in modulating neuronal hyperexcitability and seizure termination. In vivo analyses of drug transporters, e.g., P-glycoprotein, have increased our understanding of pharmacoresistance that could inform new therapeutic strategies. Finally, PET experiments targeting neuroinflammation and glutamate receptors might guide the development of novel biomarkers of epileptogenesis.
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Affiliation(s)
- Marian Galovic
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, 33 Queen Square, London, WC1N 3BG, United Kingdom.,Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, United Kingdom
| | - Matthias Koepp
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, 33 Queen Square, London, WC1N 3BG, United Kingdom. .,Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, United Kingdom.
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Yu X, Wang J, Liu J, Shen S, Cao Z, Pan J, Zhou S, Pang Z, Geng D, Zhang J. A multimodal Pepstatin A peptide-based nanoagent for the molecular imaging of P-glycoprotein in the brains of epilepsy rats. Biomaterials 2016; 76:173-86. [DOI: 10.1016/j.biomaterials.2015.10.050] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 10/15/2015] [Accepted: 10/18/2015] [Indexed: 12/21/2022]
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Juhász C, Dwivedi S, Kamson DO, Michelhaugh SK, Mittal S. Comparison of amino acid positron emission tomographic radiotracers for molecular imaging of primary and metastatic brain tumors. Mol Imaging 2015; 13. [PMID: 24825818 DOI: 10.2310/7290.2014.00015] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Positron emission tomography (PET) is an imaging technology that can detect and characterize tumors based on their molecular and biochemical properties, such as altered glucose, nucleoside, or amino acid metabolism. PET plays a significant role in the diagnosis, prognostication, and treatment of various cancers, including brain tumors. In this article, we compare uptake mechanisms and the clinical performance of the amino acid PET radiotracers (l-[methyl-11C]methionine [MET], 18F-fluoroethyl-tyrosine [FET], 18F-fluoro-l-dihydroxy-phenylalanine [FDOPA], and 11C-alpha-methyl-l-tryptophan [AMT]) most commonly used for brain tumor imaging. First, we discuss and compare the mechanisms of tumoral transport and accumulation, the basis of differential performance of these radioligands in clinical studies. Then we summarize studies that provided direct comparisons among these amino acid tracers and to clinically used 2-deoxy-2[18F]fluoro-d-glucose [FDG] PET imaging. We also discuss how tracer kinetic analysis can enhance the clinical information obtained from amino acid PET images. We discuss both similarities and differences in potential clinical value for each radioligand. This comparative review can guide which radiotracer to favor in future clinical trials aimed at defining the role of these molecular imaging modalities in the clinical management of brain tumor patients.
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Abstract
Over the past 35 years or so, PET brain imaging has allowed powerful and unique insights into brain function under normal conditions and in disease states. Initially, as PET instrumentation continued to develop, studies were focused on brain perfusion and glucose metabolism. This permitted refinement of brain imaging for important, non-oncologic clinical indications. The ability of PET to not only provide spatial localization of metabolic changes but also to accurately and consistently quantify their distribution proved valuable for applications in the clinical setting. Specifically, glucose metabolism brain imaging using (F-18) fluorodeoxyglucose continues to be invaluable for evaluating patients with intractable seizures for identifying seizure foci and operative planning. Cerebral glucose metabolism also contributes to diagnosis of neurodegenerative diseases that cause dementia. Alzheimer disease, dementia with Lewy bodies, and the several variants of frontotemporal lobar degeneration have differing typical patterns of hypometabolism. In Alzheimer disease, hypometabolism has furthermore been associated with poorer cognitive performance and ensuing cognitive and functional decline. As the field of radiochemistry evolved, novel radioligands including radiolabeled flumazenil, dopamine transporter ligands, nicotine receptor ligands, and others have allowed for further understanding of molecular changes in the brain associated with various diseases. Recently, PET brain imaging reached another milestone with the approval of (F-18) florbetapir imaging by the United States Federal Drug Administration for detection of amyloid plaque accumulation in brain, the major histopathologic hallmark of Alzheimer disease, and efforts have been made to define the clinical role of this imaging agent in the setting of the currently limited treatment options. Hopefully, this represents the first of many new radiopharmaceuticals that would allow improved diagnostic and prognostic information in these and other clinical applications, including Parkinson disease and traumatic brain injury.
