General Electric Company

Flextech Systems, Inc.

General Electric Corporation Gmbh

Stephen W Flax

Gary H Glover

Norbert Joseph Pelc

Ann Shimakawa

Matthew N O'Donnell

Dennis E Bahr

Stockton M Miller-Jones

James K Riley

Jay S Plugge

An ultrasound phantom is disclosed which can be used in an imaging method that quantifies data in decibels based on the log of a ratio of the signal intensity between adjacent regions within the ultrasound phantom. A variety of flow phantoms are disclosed that can simulate the flow of blood within surrounding tissue. In the embodiment claimed in this divisional application, the phantom is comprised of an open-cell foam matrix for generating back-scatter from an ultrasonic wave, and has at least two hollow regions which do not generate back-scatter from the ultrasonic wave. The hollow regions are separated and are not aligned within the flow phantom structure. Other phantoms disclosed and claimed in related U.S. Pat. No. 5,560,242 include a movable member, such as a movable belt having a density different than that of the surrounding foam. The geometric relationship between the moving member and the surrounding open-cell foam material provides a quantitative basis of assessing the beam forming characteristics of the imager as well as the ability of the system to separate the Doppler shifted signal from the stationary clutter signal. In another embodiment, a rotating disk has similar material as the belt such that differing blood flow rates between adjacent blood vessels can be simulated for ultrasonic imaging.

Ultrasonic system evaluation phantoms

An ultrasound phantom and method of imaging are provided wherein the method quantifies data in decibels based on the log of a ratio of the signal intensity between adjacent regions within a ultrasound phantom such that the method can be used to quantitatively determine the imaging effectiveness of ultrasound devices at various depths by comparing quantitative data to a standard or absolute base. The phantom to be used with this method has multiple, regions which are characterized by an echogenic matrix and vertical, well-shaped sonolucent regions. The sonolucent regions are of the same shape and dimension and no sonolucent region shares the same axis. Ultrasound can be focused on one of the regions and the resulting ultrasound image quantifies the ability of the ultrasound to image regions existing at depths other than the depth of focus.

Method for evaluating imaging capabilities of an ultrasound system

An ultrasound phantom and method of imaging are provided wherein the method quantifies data in decibels based on the log of a ratio of the signal intensity between adjacent regions within an ultrasound phantom. A phantom is disclosed for use with the method wherein the phantom can simulate the flow of blood within surrounding tissue. In one embodiment, the phantom is comprised of an open-cell, reticulated foam material matrix having a first density and at least one movable belt having a second density. The belt rotates on pulleys to simulate blood flow. The geometric relationship between the moving belt and the surrounding open-cell foam material provides a quantitative basis of assessing the beam forming characteristics of the imager as well as the ability of the system to separate the Doppler shifted signal from the stationary clutter signal. The belt can be provided with a shaped surface, such as scalloped, and the matrix can be biased against the surface so that rotation of the belt causes undulation at the surface interface between the belt and the matrix, thus simulating systaltic blood vessel movement. In another embodiment, the belt is replaced by a rotating disk of the same material as the belt such that differing blood flow rates between adjacent blood vessels can be simulated for ultrasonic imaging.

The present invention is a method of processing and writing data to a database wherein the method comprises four broad steps: 1) manipulating data files into a more compact and efficient bit-encoded form and preparing the files to receive additional data to link the files; 2) linking the files with pointers to form an overall data structure; 3) determining the potential physical memory address for the files' data by optimizing available memory space for a given memory media wherein the files are partitioned into blocks of data which are sufficiently inclusive to permit retrieval of all required data with a single memory media read, yet small enough to allow all of the physical memory space to be fully utilized; and 4) generating reference tables to be interspersed with the data blocks wherein the reference tables track the physical location of related data, obviating the need for additional disk reads. The invention further comprises a system wherein said method is performed on a database contained on a first computer system so that the database can be written to a memory media of fixed size which can be used with a second computer system, such that memory access speed is enhanced, the density of information stored on the memory media is increased, yet the computational power needed to retrieve such information is reduced.

System for the compacting and logical linking of data blocks in files to

NMR image data acquired from a human subject is corrected for view-to-view motion caused by respiration. As each view is acquired the position of the subject is also measured to indicate the distance of the anterior abdominal wall from a reference position. The acquired NMR image data is corrected using the associated measured distances and a simplified model of the motion.

