Analysis of J coupling-induced fat suppression in DIET imaging

The DIET (or dual interval echo train) sequence, a modification of the fast spin echo (FSE) sequence that selectively reduces signal from fat in MR im ages, has been investigated. The DIET sequence uses an initial echo spacing longer than that of a conventional FSE sequence, thus allowing J coupling- induced dephasing to take effect. The sequence is evaluated theoretically, and its effectiveness on a hydrocarbon (l-pentene) is demonstrated numerica lly using density matrix calculations. The sequence is also evaluated exper imentally using in vitro solutions and in vivo imaging. The efficacy of the sequence is compared for different lipid chemical structures, held strengt hs, and pulse sequence parameters. (C) 1999 Academic Press.