Mayo Foundation for Medical Education and Research

Ping Gong

Shigao Chen

Pengfei Song

Joshua D Trzasko

Ultrasound attenuation coefficient estimation ('ACE') techniques that can ameliorate frequency power ratio curve oscillations caused by signal interferences, non-uniform tissue structures, or both, are described. The resulting smoothed frequency power ratio curves enable more accurate ACE and reduced region-of-interest (“ROI”) sizes for linear regression.

Systems and methods for ultrasound attenuation coefficient estimation

Described here are systems and methods for improved ultrasound attenuation coefficient estimation ('ACE') techniques. In one aspect, noise can be suppressed by using signal-to-noise ratio (“SNR”) as a quality control metric for restricting depth ranges for ACE. In this way, the proper depth range for each frequency component can be adaptively changed with sufficient SNR for ACE. In another aspect, elevation focusing normalization is used to reduce errors associated with diffraction effects when estimating attenuation coefficient. In another aspect, methods for suppressing noise in ACE techniques is provided. Noise can be suppressed based on a noise field computed from measurements obtained without ultrasound transmission, based on a unique combination of consecutive image frames, based on singular value decomposition (“SVD”) clutter filtering cutoff values, or combinations thereof.

Systems and methods for estimating acoustic properties in a region-of-interest in a subject or other object being imaged using a reference frequency method ('RFM') is described. Using this RFM technique, ultrasound data acquired at a given frequency are normalized by ultrasound data acquired at different frequencies (e.g., adjacent frequencies or otherwise) in order to provide estimations of the acoustic properties (e.g., attenuation coefficient, a backscatter coefficient, or both) that are independent of the ultrasound system used to acquire the underlying data. For instance, the amplitude of each frequency component can be normalized by a different frequency in the power spectrum to cancel out the system-dependent effects. Because the methods described in the present disclosure are system independent, they can be applied to any transducer geometry (e.g., linear or curved arrays) and using any beam pattern (e.g., focused or unfocused).

Methods for ultrasound system independent attenuation coefficient estimation

Methods for contrast-enhanced ultrasound imaging that implement coded multi-pulses in each of two or more different transmission events are described. Data acquired in response to the two different transmission events are decoded and combined. In some embodiments, the coded multi-pulses include two or more consecutive Hadamard encoded ultrasound pulses. In other embodiments, multiplane wave pulses can be used. Such multiplane wave pulses can be coded using Hadamard encoding, as one example. In addition, the multiplane wave pulses can be further coded using amplitude modulation, pulse inversion, or pulse inversion amplitude modulation techniques.

Methods for encoded multi-pulse contrast enhanced ultrasound imaging

Systems and methods for ultrasound imaging using a delay-encoded harmonic imaging ('DE-HI') technique is provided. An ultrasound pulse sequence is coded using temporal delays between ultrasound emissions within a single transmission event. This coded scheme allows for harmonic imaging to be implemented. The temporal time delay-codes are applied temporally to multiple different ultrasound emissions within a single transmission event, rather than spatially across different transmitting elements. The received radio frequency ('RF') signals undergo a decoding process in the frequency domain to recover the signals, as they would be obtained from standard single emissions, for subsequent compounding. As one specific example, a one-quarter period time delay can be used to encode second harmonic signals from each angle emission during a single multiplane wave (&#x201c;MW&#x201d;) transmission event, rather than inverting the polarity of the pulses as in conventional MW imaging.

Growing community of inventors

Rochester, MN, United States of America

Ping Gong