71 results about "Saturation transfer" patented technology

An exemplary methodology, procedure, system, method and computer-accessible medium can be provided to determine one or more particular frequencies of cross-relaxation between at least one molecule and at least one particular compound, determine a chemical exchange based on magnetic resonance data using a further frequency which is different from the one or more particular frequencies, and derive particular information about the anatomical region of interest based on the chemical exchange.

The invention relates to an anti-CT saturation sampling value differential protection for predicting the CT linear transmission area, including: detecting the CT linear transmission area; predicting the linear transmission area after one cycle according to the currently known position of the linear transmission area location; in the predicted linear transmission area, apply the sampling value difference criterion to judge; if it is an internal fault, there is no linear transmission area, and the protection action; for an external fault, if it develops into the area, the sampling value difference If the fault is still outside the area, continue the above-mentioned protection judgment process of detecting the linear change area prediction, predicting the linear change area, and performing differential judgment of sampling values ​​in the predicted linear change area, and so on until Protective action or start return. The invention can judge the CT saturation, and can act quickly when the fault outside the zone is CT saturated and transfers to the zone; it is not affected by the degree of saturation; there is no limit to whether the CT is saturated when the fault is switched; it has high action sensitivity and reliability sex.

The invention provides a magnetic resonance chemical exchange saturation transfer imaging method and a magnetic resonance chemical exchange saturation transfer imaging system. The magnetic resonance chemical exchange saturation transfer imaging method comprises a main RF pulse generating step, applying a short-time main RF saturation pulse which lasts for a first preset time for aiming at a specific RF point, thereby generating the contrast of a magnetic resonance imaging signal; an image acquisition step, segmentally acquiring image data in a reading-out direction or/and a phase encoding direction based on the applied main RF saturation pulse by means of a segmental planar echo acquisition method; and a sub-RF pulse generating step, after one-time image data acquisition by means of the segmental planar echo acquisition method, applying a sub-RF saturation pulse which lasts for a second preset time, thereby keeping the contrast of the magnetic resonance imaging signal. The magnetic resonance chemical exchange saturation transfer imaging method and the magnetic resonance chemical exchange saturation transfer imaging system settle problems of low signal sensitivity and low imaging efficiency in existing magnetic resonance chemical exchange saturation transfer imaging technology.

Featured are a new class of reporter genes including reporter compositions as well as methods, MRI systems and MRI imaging kits related thereto. The genes according to the present invention provide MR contrast when the sample/subject is irradiated at a specific off-resonance radio-frequency (RF frequency), where the contrast mechanism utilizes chemical exchange saturation transfer (CEST) technique for imaging.

Described are drug carriers useful in magnetic resonance imaging (MRI)-guided drug release comprising a shell capable of releasing an enclosed biologically active agent as a result of a local stimulus, e.g. energy input, such as heat, wherein the shell encloses a ¹⁹F MR contrast agent. Preferably, the carrier also acts as a contrast enhancement agent for MRI based on the principle of Chemical Exchange-dependent Saturation Transfer (CEST). To this end the shell encloses a cavity that comprises a paramagnetic chemical shift reagent, a pool of proton analytes, and the ¹⁹F contrast agent, and wherein the shell allows diffusion of the proton analytes.

Apparatus, system, method and computer-readable medium for isolating chemical exchange saturation transfer contrast from magnetization transfer asymmetry under two-frequency RF irradiation. A two-pool model for magnetization transfer (MT) can be established fully based on Provotorov's theory of saturation, and then extended to the situation of simultaneous two-frequency RF irradiation. Numerical simulations and experimental results demonstrate that two-frequency RF irradiation can make MT effects independent of irradiation frequency over a wide range, and thus can suppress MT asymmetry. Exemplary embodiments can be provided to isolate chemical exchange saturation transfer (CEST) contrast from MT asymmetry contrast by using the two-frequency RF irradiation technique. A further embodiment can isolate a narrow-frequency spectrum MT mechanism from a broad-frequency spectrum MT mechanism.

