Typical CIDP, distal variant CIDP, and anti-MAG antibody neuropathy – an ultra-high frequency ultrasound comparison of nerve structure

Abstract

Abstract To date, little is known about the usefulness of ultra-high frequency ultrasound (UHF-US, 50–70 MHz) in clinical practice for the diagnosis of dysimmune neuropathies. We present a prospective study aimed at comparing UHF-US alterations of nerves and fascicles in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), distal CIDP (d-CIDP) and anti-MAG neuropathy and their relationships with clinical and electrodiagnostic (EDX) features. Twenty-eight patients were included (twelve CIDP, six d-CIDP and ten anti-MAG) as well as ten healthy controls. Each patient underwent neurological examination, EDX and UHF-US study of both median and ulnar nerves. UHF-US was reliable in differentiating immune neuropathies from controls when using mean and/or segmental nerve and/or fascicle cross-sectional area (CSA); furthermore, fascicle ratio (fascicle/nerve CSA, FR) was a reliable factor for differentiating d-CIDP from other types of polyneuropathies. Mean median nerve fascicle CSA, fascicle CSA and FR for the median nerve in the antecubital fossa and for the ulnar nerve in the midarm segment were able to distinguish CIDP from anti-MAG polyneuropathy, while ulnar nerve CSA in the mid-forearm differentiated between anti-MAG and d-CIDP. UHF-US offers information beyond simple nerve CSA and allows for a better characterization of the different forms of dysimmune neuropathies.