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- Borga, Magnus, 1965-, et al.
(författare)
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MRI-Based Body Composition Analysis
- 2022. - 1
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Ingår i: Basic Protocols in Foods and Nutrition. - New York, NY, United States : Springer Nature. - 9781071623442 ; , s. 307-334
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Bokkapitel (refereegranskat)abstract
- Magnetic resonance imaging (MRI) is considered being state-of-the-art technology for body composition analysis. Compared to other indirect techniques such as scales, calipers, bioimpedance, and dual-energy X-ray absorptiometry (DXA), MRI offers direct and precise measurements of the volumes of different tissue compartments and also enables quantification of diffuse fat infiltration in organs. Here, we describe a protocol for acquiring of fat–water-separated MRI data and the image postprocessing required for the quantification of several body composition biomarkers relevant for metabolic research. This protocol has successfully been used in several clinical studies and also in the large UK Biobank population study.
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| 2. |
- Chakwizira, Arthur, et al.
(författare)
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Non-parametric deconvolution using Bézier curves for quantification of cerebral perfusion in dynamic susceptibility contrast MRI
- 2022
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Ingår i: Magnetic Resonance Materials in Physics, Biology, and Medicine. - : Springer Science and Business Media LLC. - 1352-8661. ; 35:5, s. 791-804
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Tidskriftsartikel (refereegranskat)abstract
- Objective Deconvolution is an ill-posed inverse problem that tends to yield non-physiological residue functions R(t) indynamic susceptibility contrast magnetic resonance imaging (DSC-MRI). In this study, the use of Bézier curves is proposedfor obtaining physiologically reasonable residue functions in perfusion MRI.Materials and methods Cubic Bézier curves were employed, ensuring R(0)=1, bounded-input, bounded-output stability anda non-negative monotonically decreasing solution, resulting in 5 parameters to be optimized. Bézier deconvolution (BzD),implemented in a Bayesian framework, was tested by simulation under realistic conditions, including efects of arterial delayand dispersion. BzD was also applied to DSC-MRI data from a healthy volunteer.Results Bézier deconvolution showed robustness to diferent underlying residue function shapes. Accurate perfusion estimates were observed, except for boxcar residue functions at low signal-to-noise ratio. BzD involving corrections for delay,dispersion, and delay with dispersion generally returned accurate results, except for some degree of cerebral blood fow(CBF) overestimation at low levels of each efect. Maps of mean transit time and delay were markedly diferent betweenBzD and block-circulant singular value decomposition (oSVD) deconvolution.Discussion A novel DSC-MRI deconvolution method based on Bézier curves was implemented and evaluated. BzD produced physiologically plausible impulse response, without spurious oscillations, with generally less CBF underestimationthan oSVD.
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| 3. |
- Mellion, Michelle L., et al.
