Abstract: Transesophageal echocardiography is implemented using a miniature transversely oriented transducer that is preferably small enough to fit in a 7.5 mm diameter probe, and most preferably small enough to fit in a 5 mm diameter probe. Signal processing techniques improve the depth of penetration to the point where the complete trans-gastric short axis view of the left ventricle can be obtained, despite the fact that the transducer is so small. The reduced diameter of the probe (as compared to prior art probes) reduces risks to patients, reduces or eliminates the need for anesthesia, and permits long term direct-visualization monitoring of patients' cardiac function.

Abstract: Transesophageal echocardiography is implemented using a miniature transversely oriented transducer that is preferably small enough to fit in a 7.5 mm diameter probe, and most preferably small enough to fit in a 5 mm diameter probe. Signal processing techniques improve the depth of penetration to the point where the complete trans-gastric short axis view of the left ventricle can be obtained, despite the fact that the transducer is so small. The reduced diameter of the probe (as compared to prior art probes) reduces risks to patients, reduces or eliminates the need for anesthesia, and permits long term direct-visualization monitoring of patients' cardiac function.

Abstract: A phased array ultrasound transducer is made from a plurality of independently excitable elements that are arranged in a row in the azimuthal direction, configured so that azimuthal aiming of an outgoing ultrasound beam is controlled by timing the excitation of the elements. The geometry of the elements is configured to focus the outgoing beam in the elevation direction so as to improve the images of target regions located at or about a particular radial distance. In some embodiments, this is accomplished by forming each element from a plurality of subelements that are stacked in the elevation direction, with the subelements of any given element all (a) wired together and (b) positioned at about the same distance from a substantially rod-shaped focal region.

Abstract: To keep the temperature of an ultrasound probe down, the probe is operated at a low frame rate (with correspondingly low heat generation) for the vast majority of time. Probe operation is only switched to the high frame rate temporarily at times when high temporal resolution is needed, preferably under operator control. The probe is only operated at the high frame rate for a short period of time, during which a burst of images with high temporal resolution is obtained. After capturing the short burst of images, the frame rate is cut back, which reduces the generation of heat.

Abstract: Signal processing techniques reduce the impact of noise (including speckle noise and shot noise) on ultrasound images by reducing the intensity of pixels that are probably noise and increasing the intensity of pixels that are probably signal. The decision of whether a given pixel is probably noise or probably signal is made based on spectral characteristics of the samples in and around the given pixel, based on knowledge of the expected spectral characteristics of the signal and the expected spectral characteristics of the noise.

Abstract: A method for generating an enhanced ultrasound display including the steps of capturing a set of ultrasound image frames and identifying pixels in the captured set of frames that correspond to a structure. The method also includes generating a set of output frames. Each output frame within the set of output frames is generated by (a) selecting a first frame of the captured set; (b) selecting a second frame of the captured set, wherein the second frame is subsequent in time to the first frame; (c) coloring pixels of the first frame that correspond to the structure a first color; (d) coloring pixels of the second frame that correspond to the structure a second color; and (e) overlaying the colorized first frame and the colorized second frame to generate the output frame. The method also includes displaying the output frames.

Abstract: Transesophageal echocardiography is implemented using a miniature transversely oriented transducer that is preferably small enough to fit in a 7.5 mm diameter probe, and most preferably small enough to fit in a 5 mm diameter probe. Signal processing techniques improve the depth of penetration to the point where the complete trans-gastric short axis view of the left ventricle can be obtained, despite the fact that the transducer is so small. The reduced diameter of the probe (as compared to prior art probes) reduces risks to patients, reduces or eliminates the need for anesthesia, and permits long term direct-visualization monitoring of patients' cardiac function.

Abstract: Transesophageal echocardiography is implemented using a miniature transversely oriented transducer that is preferably small enough to fit in a 7.5 mm diameter probe, and most preferably small enough to fit in a 5 mm diameter probe. Signal processing techniques improve the depth of penetration to the point where the complete trans-gastric short axis view of the left ventricle can be obtained, despite the fact that the transducer is so small. The reduced diameter of the probe (as compared to prior art probes) reduces risks to patients, reduces or eliminates the need for anesthesia, and permits long term direct-visualization monitoring of patients' cardiac function.

