Assessment of water distribution changes in human cortical bone by nuclear magnetic resonance
Assessment of water distribution changes in human cortical bone by nuclear magnetic resonance
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DOI：
10.1088/0957-0233/18/3/022
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发表时间：
2007-03-01
影响因子：
2.4
通讯作者：
Nicolella, Daniel P.
中科院分区：
文献类型：
--
作者：
Ni, Qingwen;Nyman, Jeffry S.;Nicolella, Daniel P.
用核磁共振自旋-自旋(T-2)弛豫技术测定人皮质骨组织中水分分布的变化。说明了核磁共振T-2松弛技术用于骨水分布的优点。CPMG的T-2松弛数据可以反演为T-2松弛分布，然后该分布可以转换为孔尺寸分布，松弛时间越长，对应的孔洞越大。FIDT-2松弛数据可以反演为T-2松弛分布，然后该分布可以转换为结合水和流动水分布，其中最长的松弛时间对应于移动水，中等的松弛时间对应于束缚水。这项技术被应用于量化皮质骨中孔隙率、结合水和活动性水的明显变化。根据质子松弛数据除以总的骨体积，使用校准的核磁共振流体体积来确定总的骨孔率。从不同年龄的男性和女性供者的皮质骨标本中测定了核磁共振结合水和活动性水的变化。在男性和女性捐赠者的标本中发现了水分布的差异。此外，水在单个样品中的分布被发现是不均匀的。结果表明，在骨孔率相近的情况下，男性供体骨的平均结合水与活动性水的比率高于女性供体。我们还表明，男性和女性骨组的平均骨孔率乘以结合水和流动水的比率都是恒定的。这一参数可以用来衡量骨质量，描述孔隙率和水含量，这两个参数都可能是骨强度和抗折性的重要决定因素。
A NMR spin-spin (T-2) relaxation technique has been described for determining water distribution changes in human cortical bone tissue. The advantages of using NMR T-2 relaxation techniques for bone water distribution are illustrated. The CPMG T-2 relaxation data can be inverted to T-2 relaxation distribution and this distribution then can be transformed to a pore size distribution with the longer relaxation times corresponding to larger pores. The FID T-2 relaxation data can be inverted to T-2 relaxation distribution and this distribution then can be transformed to bound- and mobile-water distribution with the longest relaxation time corresponding to mobile water and the middle relaxation time corresponding to bound water. The technique is applied to quantify apparent changes in porosity, bound and mobile water in cortical bone. Overall bone porosity is determined using the calibrated NMR fluid volume from the proton relaxation data divided by overall bone volume. The NMR bound and mobile water changes were determined from cortical bone specimens obtained from male and female donors of different ages. Differences in water distribution were found between specimens from male and female donors. Furthermore, the distribution of water within a single specimen was found to be non-homogeneous. Our results show that the ratio of the average bound to mobile water in bone from male donors is higher than in bone from female donors when the bone porosities are similar between male and female groups. We also show that the average bone porosity multiplied by the ratio of bound to mobile water is constant for both male and female bone groups. This parameter may be used as a measure of bone quality describing both porosity and water content, both of which may be important determinants of bone strength and fracture resistance.