Different effects of exercise and edema on <i>T</i><sup>2</sup> relaxation in skeletal muscle

Ploutz‐Snyder, Lori L.; Nyrén, Sven; Cooper, Tim F.; Potchen, E. James; Meyer, Ronald A.

doi:10.1002/mrm.1910370509

Cited by 114 publications

(104 citation statements)

References 26 publications

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“…2016), but yet reliable interpretation of the data remains limited by the lack of specificity of the measure to the different underlying mechanism (Ploutz‐Snyder et al. 1997; Louie et al. 2009; Arpan et al.…”

Section: Discussionmentioning

confidence: 99%

Acute changes in extracellular volume fraction in skeletal muscle monitored by²³Na NMR spectroscopy

2017

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In this article, we induced acute changes in extracellular volume fraction in skeletal muscle tissue and compared the sensitivity of a standard 1H T2 imaging method with different 23Na‐NMR spectroscopy parameters within acquisition times compatible with clinical investigations. First, we analyzed the effect of a short ischemia on the sodium distribution in the skeletal muscle. Then, the lower leg of 21 healthy volunteers was scanned under different vascular filling conditions (vascular draining, filling, and normal condition) expected to modify exclusively the extracellular volume. The first experiment showed no change in the total sodium content during a 15 min ischemia, but the intracellular weighted 23Na signal slowly decreased. For the second part, significant variations of total sodium content, sodium distribution, and T1 and T2∗ of 23Na signal were observed between different vascular filling conditions. The measured sodium distribution correlates significantly with sodium T1 and with the short and long T2∗ fractions. In contrast, significant changes in the proton T2w signal were observed only in three muscles. Altogether, the mean T2w signal intensity of all muscles as well as their mean T2 did not vary significantly with the extracellular volume changes. In conclusion, at the expense of giving up spatial resolution, the proposed 23Na spectroscopic method proved to be more sensitive than standard 1H T2 approach to monitor acute extracellular compartment changes within muscle tissue.

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Section: Discussionmentioning

confidence: 99%

Acute changes in extracellular volume fraction in skeletal muscle monitored by²³Na NMR spectroscopy

2017

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“…The KEE was performed at the MRI facility to permit image collection immediately after exercise (1,2,6,7,14,21,(33)(34)(35). Subjects performed four sets of 10 repetitions of concentric (extension phase)-eccentric (flexion phase) contractions with a load equal to 50% of the 4 ϫ 10 RM with the use of a plate-loaded knee extension machine (Badger-Magnum, Milwaukee, WI).…”

Section: Subjectsmentioning

confidence: 99%

“…Standard spin-echo MR images of the left thigh were taken using a 1.5-T super-conducting magnet (Signa, General Electric, Milwaukee, WI) essentially as done previously (1,2,6,7,14,21,(33)(34)(35). Thirteen 10-mm-thick transaxial images (repetition time ϭ 1,500 ms; echo time ϭ 30 and 60 ms) of the left thigh spaced 10 mm apart were collected using 1.0 number of excitations with a whole body coil.…”

Section: Subjectsmentioning

confidence: 99%

Vastus lateralis fatigue alters recruitment of musculus quadriceps femoris in humans

Akima

Foley

Prior³

et al. 2002

Journal of Applied Physiology

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. Vastus lateralis fatigue alters recruitment of musculus quadriceps femoris in humans. J Appl Physiol 92: 679-684, 2002; 10.1152/ japplphysiol.00267.2001.-This study tested the hypothesis that fatigue of a single member of musculus quadriceps femoris (QF) would alter use of the other three muscles during knee extension exercise (KEE). Six men performed KEE with the left QF at a load equal to 50% of the 4 ϫ 10 repetitions maximum. Subsequently, electromyostimulation (EMS), intended to stimulate and fatigue the left m. vastus lateralis (VL), was applied for 30 min. Immediately after EMS, subjects repeated the KEE. Transverse relaxation time (T2)-weighted magnetic resonance images were taken before and after each bout of KEE and at 3 and 30 min of EMS to assess use and stimulation, respectively, of the QF. T2 of each of the QF muscles was increased 8-13% after the first KEE. During EMS, T2 increased (P Ͻ 0.05) even more in VL (10%), whereas it decreased (P Ͻ 0.05) to pre-KEE levels in m. vastus medials (VM) and m. rectus femoris (RF). The VL and, to some extent, the m. vastus intermedius were stimulated, whereas the VM and RF were not, thereby recovering from the first bout of KEE. Isometric torque, initially 30% of maximal voluntary, was reduced to 13% at 3 min and 7% at 30 min. T2 was greater (P Ͻ 0.05) after the second than the first bout of KEE, especially the increase for the VM and RF. These results suggest that subjects were able to perform the second bout with little contribution of the VL by greater use of the other QF muscles. The simplest explanation is increased central command to the QF such that the intended act could be accomplished despite acute fatigue of one of its synergists.

