Multiple echo frequency-domain image contrast: Improved signal-to-noise ratio and T-2 (T-2*) weighting

Conventional T-2- and T-2*-weighted image contrasts are produced by waiting a TE period for the transverse magnetic resonance (MR) signals to decay to differentiate tissue types with distinct relaxation rates, Significant ima ge signal-to-noise ratio (SNR) is compromised by this contrast-producing pr ocess. In this report, a multiple echo frequency-domain image contrast (MEF IC) method is presented. During the conventional TE period, a multiple echo train modulated by T-2 or T-2* decay is acquired, A third Fourier transfor m along the echo direction produces an image set with pixel signal intensit y modulated by the spectrum of the decay curve. This method simultaneously enhances image contrast with a large increase in SNR, Experimental studies of cerebral vasogenic edema in immature rats and functional MR imaging stud ies of the human motor cortex have demonstrated that the MEFIC method produ ces superior image quality over conventional methods for generating T-2- an d T-2*-weighted images. (C) 1999 Wiley-Liss, Inc.