| 1. |
- Knudsen, Gitte M, et al.
(författare)
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Guidelines for the content and format of PET brain data in publications and archives : A consensus paper
- 2020
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 0271-678X .- 1559-7016. ; 40:8, s. 1576-1585
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Tidskriftsartikel (refereegranskat)abstract
- It is a growing concern that outcomes of neuroimaging studies often cannot be replicated. To counteract this, the magnetic resonance (MR) neuroimaging community has promoted acquisition standards and created data sharing platforms, based on a consensus on how to organize and share MR neuroimaging data. Here, we take a similar approach to positron emission tomography (PET) data. To facilitate comparison of findings across studies, we first recommend publication standards for tracer characteristics, image acquisition, image preprocessing, and outcome estimation for PET neuroimaging data. The co-authors of this paper, representing more than 25 PET centers worldwide, voted to classify information as mandatory, recommended, or optional. Second, we describe a framework to facilitate data archiving and data sharing within and across centers. Because of the high cost of PET neuroimaging studies, sample sizes tend to be small and relatively few sites worldwide have the required multidisciplinary expertise to properly conduct and analyze PET studies. Data sharing will make it easier to combine datasets from different centers to achieve larger sample sizes and stronger statistical power to test hypotheses. The combining of datasets from different centers may be enhanced by adoption of a common set of best practices in data acquisition and analysis.
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| 2. |
- Laurell, Gjertrud L, et al.
(författare)
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Nondisplaceable Binding Is a Potential Confounding Factor in 11C-PBR28 Translocator Protein PET Studies.
- 2021
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 62:3, s. 412-417
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Tidskriftsartikel (refereegranskat)abstract
- The PET ligand 11C-PBR28 (N-((2-(methoxy-11C)-phenyl)methyl)-N-(6-phenoxy-3-pyridinyl)acetamide) binds to the 18-kDa translocator protein (TSPO), a biomarker of glia. In clinical studies of TSPO, the ligand total distribution volume, VT, is frequently the reported outcome measure. Since VT is the sum of the ligand-specific distribution volume (VS) and the nondisplaceable-binding distribution volume (VND), differences in VND across subjects and groups will have an impact on VTMethods: Here, we used a recently developed method for simultaneous estimation of VND (SIME) to disentangle contributions from VND and VS Data from 4 previously published 11C-PBR28 PET studies were included: before and after a lipopolysaccharide challenge (8 subjects), in alcohol use disorder (14 patients, 15 controls), in first-episode psychosis (16 patients, 16 controls), and in Parkinson disease (16 patients, 16 controls). In each dataset, regional VT estimates were obtained with a standard 2-tissue-compartment model, and brain-wide VND was estimated with SIME. VS was then calculated as VT - VND VND and VS were then compared across groups, within each dataset. Results: A lower VND was found for individuals with alcohol-use disorder (34%, P = 0.00084) and Parkinson disease (34%, P = 0.0032) than in their corresponding controls. We found no difference in VND between first-episode psychosis patients and their controls, and the administration of lipopolysaccharide did not change VNDConclusion: Our findings suggest that in TSPO PET studies, nondisplaceable binding can differ between patient groups and conditions and should therefore be considered.
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| 3. |
- Plaven-Sigray, Pontus, et al.
(författare)
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Accuracy and reliability of [C-11]PBR28 specific binding estimated without the use of a reference region
- 2019
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Ingår i: NeuroImage. - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 1053-8119 .- 1095-9572. ; 188, s. 102-110
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Tidskriftsartikel (refereegranskat)abstract
- [C-11]PBR28 is a positron emission tomography radioligand used to examine the expression of the 18 kDa translocator protein (TSPO). TSPO is located in glial cells and can function as a marker for immune activation. Since TSPO is expressed throughout the brain, no true reference region exists. For this reason, an arterial input function is required for accurate quantification of [C-11]PBR28 binding and the most common outcome measure is the total distribution volume (V-T). Notably, V-T reflects both specific binding and non-displaceable binding. Therefore, estimates of specific binding, such as binding potential (e.g. BPND) and specific distribution volume (V-S) should theoretically be more sensitive to underlying differences in TSPO expression. It is unknown, however, if unbiased and accurate estimates of these outcome measures are obtainable for [C-11]PBR28. The Simultaneous Estimation (SIME) method uses time-activity-curves from multiple brain regions with the aim to obtain a brain-wide estimate of the non-displaceable distribution volume (V-ND), which can subsequently be used to improve the estimation of BPND and V-S. In this study we evaluated the accuracy of SIME-derived V-ND, and the reliability of resulting estimates of specific binding for [C-11]PBR28, using a combination of simulation experiments and in vivo studies in healthy humans. The simulation experiments, based on data from 54 unique [C-11]PBR28 examinations, showed that V-ND values estimated using SIME were both precise and accurate. Data from a pharmacological competition challenge (n = 5) showed that SIME provided V-ND values that were on average 19% lower than those obtained using the Lassen plot, but similar to values obtained using the Likelihood-Estimation of Occupancy technique. Test-retest data (n = 11) showed that SIME-derived V-S values exhibited good reliability and precision, while larger variability was observed in SIME-derived BPND values. The results support the use of SIME for quantifying specific binding of [C-11]PBR28, and suggest that V-S can be used in complement to the conventional outcome measure V-T. Additional studies in patient cohorts are warranted.
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