Contemporary image-based methods for measuring passive mechanical properties of skeletal muscles in vivo

Abstract

Skeletal muscles’ primary function in the body is mechanical: to move and stabilize the skeleton. As such, their mechanical behavior is a key aspect of their physiology. Recent developments in medical imaging technology have enabled quantitative studies of passive muscle mechanics, ranging from measurements of intrinsic muscle mechanical properties, such as elasticity and viscosity, to three-dimensional muscle architecture and dynamic muscle deformation and kinematics. In this review we summarize the principles and applications of contemporary imaging methods that have been used to study the passive mechanical behavior of skeletal muscles. Elastography measurements can provide in vivo maps of passive muscle mechanical parameters, and both MRI and ultrasound methods are available (magnetic resonance elastography and ultrasound shear wave elastography, respectively). Both have been shown to differentiate between healthy muscle and muscles affected by a broad range of clinical conditions. Detailed muscle architecture can now be depicted using diffusion tensor imaging, which not only is particularly useful for computational modeling of muscle but also has potential in assessing architectural changes in muscle disorders. More dynamic information about muscle mechanics can be obtained using a range of dynamic MRI methods, which characterize the detailed internal muscle deformations during motion. There are several MRI techniques available (e.g., phase-contrast MRI, displacement-encoded MRI, and “tagged” MRI), each of which can be collected in synchrony with muscle motion and postprocessed to quantify muscle deformation. Together, these modern imaging techniques can characterize muscle motion, deformation, mechanical properties, and architecture, providing complementary insights into skeletal muscle function.

Magnetic resonance imaging based muscle strain rate mapping during eccentric contraction to study effects of unloading induced by unilateral limb suspension

“…12 . It should be noted that during the contraction phase (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11), SRfiber (defined as the eigenvector closest to the muscle fiber orientation) is the positive eigenvalue while during the relaxation (phases 12-24), SRfiber is the negative eigenvalue. No significant differences were found in the SR indices for time (pre-and post-) or region.…”

“…The in-vivo studies on muscle motion using these sequences have been applied to the study of muscle kinematics under isometric or passive plantarflexion. 9 There have been no strain or SR measurements during eccentric contractions. Eccentric contractions are of interest since many physiological functions occur when the muscle is actively lengthening.…”

Influence of Spinal Movements Associated with Physical Evaluation on Muscle Mechanical Properties of the Lumbar Paraspinal in Subjects with Acute Low Back Pain

“…New technologies, such as elastography, help to study the passive mechanical behaviour of skeletal muscles [ 22 ]. However, their high cost makes them inaccessible to a clinical setting, challenging the determination of the MMPs.…”

Scapular Dynamic Muscular Stiffness Assessed through Myotonometry: A Narrative Review

“…Muscular stiffness, described as passive or dynamic [ 1 , 2 , 3 ], is a mechanical property that traduce the resistance offered to an action that leads to muscle tissue deformation [ 1 , 3 ]. More specifically, this muscular property derived from muscle structure and intrinsic material properties [ 4 ], namely from tendon [ 5 ], myofibrillar cross-bridges [ 5 ] (particularly titin filaments [ 6 , 7 ]) and muscular connective tissue [ 6 ].…”

“…More specifically, this muscular property derived from muscle structure and intrinsic material properties [ 4 ], namely from tendon [ 5 ], myofibrillar cross-bridges [ 5 ] (particularly titin filaments [ 6 , 7 ]) and muscular connective tissue [ 6 ]. The passive stiffness, commonly assessed with elastography methods [ 2 , 3 ], mainly represents the tissue adaptation [ 3 ] in it basal/passive status [ 8 ] and the baseline level of the stiffness [ 5 ]. The dynamic stiffness, assessed through myotonometry [ 9 ], is based on the free oscillation theory and results from the natural oscillation of the tissues, in response to a brief mechanical tap on the skin [ 10 ].…”