Signal behavior in continuously ramped 2D TrueFISP for whole-body imaging

Abstract

A fast and robust imaging technique was developed based on a single-slice TrueFISP acquisition using a slice excitation frequency that is incremented, or spatially "ramped," with each repetition. The short acquisition time of single slices allows artifactfree imaging during free breathing, which demonstrates the potential use of this technique for whole-body screening. Overlapping positioning of consecutively acquired slices was used to provide gapless volume coverage in free-breathing measurements. The image contrast of ramped TrueFISP was analyzed in detail using simulations and experiments. A high ramp speed results in an increased overall signal intensity and in a modification of the known T2/T1 contrast towards a proton density-weighted contrast. A further increase in imaging speed is achieved with z-interleaved phase-encoding trajectories based on weighted transitions between adjacent views. © 2002 Wiley-Liss, Inc.