From the MRI Section, Department of Radiology, SERCOSA, Health Time, Carmelo Torres 2, 23007 Jaén, Spain (T.M.N., A.L.); Peripheral Nerve and Plexus Department, Centro Rossi, Buenos Aires, Argentina (R.B.); MRI Section, Department of Radiology, DADISA, Health Time, Cádiz, Spain (M.G.C.); Peripheral Nerve and Plexus Surgery Unit, Department of Neurosurgery, University of Buenos Aires School of Medicine, Buenos Aires, Argentina (M.S.); Department of Radiology, NYU School of Medicine, New York, NY (J.T.B.); and Department of Radiology, University Hospitals of Cleveland, Case Western Reserve University, Cleveland, Ohio (A.L.).
Radiographics. 2019 Mar-Apr;39(2):427-446. doi: 10.1148/rg.2019180112. Epub 2019 Feb 8.
Evaluation of traumatic peripheral nerve injuries has classically been based on clinical and electrophysiologic criteria. US and MRI have been widely used for morphologic assessment of nerve injury sites and concomitant lesions. In the past few years, morphologic MR neurography has significantly increased its clinical applications on the basis of three-dimensional or two-dimensional images with and without fat-suppression techniques. However, these sequences have a major drawback: absence of pathophysiologic information about functional integrity or axonal flow of peripheral nerves. In this scenario, functional MRI techniques such as diffusion-weighted imaging (DWI) or diffusion tensor imaging (DTI) can be used as a complementary tool in initial evaluation of peripheral nerve trauma or in assessment of trauma undergoing surgical repair. These approaches provide not only morphologic but also functional information about extent and degree of nerve impairment. Functional MR neurography can also be applied to selection, planning, and monitoring of surgical procedures that can be performed after traumatic peripheral nerve injuries, such as neurorrhaphy, nerve graft, or neurolysis, as it provides surgeons with valuable information about the functional status of the nerves involved and axonal flow integrity. The physical basis of DWI and DTI and the technical adjustments required for their appropriate performance for peripheral nerve evaluation are reviewed. Also, the clinical value of DWI and DTI in assessment of peripheral nerve trauma is discussed, enhancing their potential impact on selection, planning, and monitoring of surgical procedures employed for peripheral nerve repair. Online supplemental material is available for this article. RSNA, 2019.
创伤性周围神经损伤的评估传统上基于临床和电生理标准。超声和 MRI 已广泛用于损伤部位和伴随病变的形态评估。在过去几年中，形态磁共振神经成像在三维或二维图像的基础上，结合和不结合脂肪抑制技术，显著增加了其临床应用。然而，这些序列有一个主要的缺点：缺乏有关周围神经功能完整性或轴突流动的病理生理信息。在这种情况下，弥散加权成像（DWI）或弥散张量成像（DTI）等功能磁共振成像技术可作为周围神经创伤初始评估或手术修复后评估的补充工具。这些方法不仅提供了形态学信息，还提供了有关神经损伤程度和程度的功能信息。功能磁共振神经成像也可应用于选择、规划和监测创伤性周围神经损伤后的手术，如神经吻合术、神经移植术或神经松解术，因为它为外科医生提供了有关所涉及神经的功能状态和轴突流完整性的有价值的信息。本文回顾了 DWI 和 DTI 的物理基础以及为进行适当的周围神经评估所需的技术调整，并讨论了 DWI 和 DTI 在评估周围神经损伤方面的临床价值，增强了它们在选择、规划和监测周围神经修复手术中的潜在影响。本文提供了在线补充材料。