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“…Variations of the mobility of molecules in all types of tissue affect relaxation times, however, in such a complex way that they cannot be interpreted unequivocally. In skeletal muscle, multiple T 2 components 50,51 and variations with muscular edema 52 have been found. The interpretation of these effects involves the association of water with macromolecules and changes in the exchange rate between these protein-associated, short T 2 components and freely movable water.…”

Section: Effects Of Order Upon Relaxation Times and Signal Decaymentioning

confidence: 99%

Dipolar coupling and ordering effects observed in magnetic resonance spectra of skeletal muscle

Boesch

Kreis

2001

NMR in Biomedicine

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Skeletal muscle is a biological structure with a high degree of organization at different spatial levels. This order influences magnetic resonance (MR) in vivo-in particular 1 H-spectra-by a series of effects that have very distinct physical sources and biomedical applications: (a) bulk fat (extramyocellular lipids, EMCL) along fasciae forms macroscopic plates, changing the susceptibility within these structures compared to the spherical droplets that contain intra-myocellular lipids (IMCL); this effect leads to a separation of the signals from EMCL and IMCL; (b) dipolar coupling effects due to anisotropic motional averaging have been shown for 1 H-resonances of creatine, taurine, and lactate; (c) aromatic protons of carnosine show orientation-dependent effects that can be explained by dipolar coupling, chemical shift anisotropy or by relaxation anisotropy; (d) limited rotational freedom and/or compartmentation may explain differences of 1 H-MR-visibility of the creatine/phosphocreatine resonances; (e) lactate 1 H-MR resonances are reported to reveal information on tissue compartmentation; (f) transverse relaxation of water and metabolites show multiple components, indicative of intra-, extracellular and/or macromolecular-bound pools, and in addition dipolar or J-coupling lead to a modulation of the signal decay, hindering straightforward interpretation; (g) diffusion weighted 31 P-MRS has shown restricted diffusion of phosphocreatine; (h) magnetization transfer (MT) indicates that there is a motionally restricted proton pool in spin-exchange with free creatine; reduced availability or restricted motion of creatine is particularly important for an estimation of ADP from 31 P-MR spectra, and in addition MT effects may alter the signal intensity of creatine 1 H-resonances following water-suppression pulses; (i) transcytolemmal water-exchange can be studied in 1 H-MRS by contrast-agents applied to the extracellular space; (k) transport of glucose across the cell membrane has been studied in diabetes patients using a combination of 13 C-and 31 P-MRS; and (l) residual quadrupolar interaction in 23 Na MR spectra from human skeletal muscle suggest that sodium ions are bound to ordered muscular structures.

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Different effects of exercise and edema on T² relaxation in skeletal muscle

Cited by 114 publications

References 26 publications

Acute changes in extracellular volume fraction in skeletal muscle monitored by²³Na NMR spectroscopy

Acute changes in extracellular volume fraction in skeletal muscle monitored by²³Na NMR spectroscopy

Vastus lateralis fatigue alters recruitment of musculus quadriceps femoris in humans

Dipolar coupling and ordering effects observed in magnetic resonance spectra of skeletal muscle

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Different effects of exercise and edema on T2 relaxation in skeletal muscle

Cited by 114 publications

References 26 publications

Acute changes in extracellular volume fraction in skeletal muscle monitored by23Na NMR spectroscopy

Acute changes in extracellular volume fraction in skeletal muscle monitored by23Na NMR spectroscopy

Vastus lateralis fatigue alters recruitment of musculus quadriceps femoris in humans

Dipolar coupling and ordering effects observed in magnetic resonance spectra of skeletal muscle

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Different effects of exercise and edema on T² relaxation in skeletal muscle

Acute changes in extracellular volume fraction in skeletal muscle monitored by²³Na NMR spectroscopy

Acute changes in extracellular volume fraction in skeletal muscle monitored by²³Na NMR spectroscopy