Three dimensional outer volume suppression for short echo time in vivo 1H spectroscopic imaging in rat brain.

Three-dimensional in vivo spectroscopic imaging in rat brain requires additional localization to reduce the effects of lipid contamination. Outer volume suppression has been shown to be effective in two dimensions. We have extended this approach to three dimensions with additional outer volume suppression conforming to the shape of the rat brain. The technique suppresses the pericranial lipid effectively, allowing sampling of volumes close to the skull and effective localized shimming. These benefits permit three-dimensional 1H magnetic resonance spectroscopic imaging to be performed over most of the brain at shorter echo times, providing spectra more amenable to quantitative analysis.