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1,757 results on '"Van Laere, Koen"'

16. Regional accuracy of ZTE-based attenuation correction in static and dynamic brain PET/MR

Author

Schramm, Georg, Koole, Michel, Willekens, Stefanie M. A., Rezaei, Ahmadreza, Van Weehaeghe, Donatienne, Delso, Gaspar, Peeters, Ronald, Mertens, Nathalie, Nuyts, Johan, and Van Laere, Koen

Subjects
Physics - Medical Physics
Abstract

Accurate MR-based attenuation correction (MRAC) is essential for quantitative PET/MR imaging of the brain. In this study, we analyze the regional bias caused by MRAC based on Zero-Echo-Time MR images (ZTEAC) compared to CT-based AC (CTAC) in static and dynamic PET imaging. In addition the results are compared to the performance of the current default Atlas-based AC (AtlasAC) implemented in the GE SIGNA PET/MR. Methods: Thirty static [18F]FDG and 11 dynamic [18}F]PE2I acquisitions from a GE SIGNA PET/MR were reconstructed using ZTEAC (using a research tool, GE Healthcare), single-subject AtlasAC (the current default AC in GE's SIGNA PET/MR) and CTAC (from a PET/CT acquisition of the same day). In the 30 static [18F]FDG reconstructions, the bias caused by ZTEAC and AtlasAC in the mean uptake of 85 anatomical volumes of interest (VOIs) of the Hammers' atlas was analyzed in PMOD. For the 11 dynamic [18}F]PE2I reconstructions, the bias caused by ZTEAC and AtlasAC in the non displaceable binding potential BPnd in the striatum was calculated with cerebellum as the reference region and a simplified reference tissue model. Results: The regional bias caused by ZTEAC in the static [18F]FDG reconstructions ranged from -8.0% to +7.7% (mean 0.1%, SD 2.0%). For AtlasAC this bias ranged from -31.6% to +16.6% (mean -0.4%, SD 4.3%). The bias caused by AtlasAC showed a clear gradient in the cranio-caudal direction (-4.2% in the cerebellum, +6.6% in the left superior frontal gyrus). The bias in the striatal BPnd for the [18F]PE2I reconstructions ranged from -0.8% to +4.8% (mean 1.5%, SD 1.4%) using ZTEAC and from -0.6% to +9.4% using AtlasAC (mean 4.2%, SD 2.6%). Conclusion: ZTEAC provides excellent quantitative accuracy for static and dynamic brain PET/MR, comparable to CTAC, and is clearly superior to the default AtlasAC currently implemented in the GE SIGNA PET/MR., Comment: 23 pages in total, 7 figures, 1 table, 3 supplementary figures, 5 supplementary tables

Published
2018
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19. Value of [68Ga]Ga-somatostatin receptor PET/CT in the grading of pulmonary neuroendocrine (carcinoid) tumours and the detection of disseminated disease: single-centre pathology-based analysis and review of the literature

Author

Deleu, Anne-Leen, Laenen, Annouschka, Decaluwé, Herbert, Weynand, Birgit, Dooms, Christophe, De Wever, Walter, Jentjens, Sander, Goffin, Karolien, Vansteenkiste, Johan, Van Laere, Koen, De Leyn, Paul, Nackaerts, Kristiaan, and Deroose, Christophe M.

Published
2022
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22. Effects on cerebral blood flow after single doses of the β2 agonist, clenbuterol, in healthy volunteers and patients with mild cognitive impairment or Parkinson's disease.

Author

Lodeweyckx, Thomas, de Hoon, Jan, Van Laere, Koen, Bautista, Edgar, Rizzo, Gaia, Bishop, Courtney, Rabiner, Eugenii, Martin, Renee S., Ford, Anthony, and Vargas, Gabriel

Subjects
PARKINSON'S disease, MILD cognitive impairment, CENTRAL nervous system, SPIN labels, GLUCOSE metabolism
Abstract

