Fig. 3.

Examples of median (A), ulnar (B), and fibular/peroneal nerves (C) in one GBS (first row) and two CIDP patients. In the GBS patient, the echointensity of the fascicles is hypo- to isoechoic, only the median nerve (MN) is slightly enlarged—only in the upper arm—regionally restricted (13 mm², cut-off 12 mm²), whereas ulnar and fibular nerves (UN and FN) are not enlarged. Only one fascicle is enlarged (*, MN, CSA 7 mm², cut-off, 4.8 mm², 15). In the CIDP I patient in contrast, all nerves are enlarged to a different amount (MN 45 mm², the UN 26 mm², cut-off 8.5 mm² and the FN 18 mm², cut-off 11.5 mm²). In all nerves, at least one fascicle is enlarged (* 10 mm² in the MN, 6 and 7 mm² in UN and FN, cut-off 2.8 and 3.5 mm²). In CIDP II, the MN is enlarged with 25 mm² and reveals increased echointensity, and the UN is enlarged at two sites—homogeneously (18 mm² in the upper arm (B1) with reduced echo signal and 13 mm² in the forearm with increased echo signal (B)). Nerves are surrounded by white circles; the mentioned fascicles are marked with asterisk symbols