Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States.
Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States; Medical Scientist Training Program, Medical College of Wisconsin, Milwaukee, WI, United States.
J Magn Reson. 2018 Jul;292:137-148. doi: 10.1016/j.jmr.2018.04.016. Epub 2018 Apr 30.
Diffusion weighted magnetic resonance imaging (DWI) and related techniques such as diffusion tensor imaging (DTI) are uniquely sensitive to the microstructure of the brain and spinal cord. In the acute aftermath of nervous system injury, for example, DWI reveals changes caused by injury that remains invisible on other MRI contrasts such as T-weighted imaging. This ability has led to a demonstrated clinical utility in cerebral ischemia. However, despite strong promise in preclinical models and research settings, DWI has not been as readily adopted for other acute injuries such as traumatic spinal cord, brain, or peripheral nerve injury. Furthermore, the precise biophysical mechanisms that underlie DWI and DTI changes are not fully understood. In this report, we review the DWI and DTI changes that occur in acute neurological injury of cerebral ischemia, spinal cord injury, traumatic brain injury, and peripheral nerve injury. Their associations with the underlying biology are examined with an emphasis on the role of acute axon and dendrite beading. Lastly, emerging DWI techniques to overcome the limitations of DTI are discussed as these may offer the needed improvements to translate to clinical settings.
弥散加权磁共振成像（DWI）和相关技术，如扩散张量成像（DTI），对脑和脊髓的微观结构具有独特的敏感性。例如，在神经系统损伤的急性发作后，DWI 可以揭示 T 加权成像等其他 MRI 对比无法显示的损伤引起的变化。这种能力在脑缺血方面已经显示出了临床应用的价值。然而，尽管在临床前模型和研究环境中有很强的应用前景，但 DWI 在其他急性损伤（如创伤性脊髓、脑或周围神经损伤）中的应用尚未得到广泛接受。此外，DWI 和 DTI 变化背后的确切生物物理机制尚不完全清楚。在本报告中，我们回顾了 DWI 和 DTI 在脑缺血、脊髓损伤、创伤性脑损伤和周围神经损伤等急性神经损伤中的变化。还检查了它们与潜在生物学的关系，重点关注急性轴突和树突珠的作用。最后，还讨论了克服 DTI 局限性的新兴 DWI 技术，因为这些技术可能会提供必要的改进，从而转化为临床环境。
