Abstract: A magnetic resonance pulse sequence technique may acquire a water reference spectrum and two water suppressed metabolite spectra and with frequency selective inversion pulse centered at either single frequency, at multiple frequencies, or in a single acquisition. Subtraction of the inverted from non-inverted water suppressed metabolite spectrum results in single or a combination of specific metabolite peak/peaks alone with a flat baseline for easier quantification.

Abstract: Adaptive noise cancellation systems and methods comprise a reference sensor operable to sense environmental noise and generate a corresponding reference signal, an error sensor operable to sense noise in a noise cancellation zone and generate a corresponding error signal, a noise cancellation filter operable to receive the reference signal and generate an anti-noise signal to cancel the environmental noise in the cancellation zone, an adaptation module operable to receive the reference signal and the error signal and adaptively adjust the anti-noise signal, and a transient activity detection module operable to receive the reference signal, detect a transient noise event and selectively disable the adaptation module during the detected transient noise event.

Abstract: CEST imaging technique and MR scanning are used as an MRI method for detecting levels of lactate in vivo by exploiting the exchange of —OH protons on lactate with bulk water. In accordance with this method, one first obtains a lactate CEST MRI map of a slice of the body of a patient. A contrast agent such as pyruvate, glucose or glutamine is administered and a post-administration CEST MRI map is obtained. The difference in the spatial maps indicates the level of expression of lactate in the tissue of interest.

Abstract: Systems and methods for low power lattice wave filters include an input operable to receive a digital input signal having a first sample rate, a first processing branch including a first delay element operable to receive the digital input signal and output a delayed digital input signal, a second processing branch including a first adder operable to receive the digital input signal and subtract a delayed feedback signal to produce a difference signal, a second adder operable to combine the delayed digital input signal and the difference signal to produce an output signal, and wherein the second processing branch further includes a feedback path including a second delay element operable to receive the output signal and output the delayed feedback signal. In a multistage topology, a register is disposed between each stage and clocked to reduce ripple power.

Abstract: Systems and methods for low power lattice wave filters include an input operable to receive a digital input signal having a first sample rate, a first processing branch including a first delay element operable to receive the digital input signal and output a delayed digital input signal, a second processing branch including a first adder operable to receive the digital input signal and subtract a delayed feedback signal to produce a difference signal, a second adder operable to combine the delayed digital input signal and the difference signal to produce an output signal, and wherein the second processing branch further includes a feedback path including a second delay element operable to receive the output signal and output the delayed feedback signal. In a multistage topology, a register is disposed between each stage and clocked to reduce ripple power.

Abstract: A non-invasive imaging approach using CEST and MRS may be used to monitor the cleavage of the poly-L-glutamate (PLG) backbone. The cleavage of PLG by cathespsin B can expose exchangeable —NH2 protons in the PLG that are then monitored non-invasively through CEST. The technique can provide direct information on malignant tissue and tumor aggressiveness, and can also be used to monitor treatment.

Abstract: Systems and methods for multichannel, multirate lattice wave filters receive digital signal channels at a first sample rate and include a first multiplexer to combine the digital signal channels into a first digital data stream, and a first lattice wave filter comprising a first delay elements and a first feedback path to the first multiplexer, the first lattice wave filter produces a first output digital data stream having a second sample rate that is different than the first sample rate. The first multiplexer is configured to receive a first feedback signal through the first feedback path and combine the first feedback signal with the digital signal channels to produce the first digital data stream. The system may include a first processing branch comprising the first multiplexer and the first lattice wave filter structure, and a second processing branch comprising a second multiplexer and a second lattice wave filter structure.

Abstract: Adaptive noise cancellation systems and methods comprise a reference sensor operable to sense environmental noise and generate a corresponding reference signal, an error sensor operable to sense noise in a noise cancellation zone and generate a corresponding error signal, a noise cancellation filter operable to receive the reference signal and generate an anti-noise signal to cancel the environmental noise in the cancellation zone, an adaptation module operable to receive the reference signal and the error signal and adaptively adjust the anti-noise signal, and a transient activity detection module operable to receive the reference signal, detect a transient noise event and selectively disable the adaptation module during the detected transient noise event.

Abstract: The present disclosure relates to magnetic resonance imaging (MRI) methods comprising (i) obtaining a baseline chemical exchange saturation transfer (CEST) MRI image of a patient, (ii) administering an effective amount of a non-nutritive sweetener to the patient, and (iii) obtaining one or more test CEST MRI image of the patient subsequent to the administering step (ii); wherein the step (i) and (iii) acquisition parameters are substantially the same. The non-nutritive sweetener may include a natural or artificial sugar alcohol, polyol, or combinations or derivatives thereof.

Abstract: CEST imaging technique and MR scanning are used as an MRI method for detecting levels of lactate in vivo by exploiting the exchange of —OH protons on lactate with bulk water. In accordance with this method, one first obtains a lactate CEST MRI map of a slice of the body of a patient. A contrast agent such as pyruvate, glucose or glutamine is administered and a post-administration CEST MRI map is obtained. The difference in the spatial maps indicates the level of expression of lactate in the tissue of interest.

