Quantification Of Whole-body Adipose Tissue Based On Magnetic Resonance Dixon Technique

Objective:The purpose of the study was to utilize magnetic resonance Dixon Technique to quantify adipose tissue in different human body compartments, and to measure fat fraction of liver, spleen, skeletal muscle, and to explore the relationship between fat distribution and disease like hypertension, diabetes, dyslipidemia and metabolic syndrome.Material and method:100 volunteers were recruited and performed whole body scan of Dixon sequence on Siemens MEGNETOM skyra 3.0T scanner. Volunteers received measurements of height, body weight, waist circumference, hip circumference and blood pressure. Body composition was assessed by bioelectrical impedance analysis. Fasting blood was taken to detect fasting glucose level, glyccosylated hemoglobin, serum Total cholesterol and triglyceride, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol. Software ImageJ was applied to measure the volume of intra-thoracic, intra-abdominal, truncal subcutaneous and lower-limb adipose tissue. Software Osirix was utilized to measure fat fraction of liver, spleen, pancreas, L2-4 lumbar vertebral body and bilateral femoral heads. Statistical analysis was as follows: independent t test, Chi-square test and ANOVA test were used to analyze the difference between or among groups. Spearman correlation was used to analyze the relationship between groups. P value less than 0.05 was considered to be statistically significant.Results:Male volunteers possessed more intra-abdominal adipose tissue and higher proportion of intra-abdominal adipose tissue(3.47L vs.2.73L, P=0.009; 26.74% vs.16.24%, P<0.001), less truncal subcutaneous, lower-limb and total adipose tissue(5.03L vs.8.37L, P<0.001; 4.47L vs.6.12L, P<0.001; 13.26L vs.17.44L, P<0.001). Compared with pre-menopausal females, post-menopausal females possessed less total adipose tissue(17.30L vs.17.81L, P=0.015), more intra-thoracic adipose tissue(0.25L vs.0.17L, P=0.009; 2.85L vs.2.43L, P=0.068) and higher intra-abdominal adipose tissue ratio(17.20% vs.13.79%, P=0.711). Fat fraction of liver, liver-to-spleen ratio and fat fraction of lumbar vertebral body were positively related to serum TG. TC, LDLC level and negative related to HDLC. Fat fraction of lumbar vertebral body and femoral heads showed a significant difference between male and female groups(92.91%vs.91.08%, P=0.006; 93% vs.90.46%, P=0.005), postmenopausal and premenopausal groups (91.66% vs.89.62%, P=0.006; 91.78% vs.87.11%, P=0.005). Multiple binary logistic regression analysis demonstrated that age and volume of intra-abdominal adipose tissue were independent risk factors to predict metabolic syndrome.Conclusion:Total volume of adipose tissue in female exceeded that of male, but showed a predominant distribution in subcutaneous trunk and lower limbs, while adipose tissue in male tended to distribute intra-abdominally. Patients with metabolic syndrome had higher fat fraction in liver, spleen and pancreas, higher liver-to-spleen ratio, more intra-abdominal adipose tissue and higher ratio of intra-abdominal adipose tissue. Accumulation of intra-abdominal adipose tissue might increase the risk of developing metabolic syndrome.