Abstract: A medical diagnostic ultrasonic imaging method and system subdivide the transmit aperture into two or more subapertures, each subaperture having at least four adjacent transducer elements. The subapertures are phased differently with respect to one another to selectively reduce either fundamental components or harmonic components of echoes from tissue. These techniques can be used to improve contrast agent harmonic imaging as well as tissue harmonic imaging, depending upon the phase shift selected.

Abstract: An improvement to the method for harmonic imaging including the steps of (a) transmitting ultrasonic energy at a fundamental frequency and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency is provided. The transmitting step includes the step of: applying the plurality of waveforms to a respective plurality of transducer elements, a first waveform of the plurality of waveforms characterized by a first value of a harmonic power ratio, waveforms transmitted from the transducer elements and corresponding to the plurality of waveforms summing as an acoustic waveform substantially at the point, the acoustic waveform characterized by a second value of the harmonic power ratio less than the first value. The imaging method can also include a step for subdividing the transmit aperture into two or more subapertures, each subaperture having at least four adjacent transducer elements.

Abstract: A patient is first injected with a contrast agent. A complete scan along a plurality of scan lines is then performed, resulting in the destruction of some contrast agent. While some of the contrast agent is destroyed, non-scanned portions of the target, and possibly the scan region, still include at least some contrast agent. A second scan is then sequentially performed sufficiently close in time to the first scan such that reflections from the anatomy remain unchanged. The second frame of data from the second scan will differ from the first frame of data from the first scan by only contrast agent effects. The second frame of data is subtracted from the first frame of data. The resulting data is used to image the contrast agent. By varying the time between each pair of scans, differences in the speed of the contrast agent motion within the body may be assessed. The collateral damage of contrast agents from ultrasound acoustic energy is minimized while the degradation due to various changes is also minimized.

Abstract: An improvement to the method for harmonic imaging including the steps of (a) transmitting ultrasonic energy at a fundamental frequency and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency is provided. For the improvement, the transmitting step includes the step of transmitting a uni-polar waveform or a waveform characterized by an amplitude change rate of 8 or fewer times pre carrier cycle, said waveform comprising an envelope shape rising gradually to a respective maximum value and falling gradually from the respective maximum value.

Abstract: An improvement to the method for harmonic imaging including the steps of (a) transmitting ultrasonic energy at a fundamental frequency and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency is provided. The transmitting step includes the step of transmitting a waveform comprising at least a sequence of at least a first and second pulse characterized by first and second pulse durations, respectively, where the second pulse duration is different than the first duration. This arrangement can reduce harmonic energy in the waveform.