Intramyocellular lipid quantification: comparison between 3.0- and 1.5-T 1H-MRS

Abstract

OBJECTIVE-To prospectively compare measurement precision of calf intramyocellular lipid (IMCL) quantification at 3.0T and 1.5T using 1 H magnetic resonance spectroscopy ( 1 H-MRS). MATERIALS AND METHODS-We examined the soleus and tibialis anterior (TA) muscles of 15 male adults [21-48 years of age, body mass index (BMI)=21.9-38.0 kg/m 2 ]. Each subject underwent 3.0T and 1.5T single-voxel short-echo-time point-resolved 1 H-MRS both at baseline and 31-day follow-up. The IMCL-methylene peak (1.3 ppm) was scaled to unsuppressed water peak (4.7 ppm) using the LCModel routine. Full width at half maximum (FWHM) and signal-to-noise ratios (SNR) of unsuppressed water peak were measured using jMRUI software. Measurement precision was tested by comparing interexamination coefficients of variation (CV) between different field strengths using Wilcoxon matched pairs rank test in all subjects. Overweight subjects (BMI>25 kg/ m 2 ) were analyzed separately to examine benefits of 3.0T acquisitions in subjects with increased adiposity.RESULTS-No significant difference between 3.0T and 1.5T was noted in CVs for IMCL of soleus (P=0.5). CVs of TA were significantly higher at 3.0T (P=0.02). SNR was significantly increased at 3.0T for soleus (64%, P<0.001) and TA (62%, P<0.001), however lower than the expected improvement of 100%. FWHM at 3.0T was significantly increased for soleus (19%, P<0.001) and TA (7%, P<0.01). Separate analysis of overweight subjects showed no significant difference between 3.0T and 1.5T CVs for IMCL of soleus (P=0.8) and TA (P=0.4). CONCLUSION-Using current technology, 1 H-MRS for IMCL at 3.0T did not improve measurement precision compared to 1.5T.

Magnetic resonance spectroscopic analysis of multifidus muscles lipid content and association with spinopelvic malalignment in chronic low back pain

“…[10][11][12] Recently, in addition to morphological assessments, muscles have been evaluated using MRI with the multipoint Dixon technique 12,13 and MR spectroscopy (MRS). 10,14 MRS analysis of muscle physiology has been used in various fields, such as sports medicine, [15][16][17] and has facilitated detailed analyses of muscular fat masses by recording the presence of intramyocellular lipids (IMCLs) and extramyocellular lipids (EMCLs); this has helped to identify detail of fatty degeneration. 6,18 IMCLs cannot be visually detected using conventional MRI because they are stored in spheroid droplets in the cytoplasm of muscle cells in close contact with skeletal mitochondria 18,19 and are directly used as an energy source by mitochondria.…”

Evaluation of intramyocellular and extramyocellular lipids in the paraspinal muscle in patients with chronic low back pain using MR spectroscopy: preliminary results

“…12,13,15 Among MRI techniques, the multipoint Dixon technique 16,17 and MR spectroscopy (MRS) 3,18 have been used in previous studies. In recent years, MRS analysis of muscle physiology has been applied in various fields, including sports medicine; [18][19][20] this has enabled the detailed analyses of muscular fat mass, such as evaluation of the presence of intramyocellular lipids (IMCL) and extramyocellular lipids (EMCL). 3,21,22 IMCL appear as lipid droplets in skeletal muscle cells and are reportedly associated with aerobic metabolism.…”

Quantitative Imaging of Body Composition

“…Several prior studies showed accurate noninvasive quantification of IMCL compared with tissue analyses, especially when performed on calf muscles such as the tibialis anterior and soleus. 43,44 The importance of IMCL resides in the fact that its intracellular sub-products play an important role in interfering with insulin signaling, contributing to muscle insulin resistance and development of type 2 diabetes. 42 Importantly, quantification of IMCL by 1H-MRS strongly correlates with insulin resistance and has been an important surrogate in clinical research in states of insulin resistance, such as obesity, type 2 diabetes, and human immunodeficiency virus lipodystrophy.…”

“…95 Finally, as mentioned earlier, accumulation of IMCL is strongly associated with insulin resistance. [96][97][98] 1H-MRS has become a key noninvasive technique for measuring IMCL, 44 with the optimal result obtained from the lower extremity muscles of the calf, providing insights on conditions with insulin resistance such as diabetes mellitus, obesity, and metabolic syndrome.…”