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Ruwanpathirana GP, Williams RC, Masters CL, Rowe CC, Johnston LA, Davey CE. Impact of PET Reconstruction on Amyloid-β Quantitation in Cross-Sectional and Longitudinal Analyses. J Nucl Med 2024; 65:781-787. [PMID: 38575189 PMCID: PMC11064829 DOI: 10.2967/jnumed.123.266188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 02/13/2024] [Indexed: 04/06/2024] Open
Abstract
Amyloid-β (Aβ) accumulation in Alzheimer disease (AD) is typically measured using SUV ratio and the centiloid (CL) scale. The low spatial resolution of PET images is known to degrade quantitative metrics because of the partial-volume effect. This article examines the impact of spatial resolution, as determined by the reconstruction configuration, on the Aβ PET quantitation in both cross-sectional and longitudinal data. Methods: The cross-sectional study involved 89 subjects with 20-min [18F]florbetapir scans generated on an mCT (44 Aβ-negative [Aβ-], 45 Aβ-positive [Aβ+]) using 69 reconstruction configurations, which varied in number of iteration updates, point-spread function, time-of-flight, and postreconstruction smoothing. The subjects were classified as Aβ- or Aβ+ visually. For each reconstruction, Aβ CL was calculated using CapAIBL, and the spatial resolution was calculated as full width at half maximum (FWHM) using the barrel phantom method. The change in CLs and the effect size of the difference in CLs between Aβ- and Aβ+ groups with FWHM were examined. The longitudinal study involved 79 subjects (46 Aβ-, 33 Aβ+) with three 20-min [18F]flutemetamol scans generated on an mCT. The subjects were classified as Aβ- or Aβ+ using a cutoff CL of 20. All scans were reconstructed using low-, medium-, and high-resolution configurations, and Aβ CLs were calculated using CapAIBL. Since linear Aβ accumulation was assumed over a 10-y interval, for each reconstruction configuration, Aβ accumulation rate differences (ARDs) between the second and first periods were calculated for all subjects. Zero ARD was used as a consistency metric. The number of Aβ accumulators was also used to compare the sensitivity of CL across reconstruction configurations. Results: In the cross-sectional study, CLs in both the Aβ- and the Aβ+ groups were impacted by the FWHM of the reconstruction method. Without postreconstruction smoothing, Aβ- CLs increased for a FWHM of 4.5 mm or more, whereas Aβ+ CLs decreased across the FWHM range. High-resolution reconstructions provided the best statistical separation between groups. In the longitudinal study, the median ARD of low-resolution reconstructed data for the Aβ- group was greater than zero whereas the ARDs of higher-resolution reconstructions were not significantly different from zero, indicating more consistent rate estimates in the higher-resolution reconstructions. Higher-resolution reconstructions identified 10 additional Aβ accumulators in the Aβ- group, resulting in a 22% increased group size compared with the low-resolution reconstructions. Higher-resolution reconstructions reduced the average CLs of the negative group by 12 points. Conclusion: High-resolution PET reconstructions, inherently less impacted by partial-volume effect, may improve Aβ PET quantitation in both cross-sectional and longitudinal data. In the cross-sectional analysis, separation of CLs between Aβ- and Aβ+ cohorts increased with spatial resolution. Higher-resolution reconstructions also exhibited both improved consistency and improved sensitivity in measures of Aβ accumulation. These features suggest that higher-resolution reconstructions may be advantageous in early-stage AD therapies.
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Affiliation(s)
- Gihan P Ruwanpathirana
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria, Australia
- Melbourne Brain Centre Imaging Unit, University of Melbourne, Melbourne, Victoria, Australia
| | - Robert C Williams
- Melbourne Brain Centre Imaging Unit, University of Melbourne, Melbourne, Victoria, Australia
| | - Colin L Masters
- Florey Institute of Neurosciences and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
- Australian Dementia Network, Melbourne, Victoria, Australia; and
| | - Christopher C Rowe
- Florey Institute of Neurosciences and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
- Australian Dementia Network, Melbourne, Victoria, Australia; and
- Department of Molecular Imaging and Therapy, Austin Health, Melbourne, Victoria, Australia
| | - Leigh A Johnston
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria, Australia
- Melbourne Brain Centre Imaging Unit, University of Melbourne, Melbourne, Victoria, Australia
| | - Catherine E Davey
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria, Australia;
- Melbourne Brain Centre Imaging Unit, University of Melbourne, Melbourne, Victoria, Australia
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2
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Taha A, Alassi A, Gjedde A, Wong DF. Transforming Neurology and Psychiatry: Organ-specific PET Instrumentation and Clinical Applications. PET Clin 2024; 19:95-103. [PMID: 37813719 DOI: 10.1016/j.cpet.2023.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
PET technology has immense potential for furthering understanding of the brain and associated disorders, including advancements in high-resolution tomographs and hybrid imaging modalities. Novel radiotracers targeting specific neurotransmitter systems and molecular markers provide opportunities to unveil intricate mechanisms underlying neurologic and psychiatric conditions. As PET imaging techniques and analysis methods continue to be refined, the field is poised to make significant contributions to personalized medicine for more targeted and effective interventions. PET instrumentation has advanced the fields of neurology and psychiatry, providing insights into pathophysiology and development of effective treatments.
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Affiliation(s)
- Ahmed Taha
- Mallinckrodt Institute of Radiology, Washington University in St Louis, Saint Louis, MO, USA
| | - Amer Alassi
- Mallinckrodt Institute of Radiology, Washington University in St Louis, Saint Louis, MO, USA
| | - Albert Gjedde
- Department of Clinical Medicine, Translational Neuropsychiatry Unit, Aarhus University, Denmark; Department of Neuroscience, University of Copenhagen, Denmark
| | - Dean F Wong
- Mallinckrodt Institute of Radiology, Departments of Radiology, Psychiatry, Neurology, Neuroscience, Washington University in St Louis, Saint Louis, MO, USA.
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3
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Ishii K, Hanaoka K, Watanabe S, Morimoto-Ishikawa D, Yamada T, Kaida H, Yamakawa Y, Minagawa S, Takenouchi S, Ohtani A, Mizuta T. High-Resolution Silicon Photomultiplier Time-of-Flight Dedicated Head PET System for Clinical Brain Studies. J Nucl Med 2023; 64:153-158. [PMID: 35798557 PMCID: PMC9841263 DOI: 10.2967/jnumed.122.264080] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 06/29/2022] [Accepted: 06/29/2022] [Indexed: 01/28/2023] Open
Abstract
We acquired brain 18F-FDG and 18F-flutemetamol PET images using a time-of-flight system dedicated to the head (dhPET) and a conventional whole-body PET/CT (wbPET) system and evaluated the clinical superiority of dhPET over wbPET. Methods: There were 18 subjects for the 18F-FDG PET study and 17 subjects for the 18F-flutemetamol PET study. 18F-FDG PET images were first obtained using wbPET, followed by dhPET. 18F-flutemetamol PET images were first obtained using wbPET, followed by dhPET. Images acquired using dhPET and wbPET were compared by visual inspection, voxelwise analysis, and SUV ratio (SUVR). Results: All 18F-FDG and 18F-flutemetamol images acquired using dhPET were judged as visually better than those acquired using wbPET. The voxelwise analysis demonstrated that accumulations in the cerebellum, in the lateral occipital cortices, and around the central sulcus area in dhPET 18F-FDG images were lower than those in wbPET 18F-FDG images, whereas accumulations around the ventricle systems were higher in dhPET 18F-FDG images than those in wbPET 18F-FDG images. Accumulations in the cerebellar dentate nucleus, in the midbrain, in the lateral occipital cortices, and around the central sulcus area in dhPET images were lower than those in wbPET images, whereas accumulations around the ventricle systems were higher in dhPET 18F-flutemetamol images than those in wbPET 18F-flutemetamol images. The mean cortical SUVRs of 18F-FDG and 18F-flutemetamol dhPET images were significantly higher than those of 18F-FDG and 18F-flutemetamol wbPET images, respectively. Conclusion: The dhPET images had better image quality by visual inspection and higher SUVRs than wbPET images. Although there were several regional accumulation differences between dhPET and wbPET images, understanding this phenomenon will enable full use of the features of this dhPET system in clinical practice.
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Affiliation(s)
- Kazunari Ishii
- Department of Radiology, Kindai University Faculty of Medicine, Osakasayama, Japan; .,Division of Positron Emission Tomography, Institute of Advanced Clinical Medicine, Kindai University Hospital, Osakasayama, Japan; and
| | - Kohei Hanaoka
- Division of Positron Emission Tomography, Institute of Advanced Clinical Medicine, Kindai University Hospital, Osakasayama, Japan; and
| | - Shota Watanabe
- Division of Positron Emission Tomography, Institute of Advanced Clinical Medicine, Kindai University Hospital, Osakasayama, Japan; and
| | - Daisuke Morimoto-Ishikawa
- Division of Positron Emission Tomography, Institute of Advanced Clinical Medicine, Kindai University Hospital, Osakasayama, Japan; and
| | - Takahiro Yamada
- Division of Positron Emission Tomography, Institute of Advanced Clinical Medicine, Kindai University Hospital, Osakasayama, Japan; and
| | - Hayato Kaida
- Department of Radiology, Kindai University Faculty of Medicine, Osakasayama, Japan;,Division of Positron Emission Tomography, Institute of Advanced Clinical Medicine, Kindai University Hospital, Osakasayama, Japan; and
| | | | - Suzuka Minagawa
- Medical Systems Division, Shimadzu Corporation, Kyoto, Japan
| | | | - Atsushi Ohtani
- Medical Systems Division, Shimadzu Corporation, Kyoto, Japan
| | - Tetsuro Mizuta
- Medical Systems Division, Shimadzu Corporation, Kyoto, Japan
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4
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Hoye J, Toyonaga T, Zakiniaeiz Y, Stanley G, Hampson M, Morris ED. Harmonization of [ 11C]raclopride brain PET images from the HR+ and HRRT: method development and validation in human subjects. EJNMMI Phys 2022; 9:27. [PMID: 35416555 PMCID: PMC9008103 DOI: 10.1186/s40658-022-00457-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 04/04/2022] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND There has been an ongoing need to compare and combine the results of new PET imaging studies conducted with [11C]raclopride with older data. This typically means harmonizing data across different scanners. Previous harmonization studies have utilized either phantoms or human subjects, but the use of both phantoms and humans in one harmonization study is not common. The purpose herein was (1) to use phantom images to develop an inter-scanner harmonization technique and (2) to test the harmonization technique in human subjects. METHODS To develop the harmonization technique (Experiment 1), the Iida brain phantom was filled with F-18 solution and scanned on the two scanners in question (HRRT, HR+, Siemens/CTI). Phantom images were used to determine the optimal isotropic Gaussian filter to harmonize HRRT and HR+ images. To evaluate the harmonization on human images (Experiment 2), inter-scanner variability was calculated using [11C]raclopride scans of 3 human subjects on both the HRRT and HR+ using percent difference (PD) in striatal non-displaceable binding potential (BPND) between HR+ and HRRT (with and without Gaussian smoothing). Finally, (Experiment 3), PDT/RT was calculated for test-retest (T/RT) variability of striatal BPND for 8 human subjects scanned twice on the HR+. RESULTS Experiment 1 identified the optimal filter as a Gaussian with a 4.5 mm FWHM. Experiment 2 resulted in 13.9% PD for unfiltered HRRT and 3.71% for HRRT filtered with 4.5 mm. Experiment 3 yielded 5.24% PDT/RT for HR+. CONCLUSIONS The PD results show that the variability of harmonized HRRT is less than the T/RT variability of the HR+. The harmonization technique makes it possible for BPND estimates from the HRRT to be compared to (and/or combined with) those from the HR+ without adding to overall variability. Our approach is applicable to all pairs of scanners still in service.
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Affiliation(s)
- Jocelyn Hoye
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA. .,Yale Positron Emission Tomography (PET) Center, Yale School of Medicine, New Haven, CT, USA.
| | - Takuya Toyonaga
- grid.47100.320000000419368710Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT USA ,grid.47100.320000000419368710Yale Positron Emission Tomography (PET) Center, Yale School of Medicine, New Haven, CT USA
| | - Yasmin Zakiniaeiz
- grid.47100.320000000419368710Department of Psychiatry, Yale School of Medicine, New Haven, CT USA ,grid.47100.320000000419368710Yale Positron Emission Tomography (PET) Center, Yale School of Medicine, New Haven, CT USA
| | - Gelsina Stanley
- grid.47100.320000000419368710Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT USA ,grid.47100.320000000419368710Yale Positron Emission Tomography (PET) Center, Yale School of Medicine, New Haven, CT USA
| | - Michelle Hampson
- grid.47100.320000000419368710Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT USA ,grid.47100.320000000419368710Department of Biomedical Engineering, Yale University, New Haven, CT USA
| | - Evan D. Morris
- grid.47100.320000000419368710Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT USA ,grid.47100.320000000419368710Yale Positron Emission Tomography (PET) Center, Yale School of Medicine, New Haven, CT USA ,grid.47100.320000000419368710Department of Biomedical Engineering, Yale University, New Haven, CT USA
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5
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Veldman ER, Varrone A, Varnäs K, Svedberg MM, Cselényi Z, Tiger M, Gulyás B, Halldin C, Lundberg J. Serotonin 1B receptor density mapping of the human brainstem using positron emission tomography and autoradiography. J Cereb Blood Flow Metab 2022; 42:630-641. [PMID: 34644198 PMCID: PMC8943614 DOI: 10.1177/0271678x211049185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The serotonin 1B (5-HT1B) receptor has lately received considerable interest in relation to psychiatric and neurological diseases, partly due to findings based on quantification using Positron Emission Tomography (PET). Although the brainstem is an important structure in this regard, PET radioligand binding quantification in brainstem areas often shows poor reliability. This study aims to improve PET quantification of 5-HT1B receptor binding in the brainstem.Volumes of interest (VOIs) were selected based on a 3D [3H]AZ10419369 Autoradiography brainstem model, which visualized 5-HT1B receptor distribution in high resolution. Two previously developed VOI delineation methods were tested and compared to a conventional manual method. For a method based on template data, a [11C]AZ10419369 PET template was created by averaging parametric binding potential (BPND) images of 52 healthy subjects. VOIs were generated based on a predefined volume and BPND thresholding and subsequently applied to test-retest [11C]AZ10419369 parametric BPND images of 8 healthy subjects. For a method based on individual subject data, VOIs were generated directly on each individual parametric image.Both methods showed improved reliability compared to a conventional manual VOI. The VOIs created with [11C]AZ10419369 template data can be automatically applied to future PET studies measuring 5-HT1B receptor binding in the brainstem.
