An ultrasound imaging system comprising: an ultrasound probe configured to transmit ultrasound signals and receive echoes responsive to the ultrasound signals and provide radio frequency data corresponding to the echoes; a user interface configured to receive indications of a first region of interest and a second ROI; a signal processor configured to receive the RF data and separate the RF data into harmonic frequency components and fundamental frequency components; and a processor configured to: receive the indications of the first ROI and the second ROI; receive the harmonic frequency components and the fundamental frequency components for the first ROI and the second ROI; calculate a first harmonic average signal intensity value for the first ROI based on the harmonic frequency components for the first ROI; calculate a second harmonic average signal intensity value for the second ROI based on the harmonic frequency components for the second ROI; calculate a harmonic ratio of the first harmonic average signal intensity value and the second harmonic average signal intensity value; calculate a first fundamental average signal intensity value for the first ROI based on the fundamental frequency components for the first ROI; calculate a second fundamental average signal intensity value for the second ROI based on the fundamental frequency components for the second ROI; calculate a fundamental ratio of the first fundamental average signal intensity value and the second fundamental average signal intensity value; and calculate a ratio of the harmonic ratio and the fundamental ratio. an ultrasound probe configured to transmit ultrasound signals and receive echoes responsive to the ultrasound signals and provide radio frequency data corresponding to the echoes; a user interface configured to receive indications of a first region of interest and a second ROI; a signal processor configured to receive the RF data and separate the RF data into harmonic frequency components and fundamental frequency components; and a processor configured to: receive the indications of the first ROI and the second ROI; receive the harmonic frequency components and the fundamental frequency components for the first ROI and the second ROI; calculate a first harmonic average signal intensity value for the first ROI based on the harmonic frequency components for the first ROI; calculate a second harmonic average signal intensity value for the second ROI based on the harmonic frequency components for the second ROI; calculate a harmonic ratio of the first harmonic average signal intensity value and the second harmonic average signal intensity value; calculate a first fundamental average signal intensity value for the first ROI based on the fundamental frequency components for the first ROI; calculate a second fundamental average signal intensity value for the second ROI based on the fundamental frequency components for the second ROI; calculate a fundamental ratio of the first fundamental average signal intensity value and the second fundamental average signal intensity value; and calculate a ratio of the harmonic ratio and the fundamental ratio. receive the indications of the first ROI and the second ROI; receive the harmonic frequency components and the fundamental frequency components for the first ROI and the second ROI; calculate a first harmonic average signal intensity value for the first ROI based on the harmonic frequency components for the first ROI; calculate a second harmonic average signal intensity value for the second ROI based on the harmonic frequency components for the second ROI; calculate a harmonic ratio of the first harmonic average signal intensity value and the second harmonic average signal intensity value; calculate a first fundamental average signal intensity value for the first ROI based on the fundamental frequency components for the first ROI; calculate a second fundamental average signal intensity value for the second ROI based on the fundamental frequency components for the second ROI; calculate a fundamental ratio of the first fundamental average signal intensity value and the second fundamental average signal intensity value; and calculate a ratio of the harmonic ratio and the fundamental ratio.