Basic Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Radiol. Jan 28, 2019; 11(1): 1-9
Published online Jan 28, 2019. doi: 10.4329/wjr.v11.i1.1
Effects of muscle fiber orientation to main magnetic field on muscle metabolite profiles for magnetic resonance spectroscopy acquisition
Duanghathai Pasanta, Tipparat Kongseha, Suchart Kothan
Duanghathai Pasanta, Tipparat Kongseha, Suchart Kothan, Department of Radiologic Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
Author contributions: Pasanta D, Kongseha T and Kothan S contributed to the conception and design of this study; as well as the acquisition, analysis, and interpretation of all data. These authors wrote drafts of the article and made critical revisions related to the intellectual content of the manuscript and approved the final version of the article for publication.
Supported by Department of Radiologic Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Thailand.
Conflict-of-interest statement: All authors have no conflicts of interest to report.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Suchart Kothan, PhD, Associate Professor, Department of Radiologic Technology, Faculty of Associated Medical Sciences, Chiang Mai University, 110 Intawaroros Rd., Sripoom, Chiang Mai 50200, Thailand. suchart.kothan@cmu.ac.th
Telephone: +66-53-939213 Fax: +66-53-939207
Received: August 6, 2018
Peer-review started: August 7, 2018
First decision: October 16, 2018
Revised: November 14, 2018
Accepted: January 9, 2019
Article in press: January 10, 2019
Published online: January 28, 2019
Processing time: 175 Days and 14.4 Hours
Abstract
BACKGROUND

Proton magnetic resonance spectroscopy (1H MRS) is a technique widely used for investigating metabolites in humans. Lipids are stored outside the muscle cell are called extramyocellular lipids (EMCL), and lipids stored on the inside of muscle cells are called intramyocellular lipids (IMCL). The relationship between metabolic syndrome and IMCL has been extensively studied.

AIM

To determine the effects of muscle fiber orientations on muscle metabolites using 1H MRS.

METHODS

Chicken muscles were used as the subject in this study. MRS spectra were performed on a 1.5T Magnetic resonance imaging machine (1.5 Tesla Philips Achieva). A single voxel (8 mm × 8 mm × 20 mm) was placed on the chicken extensor iliotibialis lateralis muscle with the muscle fiber oriented at 0°, 30°, 60°, and 90° to the main magnetic field. 1H MRS spectra were acquired using a point-resolved spectroscopy, TR = 2000 ms, TE = 30 ms, and NSA = 256. Metabolites of interest from each orientation to the main magnetic field were compared using Wilcoxon signed-rank test. Differences less than 0.05 were considered to be statistically significant with 95%CI.

RESULTS

The metabolite profiles were different for each orientation of muscle fibers to the main magnetic field. The orientation at 90° was the most different compared to other orientations. The quantity of IMCL and EMCL exhibited statistically significantly changes with impacts at 30°, 60°, and 90° when compared with muscles aligned at 0° to the main magnetic field. Statistical analysis showed statistically significant IMCL (CH3), EMCL (CH3), and IMCL (CH2) at 30°, 60°, and 90° (P = 0.017, 0.018, and 0.018, respectively) and EMCL (CH2) at 30° and 60° (P = 0.017 and 0.042, respectively). EMCL (CH2) at 90° was unable to be measured in this study. The muscle lipids quantified at 30°, 60°, and 90° tended to be lower when compared to 0°.

CONCLUSION

Careful positioning is one of the most important factors to consider when studying 1H MRS metabolites in muscles to ensure reproducibility and uniformity of muscle metabolite spectra.

Keywords: Proton magnetic resonance spectroscopy; Metabolite; Muscle fiber orientation; Intramyocellular lipids; Extramyocellular lipids; Magnetic susceptibility

Core tip: Proton magnetic resonance spectroscopy (1H MRS) is a technique that is widely used for intramyocellular lipids and extramyocellular lipids quantification in muscles, as evidenced in various studies. However, different muscle positions can potentially lead to inconsistency in metabolite quantification and can also impede interpretation of data, which can lead to misinformation. This study reveals that the muscle orientation at 0°, 30°, 60°, and 90° to the main magnetic field significantly affects the metabolite profile and quantification. The metabolite profile changes due to the muscle fiber orientation demonstrate that the positioning potentially causes inaccuracy in 1H-MRS spectrum analysis.