MR imaging: possibility of tissue characterization of brain tumors using T1 and T2 values.

To evaluate the usefulness of T1 and T2 values for tissue characterization of brain tumors, 37 histologically confirmed brain tumors were examined with a 0.5-T superconductive MR system. With spin-echo and inversion-recovery imaging sequences, computed T1 and T2 images were reconstructed, and T1 and T2 values of the tumors were calculated. Relaxation rates (1/T1 and 1/T2), T1/T2 ratios, and malignancy indexes, which were originally designed for gastrointestinal tumors, were also calculated. Values of all these parameters were so wide-ranged that it was impossible to characterize the tumor tissue types.