Abstract: A method for monitoring, over time, changes that occur in the apparent dielectric constant of a selected volumertic space. The selected space may be formed by a substantially homogenous material, in which case, dielectric-constant changes are interpretable, according to the invention, to indicate pressure and/or temperature changes in the space. In another situation, the selected space may be nonhomogenous, in which case dielectric-constant changes are interpretable, also according to the invention, to indicate relative volumetric changes between different media within the space.

Abstract: An apparatus and method for non-invasive sensing of bone healing is disclosed. The apparatus and method uses an electromagnetic field to measure impedance changes at and about the bone fracture site during the healing process. The impedance change at the fracture site is a direct indication of the mechanical strength of the fracture site. A multi-coil sensor array is taught, which may be sutured to the patient's skin or mounted onto a plug that is inserted through a window in the cast.

Abstract: A three-dimensional imaging system for obtaining a three-dimensional image of an object being scanned ultrasonically comprises a source arrangement for sequentially transmitting ultrasonic energy toward the object in successive directions in a first scanning plane, followed by sequential transmission of ultrasonic energy toward the object in successive directions in successive scanning planes parallel to the first scanning plane, a detector arrangement for receiving reflected energy and converting the reflected energy to electrical signals, and a processor for processing the electrical signals to develop reconstructed image data of the object, the reconstructed image data comprising forward projections of the object into a left image plane and a right image plane to form left and right images, respectively, the left and right images forming a stereo pair for composite display by a display unit.

Abstract: An epicardial defibrillation electrode employing an elongated, coil electrode embedded in the surface of a flexible electrode pad. The coil electrode provides increased flexibility and superior electrode flex life. The arrangement of the coil electrode provides uniform current distribution. The electrode takes the form of a space wound coil following a tortuous path over the surface of the electrode pad to provide a large surface area to reduce current density. In some embodiments, an insulative core is located within the lumen of the coil.

Abstract: An RF receiver coil structure for NMR imaging of cardiac and thoraco-abdominal regions of a human body. The coil structure includes a coil of generally solenoidal geometry having two turns separated by an inter-element gap. The inter-element gap is sufficiently large to accommodate an average human torso at the chest level (e.g. 25 cm). The turns are cross coupled by a pair of crossed diagonal elements. The coil is formed of a tubular conductor, having a tubular diameter (outside diameter) of approximately 1/2 inch. The coil has terminal ends in one of its diagonal elements, and the coil structure further includes a component unit located where the diagonal elements cross. The component unit includes a capacitor electrically connected to the coil to form a parallel resonant circuit. The same geometry may be employed in a multi-turn structure, where preferably one-half of the total number of turns are positioned above the patient, and the other half below the patient.

Abstract: By synchronizing the radio-frequency excitations of a nuclear magnetic resonance experiment with the heart beat of a patient, notable improvement is obtained in the measurement of the molecular diffusion parameters of the tissues studied. In particular, good images of the brain are obtained in this way: the parameter represented is the molecular diffusion constant.

Abstract: An ergonometric transcutaneous electrical nerve stimulator especially designed for dysmenorrhea and low back pain. The ergonometric factors include a housing containing the electrical circuit, the housing being of a generally flattened disk shape with well rounded edges. A first power switch is located on a side edge of the housing, and one or more rocker switches controlling the amplitude of the current stimulation pulses to be supplied by one or more channels from the stimulator are mounted on a side edge of the housing. The housing of the stimulator has one or more attachment points on the side edge of the housing to allow for connection of the housing to a body or garment strap.

Abstract: An ultrasonic lithotrity apparatus is held such that its installation position can be adjusted with respect to a stone formed in a living body, and has an ultrasonic lithotrity transducer for emitting an intense ultrasonic wave for breaking up the stone. The ultrasonic lithotrity transducer emits a weak ultrasonic wave immediately before every single or every predetermined number of intense ultrasonic waves is emitted. The position of a stone in the living body can be determined in accordance with a reflected wave of the weak ultrasonic wave. On the basis of reception of the reflected echo signal, the position of the stone is determined. In accordance with the determination result, electronic circuits determine whether the weak or intense ultrasonic wave is to be emitted from the ultrasonic lithotrity transducer.

Abstract: A catheter, particularly adapted for cardiac output determination, comprises an elongated tube of flexible material, the tube having a substantially rigid distal portion on which is disposed an ultrasonic transducer and a proximate, inflatable balloon. The ultrasonic transducer is arranged so as to direct a beam of ultrasound toward a transverse plane that bisects the balloon, and is connected by appropriate leads to a conventional Doppler circuit. With the balloon deflated, the signal from the Doppler circuit is sensed to measure blood velocity. Thereafter, the balloon is inflated so that it has a predetermined cross-sectional area in the transverse plane. The signal from the Doppler circuit is again sensed to measure blood velocity. Using a simple mathematical relationship, the effective internal cross-sectional area of the blood vessel is determined from the two measured velocities and from the predetermined cross-sectional area of the balloon when inflated.