Methods and systems for producing a magnetic resonance (MR) image of a subject include acquiring a first physiological monitoring signal related to a first physiological process of the subject and acquiring a second physiological monitoring signal related to a second physiological process of the subject. The method also includes analyzing the first physiological monitoring signal and the second physiological monitoring signal to identify at least a first trigger point and a second trigger point and, upon identifying the first trigger point, applying a radiofrequency (RF) saturation module at a selected frequency to saturate a selected spin species in the subject. Upon identifying the second trigger point, the method includes performing a chemical exchange striation transfer (CEST) readout to acquire CEST data and then reconstructing the CEST data to produce a CEST image of the subject.

The embodiment of the invention discloses a magnetic resonance image processing method and device. The method comprises the steps that diffusion weighted imaging scanning and pulse parameter modulation imaging scanning based on chemical exchange saturation transfer are performed on the area of interest of the brain, and a diffusion weighted image and a chemical exchange saturation transfer image are acquired; when the chemical exchange saturation transfer image presents low signal shadow in comparison with the preset benchmark template, arterial spin mark imaging scanning is performed on the area of interest of the brain so as to acquire an arterial spin mark image; the diffusion weighted image is compared with the arterial spin mark image so as to determine a first mismatch area; the diffusion weighted image is compared with the chemical exchange saturation transfer image so as to determine a second mismatch area; and the second mismatch area is removed out of the first mismatch area, and the residual area of the first mismatch area is determined as an ischemic penumbra area. The accuracy of the ischemic penumbra can be enhanced, the image processing flow can be saved, the complexity can be reduced and the safety can be enhanced.

The invention relates to a method for mapping of a physico-chemical parameter such as pH value, temperature, PO2 or metabolite concentration, using a chemical exchange saturation transfer contrast agent in Magnetic Resonance Imaging. This method may be used with agents having only one exchangeable entity pool, e.g. proton pool, by applying two different RF frequencies for pre-saturation of the contrast agent.

A pH-weighted chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) method and system are provided that works by indirectly measuring the NMR signal from amine protons found on the backbones of amino acids and other metabolites, which resonate at a frequency of +2.8-3.2 ppm with respect to bulk water protons. The technique uses a modified magnetization transfer radiofrequency saturation pulse for the generation of image contrast. A train of three 100 ms Gaussian pulses at high amplitude (6 uT) or Sinc3 pulses are played at a particular frequency off-resonance from bulk water prior to a fast echo planar imaging (EPI) readout, with one full image acquired at each offset frequency. This non-invasive pH-weighted MRI technique does not require exogenous contrast agents and can be used in preclinical investigations and clinical monitoring in patients with malignant glioma, stroke, and other ailments.

The invention discloses a rapid chemical exchange saturation transfer imaging method and system, and the method determines that a current image employs a first downsampling rate or a second downsampling rate through judging the relation between the mean signal intensity of the image and a preset signal intensity threshold value; The method solves a problem that a low signal to noise ratio image is difficult to achieve a better reconstruction result because all CEST images employ the same downsampling rate, achieves the adaptivity of a CEST imaging undersampling mode, improves the CEST imaging speed, and guarantees the reconstruction quality of an CEST image.

The embodiment of the invention provides a chemical exchange saturation transfer effect quantification method and device, and an electronic device, and relates to the field of biomedical engineering.The method includes: obtaining chemical exchange saturation transfer imaging data and predefined data; calculating the initial overflow effect data of water molecules according to the predefined data;based on the initial overflow effect data and the chemical exchange saturation transfer imaging data, calculating the initial magnetization transfer effect data; and adjusting the initial overflow effect data and the initial magnetization transfer effect data to obtain final overflow effect data and final magnetization transfer effect data; and calculating a target chemical exchange saturation transfer effect based on the chemical exchange saturation transfer imaging data, the final overflow effect data, and the final magnetization transfer effect data. The method, the device and the electronic device can accurately analyze the chemical exchange saturation transfer effect.

A method is provided that includes applying at least one radiofrequency saturation pulse at a frequency or a range of frequencies to substantially saturate magnetization corresponding to an exchangeable proton in the ROI to generate magnetic resonance (MR) data. The MR data is then acquired using an echo-planar imaging readout, which is configured to sample a series of gradient echo pulse trains at a series of gradient echo times and a series of spin echo pulse trains at a series of spin echo times. One or more relaxometry measurement is then computed using the MR data sampled at the gradient echo times and the spin echo times. An oxygen-weighted image is then generated using the one or more relaxometry measurement, and a pH-weighted image is generated using MR data sampled at one or more of the spin echo times or gradient echo times.

