Abstract #0670

Ordidge R, Gadian D, Lythgoe M, Thomas D

A novel method for the measurement of the longitudinal relaxation time of arterial blood (T1a) is presented. The standard FAIR acquisition scheme was modified by incorporating a global saturation pulse before the recovery period. By doing this, the FAIR tissue signal has a monoexponential dependence on recovery time, with T1a as the time constant. Therefore, T1a can be calculated from FAIR measurements performed over a range of recovery times. This eliminates many of the difficulties associated with the measurement of T1a. Experiments performed in the mouse at 2.35T produced a mean value of 1.51s for T1a, consistent with published values.