A two-point volume localized T1 measurement sequence for in vivo spectroscopy using a surface coil

A technique for obtaining T1 values from well localized regions using surface coils and with a clinically practicable measurement time is described. The method uses a two-point Inversion-Recovery/Saturation-Recovery (IR/SR) sequence in conjunction with the image-selected in vivo spectroscopy localization scheme. T1 values are obtained by comparing the ratio of peak areas with those in a pre-computed look-up table. The method was tested by measuring the T1s of six calibrated water phantoms doped with different concentrations of gadolinium. This indicated an accuracy of 3% for T1 values in the range 400-1500 ms. 31P spectra and T1 values of Pi, phosphocreatine and alpha-, beta- and gamma-NTP metabolites from the calf muscle of healthy volunteers were obtained with the sequence employing beta 1-insensitive excitation pulses and a surface coil. The T1 values fall within the range of published values obtained by other techniques.