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Affiliation(s)
- Emma R Veldman
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Andrea Varrone
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Katarina Varnäs
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Marie M Svedberg
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden.,Department of Health Promotion Science, Sophiahemmet University, Stockholm, Sweden
| | - Zsolt Cselényi
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden.,PET Science Centre, Personalized Medicine and Biosamples, R&D, AstraZeneca, Stockholm, Sweden
| | - Mikael Tiger
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Balázs Gulyás
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Christer Halldin
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
| | - Johan Lundberg
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm, Sweden
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6
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Abstract
Abstract
In this partial review and partial attempt at vision of what may be the future of dedicated brain PET scanners, the key implementations of the PET technique, we postulate that we are still on a development path and there is still a lot to be done in order to develop optimal brain imagers. Optimized for particular imaging tasks and protocols, and also mobile, that can be used outside the PET center, in addition to the expected improvements in sensitivity and resolution. For this multi-application concept to be more practical, flexible, adaptable designs are preferred. This task is greatly facilitated by the improved TOF performance that allows for more open, adjustable, limited angular coverage geometries without creating image artifacts. As achieving uniform very high resolution in the whole body is not practical due to technological limits and high costs, hybrid systems using a moderate-resolution total body scanner (such as J-PET) combined with a very high performing brain imager could be a very attractive approach. As well, as using magnification inserts in the total body or long-axial length imagers to visualize selected targets with higher resolution. In addition, multigamma imagers combining PET with Compton imaging should be developed to enable multitracer imaging.
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7
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Shokri-Kojori E, Naganawa M, Ramchandani VA, Wong DF, Wang GJ, Volkow ND. Brain opioid segments and striatal patterns of dopamine release induced by naloxone and morphine. Hum Brain Mapp 2021; 43:1419-1430. [PMID: 34873784 PMCID: PMC8837588 DOI: 10.1002/hbm.25733] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/10/2021] [Accepted: 11/19/2021] [Indexed: 11/25/2022] Open
Abstract
Opioid receptors are expressed throughout the brain and play a major role in regulating striatal dopamine (DA) release. Clinical studies have shown that naloxone (NAL, a nonspecific opioid antagonist) in individuals with opioid use disorder and morphine (MRP, a nonspecific opioid agonist) in healthy controls, resulted in DA release in the dorsal and ventral striatum, respectively. It is not known whether the underlying patterns of striatal DA release are associated with the striatal distribution of opioid receptors. We leveraged previously published PET datasets (collected in independent cohorts) to study the brain‐wide distribution of opioid receptors and to compare striatal opioid receptor availability with striatal DA release patterns. We identified three major gray matter segments based on availability maps of DA and opioid receptors: striatum, and primary and secondary opioid segments with high and intermediate opioid receptor availability, respectively. Patterns of DA release induced by NAL and MRP were inversely associated and correlated with kappa (NAL: r(68) = −0.81, MRP: r(68) = 0.54), and mu (NAL: r(68) = −0.62, MRP: r(68) = 0.46) opioid receptor availability. Kappa opioid receptor availability accounted for a unique part of variance in NAL‐ and MRP‐DA release patterns (ΔR2 >0.14, p <.0001). In sum, distributions of opioid receptors distinguished major cortical and subcortical regions. Patterns of NAL‐ and MRP‐induced DA release had inverse associations with striatal opioid receptor availability. Our approach provides a pattern‐based characterization of drug‐induced DA targets and is relevant for modeling the role of opioid receptors in modulating striatal DA release.
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Affiliation(s)
- Ehsan Shokri-Kojori
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA
| | - Mika Naganawa
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Vijay A Ramchandani
- Human Psychopharmacology Laboratory, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA
| | - Dean F Wong
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - Gene-Jack Wang
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA
| | - Nora D Volkow
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA
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8
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Verwer EE, Golla SSV, Kaalep A, Lubberink M, van Velden FHP, Bettinardi V, Yaqub M, Sera T, Rijnsdorp S, Lammertsma AA, Boellaard R. Harmonisation of PET/CT contrast recovery performance for brain studies. Eur J Nucl Med Mol Imaging 2021; 48:2856-2870. [PMID: 33517517 PMCID: PMC8263427 DOI: 10.1007/s00259-021-05201-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 01/10/2021] [Indexed: 12/24/2022]
Abstract
PURPOSE In order to achieve comparability of image quality, harmonisation of PET system performance is imperative. In this study, prototype harmonisation criteria for PET brain studies were developed. METHODS Twelve clinical PET/CT systems (4 GE, 4 Philips, 4 Siemens, including SiPM-based "digital" systems) were used to acquire 30-min PET scans of a Hoffman 3D Brain phantom filled with ~ 33 kBq·mL-1 [18F]FDG. Scan data were reconstructed using various reconstruction settings. The images were rigidly coregistered to a template (voxel size 1.17 × 1.17 × 2.00 mm3) onto which several volumes of interest (VOIs) were defined. Recovery coefficients (RC) and grey matter to white matter ratios (GMWMr) were derived for eroded (denoted in the text by subscript e) and non-eroded grey (GM) and white (WM) matter VOIs as well as a mid-phantom cold spot (VOIcold) and VOIs from the Hammers atlas. In addition, left-right hemisphere differences and voxel-by-voxel differences compared to a reference image were assessed. RESULTS Systematic differences were observed for reconstructions with and without point-spread-function modelling (PSFON and PSFOFF, respectively). Normalising to image-derived activity, upper and lower limits ensuring image comparability were as follows: for PSFON, RCGMe = [0.97-1.01] and GMWMre = [3.51-3.91] for eroded VOI and RCGM = [0.78-0.83] and GMWMr = [1.77-2.06] for non-eroded VOI, and for PSFOFF, RCGMe = [0.92-0.99] and GMWMre = [3.14-3.68] for eroded VOI and RCGM = [0.75-0.81] and GMWMr = [1.72-1.95] for non-eroded VOI. CONCLUSIONS To achieve inter-scanner comparability, we propose selecting reconstruction settings based on RCGMe and GMWMre as specified in "Results". These proposed standards should be tested prospectively to validate and/or refine the harmonisation criteria.
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Affiliation(s)
- E E Verwer
- Department of Radiology & Nuclear Medicine, Amsterdam University Medical Centers, location VUmc, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
| | - S S V Golla
- Department of Radiology & Nuclear Medicine, Amsterdam University Medical Centers, location VUmc, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - A Kaalep
- Department of Medical Technology, North Estonia Medical Centre Foundation, Tallinn, Estonia.,EANM Research Limited (EARL), Vienna, Austria
| | - M Lubberink
- Department of Surgical Sciences / Nuclear Medicine & PET, Uppsala University, Uppsala, Sweden
| | - F H P van Velden
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - V Bettinardi
- IRCCS Scientific Institute San Raffaele Hospital, Milan, Italy
| | - M Yaqub
- Department of Radiology & Nuclear Medicine, Amsterdam University Medical Centers, location VUmc, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - T Sera
- EANM Research Limited (EARL), Vienna, Austria.,Department of Nuclear Medicine, University of Szeged, Szeged, Hungary
| | - S Rijnsdorp
- Department of Medical Physics, Catharina Hospital Eindhoven, Eindhoven, The Netherlands
| | - A A Lammertsma
- Department of Radiology & Nuclear Medicine, Amsterdam University Medical Centers, location VUmc, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - R Boellaard
- Department of Radiology & Nuclear Medicine, Amsterdam University Medical Centers, location VUmc, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
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9
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Song TA, Chowdhury SR, Yang F, Dutta J. PET image super-resolution using generative adversarial networks. Neural Netw 2020; 125:83-91. [PMID: 32078963 DOI: 10.1016/j.neunet.2020.01.029] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 01/22/2020] [Accepted: 01/23/2020] [Indexed: 12/25/2022]
Abstract
The intrinsically low spatial resolution of positron emission tomography (PET) leads to image quality degradation and inaccurate image-based quantitation. Recently developed supervised super-resolution (SR) approaches are of great relevance to PET but require paired low- and high-resolution images for training, which are usually unavailable for clinical datasets. In this paper, we present a self-supervised SR (SSSR) technique for PET based on dual generative adversarial networks (GANs), which precludes the need for paired training data, ensuring wider applicability and adoptability. The SSSR network receives as inputs a low-resolution PET image, a high-resolution anatomical magnetic resonance (MR) image, spatial information (axial and radial coordinates), and a high-dimensional feature set extracted from an auxiliary CNN which is separately-trained in a supervised manner using paired simulation datasets. The network is trained using a loss function which includes two adversarial loss terms, a cycle consistency term, and a total variation penalty on the SR image. We validate the SSSR technique using a clinical neuroimaging dataset. We demonstrate that SSSR is promising in terms of image quality, peak signal-to-noise ratio, structural similarity index, contrast-to-noise ratio, and an additional no-reference metric developed specifically for SR image quality assessment. Comparisons with other SSSR variants suggest that its high performance is largely attributable to simulation guidance.
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Affiliation(s)
- Tzu-An Song
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, United States of America
| | - Samadrita Roy Chowdhury
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, United States of America
| | - Fan Yang
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, United States of America
| | - Joyita Dutta
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, United States of America; Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States of America; Geriatric Research, Education and Clinical Center, Edith Nourse Rogers Memorial Veterans Hospital, Bedford, MA, United States of America.
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10
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Song TA, Chowdhury SR, Yang F, Dutta J. Super-Resolution PET Imaging Using Convolutional Neural Networks. IEEE TRANSACTIONS ON COMPUTATIONAL IMAGING 2020; 6:518-528. [PMID: 32055649 PMCID: PMC7017584 DOI: 10.1109/tci.2020.2964229] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Positron emission tomography (PET) suffers from severe resolution limitations which reduce its quantitative accuracy. In this paper, we present a super-resolution (SR) imaging technique for PET based on convolutional neural networks (CNNs). To facilitate the resolution recovery process, we incorporate high-resolution (HR) anatomical information based on magnetic resonance (MR) imaging. We introduce the spatial location information of the input image patches as additional CNN inputs to accommodate the spatially-variant nature of the blur kernels in PET. We compared the performance of shallow (3-layer) and very deep (20-layer) CNNs with various combinations of the following inputs: low-resolution (LR) PET, radial locations, axial locations, and HR MR. To validate the CNN architectures, we performed both realistic simulation studies using the BrainWeb digital phantom and clinical studies using neuroimaging datasets. For both simulation and clinical studies, the LR PET images were based on the Siemens HR+ scanner. Two different scenarios were examined in simulation: one where the target HR image is the ground-truth phantom image and another where the target HR image is based on the Siemens HRRT scanner - a high-resolution dedicated brain PET scanner. The latter scenario was also examined using clinical neuroimaging datasets. A number of factors affected relative performance of the different CNN designs examined, including network depth, target image quality, and the resemblance between the target and anatomical images. In general, however, all deep CNNs outperformed classical penalized deconvolution and partial volume correction techniques by large margins both qualitatively (e.g., edge and contrast recovery) and quantitatively (as indicated by three metrics: peak signal-to-noise-ratio, structural similarity index, and contrast-to-noise ratio).
