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Updated: Jul 11, 2026

Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease
Published on: December 18, 2016
Relationship between MRI relaxation time and muscle fiber composition
J A Houmard1, R Smith, G L Jendrasiak
1Human Performance Laboratory, East Carolina University, Greenville, North Carolina 27858, USA.
Abstract:
The relationship between nuclear magnetic resonance relaxation time obtained with magnetic resonance imaging (MRI) and muscle fiber composition of the lateral gastrocnemius was examined in 13 men. There was a positive correlation (r = 0.80, P < or = 0.001) between longitudinal relaxation time and the relative percentage of slow-twitch muscle fibers (type I). There was no relationship between transverse relaxation time and type I percentage (r = 0.17, P = 0.57). These results suggest that MRI longitudinal relaxation time can be used for the noninvasive estimation of muscle fiber composition in humans.
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