Copyright
©The Author(s) 2019.
Figure 1 Chicken’s extensor iliotibialis was used to perform muscle quantification for muscle metabolites by proton magnetic resonance spectroscopy.
A: Skinned chicken thigh showing the extensor iliotibialis lateralis muscle fiber orientation (in the yellow marked area) at various angles (0°, 30°, 60°, and 90°) with regard to the main magnetic field (B0); B: T2-weighted turbo spin echo MRI images show areas of proton magnetic resonance spectroscopy voxel placement. B0: Main magnetic field direction.
Figure 2 Original proton magnetic resonance spectroscopy spectra at different angles.
Muscle spectra at 0° are shown with spectra oriented at 30°, 60°, and 90° multiplied by a factor of 2. The spectrum at 0° showed the most-well defined lipid peaks IMCL (CH3), EMCL (CH3), IMCL (CH2), and EMCL (CH2). EMCL: Extramyocellular lipids; IMCL: Intramyocellular lipids.
Figure 3 Muscle metabolite spectra at 30°, 60°, and 90° subtracted from baseline set at 0°.
Muscle spectra at 30°, 60°, and 90° without multiplied factors are subtracted from spectrum baseline at 0°.
Figure 4 Metabolites identified by AMARES algorithm.
Metabolites are shown in the following quantities: IMCL (CH3) at 0.9 ppm, EMCL (CH3) at 1.1 ppm, IMCL (CH2) at 1.3 ppm, EMCL (CH2) at 1.5 ppm, and creatine at 3.02 ppm. At 30°, 60°, and 90°, spectra were shown by a factor of 3.8. Spectrum of muscle positioned at 90° to the main magnetic field was unable to be identified for EMCL (CH2) at 1.5 ppm. EMCL: Extramyocellular lipids; IMCL: Intramyocellular lipids.
Figure 5 Metabolites at different angle ratios to muscle metabolite at 0°.
Each lipid (IMCL (CH3), EMCL (CH3), IMCL (CH2), and EMCL (CH2)) was calculated as a ratio to creatine and then was normalized with the average of lipid/Cr ratio set at 0°. At 30°, 60°, and 90°, there was a tendency for the ratio to decrease when compared to 0°. The comparisons between 0° and the different angles were performed using Wilcoxon signed-rank test with aP-value < 0.05 being significantly different. Cr: Creatine; EMCL: Extramyocellular lipids; IMCL: Intramyocellular lipids.
- Citation: Pasanta D, Kongseha T, Kothan S. Effects of muscle fiber orientation to main magnetic field on muscle metabolite profiles for magnetic resonance spectroscopy acquisition. World J Radiol 2019; 11(1): 1-9
- URL: https://www.wjgnet.com/1949-8470/full/v11/i1/1.htm
- DOI: https://dx.doi.org/10.4329/wjr.v11.i1.1