非人灵长类动物脊髓损伤的纵向定量磁化传递评估
Longitudinal assessment of spinal cord injuries in nonhuman primates with quantitative magnetization transfer.
作者信息
Wang Feng, Li Ke, Mishra Arabinda, Gochberg Daniel, Min Chen Li, Gore John C
机构信息
Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.
Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.
出版信息
Magn Reson Med. 2016 Apr;75(4):1685-96. doi: 10.1002/mrm.25725. Epub 2015 May 8.
PURPOSE
This study aimed to evaluate the reproducibility and specificity of quantitative magnetization transfer (qMT) imaging for monitoring spinal cord injuries (SCIs).
METHODS
MRI scans were performed in anesthetized monkeys at 9.4T, before and serially after a unilateral lesion of the cervical spinal cord. A two-pool fitting model was used to derive qMT parameters.
RESULTS
qMT measures were reproducible across normal subjects, with an average pool size ratio (PSR) of 0.086 ± 0.003 (mean ± SD) for gray matter, and 0.120 ± 0.005 for white matter, respectively. Compared with normal gray matter, the PSR of abnormal tissues rostral and caudal to the injury site decreased by 19.5% (P < 0.05), while the PSR of the cyst-like volume decreased drastically weeks after SCI. Strong correlations in cyst-like regions were observed between PSR and other MRI measures including longitudinal relaxation rate (R1 ), apparent diffusion coefficient and fractional anisotropy (FA). Decreased PSR and FA values correlated well with demyelination in abnormal tissues.
CONCLUSION
The qMT parameters provide robust and specific information about the molecular and cellular changes produced by SCI. PSR detected demyelination and loss of macromolecules in abnormal tissue regions rostral and caudal to the cyst/lesion sites.
目的
本研究旨在评估定量磁化传递（qMT）成像监测脊髓损伤（SCI）的可重复性和特异性。
方法
在9.4T磁场下对麻醉的猴子进行MRI扫描，于颈髓单侧损伤前及损伤后连续进行扫描。采用双池拟合模型推导qMT参数。
结果
qMT测量在正常受试者中具有可重复性，灰质的平均池大小比（PSR）为0.086±0.003（均值±标准差），白质为0.120±0.005。与正常灰质相比，损伤部位头侧和尾侧异常组织的PSR降低了19.5%（P<0.05），而SCI数周后囊肿样区域的PSR急剧下降。在囊肿样区域观察到PSR与其他MRI测量值之间存在强相关性，包括纵向弛豫率（R1）、表观扩散系数和分数各向异性（FA）。PSR和FA值的降低与异常组织中的脱髓鞘密切相关。
结论
qMT参数提供了关于SCI所产生的分子和细胞变化的可靠且特异的信息。PSR检测到囊肿/病变部位头侧和尾侧异常组织区域的脱髓鞘和大分子丢失。
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