| 1. |
- Benlloch, Jose M., et al.
(författare)
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The MINDVIEW project : First results
- 2018
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Ingår i: European psychiatry. - : Cambridge University Press (CUP). - 0924-9338 .- 1778-3585. ; 50, s. 21-27
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Tidskriftsartikel (refereegranskat)abstract
- We present the first results of the MINDVIEW project. An innovative imaging system for the human brain examination, allowing simultaneous acquisition of PET/MRI images, has been designed and constructed. It consists of a high sensitivity and high resolution PET scanner integrated in a novel, head-dedicated, radio frequency coil for a 3T MRI scanner. Preliminary measurements from the PET scanner show sensitivity 3 times higher than state-of-the-art PET systems that will allow safe repeated studies on the same patient. The achieved spatial resolution, close to 1 mm, will enable differentiation of relevant brain structures for schizophrenia. A cost-effective and simple method of radiopharmaceutical production from 11C-carbon monoxide and a mini-clean room has been demonstrated. It has been shown that 11C-raclopride has higher binding potential in a new VAAT null mutant mouse model of schizophrenia compared to wild type control animals. A significant reduction in TSPO binding has been found in gray matter in a small sample of drug-naïve, first episode psychosis patients, suggesting a reduced number or an altered function of immune cells in brain at early stage schizophrenia.
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| 2. |
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| 3. |
- Müller, Christoph A., et al.
(författare)
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Dynamic 2D and 3D mapping of hyperpolarized pyruvate to lactate conversion in vivo with efficient multi-echo balanced steady-state free precession at 3 T
- 2020
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Ingår i: NMR in Biomedicine. - : Wiley. - 0952-3480 .- 1099-1492. ; 33:6
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to acquire the transient MRI signal of hyperpolarized tracers and their metabolites efficiently, for which specialized imaging sequences are required. In this work, a multi-echo balanced steady-state free precession (me-bSSFP) sequence with Iterative Decomposition with Echo Asymmetry and Least squares estimation (IDEAL) reconstruction was implemented on a clinical 3 T positron-emission tomography/MRI system for fast 2D and 3D metabolic imaging. Simulations were conducted to obtain signal-efficient sequence protocols for the metabolic imaging of hyperpolarized biomolecules. The sequence was applied in vitro and in vivo for probing the enzymatic exchange of hyperpolarized [1–13C]pyruvate and [1–13C]lactate. Chemical shift resolution was achieved using a least-square, iterative chemical species separation algorithm in the reconstruction. In vitro, metabolic conversion rate measurements from me-bSSFP were compared with NMR spectroscopy and free induction decay-chemical shift imaging (FID-CSI). In vivo, a rat MAT-B-III tumor model was imaged with me-bSSFP and FID-CSI. 2D metabolite maps of [1–13C]pyruvate and [1–13C]lactate acquired with me-bSSFP showed the same spatial distributions as FID-CSI. The pyruvate-lactate conversion kinetics measured with me-bSSFP and NMR corresponded well. Dynamic 2D metabolite mapping with me-bSSFP enabled the acquisition of up to 420 time frames (scan time: 180-350 ms/frame) before the hyperpolarized [1–13C]pyruvate was relaxed below noise level. 3D metabolite mapping with a large field of view (180 × 180 × 48 mm3) and high spatial resolution (5.6 × 5.6 × 2 mm3) was conducted with me-bSSFP in a scan time of 8.2 seconds. It was concluded that Me-bSSFP improves the spatial and temporal resolution for metabolic imaging of hyperpolarized [1–13C]pyruvate and [1–13C]lactate compared with either of the FID-CSI or EPSI methods reported at 3 T, providing new possibilities for clinical and preclinical applications.
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| 4. |
- Steingoetter, Andreas, et al.
(författare)
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Reference Region-Based Pharmacokinetic Modeling in Quantitative Dynamic Contract-Enhanced MRI Allows Robust Treatment Monitoring in a Rat Liver Tumor Model Despite Cardiovascular Changes
- 2011
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Ingår i: Magnetic Resonance in Medicine. - : Wiley. - 1522-2594 .- 0740-3194. ; 65:1, s. 229-238
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Tidskriftsartikel (refereegranskat)abstract
- In this work, two pharmacokinetic modeling techniques, population arterial input function model, and reference region model, were applied to dynamic contract-enhanced MRI data, to test the influence of a change in heart rate on modeling parameters. A rat population arterial input function was generated by dynamic contrast-enhanced computed tomography measurements using the MR contrast agent gadolinium diethylenetriamine penta-acetic acid. Then, dynamic contract-enhanced MRI was used for treatment monitoring in two groups of hepatocellular carcinoma bearing rats. Whereas group 1 had the same heart rate as animals analyzed for the population arterial input function (263 +/- 20 bpm), group 2 had a higher heart rate (369 +/- 11 bpm) due to a different anesthesia protocol. The pharmacokinetic modeling parameters volume transfer constant K-trans and relative extravascular extracellular space v(e) were calculated with both models and statistically compared. For group 1, good correlation and agreement was found between the models showing no difference in K-trans and v(e) (Delta K-trans:4 +/- 19% and Delta v(e):4 +/- 12%, P = 0.2). In contrast, for group 2, a bias in parameter values for the population arterial input function model was detected (Delta K-trans: -45 +/- 7% and Delta v(e):-31 +/- 7%, P <= 0.001). The presented work underlines the value of the reference region model in longitudinal treatment monitoring and provides a straightforward approach for the generation of a rat population arterial input function. Magn Reson Med 65: 229-238, 2011. (C) 2010 Wiley-Liss, Inc.
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