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Affiliation(s)
- Tzu-An Song
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, 01854 USA and co-affiliated with Massachusetts General Hospital, Boston, MA, 02114
| | - Samadrita Roy Chowdhury
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, 01854 USA and co-affiliated with Massachusetts General Hospital, Boston, MA, 02114
| | - Fan Yang
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, 01854 USA and co-affiliated with Massachusetts General Hospital, Boston, MA, 02114
| | - Joyita Dutta
- Department of Electrical and Computer Engineering, University of Massachusetts Lowell, Lowell, MA, 01854 USA and co-affiliated with Massachusetts General Hospital, Boston, MA, 02114
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11
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Anton-Rodriguez JM, Julyan P, Djoukhadar I, Russell D, Evans DG, Jackson A, Matthews JC. Comparison of a Standard Resolution PET-CT Scanner With an HRRT Brain Scanner for Imaging Small Tumors Within the Head. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2019. [DOI: 10.1109/trpms.2019.2914909] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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Boyle J, Patronas NJ, Smirniotopoulos J, Herscovitch P, Dieckman W, Millo C, Maric D, Chatain GP, Hayes CP, Benzo S, Scott G, Edwards N, Ray Chaudhury A, Lodish MB, Sharma S, Nieman LK, Stratakis CA, Lonser RR, Chittiboina P. CRH stimulation improves 18F-FDG-PET detection of pituitary adenomas in Cushing's disease. Endocrine 2019; 65:155-165. [PMID: 31062234 DOI: 10.1007/s12020-019-01944-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 04/24/2019] [Indexed: 01/04/2023]
Abstract
OBJECTIVE In MRI-negative cases Cushing's disease (CD), surgeons perform a more extensive exploration of the pituitary gland, with fewer instances of hormonal remission. 18F-fluoro-deoxy-glucose (18F-FDG) positron emission tomography (PET) has a limited role in detecting adenomas that cause CD (corticotropinomas). Our previous work demonstrated corticotropin-releasing hormone (CRH) stimulation leads to delayed, selective glucose uptake in corticotropinomas. Here, we prospectively evaluated the utility of CRH stimulation in improving 18F-FDG-PET detection of adenomas in CD. METHODS Subjects with a likely diagnosis of CD (n = 27, 20 females) each underwent two 18F-FDG-PET studies [without and with ovine-CRH (oCRH) stimulation] on a high-resolution PET platform. Standardized-uptake-values (SUV) in the sella were calculated. Two blinded neuroradiologists independently read 18F-FDG-PET images qualitatively. Adenomas were histopathologically confirmed, analyzed for mutations in the USP8 gene and for glycolytic pathway proteins. RESULTS The mean-SUV of adenomas was significantly increased from baseline (3.6 ± 1.5) with oCRH administration (3.9 ± 1.7; one-tailed p = 0.003). Neuroradiologists agreed that adenomas were visible on 21 scans, not visible on 26 scans (disagreed about 7, kappa = 0.7). oCRH-stimulation led to the detection of additional adenomas (n = 6) not visible on baseline-PET study. Of the MRI-negative adenomas (n = 5), two were detected on PET imaging (one only after oCRH-stimulation). USP8 mutations or glycolytic pathway proteins were not associated with SUV in corticotropinomas. CONCLUSIONS The results of the current study suggest that oCRH-stimulation may lead to increased 18F-FDG uptake, and increased rate of detection of corticotropinomas in CD. These results also suggest that some MRI invisible adenomas may be detectable by oCRH-stimulated FDG-PET imaging. CLINICAL TRIAL INFORMATION 18F-FDG-PET imaging with and without CRH stimulation was performed under the clinical trial NIH ID 12-N-0007 (clinicaltrials.gov identifier NCT01459237). The transsphenoidal surgeries and post-operative care was performed under the clinical trial NIH ID 03-N-0164 (clinicaltrials.gov identifier NCT00060541).
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Affiliation(s)
- Jacqueline Boyle
- Neurosurgery Unit for Pituitary and Inheritable Diseases, National Institute of Neurological Diseases and Stroke, Bethesda, MD, USA
- University of Illinois College of Medicine at Peoria, Peoria, IL, USA
| | - Nicholas J Patronas
- Diagnostic Radiology, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | | | - Peter Herscovitch
- Department of Positron Emission Tomography, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - William Dieckman
- Department of Positron Emission Tomography, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Corina Millo
- Department of Positron Emission Tomography, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Dragan Maric
- Flow Cytometry Core Facility, National Institute of Neurologic Diseases and Stroke, Bethesda, MD, USA
| | - Grégoire P Chatain
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | | | - Sarah Benzo
- Department of Neurosurgery, University of Colorado, Denver, CO, USA
| | - Gretchen Scott
- Department of Neurosurgery, University of Colorado, Denver, CO, USA
| | - Nancy Edwards
- Department of Neurosurgery, University of Colorado, Denver, CO, USA
| | | | - Maya B Lodish
- Section on Endocrinology and Genetics, Pediatric Endocrinology Inter-Institute Training Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Susmeeta Sharma
- Pituitary Endocrinology Section, MedStar Washington Hospital Center, Washington, DC, USA
| | - Lynnette K Nieman
- Diabetes, Endocrinology and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Constantine A Stratakis
- Section on Endocrinology and Genetics, Pediatric Endocrinology Inter-Institute Training Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Russell R Lonser
- Department of Neurological Surgery, The Ohio State University, Columbus, OH, USA
| | - Prashant Chittiboina
- Neurosurgery Unit for Pituitary and Inheritable Diseases, National Institute of Neurological Diseases and Stroke, Bethesda, MD, USA.
- Department of Neurosurgery, University of Colorado, Denver, CO, USA.
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13
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Cho SS, Christopher L, Koshimori Y, Li C, Lang AE, Houle S, Strafella AP. Decreased pallidal vesicular monoamine transporter type 2 availability in Parkinson's disease: The contribution of the nigropallidal pathway. Neurobiol Dis 2019; 124:176-182. [DOI: 10.1016/j.nbd.2018.11.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 11/01/2018] [Accepted: 11/20/2018] [Indexed: 11/16/2022] Open
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14
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Nørgaard M, Ganz M, Svarer C, Feng L, Ichise M, Lanzenberger R, Lubberink M, Parsey RV, Politis M, Rabiner EA, Slifstein M, Sossi V, Suhara T, Talbot PS, Turkheimer F, Strother SC, Knudsen GM. Cerebral serotonin transporter measurements with [ 11C]DASB: A review on acquisition and preprocessing across 21 PET centres. J Cereb Blood Flow Metab 2019; 39:210-222. [PMID: 29651896 PMCID: PMC6365604 DOI: 10.1177/0271678x18770107] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Positron Emission Tomography (PET) imaging has become a prominent tool to capture the spatiotemporal distribution of neurotransmitters and receptors in the brain. The outcome of a PET study can, however, potentially be obscured by suboptimal and/or inconsistent choices made in complex processing pipelines required to reach a quantitative estimate of radioligand binding. Variations in subject selection, experimental design, data acquisition, preprocessing, and statistical analysis may lead to different outcomes and neurobiological interpretations. We here review the approaches used in 105 original research articles published by 21 different PET centres, using the tracer [11C]DASB for quantification of cerebral serotonin transporter binding, as an exemplary case. We highlight and quantify the impact of the remarkable variety of ways in which researchers are currently conducting their studies, while implicitly expecting generalizable results across research groups. Our review provides evidence that the foundation for a given choice of a preprocessing pipeline seems to be an overlooked aspect in modern PET neuroscience. Furthermore, we believe that a thorough testing of pipeline performance is necessary to produce reproducible research outcomes, avoiding biased results and allowing for better understanding of human brain function.
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Affiliation(s)
- Martin Nørgaard
- 1 Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,2 Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Melanie Ganz
- 1 Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,3 Department of Computer Science, University of Copenhagen, Copenhagen, Denmark
| | - Claus Svarer
- 1 Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Ling Feng
- 1 Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Masanori Ichise
- 4 Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Rupert Lanzenberger
- 5 Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Mark Lubberink
- 6 Department of Nuclear Medicine and Positron Emission Tomography, Uppsala University, Uppsala, Sweden
| | - Ramin V Parsey
- 7 Department of Psychiatry, School of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Marios Politis
- 8 Neurodegeneration Imaging Group, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK
| | - Eugenii A Rabiner
- 9 Imanova Limited, London, UK.,10 Centre for Neuroimaging Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Mark Slifstein
- 7 Department of Psychiatry, School of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Vesna Sossi
- 11 Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
| | - Tetsuya Suhara
- 4 Department of Functional Brain Imaging Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Peter S Talbot
- 12 Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | | | - Stephen C Strother
- 14 Rotman Research Institute at Baycrest, University of Toronto, Toronto, Canada
| | - Gitte M Knudsen
- 1 Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,2 Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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15
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Joutsa J, Karlsson HK, Majuri J, Nuutila P, Helin S, Kaasinen V, Nummenmaa L. Binge eating disorder and morbid obesity are associated with lowered mu-opioid receptor availability in the brain. Psychiatry Res Neuroimaging 2018; 276:41-45. [PMID: 29655552 DOI: 10.1016/j.pscychresns.2018.03.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 01/27/2018] [Accepted: 03/02/2018] [Indexed: 01/17/2023]
Abstract
Both morbid obesity and binge eating disorder (BED) have previously been linked with aberrant brain opioid function. Behaviorally these two conditions are however different suggesting also differences in neurotransmitter function. Here we directly compared mu-opioid receptor (MOR) availability between morbidly obese and BED subjects. Seven BED and nineteen morbidly obese (non-BED) patients, and thirty matched control subjects underwent positron emission tomography (PET) with MOR-specific ligand [11C]carfentanil. Both subjects with morbid obesity and BED had widespread reduction in [11C]carfentanil binding compared to control subjects. However, there was no significant difference in brain MOR binding between subjects with morbid obesity and BED. Thus, our results indicate that there is common brain opioid abnormality in behaviorally different eating disorders involving obesity.
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Affiliation(s)
- Juho Joutsa
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Boston, MA, USA; Department of Neurology, University of Turku, Turku, Finland; Turku PET Centre, University of Turku, Turku, Finland; Division of Clinical Neurosciences, Turku University Hospital, Turku, Finland.
| | | | - Joonas Majuri
- Department of Neurology, University of Turku, Turku, Finland; Turku PET Centre, University of Turku, Turku, Finland
| | - Pirjo Nuutila
- Turku PET Centre, University of Turku, Turku, Finland; Department of Endocrinology, Turku University Hospital, Turku, Finland
| | - Semi Helin
- Turku PET Centre, University of Turku, Turku, Finland
| | - Valtteri Kaasinen
- Department of Neurology, University of Turku, Turku, Finland; Turku PET Centre, University of Turku, Turku, Finland; Division of Clinical Neurosciences, Turku University Hospital, Turku, Finland
| | - Lauri Nummenmaa
- Turku PET Centre, University of Turku, Turku, Finland; Department of Psychology, University of Turku, Turku, Finland
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16
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DuBois JM, Rousset OG, Guiot MC, Hall JA, Reader AJ, Soucy JP, Rosa-Neto P, Kobayashi E. Metabotropic Glutamate Receptor Type 5 (mGluR5) Cortical Abnormalities in Focal Cortical Dysplasia Identified In Vivo With [11C]ABP688 Positron-Emission Tomography (PET) Imaging. Cereb Cortex 2018; 26:4170-4179. [PMID: 27578494 PMCID: PMC5066831 DOI: 10.1093/cercor/bhw249] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 07/19/2016] [Indexed: 01/22/2023] Open
Abstract
Metabotropic glutamate receptor type 5 (mGluR5) abnormalities have been described in tissue resected from epilepsy patients with focal cortical dysplasia (FCD). To determine if these abnormalities could be identified in vivo, we investigated mGluR5 availability in 10 patients with focal epilepsy and an MRI diagnosis of FCD using positron-emission tomography (PET) and the radioligand [11C]ABP688. Partial volume corrected [11C]ABP688 binding potentials (BPND) were computed using the cerebellum as a reference region. Each patient was compared to homotopic cortical regions in 33 healthy controls using region-of-interest (ROI) and vertex-wise analyses. Reduced [11C]ABP688 BPND in the FCD was seen in 7/10 patients with combined ROI and vertex-wise analyses. Reduced FCD BPND was found in 4/5 operated patients (mean follow-up: 63 months; Engel I), of whom surgical specimens revealed FCD type IIb or IIa, with most balloon cells showing negative or weak mGluR5 immunoreactivity as compared to their respective neuropil and normal neurons at the border of resections. [11C]ABP688 PET shows for the first time in vivo evidence of reduced mGluR5 availability in FCD, indicating focal glutamatergic alterations in malformations of cortical development, which cannot be otherwise clearly demonstrated through resected tissue analyses.
