Abstract: A catheter is provided that has both an ultrasonic transducer array (2) and a inflatable balloon (12) mounted at or near its distal end. A sheath catheter having a transducer array and associated multiplexer (4) arrangement located substantially coaxially within it. Furthermore, a guidewire (8) catheter having an ultrasonic transducer array mounted on it distal end.

Abstract: A method of measuring the position of the tip of a catheter includes the steps of continuously monitoring the distance the catheter has travelled past a reference point, monitoring the orientation of the tip, and reconstructing the trajectory of the catheter tip.

Abstract: An ultrasound system includes a transducer array having a plurality of transducer elements for transmitting ultrasound pulses and for receiving-echo pulses in response thereto, a circuit for energizing each transducer element, or batches of elements of the array, in turn, to generate an ultrasound pulse, and for receiving echo signals from at least two transducer elements resulting from transmission of an ultrasound pulse from another transducer element so that data used to create an image of the echo signals comes from the two transducer elements, a control device for controlling the order in which the transducers are energized and the order in which the transducers receive an echo pulse so as to carry out the energization and reception sequentially, a circuit for acquiring sequentially the data in analog form for a whole aperture, for acquiring sequentially the data for successive apertures and for processing the data for beam-formation for each aperture in correspondence with an analog echo pulse received

Abstract: In a method of manufacturing an ultrasonic transducer array a plurality of discrete transducer elements are formed on an initially flat flexible substrate together with electrically conductive tracks, through which the transducer elements will be energised in use, the flexible substrate with the discrete transducer elements and conductive tracks mounted thereon then being formed into a cylinder and mounted on the end of a catheter tube, the substrate being radially outwardly of the transducer elements so that it is in a position to act also as an acoustic matching layer between the material of the transducer elements and the human tissues or blood when in use.

Abstract: In a method of manufacturing an ultrasonic transducer array a plurality of discrete transducer elements are formed on an initially flat flexible substrate together with electrically conductive tracks, through which the transducer elements will be energized in use, the flexible substrate with the discrete transducer elements and conductive tracks mounted thereon then being formed into a cylinder and mounted on the end of a catheter tube, the substrate being radially outwardly of the transducer elements so that it is in a position to act also as an acoustic matching layer between the material of the transducer elements and the human tissues or blood when in use.

Abstract: A catheter is provided either with an x-ray-opaque marker or with a device for generating a vibratory signal for transmission along a guide wire within the catheter in order to indicate the position of the catheter.

Abstract: Ultrasonic apparatus for visualizing the internal organs of the human body using an ultrasonic array probe is characterized by means for digitising the ultrasonic echo signals and means for processing the digitised signals. Data may be sampled from each array element excited separately, or on a group of elements sequentially with a very small time increment between samples. Processing of data can include switching the transmit carrier frequency between scans, compensation for ringing effects in the transducers, synthetic aperture focussing techniques, software envelope or transform demodulation, attenuation or time gain correction and data compression.

Abstract: An ultrasound system comprising a transducer array and means for energising each element, or batches of elements, of the array in turn to generate an ultra sound pulse, means for processing an echo pulse received by each transducer, and control means for controlling the order in which a transducer or transducers are energised and the order in which a transducer or transducers receive an echo pulse, characterised in that the echoes resulting from the transmission of an ultrasonic pulse from any one transducer element are received by at least one other transducer element.

Abstract: A catheter is provided either with an x-ray-opaque marker or with a device for generating a vibratory signal for transmission along a guide wire within the catheter in order to indicate the position of the catheter.

Abstract: An intravascular ultrasound imaging system in which data from an ultrasonic transducer array is digitized and processed in a pipeline, the latter having means to divert/extract data from the pipeline and reintroduce it into the pipeline to enable images to be displayed retrospectively.

Abstract: A method of overcoming the ring down problem comprises the steps of generating a reference scan and updating it on the basis of a long term running average and then subtracting that running average from the current A-scan to remove the ring down.

Abstract: An ultrasound system comprising a transducer array and means for energizing each element, or batches of elements, of the array in turn to generate an ultra sound pulse, means for processing an echo pulse received by each transducer, and control means for controlling the order in which a transducer or transducers are energized and the order in which a transducer or transducers receive an echo pulse, characterized in that the echoes resulting from the transmission of an ultrasonic pulse from any one transducer element are received by at least one other transducer element.

Abstract: A catheter having an ultrasonic transducer array at its distal end is constructed to overcome the "ringdown" problem by having a conically shaped reflecting interface space from an ultrasonic transducer array in such a way that the "dead space" is contained wholly within the catheter.

Abstract: A catheter (1a, 1b) is provided with an ultrasonic transducer array at its tip (3), the transducer array having been manufactured from an annulus of piezoelectric material (10) by making longitudinal mutually parallel slots (18) in the material.

Abstract: The internal examination of a human organ is made by means of an ultrasonic probe inserted into the organ, and in one embodiment analogue echo signals from the probe are directly converted into digital signals before any signal processing is carried out. These signals are then stored in a digital computer where they are manipulated to produce a two-dimensional real-time representation of the interior of the organ for display on a terminal or as hard copy. The two-dimensional real-time image may be displayed simultaneously with a three-dimensional nonreal-time image produced by the system.