Changes in water content of intervertebral discs and paravertebral muscles before and after bed rest.
BACKGROUND
Although low back pain can be principally produced or increased during action, it may also be induced or enhanced in the morning after bed rest. During bed rest, tissue edema (increased water content) may occur. In this study, we measured the changes in water content in the intervertebral disc and the paravertebral muscle before and after bed rest using a magnetization transfer magnetic resonance imaging (MT-MRI) technique that permits measuring water content in tissues.


METHODS
A total of 20 student volunteers were enrolled in this study. MT-MRI evaluation was performed before and after bed rest. To measure water content in the intervertebral disc and paravertebral muscle, two MRI sequences were performed using MT pulse-off and MT pulse-on. Based on the two images obtained, the equivalent cross-relaxation rate (ECR) was calculated.


RESULTS
The ECR for intervertebral discs was significantly lower after bed rest than before bed rest (P < 0.01). The ECR for paravertebral equivalent cross-relaxation rate muscles was significantly higher after bed rest than before bed rest (P < 0.05).


CONCLUSIONS
We obtained results indicating that after bed rest the water content in the intervertebral disc and the paravertebral muscle was increased and decreased, respectively.
Matsumura
Yoshihiro
Y
Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi Tsu, Mie, 514-8507, Japan.
Kasai
Yuichi
Y
Obata
Hideaki
H
Matsushima
Shigeru
S
Inaba
Tadashi
T
Uchida
Atsumasa
A
D000328:Adult; D001416:Back Pain; D001510:Bed Rest; D001825:Body Fluid Compartments; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000502:physiology*; D008161:Lumbosacral Region / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D055815:Young Adult