TY - JOUR
T1 - Acute effects of exercise on MR imaging of skeletal muscle in normal volunteers
AU - Fleckenstein, J. L.
AU - Canby, R. C.
AU - Parkey, R. W.
AU - Peshock, Ronald M
PY - 1988
Y1 - 1988
N2 - Exercise is known to produce changes in the amount and distribution of water in skeletal muscle. Because MR imaging is highly sensitive to changes in water distribution, these changes should be detectable under appropriate imaging conditions. Imaging of the forearms and/or legs was performed in 16 volunteers at 0.35 T, before and after exercise. Exercises included finger flexion and extension, wrist flexion, ankle plantar flexion, and great toe extension. In the case of handgrip exercise, the level of exertion was quantitated. Individual muscles were frequently indistinguishable on preexercise scans. After exercise, active and inactive muscles could be clearly distinguished. For example, in the flexor digitorum profundus, finger flexion resulted in an increase in the image-derived estimate of T1 (T1 postexercise was 1037 ± 162 msec vs T1 preexercise of 590 ± 49 msec, p < .001). T2 also increased (T2 postexercise was 35 ± 2 msec vs T2 preexercise of 28 ± 1 msec, p < .001). Relative spin density also increased (p < .001). T1, T2, and spin density subsequently decreased with time but were still increased above baseline at 10 min postexercise (p < .005). Signal changes correlated moderately with the level of exertion (r = .63) and fatigue (r = .45). Vascular occlusion did not prevent intensity changes. Thus, changes in skeletal muscle MR signal intensity occur with exercise and appear to parallel known alterations in water distribution.
AB - Exercise is known to produce changes in the amount and distribution of water in skeletal muscle. Because MR imaging is highly sensitive to changes in water distribution, these changes should be detectable under appropriate imaging conditions. Imaging of the forearms and/or legs was performed in 16 volunteers at 0.35 T, before and after exercise. Exercises included finger flexion and extension, wrist flexion, ankle plantar flexion, and great toe extension. In the case of handgrip exercise, the level of exertion was quantitated. Individual muscles were frequently indistinguishable on preexercise scans. After exercise, active and inactive muscles could be clearly distinguished. For example, in the flexor digitorum profundus, finger flexion resulted in an increase in the image-derived estimate of T1 (T1 postexercise was 1037 ± 162 msec vs T1 preexercise of 590 ± 49 msec, p < .001). T2 also increased (T2 postexercise was 35 ± 2 msec vs T2 preexercise of 28 ± 1 msec, p < .001). Relative spin density also increased (p < .001). T1, T2, and spin density subsequently decreased with time but were still increased above baseline at 10 min postexercise (p < .005). Signal changes correlated moderately with the level of exertion (r = .63) and fatigue (r = .45). Vascular occlusion did not prevent intensity changes. Thus, changes in skeletal muscle MR signal intensity occur with exercise and appear to parallel known alterations in water distribution.
UR - http://www.scopus.com/inward/record.url?scp=0023753906&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0023753906&partnerID=8YFLogxK
U2 - 10.2214/ajr.151.2.231
DO - 10.2214/ajr.151.2.231
M3 - Article
C2 - 3260716
AN - SCOPUS:0023753906
SN - 0361-803X
VL - 151
SP - 231
EP - 237
JO - American Journal of Roentgenology
JF - American Journal of Roentgenology
IS - 2
ER -