Superconductor Technologies Inc.

Bioprotonics, Inc.

Osteotronix Medical Pte Limited

Agile Materials and Technologies, Inc.

Acuitas Medical Limited

David R Chase

Timothy W James

Kristin James

Lance W Farr

Wallace Y Kunimoto

Ian David Parker

Robert Armstrong York

Roger J Forse

Mark W Hanes

Amr Hassan O'Baid

James Rafferty

Vicki Chen

Anthony C Jones

Jon D Burnsed

David S Cooper

A method for identifying the chemical species of various textural elements in a targeted region of tissue wherein a volume of interest (VOI) is selectively excited and a k-encode gradient pulse is applied to induce phase wrap to create a spatial encode for a specific k-value and orientation. The specific k-value is selected based on anticipated texture within the VOI. Multiple sequential samples of the NMR RF signal encoded with the specific k-value are recorded as signal data. The Fourier Transform of the acquired signal data is then taken, wherein for each k-encode, the signal recorded is indicative of the spatial frequency power density at that point in k-space. Each peak in the NMR spectrum is then evaluated, whereby the relative contribution to the texture of tissue in the VOI at a k-value for each chemical species is determined.

Method to measure tissue texture using NMR spectroscopy to identify the chemical species of component textural elements in a targeted region of tissue

A method of assessing a spatial frequency distribution within a sample comprising subjecting the sample to magnetic resonance excitation, receiving an echo signal from the sample while the sample is subjected to a magnetic field gradient, applying an invertible linear transform to the echo signal, identifying a region of interest in the transformed echo signal and deriving a corresponding window function, applying the window function (in the signal or transform domain) to the echo signal to remove echo signal coming from regions of the sample outside of the region of interest, and analyzing the one dimensional spatial frequency content in the windowed echo signal in order to access a one dimensional spatial frequency distribution within the region of interest within the sample without creating an image.

Localised one-dimensional magnetic resonance spatial-frequency spectroscopy

In a structural analysis using NMR techniques, a method for gathering k-value data from frequency encoded spin echoes generated from internal volumes selectively excited by intersecting 90&#xb0; and 180&#xb0; slice selective and refocusing RF pulses and subjected to a read gradient for the purpose of quantifying the spatial frequency content of the selected internal volume without contamination by a FID signal, comprising: acquiring spin echo data such that the FID signal generated by imperfections in the 180&#xb0; slice selective refocusing RF pulse is attenuated by the read gradient such that any remaining FID signal is spatially encoded with higher k-values than the frequency encoded k-values being recorded for subsequent structural analysis while simultaneously providing for t2 t2* and t1 contrast. Other aspects of the invention are disclosed.

Optimised pulse sequences for evaluating spatial frequency content of a selectively excited internal volume

The disclosed embodiments provide a method for acquiring MR data at resolutions down to tens of microns for application in in-vivo diagnosis and monitoring of pathology for which changes in fine tissue textures can be used as markers of disease onset and progression. Bone diseases, tumors, neurologic diseases, and diseases involving fibrotic growth and/or destruction are all target pathologies. Further the technique can be used in any biologic or physical system for which very high-resolution characterization of fine scale morphology is needed. The method provides rapid acquisition of selected values in k-space, with multiple successive acquisitions of individual k-values taken on a time scale on the order of microseconds, within a defined tissue volume, and subsequent combination of the multiple measurements in such a way as to maximize SNR. The reduced acquisition volume, and acquisition of only select values in k-space along selected directions, enables much higher in-vivo resolution than is obtainable with current MRI techniques.

Method for assessing structural spatial frequencies using hybrid sampling with non-zero gradient for enhancement of selective sampling

Selective sampling magnetic resonance-based method for assessing structural spatial frequencies

The disclosed innovation is a method for acquiring spatial frequency spectra from specific locations in a 3D sample using modifications of the current MRI techniques for localized NMR spectroscopy. The innovation in its simplest abstraction is to add the use of a read out gradient to the current NMR spectroscopy pulse sequences and record the resultant echo. These techniques generate spectra from a selected region or generate an image of the results over a region of the sample. These methods can be applied to analyzing the structure of trabecular bone as well as for analyzing or diagnosing disease in cases where there is a difference in the spatial frequency power spectrum due to physiologic or disease processes. Various embodiments are disclosed.

Magnetic field gradient structure characteristic assessment using one dimensional (1D) spatial-frequency distribution analysis

A self-tuning variable impedance circuit provides improved performance. A variation in the power applied to the variable impedance circuit causes a corresponding change in the impedance of the circuit, resulting in improved performance. For example, the variable impedance circuit may be a matching circuit that 'follows' the output power of a power amplifier, thereby increasing the power efficiency of the power amplifier.

Self-tuning variable impedance circuit for impedance matching of power amplifiers

An improved HTSC filter system design. An improved HTSC filter system comprises a cryocooler and dewar assembly, a heat dissipation assembly and at least one heat pipe providing a thermal coupling between said heat dissipation assembly and said cryocooler and dewar assembly. In a preferred embodiment, the cryocooler and dewar assembly is environmentally sealed within a double-walled aluminum canister, and the heat pipes are formed from stainless steel tubes having a predetermined amount of ammonia provided therein.

Cryocooler for HTSC filter systems

Systems and methods for regulating, for example, the temperature of high temperature superconducting (HTSC) thin film filters used in connection with a Stirling cycle cryocooler. The system employs a digital signal processor-based control system. The system includes a cryocooler drive control loop for controlling the cryocooler drive in response to a measured cryocooler driving current and a cryocooler driving current set point. The system also includes a temperature control loop for generating the cryocooler driving current set point in response to either a cooldown profile algorithm or a comparison between a measured temperature and a set point temperature stored in DSP memory.

Digital signal process control of stirling cycle cryogenic cooler drive and high temperature superconducting filter temperature control loop

Tower mountable cyrocooler and HTSC filter system

Systems and methods for regulating, for example, the temperature of high temperature superconducting (HTSC) thin film filters. A multi-stage temperature controller comprises a first loop and a second loop. The first loop is used to regulate the cold finger temperature of, for example, a Stirling cycle cryocooler, and the second loop is used to set a reference for the first loop based upon a comparison between a reference signal and a signal received from a cold stage temperature sensor. A filter loop also may be used to regulate the temperature of independent HTSC thin film filter carrier packages.

Growing community of inventors

Santa Barbara, CA, United States of America

David R Chase