31 P magnetic resonance spectroscopy in skeletal muscle: Experts' consensus recommendations.

Skeletal muscle phosphorus-31 31 P MRS is the oldest MRS methodology to be applied to in vivo metabolic research. The technical requirements of 31 P MRS in skeletal muscle depend on the research question, and to assess those questions requires understanding both the relevant muscle physiology, and how 31 P MRS methods can probe it. Here we consider basic signal-acquisition parameters related to radio frequency excitation, TR, TE, spectral resolution, shim and localisation. We make specific recommendations for studies of resting and exercising muscle, including magnetisation transfer, and for data processing. We summarise the metabolic information that can be quantitatively assessed with 31 P MRS, either measured directly or derived by calculations that depend on particular metabolic models, and we give advice on potential problems of interpretation. We give expected values and tolerable ranges for some measured quantities, and minimum requirements for reporting acquisition parameters and experimental results in publications. Reliable examination depends on a reproducible setup, standardised preconditioning of the subject, and careful control of potential difficulties, and we summarise some important considerations and potential confounders. Our recommendations include the quantification and standardisation of contraction intensity, and how best to account for heterogeneous muscle recruitment. We highlight some pitfalls in the assessment of mitochondrial function by analysis of phosphocreatine (PCr) recovery kinetics. Finally, we outline how complementary techniques (near-infrared spectroscopy, arterial spin labelling, BOLD and various other MRI and 1 H MRS measurements) can help in the physiological/metabolic interpretation of 31 P MRS studies by providing information about blood flow and oxygen delivery/utilisation. Our recommendations will assist in achieving the fullest possible reliable picture of muscle physiology and pathophysiology

Exploration combinée du métabolisme énergétique chez l'homme (standardisation des exercices et facteurs liés au coût énergétique)

Les objectifs de ce travail étaient de développer un protocole d exercice d extension du genou standardisé et de caractériser les déterminants du coût énergétique d un exercice. Ce coût énergétique est classiquement défini comme le rapport entre l énergie consommée et la puissance mécanique développée. La première étude consistait à évaluer la précision des mesures mécaniques enregistrées à l aide d un ergomètre dynamométrique conçu au sein de notre laboratoire. [...] Le but de la deuxième étude était d examiner la reproductibilité des paramètres métaboliques mesurés par SRM-P31 et plus particulièrement la production d ATP par les différentes voies métaboliques (i.e., oxydative vs. anaérobique), au cours d un protocole standardisé du type repos exercice récupération réalisés à un deux mois et un an d intervalle. [...] La troisième étude avait pour objectif d étudier si la contribution des voies métaboliques à la production d ATP, le CE et la capacité oxydative (évaluée par la resynthèse de PCr et la consommation maximale d O2) du quadriceps étaient dépendants du statut d entraînement des sujets. [...]The aims of the present work were to develop a standardised exercise protocol and to investigate the physiological determinants of exercise energy cost, which is commonly defined as the ratio between energy consumption and power output. The first study assessed the reliability of a dynamometric ergometer designed in our lab. [...] The second study was designed to assess the reliability of a large number of commonly used metabolic parameters measured or calculated (as oxidative and anaerobic ATP production) from 31P MRS data during a rest exercise ecovery protocol performed 2-months and a year apart. [...] The third study assessed whether quadriceps oxidative and anaerobic ATP production, energy cost (EC) and oxidative capacity (assessed by maximal pulmonary O2 consumption and Pcr resynthesis kinetics) was related to training status. [...]AIX-MARSEILLE2-BU Sci.Luminy (130552106) / SudocSudocFranceF