| 摘要 |
J-resolved LASER and semi-LASER sequences for localized two- dimensional magnetic resonance spectroscopy are disclosed. After a delay time &Dgr;1 from application of an excitation RF pulse, a first pair of slice-selective adiabatic full-passage (AFP) pulses, separated by an inter-pulse interval &Dgr;2, is applied. At the end of the sequence a final pair of slice-selective AFP pulses, separated by a time of &Dgr;2/2 + &Dgr;1 + t 1 /2 is applied, where t 1 is the duration of an incremental evolution period corresponding to the indirect dimension of a 2D J- resolved spectrum. In the case of J-resolved LASER, an additional intermediate pair of slice-selective AFP pulses, separated by an inter- pulse interval &Dgr;2, is applied prior to the final pair of AFP pulses. An echo signal is acquired at time t 1 /2 from the application of the last AFP pulse. The method suppresses chemical shift artifacts, J- refocused artifactual peaks, and sensitivity to RF field inhomogeneity, each being caused, at least in part, by the use of a 3T or higher main magnetic field. |
