Alteration of proton diffusivity associated with passive muscle extension and contraction.
OBJECTIVE
To determine whether passive muscle extension and contraction affect the proton diffusivity of the muscle.


METHODS
Five male subjects were examined. The fractional anisotropy (FA), and primary (lambda(1)), secondary (lambda(2)), and tertiary eigenvalues (lambda(3)) of the right tibialis anterior and medial gastrocnemius muscles were compared between conditions of passive plantar flexion and passive dorsiflexion of the ankle joint.


RESULTS
In the tibialis anterior, FA, and lambda(1) at dorsiflexion decreased significantly (P < 0.01 and P < 0.01, respectively) compared to those at plantar flexion, but lambda(3) at dorsiflexion increased significantly (P = 0.02). In the gastrocnemius, FA and lambda(1) at dorsiflexion increased significantly (P < 0.01 and P < 0.01, respectively) compared to those at plantar flexion, but lambda(3) at dorsiflexion decreased significantly (P < 0.01). The lambda(2) value showed no significant change in either the tibialis anterior or medial gastrocnemius.


CONCLUSIONS
The results indicate that passive muscle extension and contraction associated with passive joint movement would affect the proton diffusivity of the muscle. This alteration of proton diffusivity is probably associated with microscopic structural changes of the muscle.
Hatakenaka
Masamitsu
M
Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Japan. mhatake@radiol.meed.kyushu-u.ac.jp
Matsuo
Yoshio
Y
Setoguchi
Taro
T
Yabuuchi
Hidetake
H
Okafuji
Takashi
T
Kamitani
Takeshi
T
Nishikawa
Kei
K
Honda
Hiroshi
H
D000328:Adult; D000843:Ankle Joint / Q000502:physiology; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D007866:Leg; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000502:physiology*; D016059:Range of Motion, Articular