减法
矢状面
对比度(视觉)
回音时间
颞下颌关节
翻转角度
自旋回波
核磁共振
磁共振成像
Echo(通信协议)
脉冲序列
脉搏(音乐)
软组织
材料科学
梯度回波
快速自旋回波
物理
生物医学工程
计算机科学
数学
医学
光学
解剖
放射科
口腔正畸科
探测器
算术
计算机网络
作者
Michael Carl,Hatice Tuba Sanal,Eric Diaz,Jiang Du,Olivier Girard,Sheronda Statum,R Znamirowski,Christine B. Chung
摘要
Abstract Purpose: To use a tissue specific algorithm to numerically optimize UTE sequence parameters to maximize contrast within temporomandibular joint (TMJ) donor tissue. Materials and Methods: A TMJ specimen tissue block was sectioned in a true sagittal plane and imaged at 3 Tesla (T) using UTE pulse sequences with dual echo subtraction. The MR tissue properties (PD, T 2 , T 2 *, and T 1 ) were measured and subsequently used to calculate the optimum sequences parameters (repetition time [TR], echo time [TE], and θ). Results: It was found that the main contrast available in the TMJ could be obtained from T 2 (or T 2 *) contrast. With the first echo time fixed at 8 μs and using TR = 200 ms, the optimum parameters were found to be: θ ≈ 60°, and TE2 ≈ 15 ms, when the second echo is acquired using a gradient echo and θ ≈ 120°, and TE2 ≈ 15 ms, when the second echo is acquired using a spin echo. Conclusion: Our results show that MR signal contrast can be optimized between tissues in a systematic manner. The MR contrast within the TMJ was successfully optimized with facile delineation between disc and soft tissues. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.
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