Patrick J. Phillips

Dual process ultrasound contrast agent imaging

Methods and systems for detecting contrast agents is provided. Differences between different sized vessels throughout a period of contrast agent enhancement are identified without significantly depleting the available contrast agent. Dual detection paths are used for imaging, such as one path for detecting nonlinear response and another path for detecting differences between the responses to two or more pulses. Where echoes from two or more pulses of acoustic energy are combined to detect the nonlinear response, the nonlinear response may also include signals originating from a loss-of-correlation (LOC) or motion between received pulses. These signals generated from LOC or motion can be produced from agent disruption where a second received echo is different from a first received echo due to a change in a bubbles shape (i.e., destruction), or from simple spatial translation between acoustic pulses as seen from the same spatial location, respectively. Together the LOC or motion signals and the nonlinear signals can differentiate contrast agent from tissue. Additional information is gained by detecting signals more responsive to difference or motion information. Each path detects different relative amounts of nonlinear response and responses caused by differences between echo signals of multiple pulses. Various systems and methods for detecting contrast agents where one path preferentially detects difference or motion signals and another path preferentially detects nonlinear energy are provided.

Medical ultrasonic contrast agent imaging method and apparatus

A medical ultrasonic imaging system transmits a set of two or more substantially identical transmit pulses into a tissue containing a contrast agent. The associated received pulses are filtered with a broadband filter that passes both the fundamental and at least one harmonic component of the echoes. The filtered received pulses are then applied to a clutter filter that suppresses harmonic and fundamental responses from slowly moving and stationary tissue, while clearly showing contrast agent response due to the loss of correlation effect. The disclosed system includes other signal paths for generating conventional B-mode images as well as combined images that include both components from the contrast-specific image as well as components from the B-mode image. An improved user interface allows the user to switch among these three images. Preferably the transmitter generates transmitted pulses having two or more spatially distinct focus zones, thereby improving the uniformity of contrast agent imaging over the imaged region.

Contrast imaging beam sequences for medical diagnostic ultrasound

A transmit sequence for contrast agent imaging that improves sensitivity and minimizes image artifacts. The number of pulses and the interleaving of spatially distinct pulses between spatially co-linear pulses are selected such that a substantially similar pulse sequence for substantially each line in a scanned region is generated. A collateral pulse from a different scan line is interleaved between at least two imaging pulses along a scan line of interest. Such pulse sequences provide sensitive contrast agent imaging with minimized spatial variation. In another aspect, responsive signals representing the first and second scan lines are obtained. Intensities associated with the signals are determined. The intensities associated with the first scan line are compared to a value. The signals associated with the first scan line are replaced by the signals associated with the second scan line, signals associated with the first and second scan lines, or neighboring signals in time or space as a function of the comparison. Thus, signals associated with an image artifact may be replaced by signals along other scan lines so good spatial resolution is maintained.

Medical diagnostic ultrasound system and method for improved flow or movement detection with multiple clutter filters

A method and system for flow or movement detection is provided. More than one clutter filter is used. Each clutter filters magnitude versus frequency response is optimized differently. Estimates of the flow or movement are generated from the data output by each of the clutter filters. Using selection or combination of the resulting estimates, the best attributes of each filter are used for imaging.

Medical ultrasonic imaging method with improved ultrasonic contrast agent specificity

An improved method for suppressing fundamental or desired harmonic orders in an ultrasonic medical imaging system transmits at least one reverberation-suppression pulse prior to the transmission of a multiple-pulse sequence. Receive signals associated with the pulses of the multiple-pulse sequence are acquired and combined using receive weights selected to suppress energy at either the fundamental or a desired harmonic of the fundamental.

Optical transducer for reception of ultrasonic waves

A new optical transducer for the detection of acoustic pressure in the diagnostic ultrasound frequency range is described. This transducer is based on the modulation of an evanescent light field by the incident acoustic energy. Theoretical design considerations are presented for the purpose of developing the most sensitive transducer. Based on these considerations an experimental transducer was constructed. Although less sensitive than predicted this device was capable of transducing ultrasonic pulses with a 1.0-MHz center frequency at diagnostic ultrasound amplitude levels. The techniques developed here are applicable for two-dimensional transduction and may prove a viable alternative to piezoelectric array transducers.

1001-34 Noninvasive detection of carotid artery endothelial dysfunction due to hypertriglyceridemia with high-frequency real-time low mechanical index imaging of retained microbubbles

Results: In HCM pts, average IVS was 19.3 ± 5 mm, the ratio of IVS / PW was 2.1 ± 0.5, and LVOT-PG was 42 ± 41 mmHg. Also in HCM group, compared to control group, ESV (32 ± 7 vs. 40 ± 57, p 0.05), PFR decreased (154 ± 33 vs. 233 ± 47, p < 0.01) and TPFR increased (0.25 ± 0.09 vs.0.17 ± 0.04, p < 0.05). There were significant correlations between PFR and: ESV(r = 0.70, p < 0.001), EDV(r = 0.67, p < 0.001), IVS / PW (r = 0.58, p < 0.01), E / A (r = 0.65, p < 0.001). Conclusions: Our initial experience demonstrated that decreased PFR is associated with decreased LV volume and increased LV septal hypertrophy. RT3DE derived volumetime curve, as a new noninvasive method, has the potential of quantifying LV diastolic dysfunction in pts with HCM.