ORIENTATION OF TENDONS IN THE MAGNETIC-FIELD AND ITS EFFECT ON T2 RELAXATION-TIMES
ORIENTATION OF TENDONS IN THE MAGNETIC-FIELD AND ITS EFFECT ON T2 RELAXATION-TIMES
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DOI：
10.1148/radiology.155.2.3983395
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发表时间：
1985-01-01
期刊：
影响因子：
19.7
通讯作者：
ORD, VA
中科院分区：
文献类型：
--
作者：
FULLERTON, GD;CAMERON, IL;ORD, VA
在体外对构成肌腱的质子或氢核的自旋-自旋弛豫时间的研究表明，在水合作用的生理水平上，T2对取向有显著的依赖性。T2从。apprx变化。250 .mu.s。肌腱与磁场对齐，与22女士成55度角。或125.度。偏差为。+-时为4ms。15.学位。从55.学位。125度，55度。和125.度。就是所谓的魔角3cos 2。-1 = 0。因此，体内人体肌腱发出的信号将取决于它们的方向；然而，T2通常足够短，无论肌腱的方向如何，在MR图像中信号强度都会接近0，因此在大多数研究中都没有观察到这种现象。
In vitro studies of spin-spin relaxation times of the protons or hydrogen nuclei which make up the tendon demonstrated significant dependence of T2 on orientation at physiological levels of hydration. T2 varied from .apprx. 250 .mu.s. with the tendon aligned with the magnetic field to 22 ms. at an angle of 55.degree. or 125.degree. and 4 ms at deviations of .+-. 15.degree. from 55.degree. and 125.degree., 55.degree. and 125.degree. are the so-called magic angles at which 3 cos2.theta. -1 = 0. As a result, the signal from human tendons in vivo will depend on their orientation; however, T2 is generally short enough that the signal intensity will approach 0 in MR images regardless of the orientation of the tendons, thereby preventing this phenomenon from being observed in most studies.