49 results about "Proton density" patented technology

The present invention provides a method for obtaining a multi-dimensional proton density distribution from a system of nuclear spins. A plurality of nuclear magnetic resonance (NMR) data is acquired from a fluid containing porous medium having a system of nuclear spins. A multi-dimensional inversion is performed on the plurality of nuclear magnetic resonance data using an inversion algorithm to solve a mathematical problem employing a single composite kernel to arrive at a multi-dimensional proton density distribution. Ideally, the mathematical problem can be cast in the form of a Fredholm integral of the first kind wherein a two or more kernels can be reduced to a single composite kernel for ease of solution. Preferably, a series of conventional CPMG pulse sequences, using a conventional NMR tool, can be used to excite the system of nuclear spins. The present invention further includes a regression method which reduces computational efforts by retaining only those grid points, and preferably their neighboring grid points, which have non-zero values, during subsequent iterations of solving for the multi-dimensional proton density distribution. This regression process can be repeated until the density distribution is satisfactorily smooth.

A system and method for mimicking a human brain for MR imaging at various magnetic field strengths is disclosed. A phantom is constructed of a structure having a number of sections. A first section contains a mixture of nickel chloride, agarose gel powder, potassium sorbate, deuterium oxide, and water such that the T1, T2, and proton density values of the first section mimic white matter of the human brain. A second section contains different amounts of the same components such that the T1, T2, and proton density values of the second section mimic gray matter of the human brain. As such, when the phantom is scanned in an MR imaging machine, an optimized flip angle for T1-weighted imaging to improve contrast between white matter and gray matter of the human brain that takes into account proton density differences therebetween can be determined.

A fully-automated method for segmentation of white matter, gray matter, and cerebral spinal fluid (CSF) and for calculating their respective volumes is disclosed. The technique preferably uses a T2-weighted scan and a proton-density scan. The T2-weighted scans are used to highlight those portion of the brain corresponding to CSF. Thereafter, the proton density images are separated in CSF-containing and CSF-free portions, in accordance with the T2-weighted images. The CSF-free portion is then segmented into white matter and gray matter portions. The CSF-containing portion is further segmented into pure CSF-regions, and regions containing a mixture of gray and white matter and CSF. After CSF is segmented from this mixture, the white and gray matter and again segmented, and the respective volumes of white matter, gray matter, and CSF are calculated. A technique for determining a threshold gray scale value for segmenting the white and gray matter to assist in the visual identification of such regions is also disclosed.

Magnetic resonance imaging methods and apparatus for simultaneous measurement of the physical properties R1 and R2 relaxation rate, proton density, and apparent diffusion coefficient using a single magnetic resonance acquisition.

The invention discloses a magnetic resonance quantitative imaging method and device based on gradient echoes. The method comprises the following steps: firstly, changing the echo time and the turnoverangle for many times to obtain K gradient echo signals, and acquiring the k space data on each coil channel of each gradient echo signal; and then according to the gradient echo signals, k space dataand phases on each coil, and the sensitivity of each coil channel, establishing unknown factors including a mathematical model of magnetic sensitivity, proton density, T1, and T*2, and finally solving the magnetic sensitivity, the proton density, T1, and T*2 corresponding to the minimization of the mathematical model. The magnetic resonance quantification is directly solved as the unknown in themathematical model, and the regularization is directly directed to the resonance quantification, a magnetic resonance quantitative value is obtained by solving an equation solution, and more accurateresults can be obtained. According to the method, the accuracy and accuracy of magnetic resonance quantification can be improved, and the accuracy of clinical diagnosis is further improved.

The invention discloses a single scan space-time coding imaging reconstruction method based on the residual network, which relates to a magnetic resonance imaging reconstruction technique based on a deep learning network. The invention provides a single scan space-time coding imaging reconstruction method based on a residual network for obtaining a two-dimensional image in a single scan and reconstructing by a deep learning method. The excitation pulse is replaced by a linear sweep pulse, which effectively resists image distortion caused by the nonuniform magnetic field and chemical shift, andat the same time obtains imaging speed, resolution and signal-to-noise ratio similar to EPI. The SPEN imaging is undersampled along the phase encoding direction. Although the space-time coding imaging signal itself can reflect the contour of the imaged object without reconstruction, the inherent resolution of the contour is typically very low. The single scan space-time coding imaging reconstruction method based on residual network utilizes deep learning to reconstruct SPEN images from low-resolution signal space, greatly improves image resolution, exhibits proton density distribution, and obtains high signal-to-noise ratio while obtaining a resolution similar to conventional deconvolution reconstruction methods.

