MRS of Fat/Lipids

Fat Fraction using Localized MRSPerformed in Liver routinely at 1.5 and 3T

Fat Composition using Localized MRSReported at 7T and repeated at 3T forsubQ, bone marrow, and liver

Fat Composition Using Multi-peak Dixon MRIReported at 3T

Fat Composition using Localized MRS

Human Studies Reported at 7T for subQ and Bone Marrow

Copyright ©2008 American Society for Biochemistry and Molecular Biology

Ren, J. et al. J. Lipid Res. 2008;49:2055-2062

1H NMR spectra of subcutaneous fat (left) and tibial bone marrow (right) from a 26 year-old healthy male at 7 Tesla (7T)

Copyright ©2008 American Society for Biochemistry and Molecular Biology

Ren, J. et al. J. Lipid Res. 2008;49:2055-2062

Correlation of measured area (F/E) between tibial bone marrow and subcutaneous fat for the 20 healthy adult subjects studied, showing that the diunsaturated fatty acid is similar for these two adipose sites and that the fat

composition variation among subjects is detectable by 1H magnetic resonance spectroscopy

MRS Results at 3TWe Performed MRS on SubQ

Fat Composition on Four Normal Volunteers

MRS 3-4 times each

Intra Subject Reproducibility

LCModel ca 8% on average for the ratio of F/E

Lenkinski et al. unpublished results

Liver fat 3T Philips Ingenia

EF

Positive Unexpected Results

The spectral resolution of fat peaks the liver is good enough to resolve peaks E and F that are indicators of the saturated/unsaturated ratio of fatty acids

MRI Methods

CHEMICAL SHIFT-INDUCED AMPLITUDE MODULATIONS IN IMAGES OBTAINED WITH GRADIENT REFOCUSING

WEHRLI FW, PERKINS TG, SHIMAKAWA A, et al.

MAGNETIC RESONANCE IMAGING Volume: 5 Issue: 2

Pages: 157-158 1987

Huanzhou YuAnn ShimakawaJean H. Brittain

GE Healthcare

Applied Science Lab

Scott B. Reeder

University of Wisconsin, Madison

University of Western Ontario

Charles A. McKenzie

0Hz (water)

water fat

Motivation• 2-pt and 3-pt Dixon/IDEAL water-fat separation

•relatively insensitive to field inhomogeneities

• models water and fat as a single frequency

ω

water

fat

3.5ppm

CH2

CH3olefinic

Multiecho water‐fat separation and simultaneous R estimation with multifrequency fat spectrum modeling

Magnetic Resonance in MedicineVolume 60, Issue 5, pages 1122-1134, 27 OCT 2008 DOI: 10.1002/mrm.21737http://onlinelibrary.wiley.com/doi/10.1002/mrm.21737/full#fig2

Spectrum Calibration

420

318-94 47223446

freq in Hz @ 3T

considered known

Multiecho water‐fat separation and simultaneous R estimation with multifrequency fat spectrum modeling

Magnetic Resonance in MedicineVolume 60, Issue 5, pages 1122-1134, 27 OCT 2008 DOI: 10.1002/mrm.21737http://onlinelibrary.wiley.com/doi/10.1002/mrm.21737/full#fig1

ψ

420

318-94

IDEAL

420

318-94

Center Freq.

Spectrum Self-Calibration

420-94318

α1= 0.74 α2= 0.19 α3= 0.07

Results

In principle, images can be made for each of the six fat components or their ratios.