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Phase-contrast MRI reveals mechanical behavior of superficial and deep aponeuroses in human medial gastrocnemius during isometric contraction.

ABSTRACT: The behavior of the entire medial gastrocnemius (MG) superficial and deep aponeurosis structure was investigated with velocity-encoded phase-contrast, spin-tag, and three-dimensional morphometric magnetic resonance imaging. The displacements and strain of both these aponeuroses, muscle length, and the cross-sectional segment length of the deep aponeurosis were measured during isometric plantarflexion at 20% and 40% of maximal voluntary contraction (MVC). The length of the entire MG shortened during 20% and 40% MVC. All regions of interest in both aponeuroses moved proximally. Positive strain (lengthening) occurred in both ends of the deep aponeurosis and in the proximal region of the superficial aponeurosis. In contrast, negative strain (shortening) was observed in the middle region of the deep aponeurosis and in the distal region of the superficial aponeurosis. Consistent with this shortening of the deep aponeurosis length along the proximal-distal axis was expansion of the aponeuroses in the medial-lateral and anterior-posterior directions in the cross-sectional plane. It is concluded that at low to moderate force levels of isometric contraction, regional differences in strain occur along the proximal-distal axis of both aponeuroses, and some regions of both aponeuroses shorten.

SUBMITTER: Kinugasa R

PROVIDER: S-EPMC2576031 | biostudies-literature | 2008 Oct

REPOSITORIES: biostudies-literature

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Phase-contrast MRI reveals mechanical behavior of superficial and deep aponeuroses in human medial gastrocnemius during isometric contraction.

Kinugasa Ryuta R Shin Dongsuk D Yamauchi Junichiro J Mishra Chandan C Hodgson John A JA Edgerton V Reggie VR Sinha Shantanu S

Journal of applied physiology (Bethesda, Md. : 1985) 20080814 4

The behavior of the entire medial gastrocnemius (MG) superficial and deep aponeurosis structure was investigated with velocity-encoded phase-contrast, spin-tag, and three-dimensional morphometric magnetic resonance imaging. The displacements and strain of both these aponeuroses, muscle length, and the cross-sectional segment length of the deep aponeurosis were measured during isometric plantarflexion at 20% and 40% of maximal voluntary contraction (MVC). The length of the entire MG shortened dur ...[more]

PMID: 18703759

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Project description:BACKGROUND:Strain rate (SR) is a measure of the rate of regional deformation that can be computed by analyzing velocity-encoded phase-contrast 2D images. Recent studies have explored the changes in normal components of the strain tensor in aging muscle, while shear strain may also provide valuable information. PURPOSE:To compute the shear SR from velocity-encoded MRI of the lower leg and to study the correlation of SR parameters measured in the medial gastrocnemius (MG) to muscle force in a cohort of young and senior subjects. STUDY TYPE:Prospective cohort study. SUBJECTS:Six young (26.1?±?2.3 years) and six senior (76.7?±?8.3 years) healthy females; two other subjects were scanned on three separate occasions for repeatability studies. FIELD STRENGTH/SEQUENCE:1.5T using a single oblique sagittal slice with velocity-encoding in three directions (velocity-encoded phase contrast gradient echo sequence). ASSESSMENT:Age-related and regional differences in the SR eigenvalues (SRfiber , SRin-plane ), normal SRs (SRff , SRcc ), and shear SRs (SRfc , SRfc_max ) were statistically analyzed. STATISTICAL TESTS:Difference between young and senior cohorts were assessed using two-way analysis of variance (ANOVAs). The coefficient of variation and repeatability coefficient were calculated from repeat studies. Univariate and stepwise multivariable linear regression was performed to identify predictors of force. RESULTS:During isometric plantarflexion contraction, SRs in the principal basis (SRfiber , SRin-plane ) and maximum shear SR (SRfc_max ) was significantly lower in the senior cohort (P < 0.05). On multiple variable regression, maximum shear SR (SRfc_max ) and normal SR in the fiber cross-section (SRcc ) were significantly associated with force (R?=?0.681, F?=?14.034, P < 0.001). DATA CONCLUSION:This study establishes that computation of shear strain is feasible and is a significant predictor of force variability with age. LEVEL OF EVIDENCE:2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1351-1357.

Dataset Information

Phase-contrast MRI reveals mechanical behavior of superficial and deep aponeuroses in human medial gastrocnemius during isometric contraction.

Publications

Phase-contrast MRI reveals mechanical behavior of superficial and deep aponeuroses in human medial gastrocnemius during isometric contraction.

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