106 results about "Magnetization transfer" patented technology

In addition to the known MT (magnetization transfer) effect, an RMT (reverse MT) is newly found, which increases a detected MR signal strength. Both the MT and RMT effects can be explained with mutual interaction, such as phenomena of chemical exchange and/or cross relaxation, acted between a pool of water proton spins and another pool of macromolecule proton spins, for example, within an object. In order to enhance the MT or RMT effect, the frequency bandwidths of RF pulses, such as a 90° RF exciting pulse in a SE or FSE method, an inversion pulse in a FLAIR or fast FLAIR method, and others, are controlled. To enhance the MT effect, the bandwidth is controlled into a wider value (approx. more than 1250 Hz) than the normally (conventionally) used bandwidth, while to obtain the RMT effect, the bandwidth is controlled into a narrower value (approx. less than 1000 Hz) than the normally used bandwidth. Actively controlling the MT or RMT effect permits changed image contrast in MR imaging.

The present invention is directed, in general, to contrast agents (CA), and methods and systems of using such agents for producing image contrast based on a magnetization transfer (MT) mechanism. The CA comprises a tetraazacyclododecane ligand having pendent arms R, R', R" and R"' that are amides having a general formula: --CR.sub.1H--CO--NH--CH.sub.2--R.sub- .2. R.sub.1 includes organic substituents and R.sub.2 is not hydrogen. A paramagnetic metal ion (M) is coordinated to the ligand. The method, comprises subjecting a CA, in a sample, to a radio frequency pulse. The CA has pendent arms R, R', R" and R"' comprising organic substituents and the ligand further includes a M and a water molecule. A signal is obtained by applying a radio frequency pulse at a resonance frequency of the water molecule. The magnetic resonance system, comprises a magnetic resonance apparatus and the CA, the agent containing a ligand having the above described general formula.

The invention relates to a high-saturation-magnetization iron-base amorphous nanocrystal soft magnetic alloy and a preparation method thereof. The alloy is expressed as FeaMbCucSixByPz, wherein M is one or more of Al, Cr, Mn, Ti and V; and 68<=a<=90, 0<=b<=6, 0<=c<=2, 3<=x<=20, 4<=y<=20, 0<=z<=10, and a+b+c+x+y+z=100. Compared with the prior art, the product has the advantages of high saturation magnetization and the like.

A perpendicular spin-transfer torque magnetic random access memory (STTMRAM) element is configured to store a state when electrical current is applied thereto. The perpendicular STTMRAM element includes a magnetization layer having a first free layer and a second free layer, separated by a non-magnetic separation layer (NMSL). The direction of magnetization of the first and second free layers each is in-plane prior to the application of electrical current and after the application of electrical current, the direction of magnetization of the second free layer becomes substantially titled out-of-plane and the direction of magnetization of the first free layer switches. Upon electrical current being discontinued, the direction of magnetization of the second free layer remains in a direction that is substantially opposite to that of the first free layer.

A method and system for magnetic resonance imaging comprises applying at least one radiofrequency magnetization transfer (MT) pulse to a coronary venous region of a subject positioned within a magnetic field, and acquiring magnetic resonance imaging data from the coronary venous region to produce an image of a coronary venous structure. This technique can be utilized as part of a 3D free-breathing, ECG-triggered gradient-echo Cartesian acquisition of the coronary region. One or more magnetization transfer (MT) preparation pulses are used to enhance the contrast between venous blood and myocardium. The MT preparation results in myocardial signal suppression without any significant signal loss in the arterial or venous blood so as to maintain venous blood signal-to-noise ratio while improving contrast between myocardium and veins. The coronary venous structure can comprise one or more of a coronary sinus, a lateral vein and a posterior vein. The image of a coronary venous structure can be acquired in connection with an interventional cardiovascular procedure, such as a cardiac resynchronization therapy.

The invention relates to a stirring-type liquid magnetization device. A main body rack is driven to rotate by utilization of a counter-acting force generated during flow injection of a water input pipe, a group of vertical magnetic columns on the main body rack can be driven to rotate or revolve in a horizontal direction, the magnetic columns are composed of a plurality of neodymium iron boron permanent magnetism cylindrical magnets, and the magnetic line direction and the magnetic column axial direction are consistent and are vertical directions. Orthogonal cutting of a liquid is carried out in a rotating tangential direction during rotation and the purpose of magnetizing the liquid is achieved. The main body rack also can be changed to be driven by a motor. The stirring-type liquid magnetization device is a magnetization device which can be installed in a reservoir, continuous production can be achieved, the magnetization time and degree can be controlled, and various magnetic fields and fluid relative speeds can be covered. The magnetization device can be widely applied in industrial pipe and heat exchange circulating water magnetization for preventing scale, removing scale and preventing rust, concrete mixing water magnetization for enhancing the intensity and fishery culture water magnetization for resisting diseases and increasing the yield, and can provide a lot of agricultural magnetization water.

