In-vivo Measurement of Spin Lattice Relaxation Time (T1) of Bone Marrow in Healthy Volunteers: the Effects of Age and Sex

Magnetic resonance images of the spine, sternum, femoral heads and upper femoral shafts were obtained from 90 healthy volunteers to determine the normal ranges of spin lattice relaxation time (T1) for different regions of the bone marrow. The influence of age, sex and oral contraceptive usage on bone marrow T1 was assessed. Differences observed between the T1 of the various regions of the bone marrow examined were consistent with the expected distribution of erythropoietic cells and fatty marrow. Bone marrow T1 was found to decrease with age, significantly lower mean T1 values being observed in subjects over 40 years of age than for those in the 20-40 years age group. The mean bone marrow T1 of females in the 20-40 years age group was significantly higher than that for males of comparable age. For subjects over 40 years of age, the difference in bone marrow T1 observed between males and females was not significant. Oral contraceptive usage had no effect on bone marrow T1.