Aims: Cerebral hypometabolism occurs years prior to a diagnosis of neurodegenerative diseases and coincides with reduced cerebral perfusion and declining noradrenergic transmission from the locus coeruleus. In pre‐clinical models, β‐adrenoceptor (β‐AR) agonists increase cerebrocortical glucose metabolism, and may have therapeutic potential for neurodegenerative diseases. This study investigated the safety and effects on regional cerebral blood flow (rCBF) of the oral, brain‐penetrant β2‐AR agonist, clenbuterol, in healthy volunteers (HV) and patients with mild cognitive impairment (MCI) or Parkinson's disease (PD). Methods: This study evaluated the safety and effects on cerebral activity of the oral, brain‐penetrant, β2‐AR agonist clenbuterol (20–160 μg) in healthy volunteers and patients with MCI or PD. Regional CBF, which is tightly coupled to glucose metabolism, was measured by arterial spin labelling MRI in 32 subjects (25 HV and 8 MCI or PD) across five cohorts. In some cohorts, low doses of nadolol (1–5 mg), a β‐AR antagonist with minimal brain penetration, were administered with clenbuterol to control peripheral β2‐AR responses. Results: Significant, dose‐dependent increases in rCBF were seen in multiple brain regions, including hippocampus, amygdala and thalamus, following the administration of clenbuterol to HVs (mean changes from baseline in hippocampal rCBF of −1.7%, 7.3%, 22.9%, 28.4% 3 h after 20, 40, 80 and 160 μg clenbuterol, respectively). In patients with MCI or PD, increases in rCBF following 80 μg clenbuterol were observed both without and with 5 mg nadolol (in hippocampus, 18.6%/13.7% without/with nadolol). Clenbuterol was safe and well‐tolerated in all subjects; known side effects of β2‐agonists, including increased heart rate and tremor, were mild in intensity and were blocked by low‐dose nadolol. Conclusions: The effects of clenbuterol on rCBF were evident both in the absence and presence of low‐dose nadolol, suggesting central nervous system (CNS) involvement. Concomitant inhibition of the peripheral effects of clenbuterol by nadolol confirms that meaningful β2‐AR antagonism in the periphery was achieved without interrupting the central effects of clenbuterol on rCBF. [ABSTRACT FROM AUTHOR]

Published
2024
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24. MRI/PET Brain Imaging

Author

Schramm, Georg, Van Laere, Koen, Van Laar, Peter Jan, Koole, Michel, Dierckx, Rudi A. J. O., editor, Otte, Andreas, editor, de Vries, Erik F. J., editor, van Waarde, Aren, editor, and Leenders, Klaus L., editor

Published
2021
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29. Association of Cerebral Amyloid-β Aggregation With Cognitive Functioning in Persons Without Dementia

Author

Jansen, Willemijn J, Ossenkoppele, Rik, Tijms, Betty M, Fagan, Anne M, Hansson, Oskar, Klunk, William E, van der Flier, Wiesje M, Villemagne, Victor L, Frisoni, Giovanni B, Fleisher, Adam S, Lleó, Alberto, Mintun, Mark A, Wallin, Anders, Engelborghs, Sebastiaan, Na, Duk L, Chételat, Gäel, Molinuevo, José Luis, Landau, Susan M, Mattsson, Niklas, Kornhuber, Johannes, Sabri, Osama, Rowe, Christopher C, Parnetti, Lucilla, Popp, Julius, Fladby, Tormod, Jagust, William J, Aalten, Pauline, Lee, Dong Young, Vandenberghe, Rik, de Oliveira, Catarina Resende, Kapaki, Elisabeth, Froelich, Lutz, Ivanoiu, Adrian, Gabryelewicz, Tomasz, Verbeek, Marcel M, Sanchez-Juan, Páscual, Hildebrandt, Helmut, Camus, Vincent, Zboch, Marzena, Brooks, David J, Drzezga, Alexander, Rinne, Juha O, Newberg, Andrew, de Mendonça, Alexandre, Sarazin, Marie, Rabinovici, Gil D, Madsen, Karine, Kramberger, Milica G, Nordberg, Agneta, Mok, Vincent, Mroczko, Barbara, Wolk, David A, Meyer, Philipp T, Tsolaki, Magda, Scheltens, Philip, Verhey, Frans RJ, Visser, Pieter Jelle, Aarsland, Dag, Alcolea, Daniel, Alexander, Myriam, Almdahl, Ina S, Arnold, Steven E, Baldeiras, Inês, Barthel, Henryk, van Berckel, Bart NM, Blennow, Kaj, van Buchem, Mark A, Cavedo, Enrica, Chen, Kewei, Chipi, Elena, Cohen, Ann D, Förster, Stefan, Fortea, Juan, Frederiksen, Kristian S, Freund-Levi, Yvonne, Gkatzima, Olymbia, Gordon, Mark Forrest, Grimmer, Timo, Hampel, Harald, Hausner, Lucrezia, Hellwig, Sabine, Herukka, Sanna-Kaisa, Johannsen, Peter, Klimkowicz-Mrowiec, Aleksandra, Köhler, Sebastian, Koglin, Norman, van Laere, Koen, de Leon, Mony, Lisetti, Viviana, Maier, Wolfgang, Marcusson, Jan, Meulenbroek, Olga, Møllergård, Hanne M, Morris, John C, Nordlund, Arto, Novak, Gerald P, Paraskevas, George P, Perera, Gayan, Peters, Oliver, and Ramakers, Inez HGB

