(bFFE) A FFE sequence using a balanced gradient waveform. A balanced sequence starts out with a RF pulse of 90° or less and the spins in the steady state.
Before the next TR in the slicephase and frequency encoding, gradients are balanced so their net value is zero. Now the spins are prepared to accept the next RF pulse, and their corresponding signal can become part of the new transverse magnetization. Since the balanced gradients maintain the transverse and longitudinal magnetization, the result is, that both T1 and T2 contrast are represented in the image.
This pulse sequence produces images with increased signal from fluid, along with retaining T1 weighted tissue contrast. Because this form of sequence is extremely dependent on field homogeneity, it is essential to run a shimming prior the acquisition.
A fully balanced (refocused) sequence would yield higher signal, especially for tissues with long T2 relaxation times.
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