The invention relates to a method for measuring a convective mixing process velocity field in a porous medium based on nuclear magnetic resonance imaging, and the method belongs to the technical field of convective mixing process velocity field measurement. The method comprises the steps of carrying out upper-lower layered saturation on two kinds of solutions with different densities in the porous medium at first, placing a sand-filled pipe saturating the two kinds of solutions with different densities in an inverted manner and then placing the sand-filled pipe into a nuclear magnetic probe quickly, adopting a spin echo sequence method added with phase encoding gradient pulses to obtain a proton density image of a fluid and converting the proton density image into a phase image, making difference between the phase image and a stationary state phase image under the same pulsed gradient to obtain a phase shifting image, and measuring to obtain a porous medium convective mixing process velocity field by adopting a phase method. The method realizes the unconventional fluid distribution situation required by convective mixing, is applied to the nuclear magnetic resonance imaging technology, carries out visual observation on the convective mixing process velocity field by non-contact and non-interference means, and does not disturb flow of the fluid.

The invention relates to a human tissue physical characteristic parameter magnetic resonance tomography method. The method comprises the following steps: (1) calculating B1x(r), B1y(r) and B1z(r) according to B1<+>(r) obtained in a magnetic resonance radiofrequency field and B1<->(r) obtained through magnetic resonance proton density imaging in combination with a reciprocity principle and a magnetic field Gauss theorem; (2) substituting B1x(r), B1y(r) and B1z(r) into a magnetic resonance time-harmonic radiofrequency electromagnetic field FDTD (Finite Difference Time Domain) equation set, and correspondingly setting the initial values of the conductivity sigma(r) and capacity belong to (r) of each tissue in an imaging region as the average conductivity value and average capacity value of human body tissues to obtain E1x(r), E1y(r) and E1z(r); (3) performing repeated iterative operation till algorithm convergence, wherein the distribution of sigma(r) and belong to (r) of each tissue in the imaging region is the evaluated tissue electrical characteristic parameter distribution result; (4) outputting an image according to the tissue electrical characteristic parameter distribution result in the imaging region.

According to the embodiment, the invention discloses an acquisition method and an acquisition device of magnetic resonance quantitative information graphs. The method comprises the following steps: onthe basis of two groups of echos which are acquired within two different repetition times during running of a three-dimensional gradient multi-echo sequence, constructing a plurality of linear equations that unknowns are T1, Formula (shown as the Description) and/or proton density, and guaranteeing that the number of the constructed linear equations is no less than the number of unknowns in the linear equations; and through a mode of solving solutions of the linear equations, acquiring a T1 quantitative graph, a quantitative graph of the Formula and a proton density quantitative graph. Therefore, according to the acquisition method of the magnetic resonance quantitative information graphs provided by the embodiment, a process of acquiring the quantitative information graphs into a processof solving a linear equation group, and the acquisition method has the characteristic that three quantitative information graphs can be simultaneously acquired through one-time data acquisition. Eachquantitative information graph can be acquired just by conducting one-time acquisition on a patient instead of scanning the patient for several times, so that a great amount of data acquisition timeis saved and a data acquisition rate is improved.

The invention discloses a nondestructive testing method for water distribution in the drying process of roots of red-rooted salvia. Roots of red-rooted salvia samples with different drying times and different drying temperatures are coated with thread seal tapes in a sealed mode, and the coated roots of red-rooted salvia samples are placed for 3-5min at room temperature; a T2 spectrogram and proton density weighed images are obtained through the low-field nuclear magnetic resonance technology, the positions of 10 ms and 100 ms in the T2 spectrogram serve as boundaries, bound water exists at the positions of 0.1-10 ms, water not likely to flow exists at the positions of 10-100 ms, free water exists at the positions of 100-1,000 ms, the peak integral area serves as the relative content of the water, and therefore the relative content of the bound water, the relative content of the water not likely to flow and the relative content of the free water are obtained; distribution positions of the water in the roots of red-rooted salvia samples in the roots of red-rooted salvia samples are obtained according to the proton density weighed images, therefore, the distribution states of the bound water, the water not likely to flow and the free water of the roots of red-rooted salvia samples with the different drying times and the different drying temperatures are obtained, and then the water distribution in the drying process of the roots of red-rooted salvia is obtained.

