Proton echo-planar spectroscopic imaging with highly effective outer volume suppression using combined presaturation...

Area of Science:

• Neuroimaging
• Magnetic Resonance Imaging (MRI)
• Spectroscopic Imaging

Background:

• Lipid signals can interfere with accurate metabolite quantification in brain MRI.
• Existing outer volume suppression (OVS) techniques may be sensitive to magnetic field variations and lipid properties.

Purpose of the Study:

• To introduce and evaluate a novel OVS technique, spatially selective echo dephasing (SSED).
• To assess the efficacy of SSED in suppressing lipid signals for improved brain metabolite mapping.

Main Methods:

• Spatially selective echo dephasing (SSED) was developed using gradient dephasing of spin echoes.
• SSED was integrated with 2D proton echo-planar spectroscopic imaging (PEPSI) for high-resolution brain imaging.
• The method was optimized to minimize secondary spin-echo refocusing and compared with spatial presaturation techniques.

Main Results:

• SSED demonstrated robustness against T(1) dispersion and B(1) inhomogeneity.
• Combined presaturation and SSED achieved superior lipid suppression (>70) with uniform factors.
• Successful metabolite mapping (choline, creatine, NAA) was achieved with 0.3 cm(3) voxels near lipid regions.

Conclusions:

• Spatially selective echo dephasing (SSED) is a highly effective OVS technique for brain imaging.
• SSED combined with presaturation offers superior lipid suppression for accurate metabolite mapping in challenging brain regions.