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.

A solution in the MRI-CEST field is proposed for analyzing a body-part, which includes a CEST agent providing a magnetization transfer with a bulk substrate of the body-part. A corresponding diagnostic system (100) includes input means (505-550) for providing an input map including a plurality of input elements each one for a corresponding location of the body-part; each input element is indicative of a spectrum of a magnetic response of the location, which spectrum includes the magnetic response at an agent frequency of resonance of the contrast agent (with the agent frequency that is at an agent offset of frequency from a bulk frequency of resonance of the bulk substance), and at a reference frequency at the opposite of the agent offset from the bulk frequency. The system further includes calculation means (555,563) for calculating an agent value and a reference value for each one of a set of selected locations; the agent value is calculated in a non-punctual agent range of frequencies including the agent frequency e.g. by integrating the spectrum, and the reference value is calculated in a non-punctual reference range of frequencies including the reference frequency e.g. by integrating the spectrum. Comparison means (565) is then provided for calculating a parametric value for each selected location by comparison between the agent value and the reference value of the selected location.

A pulse sequence for time-of-flight (TOF) magnetic resonance angiography (MRA) includes a fatsat segment, a magnetization transfer segment, and a spatial saturation segment that are applied by an MR apparatus to acquire MR data for image reconstruction with improved image quality. The pulse sequence is constructed such that at the beginning of each iteration of the inner loop of a 3D acquisition, a fatsat pulse is applied. After the fatsat pulse, MR data is acquired in a series of imaging segments with well-suppressed fat signal. Effective fat suppression is achieved by sampling central k-space data first, before signal from fat relaxes back to a pre-saturation level. Each imaging segment is immediately preceded by one of a MT pulse or a spatial saturation pulse and immediately followed by the other one of the MT pulse or the spatial saturation pulse.

A method of differentiating tissues in Magnetic Resonance Imaging (MRI) comprising applying a Magnetization Transfer (MT) pre-pulse in combination with the Diffusion Weighted Imaging (DWI) pulse sequence to obtain an image of the tissue under evaluation. Analysis maps and/or measurements are generated from the obtained image, from which values representative of the macromolecular content are computed for obtaining tissue differentiation.

The invention discloses a high performance magnetic core transverse magnetic field heat treatment furnace, which includes a furnace liner and a material rack fixedly disposed in the furnace liner. The furnace liner is connected to a vacuum pump through a pipeline, a heating wire twines around the furnace liner externally, and an air duct and a magnetized coil are arranged outside the heating wire for separation. An air cooler for cooling the upper air duct is mounted at the furnace liner bottom. The magnetized coil is connected to a control cabinet through a pipeline. For the heating wire and the magnetized coil, power supply control is provided through the control cabinet, and the magnetized coil controls the magnetic field magnitude through current. The iron-based nanocrystalline alloy magnetic core transverse magnetic field heat treatment furnace with the structure combines the advantages of vacuum heat treatment and magnetic heat treatment. As the magnetization treatment is conducted in a vacuum state, the magnetic core has a bright surface and excellent performance. Meanwhile, because of the magnetization treatment, the magnetic performance is stable.

In a multi-slice data acquisition method and device and a magnetic resonance imaging method and apparatus, a number N_C of fractional acquisitions and a number N_S of slice individual, complete data acquisition of the multi-slice data acquisition are determined. Using an iterative odd/even arranging method, a slice data acquisition order of each of the fractional acquisitions is arranged according to an ideal number of iterations. The ideal number of iterations is obtained from multiple undetermined numbers j of iterations of the iterative odd/even arranging method according to the number N_S of slice data and the number N_C of fractional acquisitions. This multi-slice data acquisition method optimizes the slice data acquisition order so as to significantly reduce the effect of magnetization transfer and crosstalk.

A control unit capable of accurately calculating a magnetization bias of a transformer is provided, thereby appropriately reducing the magnetization bias. The control unit acquires first and second currents that flow through a transformer during a period where either first or second switches individually turn ON. The control unit predicts an amount of magnetization bias in either positive side or negative side of the excitation current that flows through the transformer. The control unit reduces the magnetization bias of the transformer based on the predicted amount of magnetization bias.

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.