The present invention provides an improved catalyst and a method for its manufacture. The catalyst comprises an acidic, porous crystalline material and has a Proton Density Index of greater than about 1.0, for example from greater than 1.0 to about 2.0, e.g. from about 1.01 to about 1.85. This catalyst may be used to effect conversion in chemical reactions, and is particularly useful in a process for selectively producing a monoalkylated aromatic compound comprising the step of contacting an alkylatable aromatic compound with an alkylating agent under at least partial liquid phase conditions. The acidic, porous crystalline material of the catalyst may comprise an acidic, crystalline molecular sieve having the structure of zeolite Beta, an MWW structure type material, e.g. MCM-22, MCM-36, MCM-49 MCM-56, or a mixture thereof.

The embodiment of the invention provides a T1 parameter image imaging method and a magnetic resonance imaging system. The method comprises the following steps: during the specified period of one or more first-type heart beat cycles with a single breath hold, proton density weighted imaging data of heart different M layers prepared by non-selective saturated pulse magnetization are collected simultaneously by using SMS method, during the specified period of one or more second-type heart beat cycles with a single breath hold, T1-weighted imaging data of heart different M layers prepared by non-selective saturated pulse magnetization are collected simultaneously by using SMS method, according to the proton density weighted imaging data and T1-weighted imaging data, the T1 parameters of the heart are obtained, by using SMS technology, two or more images in the same period can be acquired simultaneously in one heartbeat cycle, which enlarges the space coverage of T1 parameter map in singlebreath hold, and achieves the whole heart T1 parameter map, thus solving the problem of small space coverage of T1 parameter map in single breath hold.

The invention provides a method for measuring an inversion-recovery sequence T1 under a water-fat mixed system and relates to the technology of magnetic resonance imaging. The method comprises the following steps: 1, collecting a multi-echo image, performing water-fat separation on the image, calculating the fat proton density percentage of each pixel or ROI; 2, collecting a free attenuation signal; 3, performing multi-parameter fitting on the collected free attenuation signal after the fat proton density percentage of the pixel or ROI is calculated, and calculating relaxation features of water and fat to solve the defect that traditional inversion-recovery T1 measurement cannot complete tissue T1 measurement under the situation of fat existence. The method can be used for measuring the T1of a water tissue and the T1 of fat under the situation of a sufficient proportion of a fat signal.

The invention relates to a method and a device for imaging magnetic resonance electromagnetic characteristic parameters of human body biological tissues. The method comprises the following steps of respectively carrying out spin echo and proton density imaging sequence scanning to obtain image data, dividing the spin echo reconstruction image data by the proton density image data to obtain decoupled pure receiving magnetic field data, and on the basis of pure receiving magnetic field data, conducting synchronous reconstruction by utilizing a convection-reaction-diffusion or gradient indirect inversion algorithm to obtain parameter value distribution of the electrical conductivity, the dielectric constant and the magnetic conductivity of the tissue. A result obtained by utilizing the spin echo sequence and receiving magnetic field amplitude and phase component inversion does not contain contribution of quasi-static frequency components related to main magnetic field uniformity distortion in image data acquisition. The measurement process is noninvasive, and the obtained measured value does not need to be assisted by a contrast agent.

The present invention is directed to a system and method for measuring blood volume using non-contrast-enhanced magnetic resonance imaging. The method of the present invention includes a subtraction-based method using a pair of acquisitions immediately following velocity-sensitized pulse trains for the label module and its corresponding control module, respectively. The signal of static tissue is canceled out and the difference signal comes from the flowing blood compartment above a cutoff velocity. After normalizing to a proton density-weighted image acquired separately and scaled with the blood T1 and T2 relaxation factors, quantitative measurement of blood volume is then obtained.

A method is disclosed for the automated classification of an image property of a magnetic resonance image(6). In an embodiment, the method includes determining at least the parameters T1, T2 and proton density of at least two tissues imaged in the magnetic resonance image(6) or prespecifying at least two sets of at least these parameters; calculating the signal intensity in the center of the k-space for each imaged tissue or each set of parameters; and classifying the image property as a function of the calculated signal intensities. A magnetic resonance device is also disclosed.

Embodiments of the present invention provide markers, phantoms, and associated methods of calibration which are suitable for use in both medical resonance imaging and radiographic imaging systems. A marker includes a first component having a first hydrogen proton density and a first mass density; and a second component having a second hydrogen proton density different than the first hydrogen proton density, and a second mass density different than the first mass density. The first and second components are non-magnetic.