RECONSIDERING THE LAYER THICKNESS DISTRIBUTION IN AORTIC VALVE CUSPS USING HIGH-FREQUENCY ULTRASOUND

A non-destructive high-frequency ultrasound method for measuring the thickness of thin tissue layers was adapted to map the thicknesses of the fibrosa, spongiosa, and ventricularis layers of aortic valve cusps. The sound speed and layer thicknesses of thirteen porcine aortic valve cusps were measured. The measurements yielded results of (mean plusmn standard deviation) 0.81 plusmn 0.13 mm, 0.30 plusmn 0.07 mm, 0.23 plusmn 0.05 mm, and 0.32 plusmn 0.08 mm for the total, fibrosa, spongiosa, and ventricularis thicknesses, respectively, and a sound speed of 1527 plusmn 33 m/s. The uncertainty introduced by variations in sound speed plays a relatively small role in the variability of the thickness measurements. The relative distribution of layer thicknesses of fresh, intact cusps measured with this method differs from that of fixed, sliced cusps measured with conventional methods