Houchun Harry Hu1, 2, Yan Li3, Tim R. Nagy3, Michael I. Goran4, Krishna S. Nayak2
1Radiology, Children's Hospital of Los Angeles, Los Angeles, CA, United States; 2Electrical Engineering, University of Southern California, Los Angeles, CA, United States; 3Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, United States; 4Preventive Medicine, University of Southern California, Los Angeles, CA, United States
We validated an approach using the proton density fat fraction (PDFF) metric derived from chemical-shift water-fat MRI to compute absolute fat mass (in grams). The approach was validated in 97 freshly excised organ, muscle, and adipose tissue samples from four pigs against reference chemical analysis (CA). A strong agreement between MRI and CA-derived fat mass was obtained (slope=1.01, intercept=1.99g, r2=0.98, p<0.01). The mean difference between MRI and CA was 2.173.4g. The results suggest that PDFF provides an accurate means of determining absolute fat mass and can facilitate quantitative fat MRI comparisons against traditional body composition techniques in animals and humans.