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Affiliation(s)
- Jonathan M DuBois
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4
| | - Olivier G Rousset
- Division of Nuclear Medicine and Molecular Imaging, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Marie-Christine Guiot
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4.,Department of Pathology, McGill University, Montreal, Quebec, Canada H3A 2B4
| | - Jeffery A Hall
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4
| | - Andrew J Reader
- PET Unit, McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada H3A 2B4.,Division of Imaging Sciences and Biomedical Engineering, King's College London, St. Thomas' Hospital, London SE1 7EH, UK
| | - Jean-Paul Soucy
- PET Unit, McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada H3A 2B4.,Bio-Imaging Group, PERFORM Centre, Concordia University, Montreal, Quebec, Canada H4B 1R6
| | - Pedro Rosa-Neto
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4.,PET Unit, McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada H3A 2B4.,Translational Neuroimaging Laboratory, McGill Center for Studies in Aging, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada H4H 1R3
| | - Eliane Kobayashi
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4
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17
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Lassen ML, Muzik O, Beyer T, Hacker M, Ladefoged CN, Cal-González J, Wadsak W, Rausch I, Langer O, Bauer M. Reproducibility of Quantitative Brain Imaging Using a PET-Only and a Combined PET/MR System. Front Neurosci 2017; 11:396. [PMID: 28769742 PMCID: PMC5511842 DOI: 10.3389/fnins.2017.00396] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/23/2017] [Indexed: 01/02/2023] Open
Abstract
The purpose of this study was to test the feasibility of migrating a quantitative brain imaging protocol from a positron emission tomography (PET)-only system to an integrated PET/MR system. Potential differences in both absolute radiotracer concentration as well as in the derived kinetic parameters as a function of PET system choice have been investigated. Five healthy volunteers underwent dynamic (R)-[11C]verapamil imaging on the same day using a GE-Advance (PET-only) and a Siemens Biograph mMR system (PET/MR). PET-emission data were reconstructed using a transmission-based attenuation correction (AC) map (PET-only), whereas a standard MR-DIXON as well as a low-dose CT AC map was applied to PET/MR emission data. Kinetic modeling based on arterial blood sampling was performed using a 1-tissue-2-rate constant compartment model, yielding kinetic parameters (K1 and k2) and distribution volume (V T ). Differences for parametric values obtained in the PET-only and the PET/MR systems were analyzed using a 2-way Analysis of Variance (ANOVA). Comparison of DIXON-based AC (PET/MR) with emission data derived from the PET-only system revealed average inter-system differences of -33 ± 14% (p < 0.05) for the K1 parameter and -19 ± 9% (p < 0.05) for k2. Using a CT-based AC for PET/MR resulted in slightly lower systematic differences of -16 ± 18% for K1 and -9 ± 10% for k2. The average differences in V T were -18 ± 10% (p < 0.05) for DIXON- and -8 ± 13% for CT-based AC. Significant systematic differences were observed for kinetic parameters derived from emission data obtained from PET/MR and PET-only imaging due to different standard AC methods employed. Therefore, a transfer of imaging protocols from PET-only to PET/MR systems is not straightforward without application of proper correction methods. Clinical Trial Registration: www.clinicaltrialsregister.eu, identifier 2013-001724-19.
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Affiliation(s)
- Martin L Lassen
- Center for Medical Physics and Biomedical Engineering, Medical University of ViennaVienna, Austria
| | - Otto Muzik
- Department of Radiology, Detroit Medical Center, Children's Hospital of Michigan, Wayne State University School of MedicineDetroit, MI, United States
| | - Thomas Beyer
- Center for Medical Physics and Biomedical Engineering, Medical University of ViennaVienna, Austria
| | - Marcus Hacker
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of ViennaVienna, Austria
| | - Claes Nøhr Ladefoged
- Department of Clinical Physiology, Nuclear Medicine and PETRigshospitalet, Copenhagen, Denmark
| | - Jacobo Cal-González
- Center for Medical Physics and Biomedical Engineering, Medical University of ViennaVienna, Austria
| | - Wolfgang Wadsak
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of ViennaVienna, Austria.,CBmed GmbH, Center for Biomarker Research in MedicineGraz, Austria
| | - Ivo Rausch
- Center for Medical Physics and Biomedical Engineering, Medical University of ViennaVienna, Austria
| | - Oliver Langer
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of ViennaVienna, Austria.,Department for Clinical Pharmacology, Medical University of ViennaVienna, Austria.,Health and Environment Department, AIT Austrian Institute of Technology GmbHSeibersdorf, Austria
| | - Martin Bauer
- Department for Clinical Pharmacology, Medical University of ViennaVienna, Austria
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18
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Veldman ER, Svedberg MM, Svenningsson P, Lundberg J. Distribution and levels of 5-HT 1B receptors in anterior cingulate cortex of patients with bipolar disorder, major depressive disorder and schizophrenia - An autoradiography study. Eur Neuropsychopharmacol 2017; 27:504-514. [PMID: 28318898 DOI: 10.1016/j.euroneuro.2017.02.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 02/17/2017] [Accepted: 02/21/2017] [Indexed: 12/19/2022]
Abstract
The serotonin 1B receptor has recently received more interest as a possible new target for pharmacological treatment of psychiatric disorders. However, the exact mechanisms of action remain unclear. This study aimed to examine the binding distribution and levels of the serotonin 1B receptor in-depth in the anterior cingulate cortex (ACC) and provide more insight in its functional role in bipolar disorder (BD), major depressive disorder (MDD) and schizophrenia (SZ). Serotonin 1B receptor binding distribution was visualized with high resolution autoradiography (ARG), using the radioligand [3H]AZ10419369, in postmortem ACC tissue from patients diagnosed with BD (n=14), MDD (n=12), SZ (n=13) and healthy subjects (n=13). Moreover, a quantification of receptor binding was made with ARG, in relation to patient group, age and gender. In all subject groups a significantly higher specific binding of serotonin 1B receptor was measured in the outer ACC layers compared to the inner ACC layers. Correlation analysis with ARG binding patterns of several radioligands resulted in a significant correlation with glutamatergic N-methyl-D-aspartate receptor binding in the outer layers. No significant difference was found between subject groups in binding levels and distribution. In female subjects a significantly lower receptor binding was found than in male subjects, which was most profound in patients diagnosed with MDD. The binding distribution of the serotonin 1B receptor found in this study supports a role in glutamate transmission in the ACC and was not shown to be significantly altered in BD, MDD or SZ. A gender difference in serotonin 1B receptor binding was found.
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Affiliation(s)
- Emma R Veldman
- Center for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Stockholm County Council, Stockholm, Sweden.
| | - Marie M Svedberg
- Center for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Stockholm County Council, Stockholm, Sweden
| | - Per Svenningsson
- Center for Molecular Medicine, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Johan Lundberg
- Center for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Stockholm County Council, Stockholm, Sweden
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19
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Comparison of manual and automatic techniques for substriatal segmentation in 11C-raclopride high-resolution PET studies. Nucl Med Commun 2017; 37:1074-87. [PMID: 27286237 DOI: 10.1097/mnm.0000000000000559] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The striatum is the primary target in regional C-raclopride-PET studies, and despite its small volume, it contains several functional and anatomical subregions. The outcome of the quantitative dopamine receptor study using C-raclopride-PET depends heavily on the quality of the region-of-interest (ROI) definition of these subregions. The aim of this study was to evaluate subregional analysis techniques because new approaches have emerged, but have not yet been compared directly. MATERIALS AND METHODS In this paper, we compared manual ROI delineation with several automatic methods. The automatic methods used either direct clustering of the PET image or individualization of chosen brain atlases on the basis of MRI or PET image normalization. State-of-the-art normalization methods and atlases were applied, including those provided in the FreeSurfer, Statistical Parametric Mapping8, and FSL software packages. Evaluation of the automatic methods was based on voxel-wise congruity with the manual delineations and the test-retest variability and reliability of the outcome measures using data from seven healthy male participants who were scanned twice with C-raclopride-PET on the same day. RESULTS The results show that both manual and automatic methods can be used to define striatal subregions. Although most of the methods performed well with respect to the test-retest variability and reliability of binding potential, the smallest average test-retest variability and SEM were obtained using a connectivity-based atlas and PET normalization (test-retest variability=4.5%, SEM=0.17). CONCLUSION The current state-of-the-art automatic ROI methods can be considered good alternatives for subjective and laborious manual segmentation in C-raclopride-PET studies.
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20
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Systemic inflammation enhances stimulant-induced striatal dopamine elevation. Transl Psychiatry 2017; 7:e1076. [PMID: 28350401 PMCID: PMC5404612 DOI: 10.1038/tp.2017.18] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/10/2016] [Accepted: 01/09/2017] [Indexed: 12/25/2022] Open
Abstract
Changes in the mesolimbic dopamine (DA) system are implicated in a range of neuropsychiatric conditions including addiction, depression and schizophrenia. Dysfunction of the neuroimmune system is often comorbid with such conditions and affects similar areas of the brain. The goal of this study was to use positron emission tomography with the dopamine D2 antagonist tracer, 11C-raclopride, to explore the effect of acute immune activation on striatal DA levels. DA transmission was modulated by an oral methylphenidate (MP) challenge in order to reliably elicit DA elevation. Elevation in DA concentration due to MP was estimated via change in 11C-raclopride binding potential from the baseline scan. Prior to the post-MP scan, subjects were pre-treated with either the immune activator lipopolysaccharide (LPS) or placebo (PBO) in a cross-over design. Immune activation was confirmed by measuring tumor necrosis factor alpha (TNFα), interleukin (IL)-6 and IL-8 concentration in plasma. Eight healthy subjects were scanned four times each to determine the MP-induced DA elevation under both LPS and PBO pre-treatment conditions. MP-induced DA elevation in the striatum was significantly greater (P<0.01) after LPS pre-treatment compared to PBO pre-treatment. Seven of eight subjects responded similarly. This effect was observed in the caudate and putamen (P<0.02), but was not present in ventral striatum. DA elevation induced by MP was significantly greater when subjects were pre-treated with LPS compared to PBO. The amplification of stimulant-induced DA signaling in the presence of systemic inflammation may have important implications for our understanding of addiction and other diseases of DA dysfunction.
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Joers JM, Deelchand DK, Kumar A, Moheet A, Seaquist E, Henry PG, Öz G. Measurement of Hypothalamic Glucose Under Euglycemia and Hyperglycemia by MRI at 3T. J Magn Reson Imaging 2017; 45:681-691. [PMID: 27402249 PMCID: PMC5575789 DOI: 10.1002/jmri.25383] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 06/21/2016] [Indexed: 12/26/2022] Open
Abstract
PURPOSE To evaluate the feasibility of using a clinical magnetic resonance (MR) system and MR spectroscopy (MRS) to measure glucose concentration changes in the human hypothalamus, a structure central to whole-body glucose regulation. SUBJECTS AND METHODS A time series of MR spectra (semi-LASER, TE = 28 msec), localized to the bilateral hypothalamus (∼1.6 ml) were obtained at 3T in six healthy subjects at baseline (euglycemia) and during a ∼65-70-minute-long hyperglycemic clamp in 11-minute blocks with interleaved T1 FLASH images to retrospectively assess head motion, and track changes in cerebrospinal fluid (CSF) partial volume. The LCModel was used to quantify the sum of glucose and taurine concentrations, [Glc+Tau], along with their associated Cramér-Rao lower bounds (CRLB). RESULTS Spectral quality allowed quantification of [Glc+Tau] (sum reported due to high negative correlation between these metabolites) with CRLB <25% in 35/36 timepoints during hyperglycemia. Increased [Glc+Tau] was observed with hyperglycemia in all subjects, but most reliably in those with plasma glucose targets ≥300 mg/dl. For these subjects, [Glc+Tau]baseline (n = 4) was 1.5 (±0.3, SD) mM, and increased to 4.5 (±1.1) mM (n = 16) for timepoints acquired ≥25 minutes after onset of the clamp, with 15/16 timepoints having no overlap of 95% confidence intervals (CIs) between baseline and hyperglycemia. Preliminary analysis revealed a linear (1:5) relationship between hypothalamus-blood glucose concentrations. CONCLUSION It is feasible to measure glucose concentration changes in the human hypothalamus using a standard 3T scanner and a short-echo semi-LASER sequence by utilizing retrospective motion tracking, CSF correction, predetermined quality acceptance criteria, and hyperglycemic blood glucose levels ≥300 mg/dl. LEVEL OF EVIDENCE 2 J. Magn. Reson. Imaging 2017;45:681-691.
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Affiliation(s)
- James M. Joers
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Dinesh K. Deelchand
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Anjali Kumar
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Amir Moheet
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Elizabeth Seaquist
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Pierre-Gilles Henry
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Gülin Öz
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
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22
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Bauer CE, Brefczynski-Lewis J, Marano G, Mandich MB, Stolin A, Martone P, Lewis JW, Jaliparthi G, Raylman RR, Majewski S. Concept of an upright wearable positron emission tomography imager in humans. Brain Behav 2016; 6:e00530. [PMID: 27688946 PMCID: PMC5036439 DOI: 10.1002/brb3.530] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 05/19/2016] [Accepted: 06/12/2016] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Positron Emission Tomography (PET) is traditionally used to image patients in restrictive positions, with few devices allowing for upright, brain-dedicated imaging. Our team has explored the concept of wearable PET imagers which could provide functional brain imaging of freely moving subjects. To test feasibility and determine future considerations for development, we built a rudimentary proof-of-concept prototype (Helmet_PET) and conducted tests in phantoms and four human volunteers. METHODS Twelve Silicon Photomultiplier-based detectors were assembled in a ring with exterior weight support and an interior mechanism that could be adjustably fitted to the head. We conducted brain phantom tests as well as scanned four patients scheduled for diagnostic F(18-) FDG PET/CT imaging. For human subjects the imager was angled such that field of view included basal ganglia and visual cortex to test for typical resting-state pattern. Imaging in two subjects was performed ~4 hr after PET/CT imaging to simulate lower injected F(18-) FDG dose by taking advantage of the natural radioactive decay of the tracer (F(18) half-life of 110 min), with an estimated imaging dosage of 25% of the standard. RESULTS We found that imaging with a simple lightweight ring of detectors was feasible using a fraction of the standard radioligand dose. Activity levels in the human participants were quantitatively similar to standard PET in a set of anatomical ROIs. Typical resting-state brain pattern activation was demonstrated even in a 1 min scan of active head rotation. CONCLUSION To our knowledge, this is the first demonstration of imaging a human subject with a novel wearable PET imager that moves with robust head movements. We discuss potential research and clinical applications that will drive the design of a fully functional device. Designs will need to consider trade-offs between a low weight device with high mobility and a heavier device with greater sensitivity and larger field of view.
