title: Dependence of residual dipolar couplings on foot angle in (1)H MR spectra from skeletal muscle.
abstract: Foot dorsi and plantar flexion affects the pennation angle of skeletal muscle fibers and changes the fiber direction with respect to the main magnetic field, thereby affecting MR spectrum of the muscle. In order to analyze the effect that foot flexion has on the MR spectrum, tibialis anterior (TA) and soleus muscles were studied in humans and rats. Localized MRS was performed at different foot angles in clinical and pre-clinical settings using a 3T MRI/MRS GE Excite HD and 7T Bruker Clinscan scanner, respectively. In this study we show the effect of foot angle variation on total Creatine (tCr) resonance of (1)H spectrum at 3.03 and 3.93ppm for TA and soleus muscles. In addition to this, we observe a 4-line splitting pattern for methylene resonance of tCr in the rat TA spectrum for a specific foot angle. This observation is attributed to the individual splitting of creatine and phosphocreatine of the tCr signal. Novel hydrogel application is demonstrated and used to support our in vivo observations and for the first time splitting of individual resonances of Cr and PCr has been shown in an in vitro set-up.
authors.affiliation: Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, Singapore.
authors.forename: Nikita
authors.initials: N
authors.lastname: Agarwal
authors.affiliation: Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, Singapore.
authors.forename: Guilhem
authors.initials: G
authors.lastname: Pagès
authors.affiliation: Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, Singapore.
authors.forename: Loyola
authors.initials: L
authors.lastname: D' Silva
authors.affiliation: Department of Radiology and Medical Imaging, University of Virginia Health System, Charlottesville, VA 22908.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Said
authors.affiliation: School of Molecular Bioscience, University of Sydney, NSW 2006, Australia.
authors.forename: Philip W
authors.initials: PW
authors.lastname: Kuchel
authors.affiliation: Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, Singapore; Singapore Institute for Clinical Sciences, A*STAR, Singapore; Clinical Imaging Research Centre, NUS-A*STAR, Singapore. Electronic address: Sendhil_Velan@sbic.a-star.edu.sg.
authors.forename: S Sendhil
authors.initials: SS
authors.lastname: Velan
mesh_terms: D000328:Adult; D000818:Animals; D003401:Creatine / Q000378:metabolism*; D005528:Foot / Q000502:physiology*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism*; D011187:Posture / Q000502:physiology*; D011522:Protons; D016059:Range of Motion, Articular / Q000502:physiology*; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution; D055815:Young Adult
chemical_list: D011522:Protons; D010725:Phosphocreatine; D003401:Creatine
keywords: Creatine; Foot Angle; Phosphocreatine; Residual Dipolar Couplings; Skeletal Muscle