Thor Besier, Ph.D.

Garry E. Gold, M.D.

Christian Federau¹, Jean-Baptiste Ledoux¹, Patrick Omoumi¹, and Fabio Becce^1
1CHUV, University Hospital Lausanne, Lausanne, Vaud, Switzerland

Intravoxel Incoherent Motion (IVIM) offers the possibility to study microvascular perfusion properties of skeletal striated muscle. This study demonstrates the selective increase in IVIM perfusion parameters in subscapularis and posterior and lateral deltoid muscles after a lift-off test, which is a clinical test recognized to be selective for those muscles. This method is a promising new tool to investigate skeletal striated muscle physiology as well as perfusion-related muscular disorders, such as peripheral arteriopathies and diabetes mellitus-related microangiopathies.

Ericky Caldas de A. Araujo¹, Noura Azzabou¹, Alexandre Vignaud², Geneviève Guillot³, and Pierre G. Carlier^1,4
1NMR Laboratory, Institute of Myology, Paris, Île-de-France, France, ²CEA/DSV/I2BM/NeuroSpin/UNIRS, Gif Sur Yvette, Île-de-France, France,³IR4M/UMR8081/CNRS, University Paris-SUD, Orsay, Île-de-France, France, ⁴NMR Laboratory, CEA/I2BM/MIRCen, Paris, Île-de-France, France

UTE methods offer the possibility of acquiring NMR signal from protons in the hydration layers of the collagen. We have applied the UTE method for imaging the short-T2 signal in SKM tissue, which we hypothesise to reveal intramuscular connective tissue content. Dual-echo acquisition and selective long-T2 suppression methods fail to isolate the short-T2 signals in SKM. We propose a new method for processing UTE data, resulting in signal issued exclusively from the short-T2 components in the SKM. The proposed method was applied to investigate the SKM tissue of eight healthy volunteers and three patients diagnosed with NMDs.

Paola Porcari¹, Elizabeth Greally², Volker Straub², and Andrew M Blamire^1
1Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, Tyne and Wear, United Kingdom, ²Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, Tyne and Wear, United Kingdom

In this study, we investigated whether diffusion MRI might be a useful method to evaluate differences in the microarchitecture of hindlimb muscles between dystrophic (mdx) and healthy (wt) mice of three groups of age. Mice were investigated at multiple diffusion times and significant differences between the diffusion properties of hindlimb muscles in healthy and diseased mice were found for long diffusion times. High specificity and sensitivity of the method was demonstrated and also confirmed by the preliminary results of the histological assessment, thus suggesting a powerful and straightforward application on humans.

Seongjin Choi¹, David A. Reiter², Kenneth W. Fishbein², Eleanor M. Simonsick¹, Richard G. Spencer², and Luigi Ferrucci^3
1Translational Gerontology Branch, NIH/National Institute on Aging, Baltimore, Maryland, United States, ²Laboratory of Clinical Investigation, NIH/National Institute on Aging, Baltimore, Maryland, United States, ³Intramural Research Program, NIH/National Institute on Aging, Baltimore, Maryland, United States

Gait speed is an important predictor of morbidity in the elderly and skeletal muscle mitochondrial function plays a central role in mobility. ³¹P MRS of skeletal muscle permits evaluation of mitochondrial function through the phosphocreatine recovery rate (k_PCr) after exercise. In this cross-sectional study using the Baltimore Longitudinal Study of Aging cohort we assessed associations between ³¹P MRS-determined mitochondrial function, age and four walking speed metrics. We found that k_PCr, a marker of mitochondrial synthetic capacity, had the strongest correlation with 400 m walk performance at maximum pace, which was the most strenuous ambulatory exercise among the four walking metrics.

Kevin E Conley¹, Amir Ali¹, and Sharon Jubrias^1
1Radiology, University of Washington, Seattle, WA, United States

Nicotinamide adenine dinucleotide (NAD) compartmentation underlies the role of this co-enzyme as a co-factor in oxidative phosphorylation, glycolysis and mitochondrial biogenesis. Here we identify a unique resonance for mitochondrial NADH by phosphorus magnetic resonance spectroscopy (31P MRS) in vivo. This mitochondrial NADH pool is identified by chemical standards and dynamic changes in the NAD+ and NADH peaks with activation of oxidative phosphorylation in human muscle. The end result is non-invasive detection of NADH in cell vs. mitochondria, which provides sensitive natural indicators of redox compartmentation and oxidative phosphorylation in human tissues in vivo.