Introduction: The PRESS sequence is commonly used to observe the metabolites within a single voxel. However, lipids are co-resonant with lactate, and in a conventional PRESS acquisition the two peaks can not be easily distinguished. Hence, it is desirable to incorporate efficient lactate/lipid discrimination into a PRESS sequence. Methods: We implemented a two-shot lactate filter that alternates between a narrow and wide band 180 degree pulse on sequential acquisitions. The time between the 90 degree excitation pulse and the lactate filter is 1/2J (72ms). We set the center frequency of the spectrally selective lactate filter on the CH3 doublet of lactate. The narrower filter of the first sequence has a bandwidth of +/-1.57ppm (100Hz), which includes the NAA and lipids. The wider filter of the second sequence has a bandwidth of +/-7.83ppm (500)Hz, which includes the lactate quartet. The lactate doublet is reversed in the second sequence but the other metabolites are unaffected. Subtracting the data acquired from these two sequences, yields only the lactate signal, hence suppressing the lipids. Summing the data acquired from the two sequences, yields the other resonances, namely NAA and lipids. Conclusions: By interleaving two spectrally selective 180 degree RF pulses, we achieved the goal of lactate/lipid discrimination while keeping the information of the other metabolites. This method is potentially very useful for definitively identifying lactate (even in the presence of additional lipids) in a single voxel experiment, and avoids the need to acquire additional data at other echo times as is commonly done.

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
5P41RR009784-05
Application #
6122993
Study Section
Project Start
1999-01-01
Project End
2000-07-31
Budget Start
1998-10-01
Budget End
1999-09-30
Support Year
5
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Stanford University
Department
Type
DUNS #
800771545
City
Stanford
State
CA
Country
United States
Zip Code
94305
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Bian, W; Tranvinh, E; Tourdias, T et al. (2016) In Vivo 7T MR Quantitative Susceptibility Mapping Reveals Opposite Susceptibility Contrast between Cortical and White Matter Lesions in Multiple Sclerosis. AJNR Am J Neuroradiol 37:1808-1815
Vos, Sjoerd B; Aksoy, Murat; Han, Zhaoying et al. (2016) Trade-off between angular and spatial resolutions in in vivo fiber tractography. Neuroimage 129:117-132

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