TABLE I.

Summary table of the acronyms defined or mentioned in this paper.

Parameter Name	Acronym	Equation #	Brief Description
Power Spectral Estimation Region	PSER	N/A	The PSER defines an axial range and lateral width where power spectra are estimated A-line by A-line and averaged laterally. The power spectrum estimated from a PSER is spatially located at the center of the PSER.
Parameter Estimation Region	PER	N/A	The PER defines an axial range of power spectral estimation regions (that can be overlapping and can include only a single PSER or many PSERs) which are used for estimating an acoustic parameter of interest. In this paper there is only a BSPD PER, which happens to be a single PSER.
Backscattered Power Difference	BSPD	2	Log of sample power spectrum divided by reference power spectrum integrated over the bandwidth significantly contributing to the backscattered echo signal.
Normalization Angle	θnorm	5	Beam steering angle which maximizes the value of the BPSD in the selected beam steering range.
Normalized Backscatter Power Difference	nBSPD	6	Difference between the maximum BPSD in the beam steering range and the BSPD at each angle.
Asymmetric Backscatter Power Difference	aBSPD	7	The average of the difference between the nBSPD integrated over positive beam steering angles and the nBSPD integrated over negative beam stering angles.
Mean Backscatter Power Difference	mBSPD	8	Average nBSPD over all beam steering angles.