Fig. 1
From: Nerve ultrasound characterizes AMN polyneuropathy as inhomogeneous and focal hypertrophic
Representative ultrasound images of the median nerve (MN) in different diseases / disease states are shown per row. The left column (pictures labeled with an (a)) depicts cross sections of the upper arm (UA) and in the right column (b) cross sections of the forearm (FA). All ultrasound cross sections were recorded according to the UPSS protocol as previously described [8, 9]. All ultrasound pictures are presented at the same resolution and are therefore comparable in size (scale bar indicates 0.5 cm). In the first row (Ia&b) the inhomogenously enlarged median nerve of a patient with AMN and demyelinating polyneuropathy is seen (Class 1 according to [11]), with a cross-sectional area (CSA) of 44 mm2 in the UA (Ia) and 11mm2 in the FA – (Ib). Images of an AMN patient without neuropathy (Class 3, pictures IIa&b) are presented in the second row. The CSA of the MN was 8mm2 in the UA (IIa) and 9mm2 in the FA (IIb). CSA values of AMN patients without electrophysiologically proven peripheral neuropathy (PNP) correspond to normal values of healthy controls as published before [8]. For comparison purposes, we added representative pictures of a chronic inflammatory demyelinating polyneuropathy (CIDP) patient (Class 2) in the thirds row (IIIa & b) and of a Charcot-Marie-Tooth type 1a (CMT1a) patient (IVa & b) in the fourth row. The CIDP patient shows an inhomogeneously enlarged median nerve (78mm2 in the UA (IIIa) and 13mm2 in the FA (IIIb)) which is hyperechoic due to more perifascicular tissue. Nerve segments of the median nerve of a CMT1a patient (IVa & b) are in contrast homogeneously enlarged with 44mm2 in the UA (IVa) and 30mm2 in the FA (IVb) without significant changes in echointensity. The CSA in CMT1a equals the 3-4fold of known normal values in healthy adults