Subjects
Health Services and Systems, Health Sciences, Acquired Cognitive Impairment, Alzheimer's Disease Related Dementias (ADRD), Neurosciences, Aging, Dementia, Brain Disorders, Behavioral and Social Science, Neurodegenerative, Alzheimer's Disease, Alzheimer's Disease including Alzheimer's Disease Related Dementias (AD/ADRD), Clinical Research, Aetiology, 2.1 Biological and endogenous factors, Neurological, Mental health, Aged, Alzheimer Disease, Amyloid beta-Peptides, Brain, Cognition Disorders, Cognitive Dysfunction, Cross-Sectional Studies, Female, Humans, Male, Memory, Episodic, Mental Status and Dementia Tests, Middle Aged, Positron-Emission Tomography, Reference Values, Amyloid Biomarker Study Group, Other Medical and Health Sciences, Psychology, Cognitive Sciences, Clinical sciences, Clinical and health psychology
Abstract

ImportanceCerebral amyloid-β aggregation is an early event in Alzheimer disease (AD). Understanding the association between amyloid aggregation and cognitive manifestation in persons without dementia is important for a better understanding of the course of AD and for the design of prevention trials.ObjectiveTo investigate whether amyloid-β aggregation is associated with cognitive functioning in persons without dementia.Design, setting, and participantsThis cross-sectional study included 2908 participants with normal cognition and 4133 with mild cognitive impairment (MCI) from 53 studies in the multicenter Amyloid Biomarker Study. Normal cognition was defined as having no cognitive concerns for which medical help was sought and scores within the normal range on cognitive tests. Mild cognitive impairment was diagnosed according to published criteria. Study inclusion began in 2013 and is ongoing. Data analysis was performed in January 2017.Main outcomes and measuresGlobal cognitive performance as assessed by the Mini-Mental State Examination (MMSE) and episodic memory performance as assessed by a verbal word learning test. Amyloid aggregation was measured with positron emission tomography or cerebrospinal fluid biomarkers and dichotomized as negative (normal) or positive (abnormal) according to study-specific cutoffs. Generalized estimating equations were used to examine the association between amyloid aggregation and low cognitive scores (MMSE score ≤27 or memory z score≤-1.28) and to assess whether this association was moderated by age, sex, educational level, or apolipoprotein E genotype.ResultsAmong 2908 persons with normal cognition (mean [SD] age, 67.4 [12.8] years), amyloid positivity was associated with low memory scores after age 70 years (mean difference in amyloid positive vs negative, 4% [95% CI, 0%-7%] at 72 years and 21% [95% CI, 10%-33%] at 90 years) but was not associated with low MMSE scores (mean difference, 3% [95% CI, -1% to 6%], P = .16). Among 4133 patients with MCI (mean [SD] age, 70.2 [8.5] years), amyloid positivity was associated with low memory (mean difference, 16% [95% CI, 12%-20%], P

Published
2018

30. Plasma pTau181 and pTau217 predict asymptomatic amyloid accumulation equally well as amyloid-PET

Author

De Meyer, Steffi, primary, Schaeverbeke, Jolien M, additional, Luckett, Emma S, additional, Reinartz, Mariska, additional, Blujdea, Elena R, additional, Cleynen, Isabelle, additional, Dupont, Patrick, additional, Van Laere, Koen, additional, Vanbrabant, Jeroen, additional, Stoops, Erik, additional, Vanmechelen, Eugeen, additional, di Molfetta, Guglielmo, additional, Zetterberg, Henrik, additional, Ashton, Nicholas J, additional, Teunissen, Charlotte E, additional, Poesen, Koen, additional, and Vandenberghe, Rik, additional

Published
2024
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31. Synaptic density changes following electroconvulsive therapy: A longitudinal pilot study with PET-MR 11C-UCB-J imaging in late-life depression

Author

Laroy, Maarten, primary, Vande Casteele, Thomas, additional, Van Cauwenberge, Margot, additional, Koole, Michel, additional, Dupont, Patrick, additional, Sunaert, Stefan, additional, Van den Stock, Jan, additional, Sienaert, Pascal, additional, Van Laere, Koen, additional, Vandenbulcke, Mathieu, additional, Emsell, Louise, additional, and Bouckaert, Filip, additional

Published
2024
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34. Preliminary evidence for preserved synaptic density in late-life depression

