Improved MR images of the brain with use of a gated, flow-compensated, variable-bandwidth pulse sequence

Peripheral gating and first-order flow compensation were compared for their ability to improve the quality of second-echo (echo time = 80 msec) brain images obtained with a T2-weighted spin-echo sequence. The contrast-to-noise ratios (C/Ns) for interfaces between brain and cerebrospinal fluid, gray and white matter, and lesion and white matter were measured; the C/N was highest for the combination of gating and flow compensation. This combination of motion compensation also reduced motion artifacts more than did either technique alone. Further improvement in C/N was sought by using a variable-bandwidth pulse sequence, which was compared to a conventional spin-echo sequence. The variable-bandwidth technique increased the C/N of the second-echo image by 27%. The combined use of gating, flow compensation, and the variable-bandwidth option produced high-resolution brain images with a single excitation and retained flexibility in number of sections, number of echoes, and echo times.