TY - JOUR
T1 - Regional differences in intramyocellular lipids in humans observed by in vivo 1H-MR spectroscopic imaging
AU - Hwang, Jong Hee
AU - Pan, Jullie W.
AU - Heydari, S.
AU - Hetherington, Hoby P.
AU - Stein, Daniel T.
PY - 2001
Y1 - 2001
N2 - Regional differences in the content of intramyocellular lipids (IMCL), extramyocellular lipids, and total creatine (TCr) were quantified in soleus (S), tibialis posterior (TP), and tibialis anterior (TA) muscles in humans using in vivo 1H proton spectroscopic imaging at 4 T. Improved spatial resolution (0.25-ml nominal voxel resolution) made it feasible to measure IMCL in S, TP, and TA simultaneously in vivo. The most significant regional difference was found in the content of IMCL compared with extramyocellular lipids or TCr. The concentrations of TCr were found to be 29-32 mmol/kg, with little regional variation. IMCL content was measured to be 4.8 ± 1.6 mmol/kg tissue wt in S, 2.8 ± 1.3 mmol/kg tissue wt in TP, and 1.6 ± 0.9 mmol/kg tissue wt in TA in the order of S > TP > TA (P < 0.05). It is likely that these IMCL values are consistent with the known fiber types of these muscles, with S having the greatest fraction of type I (slow-twitch, oxidative) fibers and TA having a large fraction of type IIb (fast-twitch, glycolytic) fibers.
AB - Regional differences in the content of intramyocellular lipids (IMCL), extramyocellular lipids, and total creatine (TCr) were quantified in soleus (S), tibialis posterior (TP), and tibialis anterior (TA) muscles in humans using in vivo 1H proton spectroscopic imaging at 4 T. Improved spatial resolution (0.25-ml nominal voxel resolution) made it feasible to measure IMCL in S, TP, and TA simultaneously in vivo. The most significant regional difference was found in the content of IMCL compared with extramyocellular lipids or TCr. The concentrations of TCr were found to be 29-32 mmol/kg, with little regional variation. IMCL content was measured to be 4.8 ± 1.6 mmol/kg tissue wt in S, 2.8 ± 1.3 mmol/kg tissue wt in TP, and 1.6 ± 0.9 mmol/kg tissue wt in TA in the order of S > TP > TA (P < 0.05). It is likely that these IMCL values are consistent with the known fiber types of these muscles, with S having the greatest fraction of type I (slow-twitch, oxidative) fibers and TA having a large fraction of type IIb (fast-twitch, glycolytic) fibers.
KW - Body composition
KW - Magnetic resonance spectroscopy
KW - Phosphocreatine
KW - Quantification
KW - Triglyceride
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U2 - 10.1152/jappl.2001.90.4.1267
DO - 10.1152/jappl.2001.90.4.1267
M3 - Article
C2 - 11247923
AN - SCOPUS:0035103679
SN - 8750-7587
VL - 90
SP - 1267
EP - 1274
JO - Journal of applied physiology
JF - Journal of applied physiology
IS - 4
ER -