Grey-scale sonography and sonoelastography for diagnosing carpal tunnel syndrome

Figure 2 Transverse images in a 79-year-old female with carpal tunnel syndrome. A: A conventional grey scale sonographic image shows the cross-sectional area of the median nerve (CSA) corresponding to the circle in the normal side with an area of 8 mm² at the level of the pisiform bone; B: CSA in the carpal tunnel syndrome (CTS) side shows 21 mm² at pisiform bone level; C: CSA in the CTS side shows 7 mm² at the proximal third of the pronator quadratus level; D: CSA in the CTS side shows 6 mm² at a point 12 cm proximal to the pisiform bone. In this case, the calculated “delta CSA” and “CSA ratio” were 14 mm² and 3.5, respectively. *: Ulnar artery. FCR: Flexor carpi radialis; P: Pisiform bone; S: Scaphoid bone; PQ: Pronator quadratus muscle; R: Radius; U: Ulnar.