Effects of cord motion on diffusion imaging of the spinal cord
Effects of cord motion on diffusion imaging of the spinal cord
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DOI：
10.1002/mrm.20959
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发表时间：
2006-08-01
影响因子：
3.3
通讯作者：
Hackney, David B.
中科院分区：
文献类型：
--
作者：
Kharbanda, Hardave S.;Alsop, David C.;Hackney, David B.
扩散的测量及其对方向的依赖性已经成为脑的临床和研究的重要工具。脊髓的扩散成像同样可以证明是有用的组织损伤和轴突完整性的指标;然而，在脊髓中进行扩散成像比在大脑中更具挑战性。在这里，我们报告了一项研究的影响，运动的单次激发快速自旋回波（FSE）扩散张量成像（DTI）的脊髓。在心动周期中的四个不同时间进行扩散成像，不进行和进行扩散梯度的速度补偿。未补偿扩散图像显示，脊髓中存在大量信号丢失伪影，这强烈依赖于脉搏血氧仪触发后的延迟。定量扩散分析也受到这种运动伪影的强烈影响。使用血流补偿梯度有助于恢复脊髓中的正常信号，特别是在特定的触发延迟时。理论论证表明，提高空间分辨率可能有助于消除这种信号损失。即使具有更高的空间分辨率，在脊髓运动之后的病变的扩散成像中，仍然可能发生与运动相关的信号衰减。然而，当使用适当的扩散成像方法进行探测时，相同的脊髓运动可能包含有诊断价值的信息。
Measurement of diffusion and its dependence on direction has become an important tool for clinical and research studies of the brain. Diffusion imaging of the spinal cord may likewise prove useful as an indicator of tissue damage and axonal integrity; however, it is more challenging to perform diffusion imaging in the cord than in the brain. Here we report a study of the effects of motion on single-shot fast spin echo (FSE) diffusion tensor imaging (DTI) of the spinal cord. Diffusion imaging was performed at four different times in the cardiac cycle both without and with velocity compensation of the diffusion gradients. Uncompensated diffusion images demonstrated substantial signal loss artifacts in the cord that were strongly dependent on the delay after the pulse-oximeter trigger. Quantitative diffusion analysis was also strongly affected by this motion artifact. The use of flow-compensated gradients helped to restore normal signal in the cord, especially at particular trigger delays. Theoretical arguments suggest that improved spatial resolution may help eliminate this signal loss. Even with higher spatial resolution, motion-related signal attenuation may still occur in diffusion imaging of pathologies that after the motion of the cord. However, this same cord motion may contain diagnostically valuable information when probed using appropriate diffusion imaging approaches.