Novel Biomarkers in Painful Neuropathies Recent Advances in Magnetic Resonance Imaging (MRI), Microneurography, and Non-Coding RNAs

Peripheral neuropathies are common; diabetes mellitus alone affects around 8.8% of the world population, with around half developing neuropathy and a quarter of these having significant neuropathic pain which causes disability and reduced quality of life. However the pathomechanisms which lead to development of neuropathy and pain are incompletely understood. There are numerous techniques used to investigate these conditions, including neurophysiology and quantitative sensory testing, each of which has its advantages and drawbacks.

Despite widespread use of magnetic resonance imaging (MRI) in studying central nervous system (CNS) disease, the use of MRI to investigate peripheral neuropathies is still in its infancy, largely due to technological challenges including spatial resolution, although this has changed in recent years with the increased availability of 3 Tesla (T) and 7T systems. MRI at higher field strength can offer fascicular level resolution in peripheral nerves, offering the exciting possibility of developing MRI as a “virtual biopsy”. In MR neurography, combinations of T1, T2 and diffusion sequences are used to image peripheral nerves and has now been applied to numerous peripheral conditions including inflammatory, metabolic, infective, traumatic and compressive neuropathies. Here we review recent work on some common peripheral neuropathies, including applications to neuropathic pain.