Density of organic matrix of native mineralized bone measured by water- and fat-suppressed proton projection MRI
Density of organic matrix of native mineralized bone measured by water- and fat-suppressed proton projection MRI
复制标题
DOI：
10.1002/mrm.10512
复制
发表时间：
2003-07-01
影响因子：
3.3
通讯作者：
Glimcher, MJ
中科院分区：
文献类型：
--
作者：
Wu, YT;Ackerman, JL;Glimcher, MJ
水和脂肪抑制投影磁共振成像（WASPI）利用固体有机基质的质子T-2*s与骨的液体成分之间的巨大差异来抑制液体信号，同时保留固体基质信号。固体成分包括胶原蛋白和一些分子不动的水，并表现出非常短的T-2*。液体成分包括流动的水和脂肪，具有长T2*。在WASPI中，化学位移选择性低功率pi/2脉冲激发可移动的水并使其磁化，随后被梯度脉冲消除，而胶原和不移动的水的磁化主要保持在z方向。额外的选择性，pi脉冲在交替扫描进一步消除残余的水和脂肪的磁化。在水和脂肪抑制之后，矩阵信号被短硬脉冲激发，并在三维投影方法中获得梯度存在下的自由感应衰减。WASPI在4.7 T MR成像系统上实现，并在幻影和骨标本上进行了测试，实现了骨基质的出色可视化。用磁共振技术测量了牛小梁标本单位体积骨基质信号，并与化学分析结果进行了比较。该方法可与固体投影MRI测量骨密度相结合，判断骨矿化程度。中华医学杂志，2003。(C) 2003 Wiley-Liss, Inc。
Water- and fat-suppressed projection MR imaging (WASPI) utilizes the large difference between the proton T-2*s of the solid organic matrix and the fluid constituents of bone to suppress the fluid signals while preserving solid matrix signals. The solid constituents include collagen and some molecularly immobile water and exhibit very short T-2*. The fluid constituents include mobile water and fat, with long T2*. In WASPI, chemical shift selective low-power pi/2 pulses excite mobile water an at magnetization which is subsequently dephased by gradient pulses, while the magnetization of collagen and immobile water remains mostly in the z-direction. Additional selective, pi pulses in alternate scans further cancel the residual water and fat magnetization. Following water and fat suppression, the matrix signal is excited by a short hard pulse and the free induction decay acquired in the presence of a gradient in a 3D projection method. WASPI was implemented on a 4.7 T MR imaging system and tested on phantoms and bone specimens, enabling excellent visualization of bone matrix. The bone matrix signal per unit volume of bovine trabecular specimens was measured by this MR technique and compared with that determined by chemical analysis. This method could be used in combination with bone mineral density measurement by solid state projection MRI to determine the degree of bone mineralization. Magn Reson Med 50:59-68, 2003. (C) 2003 Wiley-Liss, Inc.