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Affiliation(s)
- Ilya Nasrallah
- Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, PA
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Christensen M, Kamson DO, Snyder M, Kim H, Robinette NL, Mittal S, Juhász C. Tryptophan PET-defined gross tumor volume offers better coverage of initial progression than standard MRI-based planning in glioblastoma patients. ACTA ACUST UNITED AC 2013; 3:131-138. [PMID: 25414765 DOI: 10.1007/s13566-013-0132-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
OBJECTIVE Glioblastoma is an infiltrative malignancy that tends to extend beyond the MRI-defined tumor volume. We utilized positron emission tomography (PET) imaging with the radiotracer alpha-[11C]methyl-L -tryptophan (AMT) to develop a reliable high-risk gross tumor volume (HR-GTV) method for delineation of glioblastoma. AMT can detect solid tumor mass and tumoral brain infiltration by increased tumoral tryptophan transport and metabolism via the immunosuppressive kynurenine pathway. METHODS We reviewed all patients in our database with histologically proven glioblastoma who underwent preoperative AMT-PET scan prior to surgery and chemoradiation. Treated radiotherapy volumes were derived from the simulation CT with MRI fusion. High-GTV with contrast enhanced T1-weighted MRI alone (GTVMRI) was defined as the postoperative cavity plus any residual area of enhancement on postcontrast T1-weighted images. AMT-PET images were retrospectively fused to the simulation CT, and a high-risk GTVs generated by both AMT-PET alone (GTVAMT) was defined using a threshold previously established to distinguish tumor tissue from peritumoral edema. A composite volume of MRI and AMT tumor volume was also created (combination of MRI fused with AMT-PET data; GTVMRI+AMT). In patients with definitive radiographic progression, follow-up MRI demonstrating initial tumor progression was fused with the pretreatment images and a progression volume was contoured. The coverage of the progression volume by GTVMRI, GTVAMT, and GTVMRI+AMT was determined and compared using the Wilcoxon's signed-rank test. RESULTS Eleven patients completed presurgical AMT-PET scan, seven of whom had progressive disease after initial therapy. GTVMRI (mean, 50.2 cm3) and GTVAMT (mean, 48.9 cm3) were not significantly different. Mean concordance index of the volumes was 39±15 %. Coverage of the initial recurrence volume by HR-GTVMRI (mean, 52 %) was inferior to both GTVAMT (mean, 68 %; p =0.028) and GTVMRI+AMT (mean 73 %; p =0.018). The AMT-PET-exclusive coverage was up to 41 % of the recurrent volume. There was a tendency towards better recurrence coverage with GTVMRI+AMT than with GTVAMT alone (p =0.068). Addition of 5 mm concentric margin around GTVMRI, GTVAMT, and GTVMRI+AMT would have completely covered the initial progression volume in 14, 57, and 71 % of the patients, respectively. CONCLUSION We found that a GTV defined by AMT-PET produced similar volume, but superior recurrence coverage than the treated standard MRI-determined volume. A prospective study is necessary to fully determine the usefulness of AMT-PET for volume definition in glioblastoma radiotherapy planning.
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Affiliation(s)
- Michael Christensen
- Department of Radiation Oncology, Barbara Ann, Karmanos Cancer Center, Wayne State University School of Medicine, 540 E. Canfield, Detroit, MI 48201, USA. Barbara Ann Karmanos Cancer Institute, Detroit, MI, USA
| | - David Olayinka Kamson
- Departments of Pediatrics and Neurology, Wayne State University School of Medicine, Detroit, MI, USA. PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, MI, USA
| | - Michael Snyder
- Department of Radiation Oncology, Barbara Ann, Karmanos Cancer Center, Wayne State University School of Medicine, 540 E. Canfield, Detroit, MI 48201, USA. Barbara Ann Karmanos Cancer Institute, Detroit, MI, USA
| | - Harold Kim
- Department of Radiation Oncology, Barbara Ann, Karmanos Cancer Center, Wayne State University School of Medicine, 540 E. Canfield, Detroit, MI 48201, USA. Barbara Ann Karmanos Cancer Institute, Detroit, MI, USA
| | - Natasha L Robinette
- Barbara Ann Karmanos Cancer Institute, Detroit, MI, USA. Department of Radiology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Sandeep Mittal
- Barbara Ann Karmanos Cancer Institute, Detroit, MI, USA. Department of Neurosurgery, Wayne State University School of Medicine, Detroit, MI, USA
| | - Csaba Juhász
- Departments of Pediatrics and Neurology, Wayne State University School of Medicine, Detroit, MI, USA. Barbara Ann Karmanos Cancer Institute, Detroit, MI, USA. PET Center and Translational Imaging Laboratory, Children's Hospital of Michigan, Detroit, MI, USA
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Rubí S, Costes N, Heckemann RA, Bouvard S, Hammers A, Martí Fuster B, Ostrowsky K, Montavont A, Jung J, Setoain X, Catenoix H, Hino K, Liger F, Bars DL, Ryvlin P. Positron emission tomography with α-[11C]methyl-l-tryptophan in tuberous sclerosis complex-related epilepsy. Epilepsia 2013; 54:2143-50. [DOI: 10.1111/epi.12412] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/10/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Sebastià Rubí