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Affiliation(s)
- Christopher E Bauer
- Center for Advanced Imaging West Virginia University Morgantown WV USA; Department of Radiology West Virginia University Morgantown WV USA; Center for Neuroscience West Virginia University Morgantown WV USA
| | - Julie Brefczynski-Lewis
- Center for Advanced Imaging West Virginia University Morgantown WV USA; Center for Neuroscience West Virginia University Morgantown WV USA; Department of Physiology and Pharmacology West Virginia University Morgantown WV USA
| | - Gary Marano
- Center for Advanced Imaging West Virginia University Morgantown WV USA; Department of Radiology West Virginia University Morgantown WV USA
| | - Mary-Beth Mandich
- Division of Physical Therapy Department of Human Performance West Virginia University Morgantown WV USA
| | - Alexander Stolin
- Center for Advanced Imaging West Virginia University Morgantown WV USA; Department of Radiology West Virginia University Morgantown WV USA
| | - Peter Martone
- Center for Advanced Imaging West Virginia University Morgantown WV USA; Department of Radiology West Virginia University Morgantown WV USA
| | - James W Lewis
- Center for Neuroscience West Virginia University Morgantown WV USA; Department of Neurobiology and Anatomy West Virginia University Morgantown WV USA
| | - Gangadhar Jaliparthi
- Center for Advanced Imaging West Virginia University Morgantown WV USA; Department of Radiology West Virginia University Morgantown WV USA
| | - Raymond R Raylman
- Center for Advanced Imaging West Virginia University Morgantown WV USA; Department of Radiology West Virginia University Morgantown WV USA
| | - Stan Majewski
- Department of Radiology and Medical Imaging University of Virginia Charlottesville VA USA
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Mansor S, Boellaard R, Huisman MC, van Berckel BNM, Schuit RC, Windhorst AD, Lammertsma AA, van Velden FHP. Impact of New Scatter Correction Strategies on High-Resolution Research Tomograph Brain PET Studies. Mol Imaging Biol 2016; 18:627-35. [PMID: 26728160 PMCID: PMC4927607 DOI: 10.1007/s11307-015-0921-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE The aim of this study is to evaluate the impact of different scatter correction strategies on quantification of high-resolution research tomograph (HRRT) data for three tracers covering a wide range in kinetic profiles. PROCEDURES Healthy subjects received dynamic HRRT scans using either (R)-[(11)C]verapamil (n = 5), [(11)C]raclopride (n = 5) or [(11)C]flumazenil (n = 5). To reduce the effects of patient motion on scatter scaling factors, a margin in the attenuation correction factor (ACF) sinogram was applied prior to 2D or 3D single scatter simulation (SSS). RESULTS Some (R)-[(11)C]verapamil studies showed prominent artefacts that disappeared with an ACF-margin of 10 mm or more. Use of 3D SSS for (R)-[(11)C]verapamil showed a statistically significant increase in volume of distribution compared with 2D SSS (p < 0.05), but not for [(11)C]raclopride and [(11)C]flumazenil studies (p > 0.05). CONCLUSIONS When there is a patient motion-induced mismatch between transmission and emission scans, applying an ACF-margin resulted in more reliable scatter scaling factors but did not change (and/or deteriorate) quantification.
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Affiliation(s)
- Syahir Mansor
- Department of Radiology and Nuclear Medicine, VU University Medical Center, PO Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - Ronald Boellaard
- Department of Radiology and Nuclear Medicine, VU University Medical Center, PO Box 7057, 1007 MB, Amsterdam, The Netherlands.
- Department of Nuclear Medicine and Molecular Imaging, University Medical Centre Groningen, Groningen, The Netherlands.
| | - Marc C Huisman
- Department of Radiology and Nuclear Medicine, VU University Medical Center, PO Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - Bart N M van Berckel
- Department of Radiology and Nuclear Medicine, VU University Medical Center, PO Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - Robert C Schuit
- Department of Radiology and Nuclear Medicine, VU University Medical Center, PO Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - Albert D Windhorst
- Department of Radiology and Nuclear Medicine, VU University Medical Center, PO Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - Adriaan A Lammertsma
- Department of Radiology and Nuclear Medicine, VU University Medical Center, PO Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - Floris H P van Velden
- Department of Radiology and Nuclear Medicine, VU University Medical Center, PO Box 7057, 1007 MB, Amsterdam, The Netherlands
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
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24
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van Velden FHP, Mansor SM, van Assema DME, van Berckel BNM, Froklage FE, Wang S, Schuit RC, Asselin MC, Lammertsma AA, Boellaard R, Huisman MC. Comparison of HRRT and HR+ scanners for quantitative (R)-[11C]verapamil, [11C]raclopride and [11C]flumazenil brain studies. Mol Imaging Biol 2015; 17:129-39. [PMID: 25028091 DOI: 10.1007/s11307-014-0766-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE This study was conducted to directly compare the high-resolution research tomograph (HRRT) (high-resolution brain) and HR+ (standard whole-body) positron emission tomography (PET) only scanners for quantitative brain studies using three tracers with vastly different tracer distributions. PROCEDURES Healthy volunteers underwent successive scans on HR+ and HRRT scanners (in random order) using either (R)-[(11)C]verapamil (n = 6), [(11)C]raclopride (n = 7) or [(11)C]flumazenil (n = 7). For all tracers, metabolite-corrected plasma-input functions were generated. RESULTS After resolution matching, HRRT-derived kinetic parameter values correlated well with those of HR+ for all tracers (intraclass correlation coefficients ≥0.78), having a good absolute interscanner test-retest variability (≤15 %). However, systematic differences can be seen for HRRT-derived kinetic parameter values (range -13 to +15 %). CONCLUSION Quantification of kinetic parameters based on plasma-input models leads to comparable results when spatial resolution between HRRT and HR+ data is matched. When using reference-tissue models, differences remain that are likely caused by differences in attenuation and scatter corrections and/or image reconstruction.
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Affiliation(s)
- Floris H P van Velden
- Department of Radiology & Nuclear Medicine, VU University Medical Center, PO Box 7057, 1007 MB, Amsterdam, The Netherlands,
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Qin P, Wu X, Duncan NW, Bao W, Tang W, Zhang Z, Hu J, Jin Y, Wu X, Gao L, Lu L, Guan Y, Lane T, Huang Z, Bodien YG, Giacino JT, Mao Y, Northoff G. GABAA receptor deficits predict recovery in patients with disorders of consciousness: A preliminary multimodal [(11) C]Flumazenil PET and fMRI study. Hum Brain Mapp 2015; 36:3867-77. [PMID: 26147065 DOI: 10.1002/hbm.22883] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Revised: 06/05/2015] [Accepted: 06/12/2015] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVES Disorders of consciousness (DoC)-that is, unresponsive wakefulness syndrome/vegetative state and minimally conscious state-are debilitating conditions for which no reliable markers of consciousness recovery have yet been identified. Evidence points to the GABAergic system being altered in DoC, making it a potential target as such a marker. EXPERIMENTAL DESIGN In our preliminary study, we used [(11) C]Flumazenil positron emission tomography to establish global GABAA receptor binding potential values and the local-to-global (LTG) ratio of these for specific regions. These values were then compared between DoC patients and healthy controls. In addition, they were correlated with behavioral improvements for the patients between the time of scanning and 3 months later. Functional magnetic resonance imaging resting-state functional connectivity was also calculated and the same comparisons made. PRINCIPAL OBSERVATIONS lobal GABAA receptor binding was reduced in DoC, as was the LTG ratio in specifically the supragenual anterior cingulate. Both of these measures correlated with behavioral improvement after 3 months. In contrast to these measures of GABAA receptor binding, functional connectivity did not correlate with behavioral improvement. CONCLUSIONS Our preliminary findings point toward GABAA receptor binding being a marker of consciousness recovery in DoC.
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Affiliation(s)
- Pengmin Qin
- Graduate Institute of Humanities in Medicine, Taipei Medical University, Taipei, Taiwan.,Institute of Mental Health Research, University of Ottawa, Ottawa, Canada.,Brain and Consciousness Research Centre, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan
| | - Xuehai Wu
- Neurosurgery Department, Huashan Hospital, Fudan University, Shanghai, China
| | - Niall W Duncan
- Graduate Institute of Humanities in Medicine, Taipei Medical University, Taipei, Taiwan.,Institute of Mental Health Research, University of Ottawa, Ottawa, Canada.,Brain and Consciousness Research Centre, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan.,Centre for Cognition and Brain Disorders (CCBD), Hangzhou Normal University, Hangzhou, China
| | - Weiqi Bao
- PET/CT Centre, Huashan Hospital, Fudan University, Shanghai, China
| | - Weijun Tang
- Radiologic Department of Huashan Hospital, Fudan University, Shanghai, China
| | - Zhengwei Zhang
- PET/CT Centre, Huashan Hospital, Fudan University, Shanghai, China
| | - Jin Hu
- Neurosurgery Department, Huashan Hospital, Fudan University, Shanghai, China
| | - Yi Jin
- Neurosurgery Department, Huashan Hospital, Fudan University, Shanghai, China
| | - Xing Wu
- Neurosurgery Department, Huashan Hospital, Fudan University, Shanghai, China
| | - Liang Gao
- Neurosurgery Department, Huashan Hospital, Fudan University, Shanghai, China
| | - Lu Lu
- Antai Hospital, Shanghai, China
| | - Yihui Guan
- PET/CT Centre, Huashan Hospital, Fudan University, Shanghai, China
| | - Timothy Lane
- Institute of Mental Health Research, University of Ottawa, Ottawa, Canada.,Brain and Consciousness Research Centre, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan
| | - Zirui Huang
- Institute of Mental Health Research, University of Ottawa, Ottawa, Canada
| | - Yelena G Bodien
- Spaulding Rehabilitation Hospital, Charlestown, Massachusetts
| | | | - Ying Mao
- Neurosurgery Department, Huashan Hospital, Fudan University, Shanghai, China
| | - Georg Northoff
- Graduate Institute of Humanities in Medicine, Taipei Medical University, Taipei, Taiwan.,Institute of Mental Health Research, University of Ottawa, Ottawa, Canada.,Brain and Consciousness Research Centre, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan.,Centre for Cognition and Brain Disorders (CCBD), Hangzhou Normal University, Hangzhou, China.,Research Centre for Mind, Brain and Learning, National Chengchi University, Taipei, Taiwan
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26
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Kenk M, Selvanathan T, Rao N, Suridjan I, Rusjan P, Remington G, Meyer JH, Wilson AA, Houle S, Mizrahi R. Imaging neuroinflammation in gray and white matter in schizophrenia: an in-vivo PET study with [18F]-FEPPA. Schizophr Bull 2015; 41:85-93. [PMID: 25385788 PMCID: PMC4266311 DOI: 10.1093/schbul/sbu157] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Neuroinflammation and abnormal immune responses have been implicated in schizophrenia (SCZ). Past studies using positron emission tomography (PET) that examined neuroinflammation in patients with SCZ in vivo using the translocator protein 18kDa (TSPO) target were limited by the insensitivity of the first-generation imaging agent [(11)C]-PK11195, scanners used, and the small sample sizes studied. Present study uses a novel second-generation TSPO PET radioligand N-acetyl-N-(2-[(18)F]fluoroethoxybenzyl)-2-phenoxy-5-pyridinamine ([(18)F]-FEPPA) to evaluate whether there is increased neuroinflammation in patients with SCZ. A cross-sectional study was performed using [(18)F]-FEPPA and a high-resolution research tomograph (HRRT). Eighteen patients with SCZ with ongoing psychotic symptoms and 27 healthy volunteers (HV) were recruited from a tertiary psychiatric clinical setting and the community, respectively. All participants underwent [(18)F]-FEPPA PET and magnetic resonance imaging, and PET data were analyzed to obtain [(18)F]-FEPPA total volume of distribution (VT) using a 2-tissue compartment model with an arterial plasma input function, as previously validated. All subjects were classified as high-, medium- or low-affinity [(18)F]-FEPPA binders on the basis of rs6971 polymorphism, and genotype information was incorporated into the analyses of imaging outcomes. No significant differences in neuroinflammation indexed as [(18)F]-FEPPA VT were observed between groups in either gray (F(1,39) = 0.179, P = .674) or white matter regions (F(1,38) = 0.597, P = .445). The lack of significant difference in neuroinflammation in treated patients with SCZ in the midst of a psychotic episode and HV suggests that neuroinflammatory processes may take place early in disease progression or are affected by antipsychotic treatment.
