Department of Radiology, University of California, San Diego, United States.
J Magn Reson. 2010 Dec;207(2):304-11. doi: 10.1016/j.jmr.2010.09.013. Epub 2010 Sep 25.
We describe the use of two-dimensional ultrashort echo time (2D UTE) sequences with minimum TEs of 8 μs to image and quantify cortical bone on a clinical 3T scanner. An adiabatic inversion pulse was used for long T(2) water and fat signal suppression. Adiabatic inversion prepared UTE acquisitions with varying TEs were used for T(2) measurement. Saturation recovery UTE acquisitions were used for T(1) measurement. Bone water concentration was measured with the aid of an external reference phantom. UTE techniques were evaluated on cadaveric specimens and healthy volunteers. A signal-to-noise ratio of around 30, contrast-to-noise ratio of around 27/20 between bone and muscle/fat were achieved in tibia in vivo with a nominal voxel size of 0.23 × 0.23 × 6.0 mm(3) in a scan time of 5 min. A mean T(1) of 223 ± 11 ms and mean T(2) of 390 ± 19 μs were found. Mean bone water concentrations of 23.3 ± 1.6% with UTE and 21.7 ± 1.3% with adiabatic inversion prepared UTE sequences were found in tibia in five normal volunteers. The results show that in vivo qualitative and quantitative evaluation of cortical bone is feasible with 2D UTE sequences.
我们描述了在临床 3T 扫描仪上使用最小 TE 为 8 μs 的二维超短回波时间（2D UTE）序列来对皮质骨进行成像和定量。使用绝热反转脉冲对长 T2 水和脂肪信号进行抑制。使用具有不同 TE 的绝热反转准备 UTE 采集进行 T2 测量。使用饱和恢复 UTE 采集进行 T1 测量。借助外部参考体模测量骨水浓度。在尸体标本和健康志愿者上评估了 UTE 技术。在体内胫骨中，使用名义体素大小为 0.23×0.23×6.0mm3，扫描时间为 5 分钟，实现了约 30 的信噪比，骨与肌肉/脂肪之间约 27/20 的对比噪声比。发现平均 T1 为 223±11ms，平均 T2 为 390±19μs。在 5 名正常志愿者的胫骨中，使用 2D UTE 序列测量的骨水浓度平均值为 23.3±1.6%，使用绝热反转准备 UTE 序列测量的骨水浓度平均值为 21.7±1.3%。结果表明，使用 2D UTE 序列可以对皮质骨进行体内定性和定量评估。
