New technologies for the assessment of neuropathies.

Technical advances are rapidly changing the clinical and instrumental approach to peripheral nerve diseases. Magnetic resonance neurography, diffusion tensor imaging and nerve ultrasonography are increasingly entering the diagnostic workup of peripheral neuropathies as tools that complement neurophysiology and enable investigation of proximal structures, such as plexuses and roots. Progress in the design of magnetic resonance scanners and sequences, and the development of high-frequency ultrasound probes mean that high-resolution peripheral nerve imaging is possible, enabling detailed examination of nerve size, morphology and internal fascicular structure that can integrate nerve conduction studies into clinical practice. In the growing field of small-fibre neuropathy, in which traditional nerve conduction studies are of little or no use, skin biopsy has become a reliable tool for diagnosis. Corneal confocal microscopy, nociceptive evoked potentials and microneurography are emerging techniques that are mainly used in clinical research settings, but have increasing relevance to clinical practice. We review these new and emerging techniques and their effects on diagnosis, treatment strategies and prognosis in a variety of peripheral neuropathies, including entrapments, brachial plexopathies, immune and inherited neuropathies, and small-fibre neuropathies. We discuss the most promising research findings and their potential for future application in clinical practice.