The purpose of this study was to investigate ultrasound (US)- and US elastography-detected changes in the median nerve of patients with carpal tunnel syndrome (CTS). Seventy-four wrists of 41 female patients with CTS (mean age, 47.73 +/- 11.45 y) and 45 wrists of 24 asymptomatic female controls (mean age, 42.83 +/- 10.66 y) were examined with US and US elastography. Electromyography results confirmed the diagnosis of CTS in the patients. The mean median nerve perimeter (MN-P = 15.26 +/- 2.18 mm) and median nerve cross-sectional area (MN-CSA = 11.81 +/- 4.05 mm(2)) of patients with CTS were higher than those of controls (12.08 +/- 1.54 mm and 7.76 +/- 1.40 mm(2), respectively) (p < 0.05). Mean tissue strain was lower in the patients with CTS (0.094 +/- 0.045 than in the controls (0.145 +/- 0.068) (p < 0.05). The most sensitive cut-off value for tissue strain was 0.0635, and the most specific was 0.19. US and US elastography, in addition to electromyography, proved to be beneficial in the diagnosis of CTS. US elastography is a new technique that may well find a place in the diagnosis of nerve entrapment syndromes. (E-mail: firstname.lastname@example.org) (c) 2013 World Federation for Ultrasound in Medicine & Biology.