LeBlanc A D, Schonfeld E, Schneider V S, Evans H J, Taber K H
Department of Nuclear Medicine, Methodist Hospital, Houston, TX 77030.
Radiology. 1988 Oct;169(1):105-7. doi: 10.1148/radiology.169.1.3420243.
Magnetic resonance imaging of the spine was performed in six healthy male volunteers before and after 5 weeks of continuous bed rest. Imaging studies consisted of a single 1-cm sagittal section obtained with a spin-echo technique through the center of the spinal column. The T2s of the lumbar vertebral body and nucleus pulposus and the area of the latter were measured. In both vertebrae and disks, there was a significant decrease in T2 after bed rest. The nucleus pulposus also decreased in size with bed rest. The decrease in relaxation time of the lumbar vertebrae could be explained by the replacement of hematopoietic marrow by fatty marrow, a known consequence of paralytic immobilization. The decreases in size and T2 of the disks probably represent loss of water. The significance of these changes to the mechanical integrity of these structures after immobilization or space flight is not known but will depend in part on whether changes are progressive with increasing length of immobilization and on the rate and extent that they are reversed after reambulation. These results indicate that relaxation times can be altered by simple disuse, which often accompanies the underlying disease.
对6名健康男性志愿者在连续卧床休息5周前后进行了脊柱磁共振成像检查。成像研究包括通过脊柱中心用自旋回波技术获得的单个1厘米矢状面切片。测量了腰椎椎体和髓核的T2值以及髓核的面积。卧床休息后，椎体和椎间盘的T2值均显著降低。髓核大小也随卧床休息而减小。腰椎椎体弛豫时间的降低可以用造血骨髓被脂肪骨髓替代来解释，这是麻痹性固定的一个已知后果。椎间盘大小和T2值的降低可能代表水分流失。这些变化对固定或太空飞行后这些结构的机械完整性的意义尚不清楚，但部分取决于这些变化是否随着固定时间的延长而进展，以及重新行走后它们逆转的速度和程度。这些结果表明，弛豫时间可因简单的废用而改变，而废用常伴随潜在疾病出现。
