| 1. |
- Tejani, Sanaa, et al.
(författare)
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Cardiometabolic Health Outcomes Associated With Discordant Visceral and Liver Fat Phenotypes: Insights From the Dallas Heart Study and UK Biobank
- 2022
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Ingår i: Mayo Clinic proceedings. - New York, United States : Elsevier. - 0025-6196 .- 1942-5546. ; 97:2, s. 225-237
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To evaluate the cardiometabolic outcomes associated with discordant visceral adipose tissue (VAT) and liver fat (LF) phenotypes in 2 cohorts.Patients and Methods: Participants in the Dallas Heart Study underwent baseline imaging from January 1, 2000, through December 31, 2002, and were followed for incident cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM) through 2013. Associations between VAT-LF groups (low-low, high-low, low-high, and high-high) and outcomes were assessed using multivariable- adjusted regression and were replicated in the independent UK Biobank.Results: The Dallas Heart Study included 2064 participants (mean SD age, 449 years; 54% female; 47% black). High VATehigh LF and high VATelow LF were associated with prevalent atheroscle- rosis, whereas low VATehigh LF was not. Of 1731 participants without CVD/T2DM, 128 (7.4%) developed CVD and 95 (5.5%) T2DM over a median of 12 years. High VATehigh LF and high VATelow LF were associated with increased risk of CVD (hazard ratios [HRs], 2.0 [95% CI, 1.3 to 3.2] and 2.4 [95% CI, 1.4 to 4.1], respectively) and T2DM (odds ratios [ORs], 7.8 [95% CI, 3.8 to 15.8] and 3.3 [95% CI, 1.4 to 7.8], respectively), whereas low VATehigh LF was associated with T2DM (OR, 2.7 [95% CI, 1.1 to 6.7]). In the UK Biobank (N1⁄422,354; April 2014-May 2020), only high VATelow LF remained associated with CVD after multivariable adjustment for age and body mass index (HR, 1.5 [95% CI, 1.2 to 1.9]).Conclusion: Although VAT and LF are each associated with cardiometabolic risk, these observations demonstrate the importance of separating their cardiometabolic implications when there is presence or absence of either or both in an individual.
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| 2. |
- 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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| 3. |
- Borga, Magnus, et al.
(författare)
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Reproducibility and repeatability of MRI-based body composition analysis
- 2020
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Ingår i: Magnetic Resonance in Medicine. - : WILEY. - 0740-3194 .- 1522-2594. ; 84:6, s. 3146-3156
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Tidskriftsartikel (refereegranskat)abstract
- Purpose There is an absence of reproducibility studies on MRI-based body composition analysis in current literature. Therefore, the aim of this study was to investigate the between-scanner reproducibility and the repeatability of a method for MRI-based body composition analysis. Methods Eighteen healthy volunteers of varying body mass index and adiposity were each scanned twice on five different 1.5T and 3T scanners from three different vendors. Two-point Dixon neck-to knee images and two additional liver scans were acquired with similar protocols. Visceral adipose tissue (VAT) volume, abdominal subcutaneous adipose tissue (ASAT) volume, thigh muscle volume, and muscle fat infiltration (MFI) in the thigh muscle were measured. Liver proton density fat fraction (PDFF) was assessed using two different methods, the scanner vendors 6-point method and an in-house 2-point method. Within-scanner test-retest repeatability and between-scanner reproducibility were calculated using analysis of variance. Results Repeatability coefficients were 13 centiliters (cl) (VAT), 24 cl (ASAT), 17 cl (total thigh muscle volume), 0.53% (MFI), and 1.27-1.37% for liver PDFF. Reproducibility coefficients were 24 cl (VAT), 42 cl (ASAT), 31 cl (total thigh muscle volume), 1.44% (MFI), and 2.37-2.40% for liver PDFF. Conclusion For all measures except MFI, the within-scanner repeatability explained much of the overall reproducibility. The two methods for measuring liver fat had similar reproducibility. This study showed that the investigated method eliminates effects due to scanner differences. The results can be used for power calculations in clinical studies or to better understand the scanner-induced variability in clinical applications.
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| 4. |
- Karlsson, Anette, 1986-, et al.
(författare)
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The effect on precision and T1 bias comparing two flip angles when estimating muscle fat infiltration using fat-referenced chemical shift-encoded imaging
- 2021
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Ingår i: NMR in Biomedicine. - : John Wiley & Sons. - 0952-3480 .- 1099-1492. ; 34:11
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Tidskriftsartikel (refereegranskat)abstract
- Investigation of the effect on accuracy and precision of different parameter settings is important for quantitative Magnetic Resonance Imaging. The purpose of this study was to investigate T1-bias and precision for muscle fat infiltration (MFI) using fat-referenced chemical shift magnetic resonance imaging at 5° and 10° flip angle. This [MB1] experimental study was done on forty postmenopausal women using 3T MRI test and retest images using 4-point 3D spoiled gradient multi-echo acquisition including real and imaginary images for reconstruction acquired at Flip angles 5° and 10°. Post-processing included T2* correction and fat-referenced calibration of the fat signal. The mean MFI was calculated in six different automatically segmented muscle regions using both the fat-referenced fat signal and the fat fraction calculated from the fat and water image pair for each acquisition. The variance of the difference between mean MFI from test and retest was used as measure of precision. The SNR characteristics were analyzed by measuring difference of the full width half maximum of the fat signal distribution using Student’s t-test.There was no difference in the mean fat-referenced MFI at different flip angles with the fat-referenced technique, which was the case using the fat fraction. No significant difference in the precision was found in any of the muscles analyzed. However, the full width half maximum of the fat signal distribution was significantly lower at 10° flip angle compared to 5°. Fat-referenced MFI is insensitive to T1 bias in chemical shift magnetic resonance imaging enabling usage of a higher and more SNR effective flip angle. The lower full-width-at half-maximum in fat-referenced MFI at 10° indicates that high flip angle acquisition is advantageous although no significant differences in precision was observed comparing 5° and 10°.
