MR of the spine with a fast T1-weighted fluid-attenuated inversion recovery sequence

To optimize a T1-weighted fast fluid-attenuated inversion recovery (FLAIR) sequence using computer-simulated data and to study its clinical utility for imaging the spine.

Relative signal intensities and contrast of relevant normal and pathologic tissues in the spine were computed using an inversion recovery equation modified to account for a hybrid RARE (rapid acquisition with relaxation enhancement) readout. A range of inversion time (TI) and repetition time (TR) pairs that null the signal from CSF was generated. A contrast-optimized heavily T1-weighted fast FLAIR sequence, based on the generated data, was qualitatively compared with conventional T1-weighted spin-echo sequences for imaging various spinal abnormalities.

A T1/TR pair of approximately 862/2000 was extracted from the computer-generated data to produce effective nulling of CSF signal, to achieve heavy T1 weighting, and to optimize contrast between abnormal tissues and cord/bone marrow. Clinical implementation of the optimized T1-weighted fast FLAIR sequence revealed superior contrast at the CSF-cord interface, better conspicuity of lesions of the spinal cord and bone marrow, and reduced hardware-related artifacts as compared with conventional T1-weighted spin-echo sequences.

The optimized T1-weighted fast FLAIR technique has definite advantages over spin-echo sequences for imaging the spine. Comparable acquisition times render the FLAIR sequence the method of choice for T1-weighted imaging of the spine.