Akbari Atena, Abbasi-Rad Shahrokh, Rad Hamidreza Saligheh
Quantitative MR Imaging and Spectroscopy Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran; Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran.
Quantitative MR Imaging and Spectroscopy Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran; Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran.
Bone. 2016 Feb;83:17-22. doi: 10.1016/j.bone.2015.10.006. Epub 2015 Oct 22.
Large pores of human cortical bone (>30μm) are filled with fluids, essentially consisting of water, suggesting that cortical bone free water can be considered as a reliable surrogate measure of cortical bone porosity and hence quality. Signal from such pores can be reliably captured using Short Echo Time (STE) pulse sequence with echo-time in the range of 1-1.5msec (which should be judiciously selected correspond to T2(⁎) value of free water molecules). Furthermore, it is well-known that cortical bone T1-relaxivity is a function of its geometry, suggesting that cortical bone free water increases with age. In this work, we quantified cortical bone free water longitudinal relaxation time (T1) by a Dual-TR technique using STE pulse sequence. In the sequel, we investigated relationship between STE-derived cortical bone free water T1-values and age in a group of healthy volunteers (thirty subjects covering the age range of 20-70years) at 1.5T. Preliminary results showed that cortical bone free water T1 highly correlates with age (r(2)=0.73, p<0.0001), representing cortical bone free water T1 as a reliable indicator of cortical bone porosity and age-related deterioration. It can be concluded that STE-MRI can be utilized as proper alternative in quantifying cortical bone porosity parameters in-vivo, with the advantages of widespread clinical availability and being cost-effective.
人类皮质骨的大孔隙（>30μm）充满了主要由水组成的液体，这表明皮质骨中的自由水可被视为皮质骨孔隙率及质量的可靠替代指标。使用回波时间在1 - 1.5毫秒范围内的短回波时间（STE）脉冲序列能够可靠地捕捉来自此类孔隙的信号（应根据自由水分子的T2(⁎)值谨慎选择）。此外，众所周知，皮质骨的T1弛豫率是其几何结构的函数，这表明皮质骨中的自由水会随着年龄增长而增加。在这项研究中，我们采用STE脉冲序列通过双重复时间（Dual-TR）技术对皮质骨自由水纵向弛豫时间（T1）进行了量化。接下来，我们在1.5T场强下，对一组健康志愿者（30名年龄在20 - 70岁之间的受试者）研究了STE衍生的皮质骨自由水T1值与年龄之间的关系。初步结果显示，皮质骨自由水T1与年龄高度相关（r(2)=0.73，p<0.0001），这表明皮质骨自由水T1是皮质骨孔隙率及与年龄相关退变的可靠指标。可以得出结论，STE-MRI可作为在体量化皮质骨孔隙率参数的合适替代方法，具有广泛临床可用性和成本效益的优势。
