核磁共振技术测量生物骨密度的设备及方法

诊断骨质疏松症多采用双能X射线吸收方法测得的骨密度数据作为依据,但是该方法存在一定量的辐射,且准确性不高.该文设计并改进了一套核磁共振装置,通过在发射和接收线圈之间增加快速切换开关(Q-switch),使得核磁共振自旋回波的回波时间缩短至80μs的超短回波时间范围,实现了对T_2弛豫时间很短的骨组织核磁共振自旋回波信号的采集;将T_2弛豫时间谱和双能X射线方法测量的骨密度数据进行了对比研究,发现核磁共振T_2弛豫时间谱上300~500μs之间的峰值与骨密度之间具有良好的线性关系,随着骨密度的增大,相应的T_2弛豫时间峰值缩短;利用核磁共振T_2弛豫时间谱技术,结合双能X射线吸收方法,提出了一种测量生物离体骨骼样本骨密度的方法.该测量方案具有测量速度快、对人体完全无害、跨时期比较性强等优点,很好的弥补了现有测量方法的不足,在骨质疏松症的诊断和疗效评估中有着良好的应用前景.

Measuring Bone Mineral Density with NMR

Bone mineral density (BMD) measured by dual energy X-ray absorptiometry is often used as an index for diagnosis of osteoporosis. However, ionization radiation is present in X-rayBMD measurement, and the result can be inaccurate in some caese. In this work, we constructed an NMR equipment that used a Q-switch to achieve echo time as low as 80ms, and thus have the potential to be used forBMD measurement. In theT2 relaxation time spectra of bone measured by this equipment, the peak area at 300~500ms was found to change linearly with theBMD measured by X-ray absorptiometry. Based on this observation, we put forward a method to measurein vitroBMD with NMRT2 relaxation time spectra. This kind of method has advantages such as high measuring speed, no ionization radiation, and high cross-period comparability.