- Nuclear Medicine Department; Hospital Clinic; Barcelona Spain
| | | | - Rolf A. Heckemann
- Neurodis Foundation; Lyon France
- Division of Neuroscience and Mental Health; Faculty of Medicine; Imperial College London; London United Kingdom
| | - Sandrine Bouvard
- CERMEP - Imagerie du Vivant; Lyon France
- TIGER; CRNL; INSERM U1028, CNRS 5292; Lyon France
| | - Alexander Hammers
- Neurodis Foundation; Lyon France
- Division of Neuroscience and Mental Health; Faculty of Medicine; Imperial College London; London United Kingdom
| | - Berta Martí Fuster
- Biophysics and Bioengineering Unit; Physiological Sciences Departament I; School of Medicine; University of Barcelona; Barcelona Spain
- Biomedical Research Networking Center in Bioengineering; Biomaterials and Nanomedicine (CIBER-BBN); Barcelona Spain
| | - Karine Ostrowsky
- Department of Functional Neurology and Epileptology and IDEE; Hospices Civils de Lyon; Lyon France
| | - Alexandra Montavont
- TIGER; CRNL; INSERM U1028, CNRS 5292; Lyon France
- Department of Functional Neurology and Epileptology and IDEE; Hospices Civils de Lyon; Lyon France
| | | | - Xavier Setoain
- Nuclear Medicine Department; Hospital Clinic; Barcelona Spain
| | - Hélène Catenoix
- Department of Functional Neurology and Epileptology and IDEE; Hospices Civils de Lyon; Lyon France
| | - Keiko Hino
- Department of Functional Neurology and Epileptology and IDEE; Hospices Civils de Lyon; Lyon France
| | | | | | - Philippe Ryvlin
- CERMEP - Imagerie du Vivant; Lyon France
- TIGER; CRNL; INSERM U1028, CNRS 5292; Lyon France
- Department of Functional Neurology and Epileptology and IDEE; Hospices Civils de Lyon; Lyon France
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Reoperation after failed resective epilepsy surgery. Seizure 2013; 22:493-501. [DOI: 10.1016/j.seizure.2013.04.020] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/25/2013] [Accepted: 04/26/2013] [Indexed: 11/20/2022] Open
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Alkonyi B, Barger GR, Mittal S, Muzik O, Chugani DC, Bahl G, Robinette NL, Kupsky WJ, Chakraborty PK, Juhász C. Accurate differentiation of recurrent gliomas from radiation injury by kinetic analysis of α-11C-methyl-L-tryptophan PET. J Nucl Med 2012; 53:1058-64. [PMID: 22653792 DOI: 10.2967/jnumed.111.097881] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
UNLABELLED PET of amino acid transport and metabolism may be more accurate than conventional neuroimaging in differentiating recurrent gliomas from radiation-induced tissue changes. α-(11)C-methyl-l-tryptophan ((11)C-AMT) is an amino acid PET tracer that is not incorporated into proteins but accumulates in gliomas, mainly because of tumoral transport and metabolism via the immunomodulatory kynurenine pathway. The aim of this study was to evaluate the usefulness of (11)C-AMT PET supplemented by tracer kinetic analysis for distinguishing recurrent gliomas from radiation injury. METHODS Twenty-two (11)C-AMT PET scans were obtained in adult patients who presented with a lesion suggestive of tumor recurrence on conventional MRI 1-6 y (mean, 3 y) after resection and postsurgical radiation of a World Health Organization grade II-IV glioma. Lesional standardized uptake values were calculated, as well as lesion-to-contralateral cortex ratios and 2 kinetic (11)C-AMT PET parameters (volume of distribution [VD], characterizing tracer transport, and unidirectional uptake rate [K]). Tumor was differentiated from radiation-injured tissue by histopathology (n = 13) or 1-y clinical and MRI follow-up (n = 9). Accuracy of tumor detection by PET variables was assessed by receiver-operating-characteristic analysis. RESULTS All (11)C-AMT PET parameters were higher in tumors (n = 12) than in radiation injury (n = 10) (P ≤ 0.012 in all comparisons). The lesion-to-cortex K-ratio most accurately identified tumor recurrence, with highly significant differences both in the whole group (P < 0.0001) and in lesions with histologic verification (P = 0.006); the area under the receiver-operating-characteristic curve was 0.99. A lesion-to-cortex K-ratio threshold of 1.39 (i.e., a 39% increase) correctly differentiated tumors from radiation injury in all but 1 case (100% sensitivity and 91% specificity). In tumors that were high-grade initially (n = 15), a higher lesion-to-cortex K-ratio threshold completely separated recurrent tumors (all K-ratios ≥ 1.70) from radiation injury (all K-ratios < 1.50) (100% sensitivity and specificity). CONCLUSION Kinetic analysis of dynamic (11)C-AMT PET images may accurately differentiate between recurrent World Health Organization grade II-IV infiltrating gliomas and radiation injury. Separation of unidirectional uptake rates from transport can enhance the differentiating accuracy of (11)C-AMT PET. Applying the same approach to other amino acid PET tracers might also improve their ability to differentiate recurrent gliomas from radiation injury.