Abstract: Transesophageal echocardiography is implemented using a miniature transversely oriented transducer that is preferably small enough to fit in a 7.5 mm diameter probe, and most preferably small enough to fit in a 5 mm diameter probe. Signal processing techniques improve the depth of penetration to the point where the complete trans-gastric short axis view of the left ventricle can be obtained, despite the fact that the transducer is so small. The reduced diameter of the probe (as compared to prior art probes) reduces risks to patients, reduces or eliminates the need for anesthesia, and permits long term direct-visualization monitoring of patients' cardiac function.

Abstract: The visibility of features in ultrasound images that include at least two types of tissue can be improved by processing the images using a variety of algorithms. In one such algorithm, the ratio of power in a first spatial frequency band to power in a second spatial frequency band is computed for a plurality of samples of a received ultrasound return signal that are associated with a given pixel. In another such algorithm, the ratio of power in a first spatial frequency band to total power is computed. With both algorithms, the computed ratio is then mapped to a gain for the given pixel, the raw intensity of the given pixel is modified in accordance with the gain, and the pixel is displayed with the modified intensity.

Abstract: An improved approach for implementing depth-based gain control is implemented by adjusting the gain at each depth in the image based on a family of stored curves, with each curve in the family specifying the gain adjustment for all depths as a function of depth. A user interface enables the user to select an entire curve at once (as opposed to the prior art approach of using a set of individually and independently adjustable gain controls for each depth range). The selected curve is then used to modify the gain adjustment provided by the default time gain compensation (TGC) curve.

Abstract: To keep the temperature of an ultrasound probe down, the probe is operated at a low frame rate (with correspondingly low heat generation) for the vast majority of time. Probe operation is only switched to the high frame rate temporarily at times when high temporal resolution is needed, preferably under operator control. The probe is only operated at the high frame rate for a short period of time, during which a burst of images with high temporal resolution is obtained. After capturing the short burst of images, the frame rate is cut back, which reduces the generation of heat.

Abstract: ECG data and ultrasound data are synchronized by adding a marker to both sets of data, then detecting the position of the markers in the data, and using the detected positions to align the two sets of data in time. This enables an operator to visualize which frame of ultrasound data corresponds in time to which portion of the ECG waveform.

Abstract: When an ultrasound transducer is driven by a signal that contains a relatively wide range of frequencies, the frequency-dependent attenuation characteristics of the subject being imaged can be relied on to simultaneously provide, using only a single pulse per line of the image, (a) a return from the deeper portions of the image that is dominated by lower frequencies and (b) a return from the shallower portions of the image that is dominated by higher frequencies. These returns are processed into an image with higher resolution in the shallower parts, and lower resolution with adequate SNR in the deeper parts.

Abstract: An ultrasound probe includes a flexible shaft with a channel that runs through the shaft in a proximal-distal direction, and an ultrasound transducer disposed in a housing mounted at the distal end of the shaft. Flexible wiring is disposed within the channel and is configured to carry signals to and from the transducer. The flexible wiring includes a plurality of substantially parallel conductors that are positioned above a ground plane, and separated from the ground plane by an insulating material. The substantially parallel conductors are also insulated from one another. In some embodiments, a grounded conductive shield is provided on the opposite side of the ground plane. Preferred approaches for implementing the flexible wiring include ribbon cable with a built-in ground plane and flexible printed circuit boards (i.e., flex circuits).

Abstract: A method for reducing speckle in an ultrasonic image formed from a digitized scan line including linearly arranged signal intensity data points obtained from ultrasonic energy reflected by structures within a body. The scan line is divided into intensity pixels. Each intensity pixel includes at least one data point. A raw intensity level and a feature gain factor are determined for each intensity pixel. A corrected intensity level is calculated for each intensity pixel by multiplying the raw intensity level for each intensity pixel by the corresponding feature gain factor. The corrected intensity level of each intensity pixel is displayed.

Abstract: An ultrasound method and apparatus for classification of tissue in a region of interest in a body. The raw ultrasound return data is digitized and processed without the need for human visual analysis of pixel-scale video images. Tissue classification is done by correlation of the relative amount of energy in selected frequency bands of the power spectrum of the returned demodulated ultrasound data to that of known tissue samples.