A Method for Estimating an Overlying Layer Correction in Quantitative Ultrasound Imaging

A new method is tested to compensate for attenuation losses through the intervening layers in quantitative ultrasound imaging. The method subtracts the echo signal power spectrum acquired from a uniform region beneath the overlying layers from the signal power spectrum obtained from a reference phantom using the same instrumentation system settings. Changes in spectral components with frequency are then used to estimate the attenuation of the overlying layers. Several phantoms were used to test the method, among which was a phantom having three windows, one with no overlying layers and the other two with fat and muscle mimicking layers of different degrees of irregularity. Attenuation losses through the windows were compensated for using the technique, producing backscatter estimator images of a simulated tumor inside the phantom. After applying the method, consistent results for the backscatter estimator of the tumor, as well as the backscatter coefficient of the background material, were obtained from the various windows.