BISTRO: An outer-volume suppression method that tolerates RF field inhomogeneity

A technique is described for performing frequency-selective signal suppress ion with a high degree of tolerance to RF field inhomogeneity. The method i s called B-1-insensitive train to obliterate signal (BISTRO), BISTRO consis ts of multiple amplitude- and frequency-modulated (FM) pulses interleaved w ith spoiler gradients, BISTRO was developed for the purpose of accomplishin g band-selective signal removal, as in water suppression and outer-volume s uppression (OVS), in applications requiring the use of an inhomogeneous RF transmitter, such as a surface coil, In the present work, Bloch simulations were used to illustrate the principles and theoretical performance of BIST RO, Its performance for OVS was evaluated experimentally using MRI and spec troscopic imaging of phantoms and in vivo animal and human brain. By using FM pulses featuring offset-independent adiabaticity, BISTRO permitted high- quality, broadband suppression with one (or two) discrete borders demarcati ng the edge(s) of the suppression band, Simulations and experiments demonst rated the ability to operate BISTRO with reasonably attainable peak RF powe r levels and with average RF energy deposition similar to other multipulse OVS techniques. (C) 2001 Wiley-Liss, Inc.