Abstract:
Peripheral neuropathies account for the most frequent disorders seen by neurologists, and causes are manifold. The traditional diagnostic gold-standard consists of clinical neurologic examinations supplemented by nerve conduction studies. Due to well-known limitations of standard diagnostics and atypical clinical presentations, establishing the correct diagnosis can be challenging but is critical for appropriate therapies. Magnetic resonance neurography (MRN) is a relatively novel technique that was developed for the high-resolution imaging of the peripheral nervous system. In focal neuropathies, whether traumatic or due to nerve entrapment, MRN has improved the diagnostic accuracy by directly visualizing underlying nerve lesions and providing information on the exact lesion localization, extension, and spatial distribution, thereby assisting surgical planning. Notably, the differentiation between distally located, complete cross-sectional nerve lesions, and more proximally located lesions involving only certain fascicles within a nerve can hold difficulties that MRN can overcome, when basic technical requirements to achieve sufficient spatial resolution are implemented. Typical MRN-specific pitfalls are essential to understand in order to prevent overdiagnosing neuropathies. Heavily T2-weighted sequences with fat saturation are the most established sequences for MRN. Newer techniques, such as T2-relaxometry, magnetization transfer contrast imaging, and diffusion tensor imaging, allow the quantification of nerve lesions and have become increasingly important, especially when evaluating diffuse, non-focal neuropathies. Innovative studies in hereditary, metabolic or inflammatory polyneuropathies, and motor neuron diseases have contributed to a better understanding of the underlying pathomechanism. New imaging biomarkers might be used for an earlier diagnosis and monitoring of structural nerve injury under causative treatments in the future.
摘要:
周围神经病变是神经科医生看到的最常见的疾病,原因是多方面的。传统的诊断金标准包括临床神经系统检查以及神经传导研究。由于众所周知的标准诊断和非典型临床表现的局限性,建立正确的诊断可能具有挑战性,但对于适当的治疗至关重要。磁共振神经成像(MRN)是一种相对新颖的技术,旨在对周围神经系统进行高分辨率成像。在局灶性神经病中,无论是外伤还是由于神经卡压,MRN通过直接可视化潜在的神经病变并提供有关确切病变位置的信息,提高了诊断的准确性。扩展,和空间分布,从而协助手术计划。值得注意的是,远端位置之间的差异,完整的横断面神经损伤,而更近处的病变仅涉及神经内的某些束,可以克服MRN可以克服的困难,当实现实现足够空间分辨率的基本技术要求时。为了防止过度诊断神经病,理解典型的MRN特异性陷阱是必不可少的。具有脂肪饱和度的重T2加权序列是MRN最确定的序列。较新的技术,例如T2弛豫法,磁化转移对比成像,和扩散张量成像,允许量化的神经损伤,并已变得越来越重要,尤其是在评估弥漫性时,非局灶性神经病。遗传性创新研究,代谢性或炎性多发性神经病,和运动神经元疾病有助于更好地理解潜在的病理机制。未来,新的成像生物标志物可能用于早期诊断和监测致病性治疗下的结构性神经损伤。