MR OF THE SPINE WITH A FAST T1-WEIGHTED FLUID-ATTENUATED INVERSION-RECOVERY SEQUENCE

PURPOSE: To optimize a T1-weighted fast fluid-attenuated inversion rec overy (FLAIR) sequence using computer-simulated data and to study its clinical utility for imaging the spine. METHODS: Relative signal inten sities and contrast of relevant normal and pathologic tissues in the s pine were computed using an inversion recovery equation modified to ac count for a hybrid RARE (rapid acquisition with relaxation enhancement ) readout. A range of inversion time (TI) and repetition time (TR) pai rs that null the signal from CSF was generated. A contrast-optimized h eavily T1-weighted fast FLAIR sequence, based on the generated data, w as qualitatively compared with conventional TI-weighted spin-echo sequ ences for imaging various spinal abnormalities. RESULTS: A TI/TR pair of approximately 862/2000 was extracted from the computer-generated da ta to produce effective nulling of CSF signal, to achieve heavy T1 wei ghting, and to optimize contrast between abnormal tissues and cord/bon e marrow. Clinical implementation of the optimized T1-weighted fast FL AIR sequence revealed superior contrast at the CSF-cord interface, bet ter conspicuity of lesions of the spinal cord and bone marrow, and red uced hardware-related artifacts as compared with conventional T1-weigh ted spin-echo sequences. CONCLUSION: The optimized T1-weighted fast FL AIR technique has definite advantages over spin-echo sequences for ima ging the spine. Comparable acquisition times render the FLAIR sequence the method of choice for T1-weighted imaging of the spine.