Determination of effects of physical activity and adiposity on human thigh composition using magnetic resonance techniques

magnetic resonance imaging (MRI);magnetic resonance spectroscopy (MRS);diffusion tensor imaging (DTI);Dixon;obesity;physical activity;intervention;muscle

Chen, Danchin D. ; Georgiadis ; John G.

关键词: magnetic resonance imaging (MRI);    magnetic resonance spectroscopy (MRS);    diffusion tensor imaging (DTI);    Dixon;    obesity;    physical activity;    intervention;    muscle;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/18370/Chen_Danchin.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

This thesis project developed a magnetic resonance imaging and spectroscopy (MRI/MRS) protocol to quickly and non-invasively assess the fat composition of the thigh in three groups of older women varying in adiposity and habitual physical activity levels.The primary objective was the development of a methodology to quantify gross adipose tissue depots and intramuscular lipid concentrations towards developing and substantiating the use of MRI/MRS to measure muscle quality.Secondary objectives were to quantify the differences between the three distinct groups: obese (O); lean and sedentary (LS), and lean and active (LA) and to determine the effect of two different four-month interventions on the thigh adipose composition of the obese women: weight-loss diet (DI) and weight-stable exercise (EX).In the cross-sectional portion of the study, no significant differences in relative adipose tissue volumes or intramuscular lipid concentrations were found between the groups O and LS, revealing that the lipid distribution and storage were similar between obese and lean, sedentary subjects.However, group LA had 10% less relative fat volume and double the relative amount of lipids stored in a metabolically active state than O and LS (both p<0.05).The favorable impact of physical activity on adipose composition was further confirmed empirically in the longitudinal portion of the study.Group DI increased lipid concentrations without a change in distribution, due to loss of lean mass, whereas group EX had a favorable redistribution of intramuscular lipids without a loss of overall lipid concentration.The results of this project add to the growing literature regarding the importance of physical activity for the management of intramuscular lipids, even in individuals who are normal weight.