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Affiliation(s)
- Bálint Alkonyi
- PET Center, Children's Hospital of Michigan, Detroit, MI, USA
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Kumar A, Asano E, Chugani HT. α-[¹¹C]-methyl-L-tryptophan PET for tracer localization of epileptogenic brain regions: clinical studies. Biomark Med 2012; 5:577-84. [PMID: 22003906 DOI: 10.2217/bmm.11.68] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Of several molecular probes used in PET, only α-[(11)C]-methyl-L-tryptophan (AMT) is able to pinpoint the epileptic focus itself in the interictal state, by revealing a focus of increased AMT uptake, even when an MRI or glucose metabolism PET demonstrates normal findings. AMT PET appears to be particularly useful in patients with tuberous sclerosis complex and in patients with cortical developmental malformations. Although the sensitivity of AMT PET in finding the epileptic focus is about 70%, its specificity is almost 100%, indicating that if AMT PET identifies an area of increased uptake, it likely represents the epileptic focus which needs to be resected for better surgical outcome. In nontuberous sclerosis complex patients with cortical dysplasia, increased AMT uptake is usually associated with cortical dysplasia type IIB and a very good surgical outcome. Previously, no imaging modality has been able to predict the exact pathology subtype or differentiate between epileptogenic and nonepileptogenic lesions interictally. The neuropathological similarities between tubers and type IIB cortical dysplasia suggest a common mechanism of epilepsy, for which AMT PET is a biomarker. Due to the limited access to AMT PET, as presently it is labeled with (11)C, which has a half-life of only 20 min and therefore has to be synthesized on site using a cyclotron, most of the AMT experience has originated primarily from only two centers. Therefore, there is a need for more clinical studies from other centers and this can be greatly facilitated if AMT can be labeled with (18)F, a PET radionuclide widely available with a half-life of 110 min.
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Affiliation(s)
- Ajay Kumar
- Department of Pediatrics, Children's Hospital of Michigan, Detroit Medical Center, Wayne State University School of Medicine, Detroit, MI, USA
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Alkonyi B, Mittal S, Zitron I, Chugani DC, Kupsky WJ, Muzik O, Chugani HT, Sood S, Juhász C. Increased tryptophan transport in epileptogenic dysembryoplastic neuroepithelial tumors. J Neurooncol 2011; 107:365-72. [PMID: 22048879 DOI: 10.1007/s11060-011-0750-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 10/24/2011] [Indexed: 12/26/2022]
Abstract
Dysembryoplastic neuroepithelial tumors (DNTs) are typically hypometabolic but can show increased amino acid uptake on positron emission tomography (PET). To better understand mechanisms of amino acid accumulation in epileptogenic DNTs, we combined quantitative α-[(11)C]methyl-L: -tryptophan (AMT) PET with tumor immunohistochemistry. Standardized uptake values (SUVs) of AMT and glucose were measured in 11 children with temporal lobe DNT. Additional quantification for AMT transport and metabolism was performed in 9 DNTs. Tumor specimens were immunostained for the L: -type amino acid transporter 1 (LAT1) and indoleamine 2,3-dioxygenase (IDO), a key enzyme of the immunomodulatory kynurenine pathway. All 11 tumors showed glucose hypometabolism, while mean AMT SUVs were higher than normal cortex in eight DNTs. Further quantification showed increased AMT transport in seven and high AMT metabolic rates in three DNTs. Two patients showing extratumoral cortical increases of AMT SUV had persistent seizures despite complete tumor resection. Resected DNTs showed moderate to strong LAT1 and mild to moderate IDO immunoreactivity, with the strongest expression in tumor vessels. These results indicate that accumulation of tryptophan in DNTs is driven by high amino acid transport, mediated by LAT1, which can provide the substrate for tumoral tryptophan metabolism through the kynurenine pathway, that can produce epileptogenic metabolites. Increased AMT uptake can extend to extratumoral cortex, and presence of such cortical regions may increase the likelihood of recurrent seizures following surgical excision of DNTs.
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Affiliation(s)
- Bálint Alkonyi
- PET Center, Children's Hospital of Michigan, 3901 Beaubien Blvd, Detroit, MI 48201, USA
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22
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Chugani HT, Kumar A, Kupsky W, Asano E, Sood S, Juhász C. Clinical and histopathologic correlates of 11C-alpha-methyl-L-tryptophan (AMT) PET abnormalities in children with intractable epilepsy. Epilepsia 2011; 52:1692-8. [PMID: 21569023 DOI: 10.1111/j.1528-1167.2011.03103.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
PURPOSE Interictal increase of (11) C-alpha-methyl-l-tryptophan (AMT) on positron emission tomography (PET) can be seen in cortical epileptic foci, and is particularly common in cortical developmental malformations. Therefore, in the present study, we evaluated the clinical and histopathologic correlates of AMT-PET abnormalities in children with intractable epilepsy undergoing resective surgery. METHODS Thirty children (mean age: 6.7 ± 3.2 years) were included in this study. All patients received AMT-PET as part of their presurgical evaluation and subsequently underwent epilepsy surgery. Magnetic resonance imaging (MRI) scans were normal in 15, showed nonspecific changes in 8, and suggested malformations of cortical development (MCDs) in nine children. Asymmetry indices (AIs) were calculated to determine increased AMT uptake. KEY FINDINGS Histopathology revealed MCDs in 16 (53%) children, including 12 with cortical dysplasia (CD) [mild MCD = 3; CD type IA = 2; CD type IIA = 2 and CD type IIB (severe CD with balloon cells) = 5]. Polymicrogyria and heterotopias (P&Hs) were seen in three cases and subependymal heterotopias (SEHs) in one child. The remaining 14 cases showed normal histopathology with varying degrees of gliosis. Increased AMT uptake was found in all five with CD type IIB, and all three with P&H, but in none with mild MCD and types IA-IIA CD or SEH. Whereas all five children with CD IIB and two with P&H had excellent surgical outcome (class I); children with milder CD or SEH had variable surgical outcome. The 14 patients with normal histopathology included seven patients with focally increased and seven with normal AMT uptake. Although patients with normal pathology and normal AMT-PET had better surgical outcome (class I = 5; II = 2), those with normal pathology, normal MRI, but abnormal AMT-PET had poor surgical outcome (class III = 4; IV = 3). SIGNIFICANCE Increased AMT uptake in children with CD may predict type IIB dysplasia (with balloon cells) and good surgical outcome. Histopathologic similarities between CD type IIB and epileptogenic cortical tubers may imply a common role of the inflammatory kynurenine pathway of tryptophan metabolism in these lesions. In children with normal histopathology, there is a subgroup with increased AMT uptake and poor surgical outcome.
