TY - JOUR T1 - Characterizing metabolic abnormality and adipose tissue infiltration in skeletal muscle of COPD patients using 31P MR spectroscopy and MRI imaging JF - European Respiratory Journal JO - Eur Respir J VL - 40 IS - Suppl 56 SP - 1668 AU - Graziele Coissi AU - Gregory Shields AU - Pillar Jimenez-Royo AU - Giulio Gambarota AU - Raul Dimber AU - Nicholas Hopkinson AU - Paul Mattrews AU - Andrew Brown AU - Michael Polkey Y1 - 2012/09/01 UR - http://erj.ersjournals.com/content/40/Suppl_56/1668.abstract N2 - Background: Anaerobic metabolism (AM) is an extra-pulmonary manifestation of COPD. 31P Magnetic Resonance Spectroscopy (31P MRS) is an established technique to assess the oxidative capacity of skeletal muscles, but is unknown whether similar changes occur in the upper and lower limbs. Dixon MRI has been demonstrated as a quantitative technique to determine water and fat levels in tissues.Objective: We hypothesised that AM would occur predominantly in the legs and that intermuscular adipose tissue (IMAT) infiltration would be a predictor of AM.Methods: 31P – MRS data for the quadriceps (quads) and biceps were obtained during 2 min. and 8 secs of endurance exercise and pre and post-exercise. Quads and its sub-muscle group cross-sectional area and IMAT were measured using Dixon MR imaging. Quads maximal voluntary strength (QMVC), six minute walking test (6MWT) and fat free mass index (FFMI) were additionally performed.Results: Data were obtained for 14 patients with COPD (age 66 ± 5.73) with a mean ±SD percentage predicted of forced expiratory volume in 1s (FEV1) of 36.5 ± 12.7 and 14 age matched healthy controls (age 65 ± 6, FEV1 pred% 110 ± 6.5). Patients with COPD had prolonged quads phospholcreatine recovery time [PCr (t1/2)],(p=0.006) and lower nadir intramuscular pH (p=0.002) as compared to controls. Biceps metabolism was not different between COPD patients and controls. Quads IMAT was 32% greater in COPD patients than controls (p=0.033).Conclusion: AM activation appears confined to the quads in COPD. We also suggest that IMAT, as measured by Dixon MRI, is a sensitive biomarker for AM. ER -