In-vivo measurement of spin lattice relaxation time (T1) of liver in healthy volunteers: the effects of age, sex and oral contraceptive usage.

Magnetic resonance imaging of 81 healthy adult volunteers has been undertaken to establish the normal range of liver spin lattice relaxation time (T1) at 0.08 tesla. The influence of age, sex and oral contraceptive usage has been assessed. Liver T1 decreased with age. The mean liver T1 of subjects under 40 years of age was significantly longer than that of older subjects. A wider range of T1 values was observed in the younger age group. No difference in T1 was found between males and females who were not oral contraceptive users. The mean liver T1 of females who were taking the pill was significantly longer than that of females of similar age who were not oral contraceptive users. Serial examinations of eight oral contraceptive users showed that mean liver T1 values were significantly longer in the 3 weeks during which they were taking the pill than during the week off the pill.