A magnetic resonance imaging (MRI) system (600),for acquiring magnetic resonance (MR) information of a volume, includes at least one controller (610) configured generate at least a portion of a stimulated echo acquisition mode (STEAM) CESTsequence including first through third 90degree radio frequency (RF) pulses, and a first pulse train situated before the first 90degree RF pulse. The first pulse train has first number of pulses. The controller (610) is further configured to generate at least another portion of the STEAM CEST sequence comprising a second pulse train situated between the second and third 90degree RF pulses, the second pulse train comprising a second number of pulses which is less than the first number of pulses;generating end of spoil gradients;and/or to acquire MR information during an acquisition window which is stated at least partially after the end of spoil gradients.

Surface conjugated diamagnetic Chemical Exchange Saturation Transfer (diaCEST) agent carriers and methods of making and using are described herein. The particles are safe alternatives to conventional paramagnetic or superparamagnetic metal-based MRI contrast agents that are often toxic and therefore not biocompatible. The carriers described herein can provide simultaneous monitoring of multiple particle types labeled with ‘multicolor’ diaCEST contrast agents. In some embodiments, the carriers are micro- and/or nanoparticles. In other embodiments, the carriers are liposomes. In some embodiments, the particles and/or liposomes are mucus penetrating. In other embodiments, the particles and/or liposomes are not mucus penetrating.

A method for characterizing interactions in macromolecular complexes, such as protein-protein or protein-ligand complexes, by selective isotopic labeling of the target molecule to reduce the ¹H density in a selected spectral region; by irradiating the target; and by monitoring the polarization using filtered nuclear Overhauser spectroscopy (NOESY) and/or by performing selective saturation transfer experiments to determine the docking potential of the macromolecular complex.

The invention provides for a medical imaging system (100, 300). The medical imaging system comprises a processor (104). Execution of machine executable instructions (120) causes the processor to: receive (200) magnetic resonance imaging data (122) comprising a Z-spectrum acquisition (124) for a set of saturation frequency offsets (126) and at least one reference saturation frequency offset (128); reconstruct (202) saturation frequency offset complex image data (130); reconstruct (204) a B0 map (132), a water image (134), and a fat image (136) according to a Dixon-type magnetic resonance imaging protocol; calculate (206) a water phase angle (138) using the water image and/or the fat image; calculate (208) rotated complex image data (140) by rotating the phase of the saturation frequency offset complex image data such that the complex water signal is aligned with a real axis for each voxel; perform (210) a B0 correction by calculating shifted complex image data (142); calculate (212) a frequency dependent phase angle (144) descriptive of a phase angle between the complex water signal and the complex fat signal for each of the set of saturation frequency offsets using a fat signal model comprising at least two fat species; calculate (214) a residual fat component correction factor (150) by projecting the complex fat signal onto the real axis for each of the set of saturation frequency offsets; and calculate (216) corrected water Z-spectrum image data (152) by subtracting the residual fat component correction factor for each of the set of saturation frequency offsets from the real component of the shifted complex image data.

The invention discloses a chemical exchange saturation transfer imaging method for eliminating fat artifacts, which comprises the steps of image acquisition and image reconstruction, wherein the imageacquisition is to acquire a model image and a phase image of magnetic resonance imaging by adopting a multi-echo gradient echo sequence under the condition of unsaturated radio frequency irradiationand the condition of saturated radio frequency irradiation of different frequencies; the image reconstruction comprises reconstructing a water map, a fat map, a field map and a map based on data collected under irradiation of the multimodal fat model on unsaturated radio frequency; fat models in data acquired after saturated radio frequency irradiation of different frequencies is updated on a per-entity basis by using a numerical method; a water map and a fat map are reconstructed based on the data acquired by the updated fat model under the saturated radio frequency irradiation of different frequencies; and the accurate water-fat reconstruction ensures that no fat signal interference exists in the water map, fat artifacts occurring in chemical exchange saturation transfer imaging are effectively eliminated, and the chemical exchange saturation transfer imaging method for eliminating fat artifacts can improve the accuracy of the chemical exchange saturation transfer imaging.