Thin-section, three-dimensional Fourier transform, steady-state free precession MR imaging of the brain

The authors evaluated a three-dimensional Fourier transform implementation of a very short repetition time (TR) (24 msec), steady-state free precession (SSFP) pulse sequence for clinical imaging of the brain and compared it with a conventional two-dimensional Fourier transform long TR/echo time (TE) spin-echo sequence. First, the optimal flip angle of 10 degrees for generating images with contrast similar to that of long TR/TE spin-echo images was determined. Then, 29 patients with suspected brain lesions were studied with both techniques. Although the SSFP images did not exhibit the magnetic susceptibility artifacts that plague other rapid-imaging techniques, the conspicuity of most parenchymal lesions was often less than that on the spin-echo images. Also, the visibility of paramagnetic effects, such as the low signal intensity of brain iron, was less obvious at SSFP imaging. These substantial limitations may relegate the SSFP sequence to an adjunctive role, perhaps mainly demonstration of the cystic nature of mass lesions, because of its extreme sensitivity to slow flow.