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| 5. |
- Lund, Nils, 1993-, et al.
(författare)
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Fatty infiltrate and neck muscle volume in individuals with chronic whiplash associated disorders compared to healthy controls - a cross sectional case-control study
- 2023
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Ingår i: BMC Musculoskeletal Disorders. - : BioMed Central (BMC). - 1471-2474. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: The underlying pathophysiological mechanisms of chronic Whiplash Associated Disorders (WAD) are not fully understood. More knowledge of morphology is needed to better understand the disorder, improve diagnostics and treatments. The aim was to investigate dorsal neck muscle volume (MV) and muscle fat infiltration (MFI) in relation to self-reported neck disability among 30 participants with chronic WAD grade II-III compared to 30 matched healthy controls.Methods: MV and MFI at spinal segments C4 through C7 in both sexes with mild- to moderate chronic WAD (n = 20), severe chronic WAD (n = 10), and age- and sex matched healthy controls (n = 30) was compared. Muscles: trapezius, splenius, semispinalis capitis and semispinalis cervicis were segmented by a blinded assessor and analyzed.Results: Higher MFI was found in right trapezius (p = 0.007, Cohen's d = 0.9) among participants with severe chronic WAD compared to healthy controls. No other significant difference was found for MFI (p = 0.22-0.95) or MV (p = 0.20-0.76).ConclusionsThere are quantifiable changes in muscle composition of right trapezius on the side of dominant pain and/or symptoms, among participants with severe chronic WAD. No other statistically significant differences were shown for MFI or MV. These findings add knowledge of the association between MFI, muscle size and self-reported neck disability in chronic WAD.
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| 6. |
- Niklasson, Erik, et al.
(författare)
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Assessment of anterior thigh muscle size and fat infiltration using single-slice CT imaging versus automated MRI analysis in adults
- 2022
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Ingår i: British Journal of Radiology. - London, United Kingdom : British Institute of Radiology. - 0007-1285 .- 1748-880X. ; 95:1133
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: We examined the longitudinal and cross- sectional relationship between automated MRI-analysis and single-slice axial CT imaging for determining muscle size and muscle fat infiltration (MFI) of the anterior thigh.Methods: Twenty-two patients completing sex-hormone treatment expected to result in muscle hypertrophy (n = 12) and atrophy (n = 10) underwent MRI scans using 2-point Dixon fat/water-separated sequences and CT scans using a system operating at 120 kV and a fixed flux of 100 mA. At baseline and 12 months after, auto- mated volumetric MRI analysis of the anterior thigh was performed bilaterally, and fat-free muscle volume and MFI were computed. In addition, cross-sectional area (CSA) and radiological attenuation (RA) (as a marker of fat infiltration) were calculated from single slice axial CT-images using threshold-assisted planimetry. Linear regression models were used to convert units.Results: There was a strong correlation between MRI- derived fat-free muscle volume and CT-derived CSA (R = 0.91), and between MRI-derived MFI and CT-derived RA (R = −0.81). The 95% limits of agreement were ±0.32 L for muscle volume and ±1.3% units for %MFI. The longi- tudinal change in muscle size and MFI was comparable across imaging modalities.Conclusions: Both automated MRI and single-slice CT-imaging can be used to reliably quantify anterior thigh muscle size and MFI.Advances in knowledge: This is the first study examining the intermodal agreement between automated MRI anal- ysis and CT-image assessment of muscle size and MFI in the anterior thigh muscles. Our results support that both CT- and MRI-derived measures of muscle size and MFI can be used in clinical settings.
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| 7. |
- Nilsson, Sigrid, et al.
(författare)
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Resistance training decreased abdominal adiposity in postmenopausal women
- 2023
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Ingår i: Maturitas. - : ELSEVIER IRELAND LTD. - 0378-5122 .- 1873-4111. ; 176
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate if abdominal adipose tissue volumes and ratios change after a 15-week structured resistance training intervention in postmenopausal women with vasomotor symptoms (VMS).Study design: Sixty-five postmenopausal women with VMS and low physical activity were randomized to either three days/week supervised resistance training or unchanged physical activity for 15 weeks. Women underwent clinical anthropometric measurements and magnetic resonance imaging (MRI) at baseline and after 15 weeks. MRI was done using a Philips Ingenia 3.0 T MR scanner (Philips, Best, The Netherlands). The per protocol principle was used in the analysis of data.Main outcome measurements: The absolute change from baseline to week 15 in visceral adipose tissue (VAT) volume and the relative ratio (VAT ratio) between VAT and total abdominal adipose tissue (TAAT), i.e. the sum of abdominal subcutaneous adipose tissue (ASAT) and VAT.Results: There were no significant differences between the groups in characteristics, anthropometry or MRI measures at baseline. Women who were compliant with the intervention (i.e. participated in at least two of the three scheduled training sessions per week) had significantly different reduction over time in ASAT (p = 0.006), VAT (p = 0.002), TAAT (p = 0.003) and fat ratio (p < 0.001) compared with women in the control group.Conclusions: Implementation of a 15-week resistance training regimen in midlife may help women to counteract the abdominal fat redistribution associated with the menopausal transition. Clinical trials: gov registered ID: NCT01987778.
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