scholarly journals Estimating whole body intermuscular adipose tissue from single cross-sectional magnetic resonance images

2007 ◽  
Vol 102 (2) ◽  
pp. 748-754 ◽  
Author(s):  
Xiang Yan Ruan ◽  
Dympna Gallagher ◽  
Tamara Harris ◽  
Jeanine Albu ◽  
Steven Heymsfield ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Menopausal Status ◽  
Magnetic Resonance Images ◽  
Whole Body ◽  
Adult Women ◽  
Regression Equations ◽  
Cross Sectional ◽  
Intermuscular Adipose Tissue ◽  
Single Slice ◽  
Slice Location

Intermuscular adipose tissue (IMAT), a novel fat depot linked with metabolic abnormalities, has been measured by whole body MRI. The cross-sectional slice location with the strongest relation to total body IMAT volume has not been established. The aim was to determine the predictive value of each slice location and which slice locations provide the best estimates of whole body IMAT. MRI quantified total adipose tissue of which IMAT, defined as adipose tissue visible within the boundary of the muscle fascia, is a subcomponent. Single-slice IMAT areas were calculated for the calf, thigh, buttock, waist, shoulders, upper arm, and forearm locations in a sample of healthy adult women, African-American [ n = 39; body mass index (BMI) 28.5 ± 5.4 kg/m2; 41.8 ± 14.8 yr], Asian ( n = 21; BMI 21.6 ± 3.2 kg/m2; 40.9 ± 16.3 yr), and Caucasian ( n = 43; BMI 25.6 ± 5.3 kg/m2; 43.2 ± 15.3 yr), and Caucasian men ( n = 39; BMI 27.1 ± 3.8 kg/m2; 45.2 ± 14.6 yr) and used to estimate total IMAT groups using multiple-regression equations. Midthigh was the best, or near best, single predictor in all groups with adjusted R2 ranging from 0.49 to 0.84. Adding a second and third slice further increased R2 and reduced the error of the estimate. Menopausal status and degree of obesity did not affect the location of the best single slice. The contributions of other slice locations varied by sex and race, but additional slices improved predictions. For group studies, it may be more cost-effective to estimate IMAT based on one or more slices than to acquire and segment for each subject the numerous images necessary to quantify whole body IMAT.

scholarly journals Estimating whole‐body intermuscular adipose tissue from single cross‐sectional magnetic resonance images

2006 ◽  
Vol 20 (4) ◽  
Author(s):  
Xiangyan Ruan ◽  
Dympna Gallagher ◽  
Tamara Harris ◽  
Jeanine Albu ◽  
Steven Heymsfield ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Magnetic Resonance ◽  
Magnetic Resonance Images ◽  
Whole Body ◽  
Cross Sectional ◽  
Intermuscular Adipose Tissue ◽  
Single Cross

Total body skeletal muscle and adipose tissue volumes: estimation from a single abdominal cross-sectional image

2004 ◽  
Vol 97 (6) ◽  
pp. 2333-2338 ◽  
Author(s):  
Wei Shen ◽  
Mark Punyanitya ◽  
ZiMian Wang ◽  
Dympna Gallagher ◽  
Marie-Pierre St.-Onge ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Body Mass Index ◽  
Adipose Tissue ◽  
Magnetic Resonance ◽  
Body Mass ◽  
Whole Body ◽  
Intervertebral Space ◽  
Cross Sectional ◽  
Abdominal Image ◽  
Total Body

A single abdominal cross-sectional computerized axial tomography and magnetic resonance image is often obtained in studies examining adipose tissue (AT) distribution. An abdominal image might also provide additional useful information on total body skeletal muscle (SM) and AT volumes with related physiological insights. We therefore investigated the relationships between abdominal SM and AT areas from single images and total body component volumes in a large and diverse sample of healthy adult subjects. Total body SM and AT volumes were derived by whole body multislice magnetic resonance imaging in 123 men [age (mean ± SD) of 41.6 ± 15.8 yr; body mass index of 25.9 ± 3.4 kg/m2] and 205 women (age of 47.8 ± 18.7 yr; body mass index of 26.7 ± 5.6 kg/m2). Single abdominal SM and AT slice areas were highly correlated with total body SM ( r = 0.71–0.92; r = 0.90 at L4–L5 intervertebral space) and AT ( r = 0.84–0.96; r = 0.94 at L4–L5 intervertebral space) volumes, respectively. R2 increased by only 5.7–6.1% for SM and 2.7–4.4% for AT with the inclusion of subject sex, age, ethnicity, scanning position, body mass index, and waist circumference in the model. The developed SM and AT models were validated in an additional 49 subjects. To achieve equivalent power to a study measuring total body SM or AT volumes, a study using a single abdominal image would require 17–24% more subjects for SM and 6–12% more subjects for AT. Measurement of a single abdominal image can thus provide estimates of total body SM and AT for group studies of healthy adults.

