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Issa ASM, Scheins J, Tellmann L, Brambilla CR, Lohmann P, Rota-Kops E, Herzog H, Neuner I, Shah NJ, Lerche C. Impact of improved dead time correction on the quantification accuracy of a dedicated BrainPET scanner. PLoS One 2024; 19:e0296357. [PMID: 38578749 PMCID: PMC10997125 DOI: 10.1371/journal.pone.0296357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 12/11/2023] [Indexed: 04/07/2024] Open
Abstract
OBJECTIVE Quantitative values derived from PET brain images are of high interest for neuroscientific applications. Insufficient DT correction (DTC) can lead to a systematic bias of the output parameters obtained by a detailed analysis of the time activity curves (TACs). The DTC method currently used for the Siemens 3T MR BrainPET insert is global, i.e., differences in DT losses between detector blocks are not considered, leading to inaccurate DTC and, consequently, to inaccurate measurements masked by a bias. However, following careful evaluation with phantom measurements, a new block-pairwise DTC method has demonstrated a higher degree of accuracy compared to the global DTC method. APPROACH Differences between the global and the block-pairwise DTC method were studied in this work by applying several radioactive tracers. We evaluated the impact on [11C]ABP688, O-(2-[18F]fluoroethyl)-L-tyrosine (FET), and [15O]H2O TACs. RESULTS For [11C]ABP688, a relevant bias of between -0.0034 and -0.0053 ml/ (cm3 • min) was found in all studied brain regions for the volume of distribution (VT) when using the current global DTC method. For [18F]FET-PET, differences of up to 10% were observed in the tumor-to-brain ratio (TBRmax), these differences depend on the radial distance of the maximum from the PET isocenter. For [15O]H2O, differences between +4% and -7% were observed in the GM region. Average biases of -4.58%, -3.2%, and -1.2% for the regional cerebral blood flow (CBF (K1)), the rate constant k2, and the volume of distribution VT were observed, respectively. Conversely, in the white matter region, average biases of -4.9%, -7.0%, and 3.8% were observed for CBF (K1), k2, and VT, respectively. CONCLUSION The bias introduced by the global DTC method leads to an overestimation in the studied quantitative parameters for all applications compared to the block-pairwise method. SIGNIFICANCE The observed differences between the two DTC methods are particularly relevant for research applications in neuroscientific studies as they affect the accuracy of quantitative Brain PET images.
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Affiliation(s)
- Ahlam Said Mohamad Issa
- Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany
- JARA, BRAIN, Translational Medicine, Aachen, Germany
- Department of Neurology, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
| | - Jürgen Scheins
- Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany
| | - Lutz Tellmann
- Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany
| | | | - Philipp Lohmann
- Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany
| | - Elena Rota-Kops
- Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany
| | - Hans Herzog
- Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany
| | - Irene Neuner
- Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany
- JARA, BRAIN, Translational Medicine, Aachen, Germany
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen, Germany
| | - N. Jon Shah
- Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany
- JARA, BRAIN, Translational Medicine, Aachen, Germany
- Department of Neurology, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
- Institute of Neuroscience and Medicine 11, INM-11, JARA, Forschungszentrum Jülich, Jülich, Germany
| | - Christoph Lerche
- Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany
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Widman G, Golombeck K, Hautzel H, Gross CC, Quesada CM, Witt JA, Rota-Kops E, Ermert J, Greschus S, Surges R, Helmstaedter C, Wiendl H, Melzer N, Elger CE. Treating a GAD65 Antibody-Associated Limbic Encephalitis with Basiliximab: A Case Study. Front Neurol 2015; 6:167. [PMID: 26284025 PMCID: PMC4522569 DOI: 10.3389/fneur.2015.00167] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 07/15/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Antibodies (ABs) against the 65-kDa isoform of the intracellular enzyme glutamate decarboxylase (GAD65) have been found in limbic encephalitis (LE) and other neurological conditions. The direct significance of anti-GAD65-ABs for epilepsy is unclear. However, in histological preparations from biopsies of resective epilepsy surgeries, predominantly cytotoxic T-lymphocytes were detected making close contacts to neurons. Activated T-lymphocytes can, in turn, be selectively controlled by therapeutic interleukin-2 receptor Abs, such as basiliximab. CASE PRESENTATION We report of a 25-year-old male patient with epilepsy since the age of 18 and displaying clinical signs of LE and a high titer of GAD65 ABs in cerebrospinal fluid (CSF) and serum. Monthly, repetitive, intravenous cortisone pulse therapies that were initially administered for 6 months failed to improve his condition. Subsequent flow-cytometry analysis of CSF showed especially an increased fraction of activated HLA-DR(+) CD8(+) T-lymphocytes (fCD8(+)TL) when compared to controls. Thus, a second, intravenous cortisone pulse therapy with an additional basiliximab dose of 20 mg/month was started. After 3 months, the fCD8(+)TL in the CSF normalized; after 6 months, the psychological impulse-control deficits normalized; and after 11 months the patient was seizure free. However, 7 weeks later, seizures and, later on, psychological deficits recurred and fCD8(+)TL was once again present in the CSF. Flumazenil PET, magnetic resonance imaging-volumetry, and neuropsychological changes during therapy are described. CONCLUSION The correlation of the fCD8(+)TL in the CSF with clinical and paraclinical measures of disease activity combined with the unambiguous response to basiliximab strongly argues in favor of the putative pathogenic role fCD8(+)TL in anti-GAD65 LE. The clinical relapse at the end of the observation period might be due to the formation of human anti-drug ABs, a well-known complication of therapy with chimeric ABs.