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Affiliation(s)
- Miran Kenk
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Thiviya Selvanathan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Naren Rao
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Ivonne Suridjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Pablo Rusjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Gary Remington
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Jeffrey H Meyer
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Alan A Wilson
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Sylvain Houle
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
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Chittiboina P, Montgomery BK, Millo C, Herscovitch P, Lonser RR. High-resolution(18)F-fluorodeoxyglucose positron emission tomography and magnetic resonance imaging for pituitary adenoma detection in Cushing disease. J Neurosurg 2014; 122:791-7. [PMID: 25479121 DOI: 10.3171/2014.10.jns14911] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT High-resolution PET (hrPET) performed using a high-resolution research tomograph is reported as having a resolution of 2 mm and could be used to detect corticotroph adenomas through uptake of(18)F-fluorodeoxyglucose ((18)F-FDG). To determine the sensitivity of this imaging modality, the authors compared(18)F-FDG hrPET and MRI detection of pituitary adenomas in Cushing disease (CD). METHODS Consecutive patients with CD who underwent preoperative(18)F-FDG hrPET and MRI (spin echo [SE] and spoiled gradient recalled [SPGR] sequences) were prospectively analyzed. Standardized uptake values (SUVs) were calculated from hrPET and were compared with MRI findings. Imaging findings were correlated to operative and histological findings. RESULTS Ten patients (7 females and 3 males) were included (mean age 30.8 ± 19.3 years; range 11-59 years). MRI revealed a pituitary adenoma in 4 patients (40% of patients) on SE and 7 patients (70%) on SPGR sequences.(18)F-FDG hrPET demonstrated increased(18)F-FDG uptake consistent with an adenoma in 4 patients (40%; adenoma size range 3-14 mm). Maximum SUV was significantly higher for(18)F-FDG hrPET-positive tumors (difference = 5.1, 95% CI 2.1-8.1; p = 0.004) than for(18)F-FDG hrPET-negative tumors.(18)F-FDG hrPET positivity was not associated with tumor volume (p = 0.2) or dural invasion (p = 0.5). Midnight and morning ACTH levels were associated with(18)F-FDG hrPET positivity (p = 0.01 and 0.04, respectively) and correlated with the maximum SUV (R = 0.9; p = 0.001) and average SUV (R = 0.8; p = 0.01). All(18)F-FDG hrPET-positive adenomas had a less than a 180% ACTH increase and(18)F-FDG hrPET-negative adenomas had a greater than 180% ACTH increase after CRH stimulation (p = 0.03). Three adenomas were detected on SPGR MRI sequences that were not detected by(18)F-FDG hrPET imaging. Two adenomas not detected on SE (but no adenomas not detected on SPGR) were detected on(18)F-FDG hrPET. CONCLUSIONS While(18)F-FDG hrPET imaging can detect small functioning corticotroph adenomas and is more sensitive than SE MRI, SPGR MRI is more sensitive than(18)F-FDG hrPET and SE MRI in the detection of CD-associated pituitary adenomas. Response to CRH stimulation can predict(18)F-FDG hrPET-positive adenomas in CD.
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Affiliation(s)
- Prashant Chittiboina
- Surgical Neurology Branch, National Institutes of Neurological Disorders and Stroke
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28
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Respiratory-induced errors in tumor quantification and delineation in CT attenuation-corrected PET images: effects of tumor size, tumor location, and respiratory trace: a simulation study using the 4D XCAT phantom. Mol Imaging Biol 2014; 15:655-65. [PMID: 23780352 DOI: 10.1007/s11307-013-0656-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
PURPOSE We investigated the magnitude of respiratory-induced errors in tumor maximum standardized uptake value (SUVmax), localization, and volume for different respiratory motion traces and various lesion sizes in different locations of the thorax and abdomen in positron emission tomography (PET) images. PROCEDURES Respiratory motion traces were simulated based on the common patient breathing cycle and three diaphragm motions used to drive the 4D XCAT phantom. Lesions with different diameters were simulated in different locations of lungs and liver. The generated PET sinograms were subsequently corrected using computed tomography attenuation correction involving the end exhalation, end inhalation, and average of the respiratory cycle. By considering respiration-averaged computed tomography as a true value, the lesion volume, displacement, and SUVmax were measured and analyzed for different respiratory motions. RESULTS Respiration with 35-mm diaphragm motion results in a mean lesion SUVmax error of 24 %, a mean superior inferior displacement of 7.6 mm and a mean lesion volume overestimation of 129 % for a 9-mm lesion in the liver. Respiratory motion results in lesion volume overestimation of 50 % for a 9-mm lower lung lesion near the liver with just 15-mm diaphragm motion. Although there are larger errors in lesion SUVmax and volume for 35-mm motion amplitudes, respiration-averaged computed tomography results in smaller errors than the other two phases, except for the lower lung region. CONCLUSIONS The respiratory motion-induced errors in tumor quantification and delineation are highly dependent upon the motion amplitude, tumor location, tumor size, and choice of the attenuation map for PET image attenuation correction.
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Bogdanović RM, Syvänen S, Michler C, Russmann V, Eriksson J, Windhorst AD, Lammertsma AA, de Lange EC, Voskuyl RA, Potschka H. (R)-[11C]PK11195 brain uptake as a biomarker of inflammation and antiepileptic drug resistance: evaluation in a rat epilepsy model. Neuropharmacology 2014; 85:104-12. [PMID: 24880085 DOI: 10.1016/j.neuropharm.2014.05.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 04/22/2014] [Accepted: 05/09/2014] [Indexed: 01/02/2023]
Abstract
Neuroinflammation has been suggested as a key determinant of the intrinsic severity of epilepsy. Glial cell activation and associated inflammatory signaling can influence seizure thresholds as well as the pharmacodynamics and pharmacokinetics of antiepileptic drugs. Based on these data, we hypothesized that molecular imaging of microglia activation might serve as a tool to predict drug refractoriness of epilepsy. Brain uptake of (R)-[11C]PK11195, a ligand of the translocator protein 18 kDa and molecular marker of microglia activation, was studied in a chronic model of temporal lobe epilepsy in rats with selection of phenobarbital responders and non-responders. In rats with drug-sensitive epilepsy, (R)-[11C]PK11195 brain uptake values were comparable to those in non-epileptic controls. Analysis in non-responders revealed enhanced brain uptake of up to 39% in different brain regions. The difference might be related to the fact that non-responders exhibited higher baseline seizure frequencies than responders indicating a more pronounced intrinsic disease severity. In hippocampal sections, ED1 immunostaining argued against a general difference in microglia activation between both groups. Our data suggest that TSPO PET imaging might serve as a biomarker for drug resistance in temporal lobe epilepsy. However, it needs to be considered that our findings indicate that the TSPO PET data might merely reflect seizure frequency. Future experimental and clinical studies should further evaluate the validity of TSPO PET data to predict the response to phenobarbital and other antiepileptic drugs in longitudinal studies with scanning before drug exposure and with a focus on the early phase following an epileptogenic brain insult.
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Affiliation(s)
- Renée Marie Bogdanović
- Institute of Pharmacology, Toxicology & Pharmacy, Ludwig-Maximilians-University, Munich, Germany; Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University, Munich, Germany
| | - Stina Syvänen
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Christina Michler
- Institute of Pharmacology, Toxicology & Pharmacy, Ludwig-Maximilians-University, Munich, Germany
| | - Vera Russmann
- Institute of Pharmacology, Toxicology & Pharmacy, Ludwig-Maximilians-University, Munich, Germany
| | - Jonas Eriksson
- Department Medicinal Chemistry, Preclinical PET Platform, Uppsala University, Sweden
| | - Albert D Windhorst
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | - Adriaan A Lammertsma
- Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
| | | | - Rob A Voskuyl
- Division of Pharmacology, LACDR, Leiden University, Leiden, The Netherlands; SEIN - Epilepsy Institutes of The Netherlands Foundation, Heemstede, The Netherlands
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology & Pharmacy, Ludwig-Maximilians-University, Munich, Germany.
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Carter SF, Embleton KV, Anton-Rodriguez JM, Burns A, Ralph MAL, Herholz K. Regional Neuronal Network Failure and Cognition in Late-Onset Sporadic Alzheimer Disease. AJNR Am J Neuroradiol 2014; 35:S18-30. [PMID: 24578281 DOI: 10.3174/ajnr.a3895] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- S F Carter
- From the Wolfson Molecular Imaging Centre (S.F.C., J.M.A.-R., K.H.)Institute of Population Health, Neuroscience and Aphasia Research Unit (S.F.C., M.A.L.R.)Alzheimer Neurobiology Centre (S.F.C.), Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | | | | | - A Burns
- Institute of Brain, Behaviour and Mental Health (A.B., K.H.), University of Manchester, Manchester, UK
| | - M A L Ralph
- Institute of Population Health, Neuroscience and Aphasia Research Unit (S.F.C., M.A.L.R.)
| | - K Herholz
- From the Wolfson Molecular Imaging Centre (S.F.C., J.M.A.-R., K.H.)Institute of Brain, Behaviour and Mental Health (A.B., K.H.), University of Manchester, Manchester, UK
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Suridjan I, Rusjan PM, Voineskos AN, Selvanathan T, Setiawan E, Strafella AP, Wilson AA, Meyer JH, Houle S, Mizrahi R. Neuroinflammation in healthy aging: a PET study using a novel Translocator Protein 18kDa (TSPO) radioligand, [(18)F]-FEPPA. Neuroimage 2013; 84:868-75. [PMID: 24064066 DOI: 10.1016/j.neuroimage.2013.09.021] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 09/05/2013] [Accepted: 09/12/2013] [Indexed: 11/18/2022] Open
Abstract
One of the cellular markers of neuroinflammation is increased microglia activation, characterized by overexpression of mitochondrial 18kDa Translocator Protein (TSPO). TSPO expression can be quantified in-vivo using the positron emission tomography (PET) radioligand [(18)F]-FEPPA. This study examined microglial activation as measured with [(18)F]-FEPPA PET across the adult lifespan in a group of healthy volunteers. We performed genotyping for the rs6971 TS.PO gene polymorphism to control for the known variability in binding affinity. Thirty-three healthy volunteers (age range: 19-82years; 22 high affinity binders (HAB), 11 mixed affinity binders (MAB)) underwent [(18)F]-FEPPA PET scans, acquired on the High Resolution Research Tomograph (HRRT) and analyzed using a 2-tissue compartment model. Regression analyses were performed to examine the effect of age adjusting for genetic status on [(18)F]-FEPPA total distribution volumes (VT) in the hippocampus, temporal, and prefrontal cortex. We found no significant effect of age on [(18)F]-FEPPA VT (F (1,30)=0.918; p=0.346), and a significant effect of genetic polymorphism (F (1,30)=8.767; p=0.006). This is the first in-vivo study to evaluate age-related changes in TSPO binding, using the new generation TSPO radioligands. Increased neuroinflammation, as measured with [(18)F]-FEPPA PET was not associated with normal aging, suggesting that healthy elderly individuals may serve as useful benchmark against patients with neurodegenerative disorders where neuroinflammation may be present.
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Affiliation(s)
- I Suridjan
- Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, M5T 1R8, Toronto, Ontario, Canada
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van Golen LW, Huisman MC, Ijzerman RG, Hoetjes NJ, Schwarte LA, Lammertsma AA, Diamant M. Cerebral blood flow and glucose metabolism measured with positron emission tomography are decreased in human type 1 diabetes. Diabetes 2013; 62:2898-904. [PMID: 23530004 PMCID: PMC3717848 DOI: 10.2337/db12-1159] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Subclinical systemic microvascular dysfunction exists in asymptomatic patients with type 1 diabetes. We hypothesized that microangiopathy, resulting from long-standing systemic hyperglycemia and hyperinsulinemia, may be generalized to the brain, resulting in changes in cerebral blood flow (CBF) and metabolism in these patients. We performed dynamic [(15)O]H2O and [(18)F]-fluoro-2-deoxy-d-glucose brain positron emission tomography scans to measure CBF and cerebral glucose metabolism (CMRglu), respectively, in 30 type 1 diabetic patients and 12 age-matched healthy controls after an overnight fast. Regions of interest were automatically delineated on coregistered magnetic resonance images and full kinetic analysis was performed. Plasma glucose and insulin levels were higher in patients versus controls. Total gray matter CBF was 9%, whereas CMRglu was 21% lower in type 1 diabetic subjects versus control subjects. We conclude that at real-life fasting glucose and insulin levels, type 1 diabetes is associated with decreased resting cerebral glucose metabolism, which is only partially explained by the decreased CBF. These findings suggest that mechanisms other than generalized microangiopathy account for the altered CMRglu observed in well-controlled type 1 diabetes.
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Affiliation(s)
- Larissa W. van Golen
- Diabetes Center, Department of Internal Medicine, VU University Medical Center, Amsterdam, the Netherlands
- Corresponding author: Larissa W. van Golen,
| | - Marc C. Huisman
- Department of Nuclear Medicine and Positron Emission Tomography Research, VU University Medical Center, Amsterdam, the Netherlands
| | - Richard G. Ijzerman
- Diabetes Center, Department of Internal Medicine, VU University Medical Center, Amsterdam, the Netherlands
| | - Nikie J. Hoetjes
- Department of Nuclear Medicine and Positron Emission Tomography Research, VU University Medical Center, Amsterdam, the Netherlands
| | - Lothar A. Schwarte
- Department of Anesthesiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Adriaan A. Lammertsma
- Department of Nuclear Medicine and Positron Emission Tomography Research, VU University Medical Center, Amsterdam, the Netherlands
| | - Michaela Diamant
- Diabetes Center, Department of Internal Medicine, VU University Medical Center, Amsterdam, the Netherlands
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Syvänen S, Russmann V, Verbeek J, Eriksson J, Labots M, Zellinger C, Seeger N, Schuit R, Rongen M, van Kooij R, Windhorst AD, Lammertsma AA, de Lange EC, Voskuyl RA, Koepp M, Potschka H. [11C]quinidine and [11C]laniquidar PET imaging in a chronic rodent epilepsy model: impact of epilepsy and drug-responsiveness. Nucl Med Biol 2013; 40:764-75. [PMID: 23827307 DOI: 10.1016/j.nucmedbio.2013.05.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 04/24/2013] [Accepted: 05/23/2013] [Indexed: 10/26/2022]
Abstract
INTRODUCTION To analyse the impact of both epilepsy and pharmacological modulation of P-glycoprotein on brain uptake and kinetics of positron emission tomography (PET) radiotracers [(11)C]quinidine and [(11)C]laniquidar. METHODS Metabolism and brain kinetics of both [(11)C]quinidine and [(11)C]laniquidar were assessed in naive rats, electrode-implanted control rats, and rats with spontaneous recurrent seizures. The latter group was further classified according to their response to the antiepileptic drug phenobarbital into "responders" and "non-responders". Additional experiments were performed following pre-treatment with the P-glycoprotein modulator tariquidar. RESULTS [(11)C]quinidine was metabolized rapidly, whereas [(11)C]laniquidar was more stable. Brain concentrations of both radiotracers remained at relatively low levels at baseline conditions. Tariquidar pre-treatment resulted in significant increases of [(11)C]quinidine and [(11)C]laniquidar brain concentrations. In the epileptic subgroup "non-responders", brain uptake of [(11)C]quinidine in selected brain regions reached higher levels than in electrode-implanted control rats. However, the relative response to tariquidar did not differ between groups with full blockade of P-glycoprotein by 15 mg/kg of tariquidar. For [(11)C]laniquidar differences between epileptic and control animals were only evident at baseline conditions but not after tariquidar pretreatment. CONCLUSIONS We confirmed that both [(11)C]quinidine and [(11)C]laniquidar are P-glycoprotein substrates. At full P-gp blockade, tariquidar pre-treatment only demonstrated slight differences for [(11)C]quinidine between drug-resistant and drug-sensitive animals.