scholarly journals Occupational exposures and mammographic density in Spanish women

2017 ◽  
Vol 75 (2) ◽  
pp. 124-131 ◽  
Author(s):  
Virginia Lope ◽  
Javier García-Pérez ◽  
Beatriz Pérez-Gómez ◽  
Ana María Pedraza-Flechas ◽  
Juan Alguacil ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Mammographic Density ◽  
Menopausal Status ◽  
Occupational Exposures ◽  
Population Based ◽  
Ionising Radiation ◽  
Adult Women ◽  
Linear Regression Models ◽  
Cross Sectional ◽  
Hydrocarbon Solvents

ObjectivesThe association between occupational exposures and mammographic density (MD), a marker of breast cancer risk, has not been previously explored. Our objective was to investigate the influence of occupational exposure to chemical, physical and microbiological agents on MD in adult women.MethodsThis is a population-based cross-sectional study based on 1476 female workers aged 45–65 years from seven Spanish breast cancer screening programmes. Occupational history was surveyed by trained staff. Exposure to occupational agents was assessed using the Spanish job-exposure matrix MatEmESp. Percentage of MD was measured by two radiologists using a semiautomatic computer tool. The association was estimated using mixed log-linear regression models adjusting for age, education, body mass index, menopausal status, parity, smoking, alcohol intake, type of mammography, family history of breast cancer and hormonal therapy use, and including screening centre and professional reader as random effects terms.ResultsAlthough no association was found with most of the agents, women occupationally exposed to perchloroethylene (eβ=1.51; 95% CI 1.04 to 2.19), ionising radiation (eβ=1.23; 95% CI 0.99 to 1.52) and mould spores (eβ=1.44; 95% CI 1.01 to 2.04) tended to have higher MD. The percentage of density increased 12% for every 5 years exposure to perchloroethylene or mould spores, 11% for every 5 years exposure to aliphatic/alicyclic hydrocarbon solvents and 3% for each 5 years exposure to ionising radiation.ConclusionsExposure to perchloroethylene, ionising radiation, mould spores or aliphatic/alicyclic hydrocarbon solvents in occupational settings could be associated with higher MD. Further studies are needed to clarify the accuracy and the reasons for these findings.

Intermuscular adipose tissue-free skeletal muscle mass: estimation by dual-energy X-ray absorptiometry in adults

2004 ◽  
Vol 97 (2) ◽  
pp. 655-660 ◽  
Author(s):  
Jaehee Kim ◽  
Stanley Heshka ◽  
Dympna Gallagher ◽  
Donald P. Kotler ◽  
Laurel Mayer ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Prediction Models ◽  
Model Development ◽  
Race Model ◽  
Dual Energy ◽  
Whole Body ◽  
Study Objective ◽  
X Ray ◽  
Intermuscular Adipose Tissue

Skeletal muscle (SM) is a large and physiologically important compartment. Adipose tissue is found interspersed between and within SM groups and is referred to as intermuscular adipose tissue (IMAT). The study objective was to develop prediction models linking appendicular lean soft tissue (ALST) estimates by dual-energy X-ray absorptiometry (DXA) with whole body IMAT-free SM quantified by magnetic resonance imaging. ALST and total-body IMAT-free SM were evaluated in 270 healthy adults [body mass index (BMI) of <35 kg/m2]. The SM prediction models were then validated by the leave-one-out method and by application in a new group of subjects who varied in SM mass [anorexia nervosa (AN), n = 23; recreational athletes, n = 16; patients with acromegaly, n = 7]. ALST alone was highly correlated with whole body IMAT-free SM [ model 1: R2 = 0.96, standard error (SE) = 1.46 kg, P < 0.001]; age ( model 2: R2 = 0.97, SE = 1.38 kg, P < 0.001) and sex and race ( model 3: R2 = 0.97, SE = 1.06 kg, both P < 0.001) added significantly to the prediction models. All three models validated in the athletes and patients with acromegaly but significantly ( P < 0.01–0.001) over-predicted SM in the AN group as a whole. However, model 1 was validated in AN patients with BMIs in the model-development group range ( n = 11; BMI of >16 kg/m2) but not in those with a BMI of <16 kg/m2 ( n = 12). The DXA-based models are accurate for predicting IMAT-free SM in selected populations and thus provide a new opportunity for quantifying SM in physiological and epidemiological investigations.