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Affiliation(s)
- Harry T Chugani
- Department of Pediatrics, Children's Hospital of Michigan, Detroit Medical Center, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
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Abstract
Advances in positron emission tomography (PET) techniques have allowed the measurement and imaging of neurotransmitter synthesis, transport, and receptor binding to be performed in vivo. With regard to epileptic disorders, imaging of neurotransmitter systems not only assists in the identification of epileptic foci for surgical treatment, but also provides insights into the basic mechanisms of human epilepsy. Recent investigative interest in epilepsy has focused on PET imaging of tryptophan metabolism, via the serotonin and kynurenine pathways, as well as on imaging of serotonin receptors. This review summarizes advances in PET imaging and how these techniques can be applied clinically for epilepsy treatment.
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Affiliation(s)
- Harry T Chugani
- Carman and Ann Adams Department of Pediatrics, Children's Hospital of Michigan,Wayne State University School of Medicine, Detroit, Michigan, USA
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Superparamagnetic iron oxide nanoparticles: diagnostic magnetic resonance imaging and potential therapeutic applications in neurooncology and central nervous system inflammatory pathologies, a review. J Cereb Blood Flow Metab 2010; 30:15-35. [PMID: 19756021 PMCID: PMC2949106 DOI: 10.1038/jcbfm.2009.192] [Citation(s) in RCA: 303] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Superparamagnetic iron oxide nanoparticles have diverse diagnostic and potential therapeutic applications in the central nervous system (CNS). They are useful as magnetic resonance imaging (MRI) contrast agents to evaluate: areas of blood-brain barrier (BBB) dysfunction related to tumors and other neuroinflammatory pathologies, the cerebrovasculature using perfusion-weighted MRI sequences, and in vivo cellular tracking in CNS disease or injury. Novel, targeted, nanoparticle synthesis strategies will allow for a rapidly expanding range of applications in patients with brain tumors, cerebral ischemia or stroke, carotid atherosclerosis, multiple sclerosis, traumatic brain injury, and epilepsy. These strategies may ultimately improve disease detection, therapeutic monitoring, and treatment efficacy especially in the context of antiangiogenic chemotherapy and antiinflammatory medications. The purpose of this review is to outline the current status of superparamagnetic iron oxide nanoparticles in the context of biomedical nanotechnology as they apply to diagnostic MRI and potential therapeutic applications in neurooncology and other CNS inflammatory conditions.
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Approach to pediatric epilepsy surgery: State of the art, Part I: General principles and presurgical workup. Eur J Paediatr Neurol 2009; 13:102-14. [PMID: 18692417 DOI: 10.1016/j.ejpn.2008.05.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 03/13/2008] [Accepted: 05/08/2008] [Indexed: 11/22/2022]
Abstract
In 1990, the National Institute of Health adopted epilepsy surgery in children as an option when medications fail. In the past few years several concepts have become increasingly recognized as key to a successful approach to epilepsy surgery in children. These include the concepts of neuronal plasticity, the epileptogenic lesion, the ictal onset, symptomatogenic, irritative, and epileptogenic zones. In addition, several techniques have increasingly been utilized to delineate the above areas in an attempt to determine, in each patient, the epileptogenic zone, defined as the zone the resection of which leads to seizure freedom. When seizure semiology (which defines the symptomatogenic zone), ictal EEG (which identifies the ictal onset zone), and structural imaging (which identifies the epileptogenic lesion) can be reconciled to infer the location of the epileptogenic zone, surgery is usually, subsequently, undertaken. When these diagnostic modalities are discordant, not definitive, or when the epileptogenic zone is close to eloquent cortex, invasive EEG, complemented by other imaging techniques may be needed. These include magnetoencephalography, single photon emission tomography, various types of positron emission tomography, various magnetic resonance imaging modalities (functional, diffusion weighted, other) and other emerging and experimental techniques. While MRI, video-EEG, and neuropsychological assessments are well established components of the presurgical evaluation, the use of the new emerging imaging technologies is dictated by the degree of anatomo-electro-clinical correlations, and, awaiting multicentric studies and more detailed guidelines, remains center-dependent.
