Abstract: In ultrasonic echoscopy, when an object to be examined has overlying layers of a medium (for example, fat, muscle, skin or bone) which have different ultrasonic transmission characteristics from those of the object, the echogram of the object is usually distorted. To reduce that distortion, the present invention uses a transducer comprising an array of ultrasonic transducer elements operated in a higher resolution mode than its normal imaging mode, to obtain information about the geometry of the overlying layers. Using this information and a knowledge of the transmission characteristics of the overlying layers, amplitude and phase corrections are calculated, to enable the transducer, when operated in its normal imaging mode, to generate a required beam of ultrasound. The corrections are then applied and an echogram of the object, with reduced distortion, is obtained while operating the transducer in its normal imaging mode.

Abstract: A rotating scanner for use in ultrasonic echoscopy has a linearly scanned transducer arrangement, for transmitting beams of ultrasonic energy into an object (and receiving reflected ultrasonic echoes from the object). The transducer arrangement is rotated about an axis passing through the center or one end of the linear scan. The linear scanning may be mechanical scanning, or by electronic switching of an array of transducer elements.

Abstract: In megahertz ultrasonic echoscopy of objects, echoscopes having a time gain compensation facility are often used. To ensure that a uniform ultrasonic echo signal is obtained at a predetermined depth (5) within an object, the present invention varies the sensitivity of the time gain compensation for each pulse of ultrasonic energy (8) used to obtain an echogram of the object. The present invention may include means to vary the slope of the time gain compensation so that at other predetermined depths (6) within the object, echo signals of respective intensities are received, thus overcoming problems due to shadowing by ultrasonically highly absorbing regions of the object. The main application of the invention is in medical diagnosis.

Abstract: Echoscopes incorporating signal processing circuits capable of providing a more complete and useful display of information received as a train of electrical signals. In one circuit, which is essentially a compression amplifier, the amplitude range of the input signal is limited by way of two or three amplitude limiting stages and an adder connected to sum the output of the first and last stages provides an advantageous output to input characteristic for the circuit.The second circuit includes filter means and derivating means to separately process the input signal, and an adder to combine the outputs of these means to obtain a signal of enhanced utility.

Abstract: Apparatus for the ultrasonic examination of an object, comprises:a transducer array comprising a plurality of adjacent transducer elements for directing pulses of ultrasonic energy along a beam into the object, characterized in that the width of each of the transducer elements in the direction transverse to the longitudinal direction of the element is non-uniform along the length of the element.

Abstract: A method of displaying information obtained by pulse-echo ultrasonic examination of an object, particularly in medical diagnostic examination, comprises forming a first display representing the positions of acoustic impedance discontinuities within the object and simultaneously incorporating in the display other parameters relating to the object.

Abstract: Apparatus for the pulse-echo ultrasonic examination of an object comprised f transducer means for transmitting pulses of ultrasonic energy and receiving reflected echoes of said pulses immersed in a coupling medium contained within a housing, the pulses being transmitted and echoes received through an aperture in the housing which may be covered with a flexible coupling membrane.

Abstract: Apparatus for the pulse-echo ultrasonic examination of an object comprised of transducer means for transmitting pulses of ultrasonic energy and receiving reflected echoes of said pulses immersed in a coupling medium contained within a housing, the pulses being transmitted and echoes received through an aperture in the housing which may be covered with a flexible coupling membrane and the housing including a storage header tank open to the atmosphere to maintain the pressure to the coupling medium on the membrane constant during flexing of the membrane.

Abstract: A technique of displaying information obtained by ultrasonic echoscopic examination of an object which comprises the steps of transmitting pulses of ultrasonic energy along a plurality of beams into the object and receiving echoes of said pulses reflected along the beams by acoustic impedance discontinuities within the object, the beams being directed from a plurality of spaced positions relative to the object and along a plurality of beam directions at each position, comprises forming a first display of information representative of the position of acoustic impedance discontinuities within the object from the echoes received along the plurality of beams as a compound scan of the object, and forming a second display of information from echoes received along selected beams of the plurality of beams as a simple scan of the object.

Abstract: Apparatus for the ultrasonic examination of an object comprises:A linear transducer array for directing pulses of ultrasonic energy along a plurality of beams into the object and receiving echoes of the pulses reflected along the beams by acoustic impedance discontinuities within the object, the transducer array comprising a plurality of adjacent transducer elements; and eitherMeans for sequentially activating different groups of adjacent transducer elements within the array to direct a pulse of ultrasonic energy along a beam into the object and receive echoes reflected along the beam in each of a plurality of angular directions in a single plane; orMeans for activating different groups of adjacent transducer elements within the array in turn so that each group directs pulses of ultrasonic energy into the object and receives echoes reflected along beams in a plurality of angular directions in a single plane.

Abstract: A method of pulse-echo ultrasonic examination of an object particularly in medical diagnostic examination, comprises the stepwise increase of the gain of the equipment to compensate for loss of energy as echoes are received from reflecting surfaces deeper within the object and cyclic alteration of the gain at each step.

Abstract: Apparatus for ultrasonic examination of objects, particularly in medical gnostic examination, incorporates means for focusing portions of the beam of ultrasonic pulses generated by a transducer at a plurality of distances from the transducer to reduce the width of the beam over a large distance.

Abstract: An apparatus for the pulse-echo ultrasonic examination, particularly in medical diagnostic examination, is comprised of a plurality of transducers spaced around the object to be examined, each of the transducers being steerable to direct pulses of ultrasonic energy into the object and to receive echoes in a plurality of angular directions, and means to move the plurality of transducers relative to the object during examination of the object.

Abstract: A method of pulse-echo ultrasonic examination of an object, particularly in medical diagnostic examination, to measure flow of liquid in a vessel within the object comprises determining the dimensions and orientation of the vessel and the shift in frequency of ultrasonic echoes due to flow of liquid in the vessel and correlating to obtain a quantitative measurement of the flow of liquid.

Abstract: Apparatus for pulse-echo ultrasonic examination, particularly in medical diagnostic examination, is comprised of a plurality of transducers spaced at fixed positions around the object to be examined, each of the transducers being steerable to direct pulses of ultrasonic energy into the object and to receive echoes in a plurality of angular directions from the fixed position.

Abstract: Apparatus for ultrasonic examination of objects, particularly in medical diagnostic examination, is comprised of a phased array transducer capable of focusing the beam of ultrasonic pulses in the longitudinal plane of the transducer, and focusing means to focus the dimensions of the beam normal to the longitudinal plane.