Abstract: Several sequences of radio-frequency and magnetic field gradients are presented for obtaining from a sample multiple response echo signals from which to obtain a plurality of independent angiograms, which can be combined or separately analyzed to provide more information than an individual angiogram, but in substantially the same amount of time as a single angiogram. For example, a series of angiograms, each with a different projection axis, can be obtained in the time required to obtain a single angiogram using a single echo method. If the view angle of each echo is the same, then the acquired angiograms can be added to enhance the signal-to-noise ratio. Anothe pulse sequence simultaneously obtains two or more angiograms, each sensitive to one of two orthogonal flow components of the overall blood flow, the angiograms are then added to give an angiogram which is sensitive to total flow in all directions. Multiple velocity ranges are accommodated in a fourth sequence form.

Abstract: A shock wave generator for use in an apparatus for non-contacting disintegration of calculi in the body of a life form (extracorporeal lithotripter) having a coil with helical windings and a membrane of electrically conductive material disposed opposite the coil, the membrane terminating a space filled with a liquid. The coil is connectable to a high voltage supply. The coil has two layers connected in series and overlapping each other in parallel planes, with the respective current direction and winding direction of the layers being selected in combination to intensify the magnetic fields of each layer. A layer of the coil having a smaller voltage difference relative to the membrane is disposed immediately adjacent the membrane. The arrangement increases the useful life of the membrane without significantly reducing the efficiency of converting the electrical energy into shock wave energy.

Abstract: An ultrasound device for sector scanning which includes an ultrasound transmitting/receiving system. The system is housed in a compact cylindrical applicator housing which contains ultrasound transducer heads and associated ultrasound transducer elements at both ends of the applicator housing. Each of the two ultrasound transducer heads is rotatable within the applicator housing for performing sector scanning. A single drive mechanism rotates or swivels reciprocally both transducer heads so that undesirable inertial forces are cancelled or compensated. A guiding element pivotally supports the applicator housing so that the housing can be rotated and one or the other of the two ultrasound transducer heads be used. The guiding element also provides the enclosure for the electronics associated with the ultrasound applicator.

Abstract: A respiratory gas concentration measuring apparatus includes a chopper having a first filter for passing therethrough light from a light source and having a first wavelength which can be absorbed by a gas to be measured and a second filter for passing therethrough light from the light source and having a second wavelength which cannot be absorbed by the gas. The chopper is rotatable to position the first and second filters alternately in a light path. The light having passed through the filters is converted by a photodetector into an electric signal. A first detector detects an output from the first filter based on the electric signal, and a second detector detects an output from the second filter based on the electric signal.

Abstract: A zero crossing detector including timing and logic circuitry for ascertaining and eliminating undesirable waveform characteristics. If a zero crossing indication occurs within a set time period after a trigger event due to a phase inversion or noise, then the indication is ignored. Conversely, if a zero crossing does not occur within a second set time period due to a phase reversal, an artificial crossing will be indicated. By establishing these bounds, the system will function within a specified frequency band.

Abstract: A thermodilution injectate assembly which includes a length of flexible tubing for introducing fluid from a solution container to the assembly. An insulated container which holds a heat exchange medium and into which is positioned a substantially flat plate heat exchanger. The heat exchanger includes an inlet port and an outlet port and a fluid-flow path therebetween, which path provides a heat exchange relationship between fluid flowing through the path and the heat exchange medium. A dual directional valve is connected to the outlet port of the heat exchanger and to the solution container. A three-ported stopcock is in fluid-flow communication with the dual directional valve. A syringe is connected to a port on the three-ported stopcock and a length of flexible tubing is connected to a port on the three-ported stopcock for delivering the cooled fluid to a patient for monitoring the cardiac output.

Abstract: An adjustable probe belt assembly is disclosed for quickly hooking up different size patients to an electrocardiograph. The assembly has a weighted strip of material or "probe belt" that fits against a patient's chest, wherein the belt carries a set of eccentrically mounted electrodes that can be rotated so that their patient-contacting surfaces can be adjusted to fit the chest size of the particular patient.The probe belt is preferably made of a disposable or washable material and the electrodes are especially designed so that they can be easily popped out or removed for disposability or cleaning of the belt. The electrodes can then be cleaned and snapped back into a fresh belt, which insures that the entire assembly will be sterile for the next patient's use.