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Wakamoto H, Chugani DC, Juhász C, Muzik O, Kupsky WJ, Chugani HT. Alpha-methyl-l-tryptophan positron emission tomography in epilepsy with cortical developmental malformations. Pediatr Neurol 2008; 39:181-8. [PMID: 18725063 DOI: 10.1016/j.pediatrneurol.2008.05.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 05/14/2008] [Accepted: 05/19/2008] [Indexed: 10/21/2022]
Abstract
Preliminary studies suggest that alpha[(11)C]methyl-l-tryptophan positron emission tomography can detect the epileptic focus within malformations of cortical development. We determined the sensitivity and specificity of alpha-[(11)C]methyl-l-tryptophan positron emission tomography in identifying epileptic focus in children with intractable, neocortical epilepsy with and without malformations of cortical development. Seventy-three epileptic children were classified into lesional and nonlesional groups, and compared regarding focal increased alpha-[(11)C]methyl-l-tryptophan uptake. The sensitivity and specificity of focal increased alpha-[(11)C]methyl-l-tryptophan uptake, using intracranial electroencephalogram localization of seizure onset as the standard, were compared between lesional and nonlesional groups. The specificity of alpha-[(11)C]methyl-l-tryptophan positron emission tomography for detecting seizure onset lobe was equally high in lesional (97%) and nonlesional groups (100%), whereas sensitivity was higher in the lesional than the nonlesional group (47% versus 29%; P = 0.047). The incidence of alpha-[(11)C]methyl-l-tryptophan uptake abnormality was higher in the lesional than the nonlesional group (P < 0.01). Alpha-[(11)C]methyl-l-tryptophan positron emission tomography localized and visualized epileptogenic regions in 25% of patients with nonlocalizing magnetic resonance imaging. Although overall sensitivity of alpha-[(11)C]methyl-l-tryptophan positron emission tomography in identifying neocortical epileptic focus is modest, specificity is extremely high. When an alpha-[(11)C]methyl-l-tryptophan focus is detected, it likely represents the epileptogenic region to be resected.
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Affiliation(s)
- Hiroyuki Wakamoto
- Carman and Ann Adams Department of Pediatrics, Wayne State University School of Medicine, Detroit, Michigan, USA
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Akhtari M, Bragin A, Cohen M, Moats R, Brenker F, Lynch MD, Vinters HV, Engel J. Functionalized magnetonanoparticles for MRI diagnosis and localization in epilepsy. Epilepsia 2008; 49:1419-30. [PMID: 18479391 DOI: 10.1111/j.1528-1167.2008.01615.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE The development of nonradioactive and targeted magnetonanoparticles (MNP) capable of crossing the blood-brain barrier (BBB) and of concentrating in the epileptogenic tissues of acute and chronic animal models of temporal lobe epilepsy to render these tissues visible on magnetic resonance imaging (MRI). METHODS Nonradioactive alpha methyl tryptophan (AMT) was covalently attached to MNP composed of iron oxide and dextran. A rodent model of temporal lobe epilepsy was prepared by injecting kainic acid into the right hippocampus. AMT-MNP or plain MNP was injected in the tail-vein of two animals during the acute stage 3 days after status epilepticus, and AMT-MNP in five animals during the chronic stage. MRIs were obtained before and after particle injection in all animals. Intracranial EEGs were obtained in all chronic animals after completion of MRI studies. RESULTS AMT-MNP crossed the BBB and intraparenchymal uptake was visible on MRI. In the acute condition, AMT-MNP appeared to localize to both hippocampi, whereas plain MNP only identified unilateral, presumably inflammatory, changes. In the chronic condition, AMT-MNP uptake correlated with the occurrence of spontaneous seizures, and the location of uptake appeared to agree with bilateral or unilateral epileptogenicity confirmed by subsequent intracranial EEG. DISCUSSION Nonradioactive AMT-MNP can cross the BBB and may accurately localize epileptogenic cerebral regions. The MNP-MRI approach is potentially applicable to the use of any bioactive molecules as ligands for imaging normal and abnormal localized cerebral functions, accurately, safely, and inexpensively.
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Affiliation(s)
- Massoud Akhtari
- Jane & Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
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Increased striatal serotonin synthesis following cortical resection in children with intractable epilepsy. Epilepsy Res 2007; 78:124-30. [PMID: 18083006 DOI: 10.1016/j.eplepsyres.2007.10.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Revised: 09/28/2007] [Accepted: 10/28/2007] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND PURPOSE Serotonin is a major regulator of structural brain plasticity, which may occur following cortical resection in humans. In this study we used positron emission tomography (PET) with alpha[11C]methyl-l-tryptophan (AMT) to evaluate serotonergic alterations in subcortical structures following cortical resection in children with intractable epilepsy. METHODS AMT uptake in the thalamus and lentiform nucleus was evaluated postoperatively (1-89 months following resection) in 19 children (mean age: 8.7 years) with a previous cortical resection due to intractable epilepsy. Ten children with partial epilepsy but without resection and seven normal children served as controls. RESULTS There was an increased AMT uptake in the lentiform nucleus ipsilateral to the resection as compared to the contralateral side (mean asymmetry: 4.2+/-3.0%), and the asymmetries were significantly higher than those measured in the control groups (p<or=0.001). Post-resection asymmetry indices in the lentiform nucleus correlated inversely with postoperative time (r=-0.67; p=0.002), but not with age (p=0.29) or the extent of resection (p=0.77). In contrast, thalamic AMT uptake asymmetries were not different among the three groups (p=0.63). CONCLUSIONS Cortical resection results in a sustained increase of AMT uptake in the lentiform nucleus, suggesting increased serotonin synthesis. Serotonergic activation in the deafferented striatum may play a role in the functional reorganization of cortico-striatal projections in humans.
