title: Effect of ankle flexion on the quantification of MRS for intramyocellular lipids of the tibialis anterior and the medial gastrocnemius.
abstract: Muscle proton magnetic resonance spectroscopy (MRS) has been developed for non-invasive measurement of intramyocellular lipid (IMCL) levels. The majority of previous studies measuring IMCL with MRS have been performed on the calf muscle. The appearance of muscle MRS is influenced by bulk magnetic susceptibility and residual dipolar couplings, which depend on the angle between the muscle fibers and the main magnetic field. Our objective in this study was to evaluate the effect of ankle flexion and of the pennation angle on IMCL quantification in the calf muscle using proton MRS. The subjects comprised ten healthy male volunteers. In proton MRS, the ankle flexion angle was changed, and the pennation angle was measured from the tibialis anterior (TA) and the medial gastrocnemius (MG), respectively. We considered the relationship between the quantification of IMCL with (1)H MRS and the pennation angle by ankle flexion angle. The pennation angle of the TA and MG changed with the ankle flexion angle. The IMCL on the TA decreased significantly with plantar flexion (p < 0.05). However, the IMCL on the MG demonstrated no significant difference. The MR spectrum and IMCL quantitation changed with the pennation angle. Therefore, when spectra of individual subjects in longitudinal studies or between subjects are compared in cross-sectional studies, the foot position or calf muscle orientation must be considered.
authors: Division of Radiology and Nuclear Medicine, Sapporo Medical University Hospital, South-1, West-16, Chuo-ku, Sapporo, Hokkaido, 060-8543, Japan, takashima@sapmed.ac.jp.
authors: Hiroyuki
authors: H
authors: Takashima
authors: Hiroki
authors: H
authors: Shishido
authors: Rui
authors: R
authors: Imamura
authors: Yoshihiro
authors: Y
authors: Akatsuka
authors: Keigo
authors: K
authors: Taniguchi
authors: Mitsuhiro
authors: M
authors: Nakanishi
authors: Junpei
authors: J
authors: Suzuki
authors: Hiroshi
authors: H
authors: Nagahama
authors: Yuki
authors: Y
authors: Sakurai
authors: Motomichi
authors: M
authors: Sakata
mesh_terms: D000328:Adult; D000842:Ankle / Q000502:physiology; D006801:Humans; D050356:Lipid Metabolism; D008297:Male; D009068:Movement; D018482:Muscle, Skeletal / Q000166:cytology* / Q000378:metabolism; D066244:Proton Magnetic Resonance Spectroscopy / Q000379:methods*; D013977:Tibia / Q000502:physiology