Nerve echogenicity and intranerve CSA variability in high-resolution nerve ultrasound (HRUS) in chronic inflammatory demyelinating polyneuropathy (CIDP)

Objective: HRUS is increasingly being used in the diagnosis and evaluation of autoimmune neuropathies such as CIDP. Recently, studies focused not only on changes of nerves size, but also the fascicular structure and the echogenicity changes in CIDP. However, little is known about the alterations of echogenicity in the long-term course in CIDP. The aim of this study was to evaluate echogenicity in CIDP patients in a long-term follow-up period and to analyze the benefit of the evaluation of echogenicity compared to nerve size.

Methods: 20 patients fulfilling the definite diagnostic criteria of CIDP received clinical examination, nerve conduction studies and HRUS every 6 months over a median follow-up time of 34 months. Patients were divided into clinically stable/regressive disease course or progressive disease course according to the development of the inflammatory neuropathy cause and treatment overall disability sum score. Echogenicity of peripheral nerves was measured semi-automated and quantitative. Echogenicity was divided into three classes by fraction of black: hypoechogenic, mixed hypo-/hyperechogenic, hyperechogenic.

Results: Patients with hyperechogenic arm nerves more frequently show clinical worsening, whereas patients with hypoechogenic arm nerves remain stable or even improved over time. In the long-term course of the disease, echogenicity mostly did not change, and if changes occured echogenicity did not correspond to ODSS changes.

Conclusion: Echogenicity of the arm nerves in CIDP may be used as a prognostic marker, but not as a follow-up tool for evaluating clinical changes. Further studies in a larger cohort are needed to confirm these results.