scholarly journals Impact of age on leptin and adiponectin independent of adiposity

2012 ◽  
Vol 108 (2) ◽  
pp. 363-370 ◽  
Author(s):  
Britta Schautz ◽  
Wiebke Later ◽  
Martin Heller ◽  
Achim Peters ◽  
Manfred J. Müller ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Body Fat ◽  
Fat Distribution ◽  
Cross Sectional Study ◽  
Body Fat Distribution ◽  
Whole Body ◽  
Cross Sectional ◽  
Age Related ◽  
A Minor ◽  
Age Related Changes

Age-related changes in leptin and adiponectin levels remain controversial, being affected by inconsistent normalisation for adiposity and body fat distribution in the literature. In a cross-sectional study on 210 Caucasians (127 women, eighty-three men, 18–78 years, BMI 16·8–46·8 kg/m2), we investigated the effect of age on adipokine levels independent of fat mass (FM measured by densitometry), visceral and subcutaneous adipose tissue volumes (VAT and SAT assessed by whole-body MRI). Adiponectin levels increased with age in both sexes, whereas leptin levels decreased with age in women only. There was an age-related increase in VAT (as a percentage of total adipose tissue, VAT%TAT), associated with a decrease in SATlegs%TAT. Adiposity was the main predictor of leptin levels, with 75·1 % of the variance explained by %FM in women and 76·6 % in men. Independent of adiposity, age had a minor contribution to the variance in leptin levels (5·2 % in women only). The variance in adiponectin levels explained by age was 14·1 % in women and 5·1 % in men. In addition, independent and inverse contributions to the variance in adiponectin levels were found for truncal SAT (explaining additional 3·0 % in women and 9·1 % in men) and VAT%TAT (explaining additional 13·0 % in men). In conclusion, age-related changes in leptin and adiponectin levels are opposite to each other and partly independent of adiposity and body fat distribution. Normalisation for adiposity but not for body fat distribution is required for leptin. Adiponectin levels are adversely affected by subcutaneous and visceral trunk fat.

Individual variations in steps per day for meeting physical activity guidelines in young adult women

2019 ◽  
Vol 44 (7) ◽  
pp. 713-719 ◽  
Author(s):  
Hideaki Kumahara ◽  
Makoto Ayabe
Keyword(s):  
Physical Activity ◽  
Young Adult ◽  
Vigorous Physical Activity ◽  
Adult Women ◽  
Regression Equations ◽  
Young Adult Women ◽  
Cross Sectional ◽  
Physical Activity Guidelines ◽  
Multiple Stepwise Regression Analysis ◽  
Steps Per Day

Cross-sectional studies have found a correlation between the duration or volume of moderate-to-vigorous physical activity (MVPA) and steps per day (STEP), but there is little information on why this relationship varies among individuals. No previous research has established whether STEP can be used to estimate the duration of physical activity (PA) at or above lactate threshold (≥LT), such as for maintaining cardiorespiratory fitness. This study explored the association among STEP, MVPA indices, and ≥LT under free-living conditions. Seventy young adult women measured their PA for 7 days using a validated accelerometer. The mean LT measured by an exercise test was 5.8 ± 1.0 METs. STEP, MVPA, METs×h, and ≥LT were 9324 ± 2677 steps/day, 231.9 ± 101.5 min/week, 16.6 ± 7.4 METs×h/week and 24.0 ± 22.2 min/week, respectively. Significant correlations were found between STEP and MVPA duration and between STEP and METs×h/week (r = 0.81 and r = 0.81); however, approximately 1600 steps/day of the standard error of estimates in the regression equations were found. Multiple stepwise regression analysis revealed that the percentage of total time spent at light-intensity PA (LPA) and MVPA were significant determinants of the percent deviation of STEP from the linear relationships between STEP and MVPA indices. No significant relationship was observed between ≥LT and STEP. The association between STEP and MVPA fluctuated depending on individual daily LPA and MVPA. Thus, consideration of both STEP and the PA at specific intensities are necessary to ensure the PA guidelines are met and the health benefits gained. STEP alone would be not a sufficient indicator for assessing the ≥LT.

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