Fig. 2

Stability and validity of shear waves and the elastographic image of the PB. The validity was 92% (a) at rest and 94% during the maximal Valsalva maneuver (d); (b) and (e) shown the outlined PB and the calculation of the E values; (c) and (f) shown good stability with an M-STB index of 5 stars at rest and the maximal Valsalva maneuver, respectively.