Abstract: An ultrasound imaging catheter system includes a pivot head assembly coupled between a ultrasound transducer array and the distal end of the catheter. The pivot head assembly includes a pivot joint enabling the transducer array to pivot through a large angle about the catheter centerline in response pivot cables controlled by a wheel within a handle assembly. Pivoting the ultrasound transducer array approximately 90° once the catheter is positioned by rotating the catheter shaft and bending the distal section of the catheter, clinicians may obtain orthogonal 2-D ultrasound images of anatomical structures of interest in 3-D space. Combining bending of the catheter by steering controls with pivoting of the transducer head enables a greater range of viewing perspectives. The pivot head assembly enables the transducer array to pan through a large angle to image of a larger volume than possible with conventional ultrasound imaging catheter systems.

Abstract: Methods for processing two-dimensional ultrasound images from an intracardiac ultrasound imaging catheter provide improved image quality and enable generating three-dimensional composite images of the heart. Two-dimensional ultrasound images are obtained and stored in conjunction with correlating information, such as time or an electrocardiogram. Images related to particular conditions or configurations of the heart can be processed in combination to reduce image noise and increase resolution. Images may be processed to recognize structure edges, and the location of structure edges used to generate cartoon rendered images of the structure. Structure locations may be averaged over several images to remove noise, distortions and blurring from movement.

Abstract: A dynamic ultrasound image catheter includes a catheter body with an acoustic window on the distal end, an ultrasound phased array transducer assembly configured to rotate within the acoustic window through an angle of rotation, an acoustic coupling fluid filling a gap between the transducer array and the acoustic window, and a drive motor at the proximal end of the catheter body that is configured to rotate the transducer array. The drive motor may transmit a rotational force to the ultrasound phased array transducer by a drive wire or by tension wires coupled to drive spools. A system processor coupled to the drive motor controls rotation of the transducer array and estimates the angular orientation of the transducer array. By taking ultrasound images at increments through the angle of rotation, the dynamic ultrasound image catheter can obtain images spanning a volume which can be processed to generate three-dimensional composite images.

Abstract: Methods for determine the position and rotational orientation of the transducer array of an ultrasound imaging catheter within a patient include imaging the distal end of the catheter using fluoroscopy and determining the angular orientation based upon the shape and dimensions of the image of the transducer array and wire connecting harness. Additional rotational and translational information may be obtained from sensors located at the proximal end of the catheter. By combining position information obtained using fluoroscopy with information from relative rotation/translation sensors, the imaging transducer position and orientation can be determined more accurately. The resulting accurate imaging transducer position information enables combining multiple images from different positions or orientations to generate multi-dimensional images. Catheters including rotation and translation motion sensors at the proximal end, and radio-opaque materials near the distal end can be provided to enhance the methods.

Abstract: An ultrasound imaging system includes a catheter-based ultrasound transducer, an external ultrasound transducer and a compact ultrasound unit including an isolation circuit, an ultrasound signal generator, and a beam former within a single unit. The ultrasound unit may include circuitry and software to enable simultaneous imaging by both transducers. The isolation circuit may limit unintended, leakage current from the ultrasound system through the transducer array of the ultrasound system.

Abstract: A compact, portable ultrasound imaging system includes a combination of an isolation circuit, an ultrasound signal generator, and a beam former within a single unit. The isolation circuit may limit unintended, leakage current from the ultrasound system through the transducer array of the ultrasound system. The signal generator and beam-former may be implemented using large scale integration semiconductor chips. Connections are provided for connecting an ultrasound transducer array, for outputting ultrasound data and for receiving user input and commands.

Abstract: An ultrasound imaging system includes one or more accelerometers positioned near the imaging transducer. Acceleration data from the accelerometers are used to estimate the position of the imaging transducer. By combining position information calculated based on acceleration data with position information obtained by other methods, the imaging transducer position can be determined more accurately and closer in time to when images are obtained. The resulting accurate imaging transducer position information enables combining multiple images from different positions or orientations to generate multi-dimensional images.

Abstract: An integrated electrophysiology and ultrasound imaging system includes a workstation, electrophysiology processing circuits, a compact ultrasound imaging system having a combination of an isolation circuit, an ultrasound signal generator, and a beam former within a single unit. The integrated workstation provides a single control interface and data display for the electrophysiology and ultrasound imaging subsystems. Integrating the control of electrophysiology and ultrasound imaging equipment within a single workstation reduces clinician workload.

Abstract: Ultrasound imaging methods and systems for assisting a clinician in configuring the operation of a pacemaker and for determining an optimal site for the pacemaker electrode are presented. The methods and systems provide a toolbox for analyzing and optimizing the effectiveness of the pacemaker and proposed electrode sites. The method includes a function which evaluates one or more electrode sites and pacemaker configurations. The function may be based, for example, on the activation voltage of the pacemaker, on an estimate of the volume of blood ejected from the heart and/or on the cardiac dysynchrony. The ejection volume and the dysynchrony may be estimated using an imaging cardiac catheter ultrasound transducer array and ultrasound unit.

