47 results about "T1 contrast" patented technology

In a method in the form of a turbo spin echo imaging sequence with long echo trains and optimized T1 contrast for generation of T1-weighted images of an examination subject by magnetic resonance, magnetization in the examination subject is excited with an RF excitation pulse, a number N of RF refocusing pulses with variable flip angle are radiated to generate multiple spin echoes for an excitation pulse, a restoration pulse chain is activated after switching of the N refocusing pulses and before the next RF excitation pulse. The restoration pulse chain influences the magnetization such that the magnetization is aligned opposite to the direction of the basic magnetic field by the restoration pulse chain before the next RF excitation pulse.

The invention discloses preparation of a photothermal diagnosis and treatment agent based on a gadolinium modified Fe3O4@ PDA nano material, and belongs to a preparation technology of a novel nano composite material. A T1 contrast agent Gd-DTPA and a T2 contrast agent Fe3O4 which have been applied clinically and PDA which has good biological compatibility and near infrared absorbing ability are used; Fe3O4 nano particles with sizes about 10 nanometers are synthesized by a coprecipitation method, and PDA wraps the surfaces of the Fe3O4 nano particles to obtain the Fe3O4@ PDA nano material with good monodispersity; in order to connect Gd-DTPA with the Fe3O4 nano particles, Fe3O4@ PDA is subjected to amination, and finally, the required Fe3O4@ PDA-NH2-DTPA-Gd nano composite material is obtained. Experimental results prove that the material simultaneously has good T1 and T2 imaging effect and photothermal conversion ability.

MRI imaging compositions are disclosed comprising non-chelated MRI contrast agents in the pores of at least one porous microparticle or nanoparticle. The compositions of the invention have been found to exhibit increased relaxivity and therefore, enhanced MRI imaging. The non-chelated contrast agents include T1 contrast agents, such as those including Gd(III) or Mn(II). Methods of MRI imaging and methods of making the compositions are also disclosed.

A method and magnetic resonance apparatus for image acquisition using a magnetic resonance sequence (in particular a PETRA sequence) in which k-space corresponding to the imaging area is scanned, with a first region of k-space, which does not include the center of k-space, being scanned radially along a number of spokes emanating from the center of k-space, and with at least two phase coding gradients being completely ramped up before administration of the excitation pulse, and a second central region of k-space, which remains without the first region, is scanned in a Cartesian manner (in particular via single point imaging). For the purpose of a contrast increase a pre-pulse—in particular an inversion pulse to establish a T1 contrast—is provided before a predetermined number of individual measurements. The number of spokes to be measured is selected such that a measurement point located (in a Cartesian manner) nearest to the center of k-space is measured at a predetermined point in time after a pre-pulse, which point in time is optimal with regard to the signal-to-noise ratio and/or the contrast.

The invention discloses a preparation method for a high-sensitivity bimodal magnetic resonance contrast agent. According to the preparation method, by means of a method for preparing ferric oleate andmanganese chloride through thermal decomposition, a high-boiling-point solvent is adopted as a reaction medium, oleic acid and oleylamine are used as stabilizers, and therefore manganese oxide embedded iron oxide nanoparticles with narrow particle size distribution and high degree of crystallinity are obtained. The invention particularly relates to a preparation method for modifying the manganeseoxide embedded iron oxide nanoparticles by utilizing the oleic acid/the oleamine, or a preparation method for the biocompatible and water-soluble manganese oxide embedded iron oxide nanoparticles. The preparation method for the high-sensitivity dual-mode magnetic resonance contrast agent has the advantages that the requirements of magnetic resonance imaging for the contrast agent and the characteristics of the Nanotechnology are combined, by means of regulation and control over chemical synthesis, manganese oxide with the T1 contrast capability and superparamagnetic iron oxide nanoparticles with the T2 contrast capability are combined so as to form the manganese oxide embedded iron oxide nanoparticles, and therefore the cooperatively-enhancing dual-mode magnetic resonance contrast effectcan be achieved between the two imaging modes, namely, the T1 imaging mode and the T2 imaging mode.

The invention relates to a ZIF-8 coated ferroferric oxide nanoparticle material and a preparation method and application thereof. Fe3O4 nanoparticles with a T1 weighing MRI effect are embedded in ZIF-8 to obtain the ZIF-8 coated ferroferric oxide nanoparticle material with a T2 weighing MRI effect. In the preparation process of the material, oil-soluble Fe3O4 is synthesized by utilizing a high-temperature pyrolysis method, and the oil-soluble Fe3O4 is prepared into water-soluble Fe3O4 nanoparticles through a ligand exchange method; ZIF-8 coated ferroferric oxide nanoparticles are synthesized through a one-pot synthesis method. Compared with the prior art, the preparation method is simple, the water-soluble Fe3O4 nanoparticles can serve as a T1 contrast medium, Fe3O4@ZIF-8 serves as a T2 contrast medium, Fe3O4@ZIF-8 responds to weak acid and GSH in tumors, MRI contrast transfer happens, and the tumor diagnosis efficiency can be improved.

A system and method for double inversion recovery for reduction of T1 contribution to fluid-attenuated inversion recovery imaging include a computer programmed to prepare a double inversion recovery (DIR) sequence comprising a pair of inversion pulses and an excitation pulse, execute the DIR sequence to acquire MR data from an imaging subject, and reconstruct an image based on the acquired MR data. The preparation of the DIR sequence comprises optimizing a first inversion time (TI₁) between the pair of inversion pulses and a second inversion time (TI₂) between one of the pair of inversion pulses and the excitation pulse to cause a first tissue of the imaging subject to be suppressed in the image and to reduce a T1 contrast between a second tissue and a third tissue of the imaging subject in the image.

