Figure 2.

Measuring the shear wave velocity of target structures using acoustic radiation force impulse elastography. (A) Representative B-mode image at the carpal tunnel inlet showing target structures such as the median nerve, flexor digitorum superficialis, flexor digitorum profundus, and transverse carpal ligament. (B) Qualification of the acoustic radiation force impulse image. A homogenous green color map indicates a good-quality image. (C) and (D) Acquired acoustic radiation force impulse images and region-of-interest box placement for measuring shear wave velocity. A total of seven boxes were placed on the image (top to bottom of the image): two for the transverse carpal ligament, one for the median nerve, two for the flexor digitorum superficialis, and two for the flexor digitorum profundus. Red, green, and blue hues indicate high, medium, and low stiffness, respectively.