Reduction of NMR artifacts caused by time varying linear geometric

An apparatus for reducing image artifacts in NMR imaging matches elements of a set to values of a substantially periodic function so that the values exhibit a predetermined relationship to the elements. The matching is performed by evaluating the relative probability of the values of the substantially periodic function from the samples in the growing database of the values and assigning the values to the elements by using the evaluated relative probability, so as to maximize the probability that subsequent valves may be assigned the remaining elements according the predetermined relationship. A method for correcting the matching of values with elements freezes the database and acquires additional values which are substituted for earlier matched values based on the frozen database.

Method and apparatus for predicting values of a varying periodic

Displacement values which indicate respiration phase are acquired along with each view of an NMR scan. Two or more such NMR scans are conducted and the deviation of each displacement value from a smooth reference curve is employed to measure the integrity of its associated NMR image data. The NMR image data from the separate scans are combined to reduce random noise and motion artifacts, and the combination is accomplished by weighting the data in accordance with its measured integrity.

Method for combining acquired NMR data to suppress motion artifacts

NMR data indicative of the motion of the anterior abdominal wall of a subject is acquired just prior to each image data pulse sequence in an NMR scan. The acquired motion NMR data is processed on-line to produce a signal indicative of the displacement of the abdominal wall from a reference position. The displacement values may be employed to produce a signal indicative of a respiration phase that can be used in connection with motion artifact reduction techniques.

Method for monitoring respiration with acquired NMR data

A method for iterative phase conjugation adaptive reduction of phase aberration effects upon the time delays necessary for formation of a beam of coherent energy focused within non-homogeneous medium at a selected range R from, and at an angle .theta. with respect to the normal to, the surface of an array of a plurality N of transducers, each for providing a portion of the energy of the beam when excited and for converting energy reflected thereto to a signal therefrom, first bounces from a large collection of scatterers, contained in a portion of the medium to be investigated, a probe beam for that beam angle .theta.. The received signals from each of the (N-1) pairs of adjacent transducers are cross-correlated to drive a like number of phase conjugation correction signals, which are then arithmetically operated upon to provide a time correction for the time delay associated with each probe beam transducer, for that range R and angle .theta.. The time correction for each transducer then modifies each of at least one iteration of excitation to, and return signal received from, the media portion. A plurality of iterations, with each excitation made with the most recent corrected delays values, better focuses the interrogating beam, until, after a selected number of iterations, actual imaging data can be obtained with minimal phase aberrations.

Adaptive coherent energy beam formation using iterative phase conjugation

Tissue attenuation of ultrasound energy is determined by transmitting a wide band ultrasonic pulse into tissue and obtaining a measure of the average center frequency of the reflected pulse between two levels in the tissue. The log amplitude decay is estimated from a reflected pulse, and the attenuation coefficient is then obtained from the ratio of log amplitude decay to average center frequency between the two levels.

Method of estimating tissue attenuation using wideband ultrasonic pulse

Blood flow measurements are obtained by determining changes in time varying textural patterns of reflected ultrasonic waves from the blood flow at a predetermined position in a blood vessel. Electrical signals generated in response to reflected ultrasonic waves from moving blood cells are autocorrelated to indicate changes in the textural patterns.

Ultrasonic method and means for measuring blood flow and the like using

Obstructions in a blood vessel are identified and displayed by determining changes in textural patterns based on the ultrasonic waves reflected from the blood vessel. The textural pattern from stationary scatterers, such as found in a clot, remains essentially constant, whereas the texture pattern for moving scatterers such as flowing blood cells is ever changing. By determining and imaging the variations in textural pattern of the reflected ultrasonic waves the identification of obstructions in the vessel is realized.

Method and means for imaging obstructed blood vessels

The frequency of a reflected ultrasonic wave decreases in frequency as the wave is attenuated in passing through tissue. A measure of attenuation is obtained by applying an electrical signal generated from the ultrasonic wave to a phase detector along with a signal from a voltage controlled oscillator and controlling the voltage controlled oscillator with the output of the phase detector. By measuring the voltage applied to control the oscillator, an estimation of the mean frequency (first moment) of the power spectrum is obtained. This frequency estimator can, in turn, be used to estimate the attenuation of the ultrasonic wave as it propagates through the media by noting the shift in frequency with propagation depth.

Method and means for determining ultrasonic wave attenuation in tissue

Ultrasonic wave attenuation in passing through tissue is determined from frequency changes in reflected ultrasonic waves passing through the tissue. In a baseband ultrasonic imaging system in which transducer generated signals are coherently detected by mixing the signals with a fixed frequency signal both in phase and in phase quadrature, a measure of frequency change in the reflected ultrasonic signal is obtained by measuring phase shift in a side band of the mixed signals.

Method and means for determining frequency selective tissue attenuation

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.

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Waukesha, WI, United States of America

Stephen W Flax