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Affiliation(s)
- Guido Widman
- Department of Epileptology, University of Bonn , Bonn , Germany
| | | | - Hubertus Hautzel
- Department of Nuclear Medicine (KME), Medical Faculty, Research Center Jülich, Heinrich-Heine-University Düsseldorf , Jülich , Germany
| | | | | | | | - Elena Rota-Kops
- Department of "Neurowissenschaften und Medizin" 4 (INM-4), Research Center Jülich , Jülich , Germany
| | - Johannes Ermert
- Department of "Neurowissenschaften und Medizin" 4 (INM-4), Research Center Jülich , Jülich , Germany
| | | | - Rainer Surges
- Department of Epileptology, University of Bonn , Bonn , Germany
| | | | - Heinz Wiendl
- Department of Neurology, University of Münster , Münster , Germany
| | - Nico Melzer
- Department of Neurology, University of Münster , Münster , Germany
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Shah NJ, Oros-Peusquens AM, Arrubla J, Zhang K, Warbrick T, Mauler J, Vahedipour K, Romanzetti S, Felder J, Celik A, Rota-Kops E, Iida H, Langen KJ, Herzog H, Neuner I. Advances in multimodal neuroimaging: hybrid MR-PET and MR-PET-EEG at 3 T and 9.4 T. J Magn Reson 2013; 229:101-115. [PMID: 23317760 DOI: 10.1016/j.jmr.2012.11.027] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2012] [Revised: 11/28/2012] [Accepted: 11/29/2012] [Indexed: 06/01/2023]
Abstract
Multi-modal MR-PET-EEG data acquisition in simultaneous mode confers a number of advantages at 3 T and 9.4 T. The three modalities complement each other well; structural-functional imaging being the domain of MRI, molecular imaging with specific tracers is the strength of PET, and EEG provides a temporal dimension where the other two modalities are weak. The utility of hybrid MR-PET at 3 T in a clinical setting is presented and critically discussed. The potential problems and the putative gains to be accrued from hybrid imaging at 9.4 T, with examples from the human brain, are outlined. Steps on the road to 9.4 T multi-modal MR-PET-EEG are also illustrated. From an MR perspective, the potential for ultra-high resolution structural imaging is discussed and example images of the cerebellum with an isotropic resolution of 320 μm are presented, setting the stage for hybrid imaging at ultra-high field. Further, metabolic imaging is discussed and high-resolution images of the sodium distribution are presented. Examples of tumour imaging on a 3 T MR-PET system are presented and discussed. Finally, the perspectives for multi-modal imaging are discussed based on two on-going studies, the first comparing MR and PET methods for the measurement of perfusion and the second which looks at tumour delineation based on MRI contrasts but the knowledge of tumour extent is based on simultaneously acquired PET data.
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Affiliation(s)
- N Jon Shah
- Institute of Neuroscience and Medicine-4, Research Centre Jülich, 52425 Jülich, Germany.
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Minnerop M, Herzog H, Rota-Kops E, Leenders K, Brunt E, Klinke I, Helmstaedter C, Klockgether T, Wüllner U. [18F]fluordeoxyglucose positron emission tomography in spinocerebellar ataxias type 1,2,3 and 6. Akt Neurol 2006. [DOI: 10.1055/s-2006-952992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Klimke A, Boy C, Eickhoff M, Herzog H, Holschbach M, Mühlensiepen H, Weckessec M, Rota-Kops E, Sonnenberg F, Gaebel W, Markstein R, Stöcklin G, Coenen H, Müller-Gärtner H. Dopamine D 1 and D 4-like receptors in untreated schizophrenic patients and healthy controls. Eur Psychiatry 1998. [DOI: 10.1016/s0924-9338(99)80289-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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