Muscle blood flow and oxygenation measured by NMR imaging and spectroscopy

Abstract

Tissue perfusion and oxygenation in many organs can be evaluated by various NMR techniques. This review focuses on the specificities, limitations and adaptations of the NMR tools available to investigate perfusion and oxygenation in the skeletal muscle of humans and animal models. A description of how they may be used simultaneously is provided as well.1 H NMR spectroscopy of myoglobin (Mb) monitors intramyocytic oxygenation. It measures the level of deoxy-Mb, from which Mb concentration, Mb desaturation/resaturation rates, muscle oxygenation changes and intracellular partial oxygen pressure (pO 2 ) can be calculated. Positive and negative blood oxygen level-dependent (BOLD) contrasts exist in skeletal muscle. BOLD contrasts primarily reflect changes in capillary-venous oxygenation, but are also directly or indirectly dependent on muscle blood volume, perfusion, vascular network architecture and angulation, relative to the main magnetic field. Arterial spin labelling (ASL) techniques, having high spatial and temporal resolution, are the methods of choice to quantify and map skeletal muscle perfusion non-invasively. Limitations of ASL are poor contrast-to-noise ratio and sensitivity to movement; however, with the introduction of specific adaptations, it has been proven possible to measure skeletal muscle perfusion at both rest and during exercise. The possibility of combining these NMR measurements with others into a single dynamic protocol is most interesting. The 'multiparametric functional (mpf) NMR' concept can be extended to include the evaluation of muscle energy metabolism simultaneously with 31 P NMR or with lactate double quantum filtered 1 H NMR spectroscopy, an approach which would make NMR an exceptional tool for non-invasive investigations of integrative physiology and biochemistry in skeletal muscle in vivo.

Discrepancies between the fate of myoblast xenograft in mouse leg muscle and NMR label persistency after loading with Gd-DTPA or SPIOs

“…High-resolution functional NMR imaging has the potential to quantify fiber groups' contractility with velocity-encoding or -tagging techniques, to map local perfusion and blood oxygenation with arterial spin labeling and BOLD sequences. 48 It could be adapted to measure contractility, perfusion and oxygenation in areas with high therapeutic cell density detected by contrast enhancement on high-resolution anatomical images. Similarly, high-resolution chemical shift NMR spectroscopy can quantify the creatine pool, 49 an index of muscle metabolic activity, which could be used to evaluate energy metabolism in grafted areas as well.…”

Effects of percutaneous transluminal angioplasty on muscle BOLD-MRI in patients with peripheral arterial occlusive disease: preliminary results

“…Muscle BOLD is also dependent on muscle blood volume, perfusion vascular architecture and magnetic field angulation [15][16][17], but it seems to be more complex compared with the BOLD response in the brain.…”

Imagerie et spectroscopie par résonance magnétique nucléaire du muscle strié squelettique

“…Des approches très similaires ont été développées et appliquées avec succès au muscle squelettique (Carlier et al 2006 ;Partovi et al 2015). La perfusion tissulaire peut être mesurée de façon atraumatique au moyen d'un groupe de techniques qui marquent magnétiquement le sang artériel en amont du tissu d'intérêt (techniques dites « ASL »).…”

“…La plupart des études en ASL a consisté à mesurer la perfusion post-exercice ou post-ischémie. Néanmoins, si un sacrifice est réalisé sur la résolution temporelle des expériences, la perfusion au repos peut également être mesurée par ASL en moyennant le signal pendant quelques minutes (Carlier et al, 2006 ;Bertoldi et al, 2008). Le contraste BOLD (pour blood oxygen level dependant) (Ogawa et al 1990), qui est bien connu pour sa capacité à détecter les activations cérébrales, est sensible au taux d'oxygéna-tion des capillaires et du sang veineux dans les muscles squelettiques et peut également fournir des mesures semi-quantitatives de la saturation sanguine en oxygène (Jordan et al 2004 ;Jacobi et al 2012).…”