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Mohamed IS, Otsubo H, Ochi A, Elliott I, Donner E, Chuang S, Sharma R, Holowka S, Rutka J, Snead OC. Utility of Magnetoencephalography in the Evaluation of Recurrent Seizures after Epilepsy Surgery. Epilepsia 2007; 48:2150-9. [PMID: 17727666 DOI: 10.1111/j.1528-1167.2007.01271.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE To study the role of magnetoencephalography (MEG) in the surgical evaluation of children with recurrent seizures after epilepsy surgery. METHODS We studied 17 children with recurrent seizures after epilepsy surgery using interictal and ictal scalp EEG, intracranial video EEG (IVEEG), MRI, and MEG. We analyzed the location and distribution of MEG spike sources (MEGSSs) and the relationship of MEGSSs to the margins of previous resections and surgical outcome. RESULTS Clustered MEGSSs occurred at the margins of previous resections within two contiguous gyri in 10 patients (group A), extended spatially from a margin by < or =3 cm in three patients (group B), and were remote from a resection margin by >3 cm in six patients (group C). Two patients had concomitant group A and C clusters. Thirteen patients underwent second surgeries. IVEEG was used in four patients. Six of seven patients with group A MEGSS clusters did not require IVEEG for second surgeries. Follow-up periods ranged from 0.6 to 4.3 years (mean: 2.6 years). Eleven children, including eight who became seizure-free, achieved Engel class I or II. CONCLUSION Our data demonstrate the utility of MEG for evaluating patients with recurrent seizures after epilepsy surgery. Specific MEGSS cluster patterns delineate epileptogenic zones. Removing cluster regions adjacent to the margins of previous resections, in addition to removing recurrent lesions, achieves favorable surgical outcome. Cluster location and extent identify which patients require IVEEG, potentially eliminating IVEEG for some. Patients with remotely located clusters require IVEEG for accurate assessment and localization of the entire epileptogenic zone.
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Affiliation(s)
- Ismail S Mohamed
- Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, Unviersity of Toronto, Toronto, Ontario, Canada
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Patil S, Biassoni L, Borgwardt L. Nuclear Medicine in Pediatric Neurology and Neurosurgery: Epilepsy and Brain Tumors. Semin Nucl Med 2007; 37:357-81. [PMID: 17707242 DOI: 10.1053/j.semnuclmed.2007.04.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In pediatric drug-resistant epilepsy, nuclear medicine can provide important additional information in the presurgical localization of the epileptogenic focus. The main modalities used are interictal (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) and ictal regional cerebral perfusion study with single-photon emission computed tomography (SPECT). Nuclear medicine techniques have a sensitivity of approximately 85% to 90% in the localization of an epileptogenic focus in temporal lobe epilepsy; however, in this clinical setting, they are not always clinically indicated because other techniques (eg, icterictal and ictal electroencephalogram, video telemetry, magnetic resonance imaging [MRI]) may be successful in the identification of the epileptogenic focus. Nuclear medicine is very useful when MRI is negative and/or when electroencephalogram and MRI are discordant. A good technique to identify the epileptogenic focus is especially needed in the setting of extra-temporal lobe epilepsy; however, in this context, identification of the epileptogenic focus is more difficult for all techniques and the sensitivity of the isotope techniques is only 50% to 60%. This review article discusses the clinical value of the different techniques in the clinical context; it also gives practical suggestions on how to acquire good ictal SPECT and interictal FDG-PET scans. Nuclear medicine in pediatric brain tumors can help in differentiating tumor recurrence from post-treatment sequelae, in assessing the response to treatment, in directing biopsy, and in planning therapy. Both PET and SPECT tracers can be used. In this review, we discuss the use of the different tracers available in this still very new, but promising, application of radioisotope techniques.