The invention belongs to the technical field of biomedical materials, particularly relates to mesoporous polydopamine (MPDA) nanoparticles for tumor T1-T2 magnetic resonance imaging, and aims to prepare mesoporous polydopamine nanoparticles which are internally doped with metal and have a T1-T2 bimodal imaging effect. The manganese-mesoporous polydopamine nanoparticles are prepared by taking dopamine hydrochloride and an Mn precursor as basic raw materials and taking F127 and TMB as templates, and the nanoparticles are polydopamine nanoparticles which are internally doped with metal manganese and have a mesoporous structure, and have tumor microenvironment responsiveness, good photothermal conversion capability and good photothermal stability; the nanoparticles have good biocompatibility, and can be used as a T1 contrast agent and a T2 contrast agent for magnetic resonance imaging of tumors at the same time.

The invention discloses a tumor-targeted multi-purpose nanometer drug delivery system as well as a preparation method and applications of the tumor-targeted multi-purpose nanometer drug delivery system. The system comprises multi-purpose nanoparticles modified by tumor penetrating peptide RGERPPR and an anti-tumor medicine, wherein the multi-purpose nanoparticles adopt the T1-T2 dual-mode magnetic resonance contrast agent; the anti-tumor medicine is adriamycin or pharmorubicin; and the weight of the anti-tumor medicine accounts for 10-35 % in the system. The drug delivery system has the following features: the grain diameter is 60-200 nm, and the particles are spherical; the T1 contrast agent Gd-DTPA and the T2 contrast agent Fe3O4 are simultaneously utilized, and the highly accurate diagnosis information is provided; the water solubility and biocompatibility of the medicine are improved, and the curative effects and bioavailability of the medicine are improved; the drug delivery system can be used for intravenous injection, and targets to the tumor tissue by utilizing the RGERPPR mediation effect and the tumor EPR effect, and the system has the obvious inhibiting effect for the growth of the brain glioma tumor; and the drug delivery system can be used for realizing the tumor diagnosis and treatment integration.

The invention provides a T1-T2 double-activated magnetic resonance imaging contrast agent as well as a preparation method and application thereof. The T1-T2 double-activated magnetic resonance imagingcontrast agent has a core-shell structure and sequentially comprises T2 contrast agent nanoparticles, a silicon dioxide layer, a T1 contrast agent layer and a modification layer from inside to outside, and the T2 contrast agent nanoparticles are superparamagnetic iron oxide nanoparticles. The T1-T2 double-activated magnetic resonance imaging contrast agent is in a T1 and T2 contrast agent signaldouble-quenching state in normal tissues around an in-vivo tumor, and T1 and T2 contrast agent signals can be activated at the same time at a tumor part, so that the tumor part and the surrounding normal tissues have a remarkable MRI signal difference, and the T1-T2 double-activated magnetic resonance imaging contrast agent has targeting property on tumor cells, so as to realize high-quality imaging for the tumor part.

The invention provides a preparation method and application of a manganese oxide nano-cluster, and relates to the field of nano biomedicine. According to the preparation method, a manganese precursor,a hydrophobic ligand and a reaction solvent are mixed, the manganese precursor is rapidly decomposed and nucleated in a high-temperature environment, and ultra-small manganese oxide nano-cluster particles coated with the hydrophobic ligand on the surfaces and uniform in particle size distribution are obtained. The manganese oxide nano-cluster particles are dispersed in an aqueous solution throughphase inversion to form a stable colloid, show high-efficiency nano-enzyme activity in a weakly acidic tumor microenvironment, and release ROS to kill tumor cells. Meanwhile, the manganese oxide nano-cluster particles can also be used as a T1 contrast agent for magnetic resonance imaging of liver cancer lesion tissues. Compared with the prior art, the manganese oxide nano-cluster prepared by themethod has the advantages of high yield, uniform particle size, good dispersity, good stability, strong nano-enzyme activity, high T1 relaxation rate and the like.

The present invention relates a T1-T2 dual-modal MRI (magnetic resonance imaging) contrast agent, comprising (a) a first layer consisting of T1 contrast material; (b) a second layer consisting of T2 contrast material; and (c) a separating layer which is present in a space between the first layer and the second layer, and inhibits a reciprocal interference between T1 contrast material and T2 contrast material, and a heat-generating composition and a drug delivery composition having the same. The T1-T2 dual-modal contrast agent of the present invention may generate both T1 and T2 signal and thus observe the signal complementarily, resulting in accurate diagnosis through reduction of misdiagnosis. Further, T1 and T2 MR imaging may be simultaneously obtained by simple operation within the same MR imaging device, enabling to remarkably reduce a diagnosis time and diagnosis cost. In addition, the particle constituting the T1-T2 dual-modal contrast agent of the present invention may be applied to hyperthermia and drug delivery systems.

The invention relates to a nano particle of a core-shell structure with amorphous Fe coated with crystalline Fe3O4 and preparation method and application of the nano particle. The synthesized ultra-small Fe@Fe3O4 nano particle with Fe core which is amorphous, while a Fe3O4 shell formed by surface oxidation is crystalline under high temperature treatment, so that the whole nano particle has suitable magnetic strength, and compared with a crystalline Fe core, the amorphous Fe core is more likely to form ultra-small particle size through pyrolysis, and the small size effect and surface effect cause magnetic nanoparticles to have the low Curie temperature, so that the T2 effect is effectively inhibited, and the T1 contrast effect is maximized, and thus T1-T2 dual-mode imaging is achieved, andthe accuracy of diagnosis is improved through complementary T1-T2 dual-mode weighted MRI images.