Author

Vande Casteele, Thomas, primary, Laroy, Maarten, additional, Van Cauwenberge, Margot, additional, Koole, Michel, additional, Dupont, Patrick, additional, Sunaert, Stefan, additional, Van den Stock, Jan, additional, Bouckaert, Filip, additional, Van Laere, Koen, additional, Emsell, Louise, additional, and Vandenbulcke, Mathieu, additional

Published
2024
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38. Presynaptic density determined by SV2A PET is closely associated with postsynaptic metabotropic glutamate receptor 5 availability and independent of amyloid pathology in early cognitive impairment

Author

Wang, Jie, Huang, Qi, He, Kun, Li, Junpeng, Guo, Tengfei, Yang, Yang, Lin, Zengping, Li, Songye, Vanderlinden, Greet, Huang, Yiyun, Van Laere, Koen, Guan, Yihui, Guo, Qihao, Ni, Ruiqing; https://orcid.org/0000-0002-0793-2113, Li, Binying, Xie, Fang, Wang, Jie, Huang, Qi, He, Kun, Li, Junpeng, Guo, Tengfei, Yang, Yang, Lin, Zengping, Li, Songye, Vanderlinden, Greet, Huang, Yiyun, Van Laere, Koen, Guan, Yihui, Guo, Qihao, Ni, Ruiqing; https://orcid.org/0000-0002-0793-2113, Li, Binying, and Xie, Fang

Abstract

INTRODUCTION: Metabotropic glutamate receptor 5 (mGluR5) is involved in regulating integrative brain function and synaptic transmission. Aberrant mGluR5 signaling and relevant synaptic failure play a key role in the pathophysiological mechanism of Alzheimer's disease (AD). METHODS: Ten cognitively impaired (CI) individuals and 10 healthy controls (HCs) underwent 18FSynVesT-1 and 18FPSS232 positron emission tomography (PET)/magnetic resonance to assess synaptic density and mGluR5 availability. The associations between mGluR5 availability and synaptic density were examined. A mediation analysis was performed to investigate the possible mediating effects of mGluR5 availability and synaptic loss on the relationship between amyloid deposition and cognition. RESULTS: CI patients exhibited lower mGluR5 availability and synaptic density in the medial temporal lobe than HCs. Regional synaptic density was closely associated with regional mGluR5 availability. mGluR5 availability and synaptic loss partially mediated the relationship between amyloid deposition and cognition. CONCLUSIONS: Reductions in mGluR5 availability and synaptic density exhibit similar spatial patterns in AD and are closely linked. Highlights - Cognitively impaired patients exhibited lower mGluR5 availability and synaptic density in the medial temporal lobe than HCs. - Reductions in mGluR5 availability and synaptic density exhibit similar spatial patterns in AD. - Regional synaptic density was closely associated with regional mGluR5 availability. - mGluR5 availability and synaptic loss partially mediated the relationship between amyloid deposition and global cognition. - With further research, modulating mGluR5 availability might be a potential therapeutic strategy for improving synaptic function in AD.

Published
2024

41. A single-dose live-attenuated YF17D-vectored SARS-CoV-2 vaccine candidate

Author

Sanchez-Felipe, Lorena, Vercruysse, Thomas, Sharma, Sapna, Ma, Ji, Lemmens, Viktor, Van Looveren, Dominique, Arkalagud Javarappa, Mahadesh Prasad, Boudewijns, Robbert, Malengier-Devlies, Bert, Liesenborghs, Laurens, Kaptein, Suzanne J. F., De Keyzer, Carolien, Bervoets, Lindsey, Debaveye, Sarah, Rasulova, Madina, Seldeslachts, Laura, Li, Li-Hsin, Jansen, Sander, Yakass, Michael Bright, Verstrepen, Babs E., Böszörményi, Kinga P., Kiemenyi-Kayere, Gwendoline, van Driel, Nikki, Quaye, Osbourne, Zhang, Xin, ter Horst, Sebastiaan, Mishra, Niraj, Deboutte, Ward, Matthijnssens, Jelle, Coelmont, Lotte, Vandermeulen, Corinne, Heylen, Elisabeth, Vergote, Valentijn, Schols, Dominique, Wang, Zhongde, Bogers, Willy, Kuiken, Thijs, Verschoor, Ernst, Cawthorne, Christopher, Van Laere, Koen, Opdenakker, Ghislain, Vande Velde, Greetje, Weynand, Birgit, Teuwen, Dirk E., Matthys, Patrick, Neyts, Johan, Jan Thibaut, Hendrik, and Dallmeier, Kai

Published
2021
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