title: Direct noninvasive quantification of lactate and high energy phosphates simultaneously in exercising human skeletal muscle by localized magnetic resonance spectroscopy.
abstract: A novel method based on interleaved localized 31P- and 1H MRS is presented, by which lactate accumulation and the accompanying changes in high energy phosphates in human skeletal muscle can be monitored simultaneously during exercise and recovery. Lactate is quantified using a localized double quantum filter suppressing the abundant lipid signals while taking into account orientation dependent signal modulations. Lactate concentration after ischemic exercise directly quantified by DQF 1H spectroscopy was 24 +/- 3 mmol/L cell water, while 22 +/- 3 mmol/L was expected on the basis of 31P MRS acquired simultaneously. Lactate concentration in a sample of porcine meat was estimated to be 40 +/- 7 mmol/L by means of DQF quantitation, versus 39 +/- 5 mmol/L by biochemical methods. Excellent agreement is shown between lactate concentrations measured noninvasively by 1H MRS, measured biochemically ex vivo, and inferred indirectly in vivo from changes in pH, P(i), and PCr as obtained from 31P MRS data.
authors: MR Centre of Excellence, Medical University of Vienna, Austria.
authors: Martin
authors: M
authors: Meyerspeer
authors: Graham J
authors: GJ
authors: Kemp
authors: Vladimir
authors: V
authors: Mlynárik
authors: Martin
authors: M
authors: Krssák
authors: Julia
authors: J
authors: Szendroedi
authors: Peter
authors: P
authors: Nowotny
authors: Michael
authors: M
authors: Roden
authors: Ewald
authors: E
authors: Moser
mesh_terms: D000818:Animals; D001834:Body Water / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000378:metabolism*; D007866:Leg; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000378:metabolism*; D019047:Phantoms, Imaging; D010710:Phosphates / Q000378:metabolism*; D013552:Swine
chemical_list: D007773:Lactates; D010710:Phosphates