Abstract: An endogenous source of magnetic resonance image contrast of biological tissues is provided by modeling a conventional magnetization transfer (CMT) spectrum using z-spectral data and generating magnetization transfer ratio maps from the magnetization transfer spectrum at a frequency of interest. A contribution by the CMT spectrum from the z-spectral data is removed and a direct water saturation component is modeled using the z-spectral data with removed CMT spectrum (z-spectral). When this modeled direct water saturation component contribution is removed from the z-spectral, then the remaining z-spectra reflects new contrast due to chemical exchange saturation transfer (CEST) and magnetization transfer/exchange effect from aliphatic protons probably associated with labile proteins, peptides and lipids, named as novel magnetization transfer (NMT).

Abstract: A magnetic resonance pulse sequence technique may acquire a water reference spectrum and two water suppressed metabolite spectra and with frequency selective inversion pulse centered at either single frequency, at multiple frequencies, or in a single acquisition. Subtraction of the inverted from non-inverted water suppressed metabolite spectrum results in single or a combination of specific metabolite peak/peaks alone with a flat baseline for easier quantification.

Abstract: A non-invasive imaging approach using CEST and MRS may be used to monitor the cleavage of the poly-L-glutamate (PLG) backbone. The cleavage of PLG by cathespsin B can expose exchangeable —NH2 protons in the PLG that are then monitored non-invasively through CEST. The technique can provide direct information on malignant tissue and tumor aggressiveness, and can also be used to monitor treatment.

Abstract: CEST imaging technique and MR scanning are used as an MRI method for measuring glutaminase mediated tumors. The method takes advantage of the fact that glutamine does not exhibit a significant Chemical Exchange Saturation Transfer (CEST) effect while glutamate does. In accordance with this method, one first obtains a glutamate CEST MRI map of the area of a tumor. L-glutamine (nontoxic up to several millimolar level) or glutaminase blocker is then injected and a post injection Glutamate CEST map is obtained. The difference in the spatial maps indicates the level of expression of glutaminase in the tumor.

Abstract: CEST imaging technique and MR scanning are used as an MRI method for measuring glutaminase mediated tumors. The method takes advantage of the fact that glutamine does not exhibit a significant Chemical Exchange Saturation Transfer (CEST) effect while glutamate does. In accordance with this method, one first obtains a glutamate CEST MRI map of the area of a tumor. L-glutamine (nontoxic up to several millimolar level) or glutaminase blocker is then injected and a post injection Glutamate CEST map is obtained. The difference in the spatial maps indicates the level of expression of glutaminase in the tumor.

Abstract: The CEST effect for various neurotransmitters and energy metabolites in the brain and muscles and various endogenous metabolites in the liver, brain, and myocardium are imaged using MR imaging to illustrate a unique CEST effect that may be used to monitor the concentration of the metabolite and hence to characterize and monitor various disease states in the body correlated to the concentration of that metabolite. By adjusting the timing, amplitude, and length of the RF pulse as well as other parameters of the CEST pulse sequence to address the unique chemical shifts and exchange rates of the target, new targets with unique characteristics may be acquired using CEST MR imaging.

Abstract: A method of calibrating an imaging sequence includes the application of a pre-scan pulse sequence to acquire MR signals from a region-of-interest to be imaged with an imaging pulse sequence. The pre-scan pulse sequence is interrupted to acquire pre-scan data in a low bandwidth acquisition window. A frequency spectrum is generated from the pre-scan data and displayed to interactively allow a user to establish scan parameters for the imaging pulse sequence.

Abstract: The CEST effect for various neurotransmitters and energy metabolites in the brain and muscles and various endogenous metabolites in the liver, brain, and myocardium are imaged using MR imaging to illustrate a unique CEST effect that may be used to monitor the concentration of the metabolite and hence to characterize and monitor various disease states in the body correlated to the concentration of that metabolite. By adjusting the timing, amplitude, and length of the RF pulse as well as other parameters of the CEST pulse sequence to address the unique chemical shifts and exchange rates of the target, new targets with unique characteristics may be acquired using CEST MR imaging.

Abstract: An imaging technique is disclosed to reduce ringing artifacts from amplitude decay in MR multi-echo acquisition. A flip angle train is determined to match scan parameters for an MR scan to acquire MR data from a given tissue. Reducing the effects of amplitude decay in the echo signal reduces ringing artifacts and thereby improves image quality.

Abstract: A method for imaging cancer using a combined PET-MRI system takes advantage of the performance characteristics for both PET and MRI in the context of cancer imaging. MRI is used to assess a large area of the body with high sensitivity for cancer and PET is then used in localized areas of concern to provide physiological information. Optionally, MRI may also then be used to re-scan the localized areas of concern with high spatial resolution and additional tissue contrasts to provide anatomical information and soft tissue contrast to supplement the PET information. The use of a combined PET-MRI system ensures that the imaging data from both modalities is accurately referenced to the same locations in the body.