Magnetic resonance imaging of total body fat in young adult men

Magnetic resonance imaging (MRI) offers an excellent opportunity to study human body composition. Differentiation of fat and nonfat tissue allows quantitative analysis of adipose tissue volume from MRI images. Cylindrical phantoms containing various proportions of water and oil were scanned using a spin echo sequence with an echo time of 12 ms, a repetition time of 150 ms with 20 mm slices. A previously described method of defining a fat pixel threshold underestimated the known volume of fat in the phantoms by a mean of 9.7%. Eight young male volunteers (mean age, 22 years) were scanned twice in succession using the same protocol as with the phantoms. The volume of fat calculated from images of eight subjects was upwardly adjusted by the amount the pixel thresholding method underestimated the known volumes of fat in the phantoms. The fat volume determined from the images of human subjects was converted to weight and then percent body fat (BF). The mean percent BF of the two MRI scans of the eight subjects...