6 results about "Magnetic resonance imaging" patented technology

A magnetic field generator includes a power source and a segmented or un-segmented coil connected to the power source to generate a time-varying magnetic field. Energy is applied to the coil so that the coil generates a time-varying magnetic field gradient with a magnitude of at least 1 milliTesla per meter and a rise-time of less than 10 microseconds. The coil may be comprised of overlapping, non-overlapping or partially overlapping coil segments that may individually energized to further improve the operating characteristics of the coil to further decrease bio-effects in magnetic resonance imaging through the use of reduced pulse lengths and multi-phasic magnetic gradient pulses.

For the purpose of providing an RF coil apparatus capable of forming an arbitrary FOV, a A magnetic resonance imaging apparatus is provided for collecting magnetic resonance signals while applying a static magnetic field, a gradient magnetic field and an RF magnetic field to a subject to be imaged, and producing an image based on the magnetic resonance signals, the apparatus comprising: an RF coil (108) for conducting at least one of the application of the RF magnetic field and reception of the magnetic resonance signals, in which RF coil, ratios of the electric currents flowing through a plurality of coil elements connected in parallel are adjusted by adjusting device (110, 160, 170).

Methods and apparatuses for 3D tomographic imaging of objects such as soft-tissues in humans are disclosed. They are similar to the Magnetic Resonance Imaging (MRI) methods and apparatuses but they are based on the new Field Paradigm founded on the principle that the field intensity distribution in a 3D volume space uniquely determines the 3D density distribution of the field emission source and vice versa. The object to be imaged is first magnetized by a polarizing magnetic field pulse. The magnetization of the object is specified by a 3D spatial Magnetic Density Image (MDI) that needs to be determined. The magnetic field due to the magnetized object is measured in a 3D volume space that extends in all directions and in particular substantially along the radial direction from the center of the object being imaged. Further, magnetic field intensity may be measured along multiple directions at each point. This measured data captures all the available information and facilitates fast and accurate 3D image reconstruction. This is unlike prior art where measurements are made only on a surface at a nearly constant radial distance from the center of the target object. Therefore useful and available data is ignored and not measured in prior art. Consequently, prior art does not provide a fast and accurate solution to 3D imaging. The methods and apparatuses of the present invention are combined with frequency and phase encoding techniques of MRI in prior art to achieve different trade-offs.

The invention relates to a method for establishing an animal model for senile dementia, a special liquid medicine and a dosing device, and belongs to the technical field of neurosciences. The method comprises the following steps: obtaining positioning coordinates of paraceles according to brain atlases or/and magnetic resonance image data of an experimental animal; respectively burying a conduit of the dosing device in left and right paraceles of the animal, and injecting the special liquid medicine to the paraceles at a constant speed in 14-16 minutes under a sterile environment within 2-3 weeks, wherein the liquid medicine amount is 100-250 ml methanol per day; alternately dosing the left and right paraceles, wherein the dosing frequency is 18-30 hours at an interval; and continuously dosing for 2-10 months to obtain a non-human primate animal model for senile dementia. With the adoption of a novel dosing mode: dosing to the paraceles at the constant speed, medicine can circulate to whole brain through the cerebrospinal fluid to exert the toxic effect, so that peripheral damage by the medicine is avoided. The AD model is established by injecting methanol or formaldehyde to the paraceles, so that behaviors and pathological symptoms are typical, the basic physiological status is good and the individual difference is relatively smaller.

The invention discloses a cell tracer with low toxicity and a high cell uptake rate as well as a preparation method and application of the cell tracer. The cell tracer is a PAA and PEG coated ultra-small superparamagnetic iron oxide nanoparticle. The cell tracer is obtained by synthesizing an ultra-small superparamagnetic iron oxide nanoparticle through a thermal decomposition method and then sequentially coating PAA and PEG. The cell tracer with the low toxicity and the high cell uptake rate is obtained by coating the ultra-small superparamagnetic iron oxide nanoparticles with the PAA and thePEG, and can be used as a cell tracer applied to nuclear magnetic resonance imaging; the cell tracer can be used for efficiently marking human adipose tissue-derived stromal cells without using a transfection reagent, has no obvious toxicity to the human adipose tissue-derived stromal cells and induced pluripotent stem cells, and can be used for tracing the human umbilical cord mesenchymal stem cells transplanted into a brain of a rat.