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Affiliation(s)
- Stina Syvänen
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
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Application of image-derived and venous input functions in major depression using [carbonyl-11C]WAY-100635. Nucl Med Biol 2013; 40:371-7. [DOI: 10.1016/j.nucmedbio.2012.12.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 11/30/2012] [Accepted: 12/31/2012] [Indexed: 11/18/2022]
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MR/PET or PET/MRI: does it matter? MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2013; 26:1-4. [PMID: 23385880 DOI: 10.1007/s10334-012-0365-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 12/20/2012] [Accepted: 12/21/2012] [Indexed: 01/01/2023]
Abstract
After the very successful clinical introduction of combined PET/CT imaging a decade ago, a hardware combination of PET and MR is following suit. Today, three different approaches towards integrated PET/MR have been proposed: (1) a triple-modality system with a 3T MRI and a time-of-flight PET/CT installed in adjacent rooms, (2) a tandem system with a 3T MRI and a time-of-flight PET/CT in a co-planar installation with a joint patient handling system, and (3) a fully-integrated system with a whole-body PET system mounted inside a 3T MRI system. This special issue of MAGMA brings together contributions from key experts in the field of PET/MR, PET/CT and CT. The various papers share the author's perspectives on the state-of-the-art PET/MR imaging with any of the three approaches mentioned above. In addition to several reviews discussing advantages and challenges of combining PET and MRI for clinical diagnostics, first clinical data are also presented. We expect this special issue to nurture future improvements in hardware, clinical protocols, and efficient post-processing strategies to further assess the diagnostic value of combined PET/MR imaging. It remains to be seen whether a so-called "killer application" for PET/MRI will surface. In that case PET/MR is likely to excel in pre-clinical and selected research applications for now. This special issue helps the readers to stay on track of this exciting development.
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Syvänen S, Labots M, Tagawa Y, Eriksson J, Windhorst AD, Lammertsma AA, de Lange EC, Voskuyl RA. Altered GABAA Receptor Density and Unaltered Blood–Brain Barrier Transport in a Kainate Model of Epilepsy: An In Vivo Study Using 11C-Flumazenil and PET. J Nucl Med 2012; 53:1974-83. [DOI: 10.2967/jnumed.112.104588] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Improved mapping and quantification of serotonin transporter availability in the human brainstem with the HRRT. Eur J Nucl Med Mol Imaging 2012; 40:228-37. [PMID: 23076621 DOI: 10.1007/s00259-012-2260-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 09/21/2012] [Indexed: 02/06/2023]
Abstract
PURPOSE The serotonin system is involved in many physiological functions and clinical conditions. Serotonergic neurons originate from the raphe nuclei in the brainstem, and reliable estimates of receptor/transporter availability in the raphe in vivo are thus of interest. Though positron emission tomography (PET) can be used to quantify receptor distribution in the brain, high noise levels prevent reliable estimation of radioligand binding in small regions such as the raphe. For this purpose, parametric imaging in combination with high-resolution PET systems may provide images with reduced noise levels and sufficient contrast for reliable quantification. This study examined the potential to evaluate radioligand binding in brainstem nuclei, and assessed the effect of improved resolution on the outcome measures. METHODS For comparative purposes, radioligand binding was measured with an ECAT EXACT HR PET system (resolution about 4.5 mm FWHM) and a high-resolution research tomograph (HRRT) system (resolution about 1.5 mm FWHM). Six subjects were examined with both systems on the same day using the serotonin transporter radioligand [(11)C]MADAM. Parametric images of binding potential (BP (ND)) were obtained using a wavelet-aided approach. Regions of interest (ROIs) were delineated using a threshold-based semiautomatic delineation procedure for five brainstem structures. Regional BP (ND) values were estimated by applying the ROIs to the parametric images, and the percentage difference in BP (ND) between the systems was calculated. RESULTS Signals for [(11)C]MADAM binding were obtained for all five brainstem structures. Overall, the HRRT provided 30-40 % higher BP (ND) values than the HR (p = 0.0017), independent of thresholds used in the ROI delineation procedure. CONCLUSION The methodology used enabled the estimation of [(11)C]MADAM binding in the small nuclei of the brainstem. Differences in the BP (ND) values calculated using data from the two systems were mainly attributable to their differing resolutions. The estimated BP (ND) values provided lower across-subject variability than those previously obtained using compartment analysis. This procedure may therefore facilitate quantitative studies of receptor/transporter availability in the brainstem.
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Sandiego CM, Weinzimmer D, Carson RE. Optimization of PET-MR registrations for nonhuman primates using mutual information measures: a Multi-Transform Method (MTM). Neuroimage 2012; 64:571-81. [PMID: 22926293 DOI: 10.1016/j.neuroimage.2012.08.051] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 08/17/2012] [Accepted: 08/20/2012] [Indexed: 10/28/2022] Open
Abstract
An important step in PET brain kinetic analysis is the registration of functional data to an anatomical MR image. Typically, PET-MR registrations in nonhuman primate neuroreceptor studies used PET images acquired early post-injection, (e.g., 0-10 min) to closely resemble the subject's MR image. However, a substantial fraction of these registrations (~25%) fail due to the differences in kinetics and distribution for various radiotracer studies and conditions (e.g., blocking studies). The Multi-Transform Method (MTM) was developed to improve the success of registrations between PET and MR images. Two algorithms were evaluated, MTM-I and MTM-II. The approach involves creating multiple transformations by registering PET images of different time intervals, from a dynamic study, to a single reference (i.e., MR image) (MTM-I) or to multiple reference images (i.e., MR and PET images pre-registered to the MR) (MTM-II). Normalized mutual information was used to compute similarity between the transformed PET images and the reference image(s) to choose the optimal transformation. This final transformation is used to map the dynamic dataset into the animal's anatomical MR space, required for kinetic analysis. The chosen transforms from MTM-I and MTM-II were evaluated using visual rating scores to assess the quality of spatial alignment between the resliced PET and reference images. One hundred twenty PET datasets involving eleven different tracers from 3 different scanners were used to evaluate the MTM algorithms. Studies were performed with baboons and rhesus monkeys on the HR+, HRRT, and Focus-220. Successful transformations increased from 77.5%, 85.8%, to 96.7% using the 0-10 min method, MTM-I, and MTM-II, respectively, based on visual rating scores. The Multi-Transform Methods proved to be a robust technique for PET-MR registrations for a wide range of PET studies.
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Affiliation(s)
- Christine M Sandiego
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA.
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Schain M, Tóth M, Cselényi Z, Stenkrona P, Halldin C, Farde L, Varrone A. Quantification of serotonin transporter availability with [11C]MADAM — A comparison between the ECAT HRRT and HR systems. Neuroimage 2012; 60:800-7. [DOI: 10.1016/j.neuroimage.2011.12.047] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 12/13/2011] [Accepted: 12/18/2011] [Indexed: 10/14/2022] Open
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Verbeek J, Syvänen S, Schuit RC, Eriksson J, de Lange EC, Windhorst AD, Luurtsema G, Lammertsma AA. Synthesis and preclinical evaluation of [11C]D617, a metabolite of (R)-[11C]verapamil. Nucl Med Biol 2012; 39:530-9. [PMID: 22226023 DOI: 10.1016/j.nucmedbio.2011.10.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 09/30/2011] [Accepted: 10/22/2011] [Indexed: 01/16/2023]
Abstract
OBJECTIVES (R)-[(11)C]verapamil is widely used as a positron emission tomography (PET) tracer to evaluate P-glycoprotein (P-gp) functionality at the blood-brain barrier in man. A disadvantage of (R)-[(11)C]verapamil is the fact that its main metabolite, [(11)C]D617, also enters the brain. For quantitative analysis of (R)-[(11)C]verapamil data, it has been assumed that the cerebral kinetics of (R)-[(11)C]verapamil and [(11)C]D617 are the same. The aim of the present study was to investigate whether the cerebral kinetics of (R)-[(11)C]verapamil and [(11)C]D617 are indeed similar and, if so, whether [(11)C]D617 itself could serve as an alternative PET tracer for P-gp. METHODS [(11)C]D617 was synthesized and its ex vivo biodistribution was investigated in male rats at four time points following intravenous administration of [(11)C]D617 (50 MBq) without (n=4) or with (n=4) pretreatment with the P-gp inhibitor tariquidar (15 mg·kg(-1), intraperitoneally). Brain distribution was further assessed using consecutive PET scans (n=8) before and after pretreatment with tariquidar (15 mg·kg(-1), intravenously), as well as metabolite analysis (n=4). RESULTS The precursor for the radiosynthesis of [(11)C]D617, 5-amino-2-(3,4-dimethoxy-phenyl)-2-isopropyl-pentanitrile (desmethyl D617), was synthesized in 41% overall yield. [(11)C]D617 was synthesized in 58%-77% decay-corrected yield with a radiochemical purity of ≥99%. The homogeneously distributed cerebral volume of distribution (V(T)) of [(11)C]D617 was 1.1, and this increased 2.4-fold after tariquidar pretreatment. CONCLUSION V(T) of [(11)C]D617 was comparable to that of (R)-[(11)C]verapamil, but its increase after tariquidar pretreatment was substantially lower. Hence, (R)-[(11)C]verapamil and [(11)C]D617 do not show similar brain kinetics after inhibition of P-gp with tariquidar.
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Affiliation(s)
- Joost Verbeek
- Department of Nuclear Medicine & PET Research, VU University Medical Center, Amsterdam, the Netherlands.
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Uchida H, Chow TW, Mamo DC, Kapur S, Mulsant BH, Houle S, Pollock BG, Graff-Guerrero A. Effects of aging on 5-HT(2A) R binding: a HRRT PET study with and without partial volume corrections. Int J Geriatr Psychiatry 2011; 26:1300-8. [PMID: 21351153 DOI: 10.1002/gps.2682] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Accepted: 12/01/2010] [Indexed: 11/12/2022]
Abstract
OBJECTIVE We explored whether prior findings of reduction in serotonin 2A receptor (5-HT(2A) R) binding with age could be replicated and whether high resolution research tomography (HRRT) for positron emission tomography could compensate for partial volume effects in the presence of age-related brain atrophy, which has been a traditional concern for radioligand PET studies in the elderly. METHODS We derived 5-HT(2A) R nondisplaceable binding potentials (BP(ND) ) in frontal, temporal, anterior-cingulate, insula, caudate and putamen volumes of interest (VOIs) for 28 healthy subjects (mean ± SD age = 43.9 ± 17.0 years, range: 19-78 years) using HRRT. Partial volume correction (PVC) was performed in the VOI analysis. RESULTS The 5-HT(2A) R BP(ND) s decreased with age, a relationship best described by an exponential-decay regression. The BP(ND) s were found to be consistent before and after PVC, with an intra-class correlation coefficient of 0.84 and 95% confidence interval = 0.78-0.88. CONCLUSIONS These new findings update current knowledge, in that the aging process is not always uniform across the life span and suggest that PVC may not be necessary with HRRT in healthy subjects.
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Affiliation(s)
- Hiroyuki Uchida
- Centre for Addiction and Mental Health, Toronto, Ontario, Canada
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Syvänen S, de Lange EC, Tagawa Y, Schenke M, Molthoff CF, Windhorst AD, Lammertsma AA, Voskuyl RA. Simultaneous in vivo measurements of receptor density and affinity using [11C]flumazenil and positron emission tomography: Comparison of full saturation and steady state methods. Neuroimage 2011; 57:928-37. [DOI: 10.1016/j.neuroimage.2011.05.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 04/27/2011] [Accepted: 05/06/2011] [Indexed: 10/18/2022] Open
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la Fougère C, Grant S, Kostikov A, Schirrmacher R, Gravel P, Schipper HM, Reader A, Evans A, Thiel A. Where in-vivo imaging meets cytoarchitectonics: The relationship between cortical thickness and neuronal density measured with high-resolution [18F]flumazenil-PET. Neuroimage 2011; 56:951-60. [PMID: 21073964 DOI: 10.1016/j.neuroimage.2010.11.015] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 10/25/2010] [Accepted: 11/02/2010] [Indexed: 11/28/2022] Open
Affiliation(s)
- Christian la Fougère
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, Canada.