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Affiliation(s)
- Shekhar Patil
- University College London-Institute of Child Health, Great Ormond Street Hospital for Children NHS Trust and the National Centre for Young People with Epilepsy, London, United Kingdom
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Rosa-Neto P, Benkelfat C, Sakai Y, Leyton M, Morais JA, Diksic M. Brain regional α-[11C]methyl-L-tryptophan trapping, used as an index of 5-HT synthesis, in healthy adults: absence of an age effect. Eur J Nucl Med Mol Imaging 2007; 34:1254-64. [PMID: 17318550 DOI: 10.1007/s00259-007-0365-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Accepted: 12/26/2006] [Indexed: 01/01/2023]
Abstract
PURPOSE Previous functional neuroimaging studies suggest that selective aspects of the brain serotonin (5-HT) system change during the aging process. Here, we assessed the effects of aging on the brain regional alpha-[(11)C]methyl-L: -tryptophan (alpha-[(11)C]MTrp) trapping rate constant (K*; microl.g(-1).min(-1)), which, with certain assumptions, could be taken as a proxy of 5-HT synthesis. METHODS Thirty-six healthy right-handed subjects had positron emission tomography (PET) scans following injection with alpha-[(11)C]MTrp [18 males aged 46.6 +/- 22.2 years (range 20-80 years) and 18 females aged 33.0 +/- 15.5 years (range 20-80 years)]. The trapping rate constant, K*, was calculated with the graphical method for irreversible ligands using the sinus-venous input function. A priori selected volumes of interest (VOIs) were defined using an automatic algorithm. RESULTS VOI analysis showed no correlation between age and brain regional K* values. As reported by others, significant age-related reductions of gray matter were observed in the thalamus and frontal and cingulate cortices; even with partial volume correction there was still no significant relationship between K* and age. Further exploratory SPM voxelwise correlation between age and alpha-[(11)C]MTrp trapping, using p = 0.05 (uncorrected), as well as voxel-based morphometry, was in agreement with the VOI analysis. CONCLUSION The dissociation between age-related changes in brain anatomy and this index of serotonin synthesis suggests independent mechanisms underlying the normal aging process.
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Affiliation(s)
- Pedro Rosa-Neto
- Department of Neurology and Neurosurgery, McGill University, 3801 University Street, Montreal, Canada
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Juhász C, Chugani DC, Muzik O, Wu D, Sloan AE, Barger G, Watson C, Shah AK, Sood S, Ergun EL, Mangner TJ, Chakraborty PK, Kupsky WJ, Chugani HT. In vivo uptake and metabolism of alpha-[11C]methyl-L-tryptophan in human brain tumors. J Cereb Blood Flow Metab 2006; 26:345-57. [PMID: 16079785 DOI: 10.1038/sj.jcbfm.9600199] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Abnormal metabolism of tryptophan has been implicated in modulation of tumor cell proliferation and immunoresistance. alpha-[(11)C]Methyl-L-tryptophan (AMT) is a PET tracer to measure cerebral tryptophan metabolism in vivo. In the present study, we have measured tumor tryptophan uptake in 40 patients with primary brain tumors using AMT PET and standard uptake values (SUV). Tryptophan metabolism was further quantified in 23 patients using blood input data. Estimates of the volume of distribution (VD') and the metabolic rate constant (k(3)') were calculated and related to magnetic resonance imaging (MRI) and histology findings. All grade II to IV gliomas and glioneuronal tumors showed increased AMT SUV, including all recurrent/residual tumors. Gadolinium enhancement on MRI was associated with high VD' values, suggesting impaired blood-brain barrier, while k(3)' values were not related to contrast enhancement. Low-grade astrocytic gliomas showed increased tryptophan metabolism, as measured by k(3)'. In contrast, oligodendrogliomas showed high VD' values but lower k(3)' as compared with normal cortex. In astrocytic tumors, low grade was associated with high k(3)' and lower VD', while high-grade tumors showed the reverse pattern. The findings show high AMT uptake in primary and residual/recurrent gliomas and glioneuronal tumors. Increased AMT uptake can be due to increased metabolism of tryptophan and/or high volume of distribution, depending on tumor type and grade. High tryptophan metabolic rates in low-grade tumors may indicate activation of the kynurenine pathway, a mechanism regulating tumor cell growth. AMT PET might be a useful molecular imaging method to guide therapeutic approaches aimed at controlling tumor cell proliferation by acting on tryptophan metabolism.
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Affiliation(s)
- Csaba Juhász
- Carman and Ann Adams Department of Pediatrics, Children's Hospital of Michigan, Detroit Medical Center, Wayne State University School of Medicine, 48201, USA.
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Abstract
PURPOSE OF REVIEW The purpose of this review is to consider the current and potential role of neuroimaging from an epilepsy perspective, and to illustrate that by combining appropriate imaging techniques, neuroimaging can contribute greatly to elucidating the basic mechanisms of the various forms of epileptic disorders. RECENT FINDINGS New magnetic resonance imaging sequences (magnetization transfer imaging) and positron emission tomography ligands (serotonergic system) were biologically validated in large groups of patients with localization-related epilepsies. Investigations in genetically determined homogenous patient populations (PAX6, juvenile myoclonic epilepsy) have strengthened the link between genetic defects and neuropathological targets (anterior commissure, thalamus). Magnetic resonance spectroscopy and electroencephalogram-triggered functional magnetic resonance imaging provided converging evidence for a key role of the thalamus in the generation of generalized seizures. The role of functional magnetic resonance imaging in identifying eloquent areas of cortex and its relationship to structural lesions, in particular malformations of cortical development, has been further elucidated. Longitudinal magnetic resonance imaging studies reported progressive volume loss after febrile convulsions and in active epilepsy. SUMMARY Neuroimaging is essential for improving the efficacy and safety of therapeutic, in particular, surgical procedures. Investigations of larger, more homogenous genetic disorders and longitudinal rather than cross-sectional neuroimaging studies have advanced our knowledge about the cause and effect of epileptic disorders, and will ultimately link defects in molecular genetics with specific neuropathological targets.
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Affiliation(s)
- Matthias J Koepp
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK.
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