Rotating frame MRI relaxations as markers of diffuse white matter abnormalities in multiple sclerosis
Rotating frame MRI relaxations as markers of diffuse white matter abnormalities in multiple sclerosis
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DOI：
10.1016/j.nicl.2020.102234
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发表时间：
2020-01-01
影响因子：
4.2
通讯作者：
Mangia, Silvia
中科院分区：
文献类型：
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作者：
Filip, Pavel;Svatkova, Alena;Mangia, Silvia
尽管白质病变的 MRI 可视化对于多发性硬化症 (MS) 的诊断和治疗至关重要，但检测超出明显 T2 高信号病变的弥漫性脑组织损伤的问题仍然引起了人们的极大兴趣。受旋转架 MRI 方法对对组织表征至关重要的慢运动机制敏感这一概念的启发，我们在临床 3 Tesla 平台上使用了旋转架 MRI 的新型成像协议，包括绝热纵向、T1 rho 和横向、T2 rho、松弛方法以及 4 级旋转框架 (RAFF4) 中的沿虚拟场松弛 (RAFF)，在 10 名复发缓解型多发性硬化症患者和 10 名复发缓解型多发性硬化症患者中进行了研究。性别和年龄匹配的健康对照。与对照组相比，从整个白质中提取的 T1 rho、T2 rho 和 RAFF4 松弛图显示 MS 患者的松弛时间常数显着转向更长。即使仅考虑正常出现的白质 (NAWM) 区域，T1 rho 和 RAFF4 也能检测到变化，而其他 MRI 指标（例如 T1w/T2w 比率和扩散张量成像测量）未能发现组间差异。此外，RAFF4、T2 rho 以及较小程度上的 T1 rho 在皮质下灰质结构（主要是海马体）中表现出差异，而在静息态功能 MRI 指标中未检测到该区域的功能变化。我们得出的结论是，旋转框架 MRI 技术对于检测 NAWM 以及 MS 深部灰质的细微异常异常敏感，甚至超过了功能变化的高度敏感测量，而功能变化通常被认为先于可检测的结构改变。这种异常与 MS 的多种不同但相互关联的病理特征一致，包括神经元细胞及其轴突的损失、髓鞘质水平的降低（甚至在 NAWM 中也是如此）以及铁含量的改变。
Even though MRI visualization of white matter lesions is pivotal for the diagnosis and management of multiple sclerosis (MS), the issue of detecting diffuse brain tissue damage beyond the apparent T2-hyperintense lesions continues to spark considerable interest. Motivated by the notion that rotating frame MRI methods are sensitive to slow motional regimes critical for tissue characterization, here we utilized novel imaging protocols of rotating frame MRI on a clinical 3 Tesla platform, including adiabatic longitudinal, T1 rho, and transverse, T2 rho, relaxation methods, and Relaxation Along a Fictitious Field (RAFF) in the rotating frame of rank 4 (RAFF4), in 10 relapsing-remitting multiple sclerosis patients and 10 sex- and age-matched healthy controls. T1 rho, T2 rho and RAFF4 relaxograms extracted from the whole white matter exhibited a significant shift towards longer relaxation time constants in MS patients as compared to controls. T1 rho and RAFF4 detected alterations even when considering only regions of normally appearing white matter (NAWM), while other MRI metrics such as T1w/T2w ratio and diffusion tensor imaging measures failed to find group differences. In addition, RAFF4, T2 rho and, to a lesser extent, T1 rho showed differences in subcortical grey matter structures, mainly hippocampus, whereas no functional changes in this region were detected in resting-state functional MRI metrics. We conclude that rotating frame MRI techniques are exceptionally sensitive methods for the detection of subtle abnormalities not only in NAWM, but also in deep grey matter in MS, where they surpass even highly sensitive measures of functional changes, which are often suggested to precede detectable structural alterations. Such abnormalities are consistent with a wide spectrum of different, but interconnected pathological features of MS, including the loss of neuronal cells and their axons, decreased levels of myelin even in NAWM, and altered iron content.