Concurrent and/or progressive degeneration of upper and lower motor neurons (LMNs) causes neurological symptoms and dysfunctions in motor neuron diseases (MNDs) such as amyotrophic lateral sclerosis (ALS). Although brain lesions are readily detected, magnetic resonance imaging of the brainstem and cervical spinal cord lesions resulting from damage to LMNs has proven to be difficult. With the development of mouse models of MNDs, a noninvasive neuroimaging modality capable of detecting lesions resulting from axonal and neuronal injury in mouse brainstem and cervical spinal cord could improve our understanding of the underlying mechanism of MNDs and aid in the development of effective treatments. Here we present a protocol that allows the concomitant acquisition of high-quality in vivo full-diffusion tensor magnetic resonance images from the mouse brainstem and cervical spinal cord using the actively decoupled, anatomically shaped pair of coils--the surface-receive coil and the minimized volume-transmit coil. To improve the data quality, we used a custom-made nose cone to monitor respiratory motion for synchronizing data acquisition and assuring physiological stability of mice under examination. The protocol allows the acquisition of in vivo diffusion tensor imaging of the mouse brainstem and cervical spinal cord at 117 μm × 117 μm in-plane resolution with a 500-μm slice thickness in 1 h on a 4.7-T horizontal small animal imaging scanner equipped with an actively shielded gradient coil capable of pulsed gradient strengths up to 18 G cm(−1) with a gradient rise time of ≤295 μs.

中文翻译：

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小鼠脑干和颈脊髓的弥散张量成像。

上下运动神经元 (LMN) 的并发和/或进行性退化会导致运动神经元疾病 (MND) 的神经症状和功能障碍，例如肌萎缩侧索硬化 (ALS)。虽然脑部病变很容易检测到，但已证明对 LMN 损伤导致的脑干和颈脊髓病变进行磁共振成像是困难的。随着 MNDs 小鼠模型的发展，一种能够检测小鼠脑干和颈脊髓中轴突和神经元损伤引起的病变的无创神经成像模式可以提高我们对 MNDs 潜在机制的理解，并有助于开发有效的治疗方法。在这里，我们提出了一个协议，允许使用主动解耦、解剖形状的线圈对从小鼠脑干和颈脊髓中同时获取高质量的体内全扩散张量磁共振图像 - 表面接收线圈和最小的音量传输线圈。为了提高数据质量，我们使用定制的鼻锥来监测呼吸运动，以同步数据采集并确保被检查小鼠的生理稳定性。该协议允许在 117 μm × 117 μm 平面分辨率下获得小鼠脑干和颈脊髓的体内扩散张量成像，500 μm 切片厚度在 4.