(författare)
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Quantitative Muscle Analysis in FSHD Using Whole-Body Fat-Referenced MRI Composite Scores for Longitudinal and Cross-sectional Analysis
- 2022
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Ingår i: Neurology. - : LIPPINCOTT WILLIAMS & WILKINS. - 0028-3878 .- 1526-632X. ; 99:9, s. E877-E889
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Tidskriftsartikel (refereegranskat)abstract
- Background and Objectives Facioscapulohumeral muscular dystrophy (FSHD) is a rare, debilitating disease characterized by progressive muscle weakness. MRI is a sensitive assessment of disease severity and progression. We developed a quantitative whole-body (WB) musculoskeletal MRI (WB-MSK-MRI) protocol analyzing muscles in their entirety. This study aimed to assess WB-MSK-MRI as a potential imaging biomarker providing reliable measurements of muscle health that capture disease heterogeneity and clinically meaningful composite assessments correlating with severity and more responsive to change in clinical trials. Methods Participants aged 18-65 years, with genetically confirmed FSHD1, clinical severity 2 to 4 (Ricci scale, range 0-5), and >= 1 short tau inversion recovery-positive lower extremity muscle eligible for needle biopsy, enrolled at 6 sites and were imaged twice 4-12 weeks apart. Volumetric analysis of muscle fat infiltration (MFI), muscle fat fraction (MFF), and lean muscle volume (LMV) in 18 (36 total) muscles from bilateral shoulder, proximal arm, trunk, and legs was performed after automated atlas-based segmentation, followed by manual verification. A WB composite score, including muscles at highest risk for progression, and functional cross-sectional composites for correlation with relevant functional outcomes including timed up and go (TUG), FSHD-TUG, and reachable workspace (RWS), were developed. Results Seventeen participants enrolled in this study; 16 follow-up MRIs were performed at 52 days (range 36-85 days). Functional cross-sectional composites (MFF and MFI) showed moderate to strong correlations: TUG (rho = 0.71, rho = 0.83), FSHD-TUG (rho = 0.73, rho = 0.73), and RWS (left arm: rho = -0.71, rho = -0.53; right arm: rho = -0.61, rho = -0.65). WB composite variability: LMVtot, coefficient of variation (CV) 1.9% and 3.4%; MFFtot, within-subject SD (S-w) 0.5% and 1.5%; and MFItot (S-w), 0.3% and 0.4% for normal and intermediate muscles, respectively. CV and S-w were higher in intermediate (MFI >= 0.10; MFF <0.50) than in normal (MFI <0.10, MFF <0.50) muscles. Discussion We developed a WB-MSK-MRI protocol and composite measures that capture disease heterogeneity and assess muscle involvement as it correlates with FSHD-relevant clinical endpoints. Functional composites robustly correlate with functional assessments. Stability of the WB composite shows that it could be an assessment of change in therapeutic clinical trials. Classification of Evidence This study provides Class II evidence that quantitative WB-MSK-MRI findings associate with FSHD1 severity measured using established functional assessments.
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| 4. |
- Widholm, Per, et al.
(författare)
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Quantitative muscle analysis in facioscapulohumeral muscular dystrophy using whole-body fat-referenced MRI: Protocol development, multicenter feasibility, and repeatability
- 2022
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Ingår i: Muscle and Nerve. - : WILEY. - 0148-639X .- 1097-4598. ; 66:2, s. 183-192
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Tidskriftsartikel (refereegranskat)abstract
- Introduction/Aims Functional performance tests are the gold standard to assess disease progression and treatment effects in neuromuscular disorders. These tests can be confounded by motivation, pain, fatigue, and learning effects, increasing variability and decreasing sensitivity to disease progression, limiting efficacy assessment in clinical trials with small sample sizes. We aimed to develop and validate a quantitative and objective method to measure skeletal muscle volume and fat content based on whole-body fat-referenced magnetic resonance imaging (MRI) for use in multisite clinical trials. Methods Subjects aged 18 to 65 years, genetically confirmed facioscapulohumeral muscular dystrophy 1 (FSHD1), clinical severity 2 to 4 (Riccis scale, range 0-5), were enrolled at six sites and imaged twice 4-12 weeks apart with T1-weighted two-point Dixon MRI covering the torso and upper and lower extremities. Thirty-six muscles were volumetrically segmented using semi-automatic multi-atlas-based segmentation. Muscle fat fraction (MFF), muscle fat infiltration (MFI), and lean muscle volume (LMV) were quantified for each muscle using fat-referenced quantification. Results Seventeen patients (mean age +/- SD, 49.4 years +/- 13.02; 12 men) were enrolled. Within-patient SD ranged from 1.00% to 3.51% for MFF and 0.40% to 1.48% for MFI in individual muscles. For LMV, coefficients of variation ranged from 2.7% to 11.7%. For the composite score average of all muscles, observed SDs were 0.70% and 0.32% for MFF and MFI, respectively; composite LMV coefficient of variation was 2.0%. Discussion We developed and validated a method for measuring skeletal muscle volume and fat content for use in multisite clinical trials of neuromuscular disorders.
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