Two-dimensional J-resolved laser and semi-laser spectroscopy

摘要

J-resolved LASER and semi-LASER sequences for localized two-dimensional magnetic resonance spectroscopy are disclosed. After a delay time Δ1 from application of an excitation RF pulse, a first pair of slice-selective adiabatic full-passage (AFP) pulses, separated by an inter-pulse interval Δ₂, is applied. At the end of the sequence a final pair of slice-selective AFP pulses, separated by a time of Δ₂/2+Δ₁+t₁/2 is applied, where t₁ 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 Δ2, is applied prior to the final pair of AFP pulses. An echo signal is acquired at time t₁/2 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 3 T or higher main magnetic field.