Abstract: A method for assessing cardiac function using an ultrasound imaging catheter system includes positioning an ultrasound catheter so the ultrasound transducer can image a ventricle, obtaining images of the ventricle at two or more times within the cardiac cycle, recognizing an edge of the endocardium, measuring dimensions of the ventricle, calculating a volume or area of the ventricle at the two or more points in the cardiac cycle, and calculating the ejection fraction based upon the difference in volume or area at the two or more times in the cardiac cycle. The method can be used to determine a location for an intervention, such as placement of a pacemaker pacing lead, and may be performed before and after an intervention to assess the impact of the treatment on cardiac function.

Abstract: A medical imaging system is provided which includes a signal generator configured to obtain a trigger signal corresponding to a timing of interest, imaging equipment configured to obtain a plurality of images of a feature of interest, and a processor programmed to correlate the plurality of images with the trigger signal. Also provided is a method of correlating a plurality of medical images by obtaining a trigger signal of a timing of interest, obtaining a plurality of images of a feature of interest, and correlating the plurality of images with the trigger signal.

Abstract: A method for reversing ventricular dyssynchrony uses intracardiac echocardiographic measured parameters to systematically determine an optimal, individualized configuration for a cardiac resynchronization stimulator device. This method is particularly relevant for patients with congestive heart failure. The algorithm evaluates improvement in aortic flow and in left ventricular ejection fraction as atrioventricular and interventricular delay parameters of the patient's resynchronization stimulator device are varied.

Abstract: A method for diagnosing and mapping atrial fibrillation correlates recordings of electrical activity from intracardiac multielectrode catheters with the locations of electrodes within the heart to obtain a global mapping of cardiac electrical activity. Time delay and/or amplitude information in the recorded electrical activities is fused with electrode location information to generate a display on a 3-D anatomical template of the heart. Time delay and/or amplitude information is displayed using color code and/or lines of equal value, to aid diagnosis and localization of electrical activity irregularities. Mapping of atrial fibrillation enables physicians to treat arrhythmia by ablation, pacing, shock therapy and/or drugs at initiation or during an episode based on therapy delivery at critical mapped locations for arrhythmia onset or maintenance. Locations for placement of pacing leads and pacemaker timing parameters may also be obtained from the display.

Abstract: A method and apparatus for enhancing evaluation of valvular function in terms of regurgitation is described. The techniques include a method and apparatus for monitoring flow across a valve and evaluating regurgitation through the valve. An ultrasound scanner with Doppler capabilities processes and represents Doppler signal data in a color scale. The Doppler signal data is processed such that different colors are assigned to signals that have different power levels. An ECG signal may be correlated to the Doppler signals to determine systole and diastole periods, then the regurgitation is determined by estimating a peak reverse blood flow based on Doppler signals from blood at systole. The Doppler signals may also be processed so as to determine a cardiac cycle, then regurgitation is determined as the ratio of a reverse blood flow as a percentage of a forward blood flow.

Abstract: A method and system for estimating the volume of blood ejected from a cardiac ventricle or atrium uses ultrasound to track speckle patterns in the heart. The process utilizes the M-mode to estimate volume differences in a view of the ventricle or atrium over time using speckle pattern motion to estimate volume differences between systole and diastole. Alternatively, the ultrasound speckle tracking method may be used in combination with Doppler processing techniques or to obtain temporal flow profiles across flow cross-sectional areas, from which the flow volume is computed. The method can also measure the phase delay of motion of sites on the cardiac wall relative to each other or relative to an ECG signal.

Abstract: A method and system for enhancing Doppler spectrum displays is described. Two or more colors are utilized to represent the power scale in the spectral Doppler display. Doppler signals from stronger reflectors of ultrasound, such as cardiac muscle or vessel walls, can then be assigned a different color than Doppler signals from weaker reflectors, such as blood, allowing for better understanding and interpretation of the Doppler spectra.

Abstract: A method and system for estimating the volume of blood ejected from the left ventricle of the heart to a succeeding chamber/conduit, or vice-versa, while imaging the intersection of such structures is described. The process utilizes either the M-mode to estimate volume differences in a view of the ventricle over time or Doppler processing techniques to obtain flow profiles across intersections (e.g., valves), or blood vessels, which are then utilized to calculate output. This process can be combined with ECG guidance/triggering to measure/track changes in output from beat to beat, or during the course of an evaluation or therapeutic procedure. This process can be specifically used for the placement of permanent pacemaker electrodes.

Abstract: A method and system for estimating the volume of blood ejected from a cardiac ventricle or atrium uses spectral Doppler ultrasound while imaging a portion of the heart. The method computes the mean ejection velocity Vavg(t) at time t from the spectral Doppler data. The process may further utilize a discrete graphical technique to compute a measure of cardiac output. Further, the measure of cardiac output can yield an approximation to the mean-ejection-velocity integral, which is the area under the curve Vavg(t) for all moments t within a cardiac cycle.

Abstract: A method and apparatus for processing ultrasound images is provided, including extracting an M-mode data set from the ultrasound images, discerning, from the M-mode data set, a first velocity for a first moving structure and a second velocity for a second moving structure, the second velocity being different from the first velocity, and differentiating between the first moving structure and the second moving structure based on the discerned velocities.

Abstract: An imaging system is provided with an ultrasound catheter and a controller coupled to the ultrasound catheter. The catheter includes a localizer sensor configured to generate positional information for the ultrasound catheter, and an imaging ultrasound sensor having a restricted field of view. The controller co-registers images from the imaging ultrasound sensor with positional information from the localizer sensor.