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Cho ZH, Son YD, Kim HK, Kim NB, Choi EJ, Lee SY, Chi JG, Park CW, Kim YB, Ogawa S. Observation of glucose metabolism in the thalamic nuclei by fusion PET/MRI. J Nucl Med 2011; 52:401-4. [PMID: 21321261 DOI: 10.2967/jnumed.110.081281] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED The anatomy of the thalamus and its connectivity with surrounding areas are known. Localized metabolic activities at the thalamic substructural level have not been measured in vivo in human brains because of limited resolution and contrast. METHODS The energy metabolism and fine anatomic structures of the thalamus were measured simultaneously in 5 healthy subjects using a PET/MRI fusion imaging system. Measured metabolism in individual thalamic nuclei was quantified by corresponding PET/MRI images. RESULTS Substructures of the thalamus were clearly distinguished in 7.0-T MRI images, and the corresponding metabolic activities measured by PET were integrated by the PET/MRI system. The medial dorsal thalamic nucleus consistently showed the highest glucose uptake among the thalamic nuclei. CONCLUSION These results demonstrate that substructure-specific metabolic activities in the thalamus can be measured with a PET/MRI system consisting of an ultra-high-resolution PET component and an ultra-high-field MRI component.
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Affiliation(s)
- Zang-Hee Cho
- Neuroscience Research Institute, Gachon University of Medicine and Science, Incheon, South Korea.
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Narendran R, Mason NS, May MA, Chen CM, Kendro S, Ridler K, Rabiner EA, Laruelle M, Mathis CA, Frankle WG. Positron emission tomography imaging of dopamine D₂/₃ receptors in the human cortex with [¹¹C]FLB 457: reproducibility studies. Synapse 2011; 65:35-40. [PMID: 20506186 DOI: 10.1002/syn.20813] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In a recent PET study, we demonstrated the ability to measure amphetamine-induced DA release in the human cortex with the relatively high affinity dopamine D₂/₃ radioligand [¹¹C]FLB 457 (Narendran et al., [2009] Synapse 63:447-461). The aim of this study was to evaluate the reproducibility and reliability of [¹¹C]FLB 457 in the same imaging paradigm we used to measure amphetamine-induced DA transmission. Six healthy human subjects (three males/three females)were studied twice with [¹¹C]FLB 457, once at baseline and again 3 h following the end of the baseline scan. D₂/₃ receptor binding parameters were estimated using a two-tissue compartment kinetic analysis in the cortical regions of interest and cerebellum (reference region). The test-retest variability and intraclass correlation coefficient were assessed for distribution volume (VT), binding potential relative to plasma concentration (BP(P)), and binding potential relative to non-displaceable uptake (BP(ND)) of [¹¹C]FLB 457. The test-retest variability of [¹¹C]FLB 457 VT, BPP, and BP(ND) were ≤15%, consistent with the published test-retest variability for this ligand in other brain regions (Sudo et al., [2001] Nucl Med Commun 22:1215-1221; Vilkman et al., [2000] Eur J Nucl Med 27:1666-1673). In addition, no significant decrease in [¹¹C]FLB457 BP(ND) was observed in the second scan compared to the first one. This suggests that the contribution of carryover mass of [¹¹C]FLB 457 to the measured reduction in[¹¹C]FLB 457 BP(ND) following amphetamine was relatively low. These data support the further validation of [¹¹C]FLB 457 as a tool to measure amphetamine-induced dopamine release in the human cortex.
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Affiliation(s)
- Rajesh Narendran
- Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
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Syvänen S, Luurtsema G, Molthoff CFM, Windhorst AD, Huisman MC, Lammertsma AA, Voskuyl RA, de Lange EC. (R)-[11C]verapamil PET studies to assess changes in P-glycoprotein expression and functionality in rat blood-brain barrier after exposure to kainate-induced status epilepticus. BMC Med Imaging 2011; 11:1. [PMID: 21199574 PMCID: PMC3022839 DOI: 10.1186/1471-2342-11-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 01/03/2011] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Increased functionality of efflux transporters at the blood-brain barrier may contribute to decreased drug concentrations at the target site in CNS diseases like epilepsy. In the rat, pharmacoresistant epilepsy can be mimicked by inducing status epilepticus by intraperitoneal injection of kainate, which leads to development of spontaneous seizures after 3 weeks to 3 months. The aim of this study was to investigate potential changes in P-glycoprotein (P-gp) expression and functionality at an early stage after induction of status epilepticus by kainate. METHODS (R)-[11C]verapamil, which is currently the most frequently used positron emission tomography (PET) ligand for determining P-gp functionality at the blood-brain barrier, was used in kainate and saline (control) treated rats, at 7 days after treatment. To investigate the effect of P-gp on (R)-[11C]verapamil brain distribution, both groups were studied without or with co-administration of the P-gp inhibitor tariquidar. P-gp expression was determined using immunohistochemistry in post mortem brains. (R)-[11C]verapamil kinetics were analyzed with approaches common in PET research (Logan analysis, and compartmental modelling of individual profiles) as well as by population mixed effects modelling (NONMEM). RESULTS All data analysis approaches indicated only modest differences in brain distribution of (R)-[11C]verapamil between saline and kainate treated rats, while tariquidar treatment in both groups resulted in a more than 10-fold increase. NONMEM provided most precise parameter estimates. P-gp expression was found to be similar for kainate and saline treated rats. CONCLUSIONS P-gp expression and functionality does not seem to change at early stage after induction of anticipated pharmacoresistant epilepsy by kainate.
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Affiliation(s)
- Stina Syvänen
- Division of Pharmacology, LACDR, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Gert Luurtsema
- Department of Nuclear Medicine & Molecular Imaging, Groningen University Medical Center, P.O. Box 30.001 9700 RB Groningen, The Netherlands
| | - Carla FM Molthoff
- Department of Nuclear Medicine & PET Research, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - Albert D Windhorst
- Department of Nuclear Medicine & PET Research, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - Marc C Huisman
- Department of Nuclear Medicine & PET Research, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - Adriaan A Lammertsma
- Department of Nuclear Medicine & PET Research, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - Rob A Voskuyl
- Division of Pharmacology, LACDR, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
- Epilepsy Institute of The Netherlands Foundation (SEIN), P.O. Box 21, 2100 AA, Heemstede, The Netherlands
| | - Elizabeth C de Lange
- Division of Pharmacology, LACDR, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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Kodaka F, Ito H, Shidahara M, Takano H, Takahashi H, Arakawa R, Nakayama K, Suhara T. Positron emission tomography inter-scanner differences in dopamine D₂ receptor binding measured with [¹¹C]FLB457. Ann Nucl Med 2010; 24:671-7. [PMID: 20734246 DOI: 10.1007/s12149-010-0407-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Accepted: 07/23/2010] [Indexed: 11/29/2022]
Abstract
OBJECTIVE It is well known that the positron emission tomography (PET) system is subject to inter-scanner differences of regional radioactivity distribution. In the present study, the effect of inter-scanner difference of regional radioactivity on estimated binding potential (BP(ND)) of [¹¹C]FLB457 using the simplified reference tissue model (SRTM) was investigated. METHODS Each of the 11 subjects was given two PET scans using [¹¹C]FLB457, one each with both SET-3000 GCT/X (Shimadzu) and with ECAT EXACT HR+ (Siemens/CTI). In order to assess regional differences between the two scanners, estimated BP(ND) values in six volumes of interest (VOIs) by SRTM method were compared in both individual PET space and anatomical template space after anatomical normalization. Statistical voxel-by-voxel paired t test of BP(ND) images between SET-3000 GCT/X and ECAT EXACT HR+ was also performed. RESULTS Shapes of time-activity curves of the two PET scanners were slightly different in each VOI, with estimated BP(ND) values from ECAT EXACT HR+ appearing greater in the cerebral cortical regions and thalamus than that of SET-3000 GCT/X in both individual PET space and anatomical template space after anatomical normalization. Statistical voxel-by-voxel analysis showed similar tendency to BP(ND) value estimation, with greater BP(ND) values from ECAT EXACT HR+ than from SET-3000 GCT/X. CONCLUSIONS We demonstrated the inter-scanner differences in dopamine D(2) receptor binding measured with [¹¹C]FLB457. In particular, statistically significant differences of BP(ND) in certain regions were observed between two PET scanners, despite the subject groups being the same. Our results suggest that we reconsider the effect of the scanner model on the measurement of receptor binding.
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Affiliation(s)
- Fumitoshi Kodaka
- Clinical Neuroimaging Team, Molecular Neuroimaging Group, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, Japan
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48
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Abstract
Many neurodegenerative dementias produce significant alterations in the brain that are often not detectable by neurologic tests or with structural imaging. PET is ideally suited for monitoring cell/molecular events early in the course of a disease as well as during pharmacologic therapy. During the past 2 decades, molecular neuroimaging using PET and magnetic resonance (MR) has advanced elegantly and steadily gained importance in the clinical and research arenas. Software- and hardware-based multimodality brain imaging allowing the correlation between anatomic and molecular information has revolutionized clinical diagnosis and now offers unique capabilities for the clinical neuroimaging community and neuroscience researchers at large.
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49
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Blockade of [11C](+)-PHNO binding in human subjects by the dopamine D3 receptor antagonist ABT-925. Int J Neuropsychopharmacol 2010; 13:273-87. [PMID: 19751545 DOI: 10.1017/s1461145709990642] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Dopamine D3 receptors are preferentially localized in the limbic system and midbrain, and thus may be involved in the pathophysiology of neuropsychiatry disorders. [11C](+)-PHNO is the first preferential D3 receptor radioligand in humans, yet there are no blockade studies with a D3 receptor antagonist in humans. This study characterized the blockade of [11C](+)-PHNO binding by ABT-925, a D3 receptor antagonist, in healthy male subjects. Sixteen subjects underwent 2-3 positron emission tomography (PET) scans, at baseline and following one or two doses of ABT-925 ranging from 50 mg to 600 mg. Receptor occupancies were estimated for globus pallidus, substantia nigra, caudate, putamen, and ventral striatum. At the 600-mg dose (n=9), ABT-925 receptor occupancy (mean+/-s.d.) was higher in substantia nigra (75+/-10%) and globus pallidus (64+/-22%) than in ventral striatum (44+/-17%), caudate (40+/-18%) and putamen (38+/-17%) (ANOVA: F4,140=15.02, p<0.001). The fractions of [11C](+)-PHNO binding attributable to D3 receptors in D3 receptor-rich regions were 100% (substantia nigra) and 90% (globus pallidus), and in D2 receptor-rich regions were 55% (caudate) and 53% (putamen). The ED50 of ABT-925 was 4.37 microg/ml across regions. Our results demonstrate that [11C](+)-PHNO binding can be blocked by a D3 receptor antagonist and confirm preclinical findings that [11C](+)-PHNO signal in the substantia nigra and globus pallidus is mainly reflective of its binding to D3 receptors. Thus, [11C](+)-PHNO seems a suitable PET radiotracer to estimate D3 receptor occupancy in humans.
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50
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Mourik JEM, Lubberink M, van Velden FHP, Kloet RW, van Berckel BNM, Lammertsma AA, Boellaard R. In vivo validation of reconstruction-based resolution recovery for human brain studies. J Cereb Blood Flow Metab 2010; 30:381-9. [PMID: 19844240 PMCID: PMC2949117 DOI: 10.1038/jcbfm.2009.225] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The aim of this study was to validate in vivo the accuracy of a reconstruction-based partial volume correction (PVC), which takes into account the point spread function of the imaging system. The NEMA NU2 Image Quality phantom and five healthy volunteers (using [(11)C]flumazenil) were scanned on both HR+ and high-resolution research tomograph (HRRT) scanners. HR+ data were reconstructed using normalization and attenuation-weighted ordered subsets expectation maximization (NAW-OSEM) and a PVC algorithm (PVC-NAW-OSEM). HRRT data were reconstructed using 3D ordinary Poisson OSEM (OP-OSEM) and a PVC algorithm (PVC-OP-OSEM). For clinical studies, parametric volume of distribution (V(T)) images were generated. For phantom data, good recovery was found for both OP-OSEM (0.84 to 0.97) and PVC-OP-OSEM (0.91 to 0.98) HRRT reconstructions. In addition, for the HR+, good recovery was found for PVC-NAW-OSEM (0.84 to 0.94), corresponding well with OP-OSEM. Finally, for clinical data, good correspondence was found between PVC-NAW-OSEM and OP-OSEM-derived V(T) values (slope: 1.02+/-0.08). This study showed that HR+ image resolution using PVC-NAW-OSEM was comparable to that of the HRRT scanner. As the HRRT has a higher intrinsic resolution, this agreement validates reconstruction-based PVC as a means of improving the spatial resolution of the HR+ scanner and thereby improving the quantitative accuracy of positron emission tomography.
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Affiliation(s)
- Jurgen E M Mourik
- Department of Nuclear Medicine & PET Research, VU University Medical Center, Amsterdam, The Netherlands.
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