Department of Radiology, Kobe University Hospital, Kobe, Japan.
J Magn Reson Imaging. 2010 Mar;31(3):632-5. doi: 10.1002/jmri.22073.
To assess the state of cancellous tissue we analyzed the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in vertebral bone marrow.
With 1.5 T magnetic resonance imaging (MRI), single-shot diffusion echo planar imaging was used with b factors of 0 and 1000 s/mm(2), diffusion-sensitizing gradient in six directions, sensitivity encoding technique, effective TE of 74 msec, and TR of 1800 msec. ADC and FA were determined in the lumbar vertebral body of 11 normal subjects (age 31 632-635 years), and then compared with the bone mineral density (BMD) obtained with dual-energy x-ray absorptiometry (DXA). Moreover, fat fraction (FF) of the bone marrow was measured with spectral presaturation with inversion recovery (SPIR) in the same subject.
A strong negative correlation was found between ADC and BMD for low or moderate FF in vertebral bone marrow. Moreover, a significant positive correlation was noted between ADC and FF in this region. There was a positive correlation between FA and BMD, and no correlation between FA and FF in the vertebral bone marrow.
Diffusion analyses with ADC and FA make it possible to obtain more detailed information on the structure of cancellous tissue and bone metabolism.
评估松质骨状态，我们分析了骨髓的表观扩散系数（ADC）和各向异性分数（FA）。
采用 1.5 T 磁共振成像（MRI），单次激发扩散回波平面成像，b 值为 0 和 1000 s/mm(2)，扩散敏感梯度 6 个方向，敏感编码技术，有效 TE 为 74 msec，TR 为 1800 msec。在 11 例正常受试者（年龄 31-63 岁）的腰椎体中确定 ADC 和 FA，然后与双能 X 线吸收法（DXA）获得的骨矿物质密度（BMD）进行比较。此外，在同一受试者中采用频率选择饱和反转恢复（SPIR）测量骨髓的脂肪分数（FF）。
在低或中度骨髓脂肪分数时，ADC 与 BMD 呈强烈负相关。此外，在该区域，ADC 与 FF 之间存在显著正相关。FA 与 BMD 呈正相关，而与骨髓 FF 无相关性。
ADC 和 FA 的扩散分析可提供有关松质骨结构和骨代谢的更详细信息。
