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: 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: 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: 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: 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: Prior approaches have delivered 17O2 to a subject by inhalation, but the relationship between local signal changes and metabolism has been complicated by H217O created in non-cerebral tissues. During a brief pulse of 17O2 inhalation, this arterial input function for H217O is negligible due to convective transport delays. Additional delays in the arterial input function due to restricted diffusion of water makes pulsed inhalation of 17O2 even more effective. Accordingly, ventilator system are provided to deliver 17O2 as a brief pulse to a subject. Subsequent MR imaging demonstrates delayed appearance of H217O in the cerebral ventricles, suggesting that the arterial input function of H217O is delayed by restricted water diffusion in addition to convective transit delays. Delivery as a brief pulse therefore offers significant advantages in relating MR signal changes directly to metabolism.

Abstract: Methods of, and systems for, magnetic resonance imaging of diagnostic mapping of tissues, where sodium mapping is performed individually, as well as in combination with other images of tissue, such as T1?, T2, and/or T1-weighted images. In one method embodiment, a sodium image of the tissue is acquired during the same scanning session. Maps are constructed of each of the first and sodium images individually, and in combination, and further facilitate viewing in combination with each other as a single, blended image of the tissue. Maps of the images may be displayed individually or in combination with each other.

Abstract: A spin locked balanced steady-state free precession (slSSFP) pulse sequence combines a balanced gradient echo acquisition with an off-resonance spin lock pulse for fast MRI. The transient and steady-state magnetization trajectory is solved numerically using the Bloch equations and is shown to be similar to balanced steady-state free precession (bSSFP) for a range of T2/T1 and flip angles, although the slSSFP steady-state could be maintained with considerably lower RF power. In both simulations and brain scans performed at 7T, slSSFP is shown to exhibit similar contrast and SNR efficiency to bSSFP, but with significantly lower power.

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: Provided are methods and systems for rapid MRI imaging-scanning that provides 2D or 3D coverage, high precision, and high-temporal efficiency, without exceeding SAR limits. In one embodiment, a pulse sequence process is performed that includes a T1? preparation period, followed by a very rapid image acquisition process, which acquires multiple lines of k-space data. The combination of T1? preparation and acquisition of multiple lines of k-space, allows scan times to be shortened by as much as 3- or 4-fold or more, over conventional MRI scanning methods.

Abstract: Methods for diagnosis of fibrotic diseases, staging of fibrotic diseases and monitoring treatment of fibrosis. The presence of fibrotic tissue is detected. First, a T1? relaxation time of tissue is determined using magnetic resonance imaging. The determined T1? relaxation time is then compared to a baseline T1? relaxation time indicative of healthy tissue, and the presence of fibrotic tissue is then determined based on results of said comparison step. To determine a stage of fibrosis, a T1? relaxation time of tissue is determined and compared to one or more calibrated T1? relaxation times indicative of one or more stages of fibrosis, and the stage of fibrosis is determined based on results of said comparison step. The proposed technology offers a non-invasive MRI technique based on T1? contrast that is sensitive enough to detect small changes of ECM hepatic protein concentration and architecture in all stages of hepatic fibrosis.

Abstract: Prior approaches have delivered O2 to a subject by inhalation, but the relationship between local signal changes and metabolism has been complicated by H217O created in non-cerebral tissues. During a brief pulse of 17O2 inhalation, this arterial input function for H217O is negligible due to convective transport delays. Additional delays in the arterial input function due to restricted diffusion of water makes pulsed inhalation of 17O2 even more effective. Accordingly, ventilator system are provided to deliver 17O2 as a brief pulse to a subject. Subsequent MR imaging demonstrates delayed appearance of H217O in the cerebral ventricles, suggesting that the arterial input function of H217O is delayed by restricted water diffusion in addition to convective transit delays. Delivery as a brief pulse therefore offers significant advantages in relating MR signal changes directly to metabolism.

Abstract: A spin locked balanced steady-state free precession (slSSFP) pulse sequence combines a balanced gradient echo acquisition with an off-resonance spin lock pulse for fast MRI. The transient and steady-state magnetization trajectory is solved numerically using the Bloch equations and is shown to be similar to balanced steady-state free precession (bSSFP) for a range of T2/T1 and flip angles, although the slSSFP steady-state could be maintained with considerably lower RF power. In both simulations and brain scans performed at 7 T, slSSFP is shown to exhibit similar contrast and SNR efficiency to bSSFP, but with significantly lower power.