34 results about "Longitudinal Relaxation Rate" patented technology

The invention discloses a method for preparing a Gd3<+> magnetic resonance imaging contrast agent with graphene oxide serving as a carrier, and belongs to the technical field of preparation of medical materials. The method comprises the following steps of: 1) dispersing graphene oxide into distilled water to obtain a graphene oxide dispersing solution; 2) adding an alkaline substance and chloroacetic acid or sodium monochloroacetate to the graphene oxide dispersing solution, ultrasonically dispersing, centrifugally washing and processing, and dialyzing to obtain carboxylation graphene oxide; and 3) dispersing the carboxylation graphene oxide into the distilled water to obtain a carboxylation graphene oxide dispersing solution, adding an aqueous solution of gadolinium salt to the carboxylation graphene oxide dispersing solution, adding a DTPA (Diethylene Triamine Pentacetic Acid) aqueous solution after the stirring reaction is done, uniformly mixing to obtain a mixing solution, and dialyzing to obtain carboxylation graphene oxide with Gd3<+> loaded on the surface, thus obtaining the Gd3<+> magnetic resonance imaging contrast agent. The method is simple and feasible, and the Gd3<+> is firmly loaded; and the preparation magnetic resonance imaging contrast agent is high in water-borne dispersion stability and has high longitudinal relaxation rate.

The invention relates to a device and a method for quantifying a variation of oxygenation in a tissue by using a magnetic resonance imaging technique. The variation of oxygenation in a tissue can be quantified from a measured variation of a proton longitudinal relaxation rate ΔR1 and from calibration data. The method of the invention is characterized in that the variation of proton longitudinal relaxation rate ΔR1 that is used is a variation of proton longitudinal relaxation rate of lipids rather than a variation of proton longitudinal relaxation rate of water molecules.

The invention relates to the field of multi-mode molecular image probes, in particular to a heteronuclear (Ir-Gd) metal complex containing two functional units, namely an iridium phosphorescent complex and a rare-earth macrocyclic polyamine polyacid complex for magnetic resonance-phosphorescent dual-mode imaging of a living body. The cell fluorescent confocal imaging experiment proves that the Ir-Gd complex in the invention can penetrate a cell membrane to enter the cell, specifically colors the cytoplasm region of the cell, and has high water solubility and lower cell toxicity; and in vitro magnetic resonance imaging data proves that the Ir-Gd complex has higher longitudinal relaxation rate, and further research finds that the complex can be used as a magnetic resonance imaging probe for the living body.

The application discloses a magnetic nano composite material, and a preparation method and application of the material, and belongs to the field of medical materials. The magnetic nano composite material comprises magnetic nanoparticles and a hydrophilic compound layer coated outside the magnetic nanoparticles, the magnetic nanoparticles are iron oxides, the particle size of the magnetic nanoparticles is 0.1-20 nm, the particle size of the magnetic nano composite material is 0.5-300 nm, and the longitudinal relaxation rate r1 of the magnetic nano composite is >= 20 mM-1s-1. The provided magnetic nano composite material can be used as a contrast material, and can be used in the aspects of magnetic resonance imaging contrast agents, targeted drugs, cell separation, etc.

The invention discloses a glucan-gadolinium MRI nanometer developer and a preparation method of the glucan-gadolinium MRI nanometer developer. According to a carrier disclosed by the invention, the glucan-polyacrylate nano-carrier is efficiently synthesized through one step by adopting a grafting copolymerization reaction induction self-assembly method, hydrazino is grafted through modification, gadolinium ions are grafted through physical or chemical bonding, finally, the glucan-gadolinium MRI nanometer developer is prepared, and the developer is a nuclear magnetic resonance developer and isapplied to the field of biomedicine. The preparation method disclosed by the invention is simple and efficient, the yield is high, the cost is low, for the prepared nanometer developer, the particle size is uniform, the stability is good, the loading rate of the gadolinium ions is high, the property is excellent, the longitudinal relaxation rate is high, the longitudinal relaxation rate of the prepared nanometer developer provided by the invention is 7-14 times of that of a commercial dimeglnmine gadopentetate injection (Magnevist ), and in addition, the system is low in toxicity, has good biocompatibility, and has a wide application prospect in the fields of disease diagnosis and treatment.

The invention relates to a gadolinium-containing macromolecule magnetic resonance intravascular contrast medium and a preparation method thereof. The easy degradable gadolinium (III) macromolecule magnetic resonance intravascular contrast medium is an intercalation compound of a gadolinium complex and inorganic layered double hydroxides (LDHs) and has the average grain diameter of 17-34nm. The contrast medium adopts the easily biodegradable LDHs as a main material and realizes the nano compounding of the gadolinium-containing complex and the LDHs by intercalation reaction, and the inorganic macromolecule product grain diameter is controlled in a required range of the intravascular contrast medium by a reverse-phase micro-emulsion system; the longitudinal relaxation rate r1 and the transverse relaxation rate r2 are respectively 7.5mM-1s-1 and 10mM-1s-1 and are respectively twice and three times higher than free gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA); and meanwhile, the macromolecule compound can be degraded into inorganic ions and a micromolecule gadolinium complex by simple processing due to the LDHs, thereby solving the problems of slow degradation and difficult gadolinium removal of the gadolinium (III) macromolecule magnetic resonance intravascular contrast medium.

The invention discloses a preparation method of a tumor targeting gadolinium-based magnetic resonance imaging contrast agent and biomedical application of the tumor targeting gadolinium-based magneticresonance imaging contrast agent. The contrast agent can be specifically bound to a transferrin receptor 1 highly expressed on the surfaces of tumor cells, and consists of genetic engineering recombinant proteins and a gadolinium chelate, and has a higher longitudinal relaxation rate than a commercial contrast agent of Magnevist (Gd-DTPA). The animal tumor model imaging effect comparison with theMagnevist is provided; the result indicates that the contrast agent provided by the invention can realize the tumor specific recognition and longer-time magnetic resonance imaging at a lower injection dose; and repeated injection is not needed. The contrast agent provided by the invention can be used through intravenous administration, and can be applied to early diagnosis of cancer, further identification of tumor metastasis and diagnosis of suspected postoperative recurrence.

The invention discloses a preparation method of a fluorescence/magnetic resonance/electron computed tomography three-mode imaging nano contrast agent, which comprises the following steps: step 1: carrying out ultrasonic treatment on anhydrous citric acid, urea, a compound containing I and a compound containing Gd in N, N-dimethylformamide to obtain a mixed emulsion; 2, adding the mixed emulsion into a polytetrafluoroethylene reaction kettle, and carrying out sealed high-temperature reaction; and 3, treating the product obtained in the step 2 with a sodium hydroxide solution, centrifuging, dialyzing a supernatant in water to obtain a dialysate, and freeze-drying the dialysate to obtain the I/Gd doped carbon dots. Meanwhile, the invention further discloses the nano contrast agent for fluorescence/magnetic resonance electron computed tomography three-mode imaging, and the contrast agent is simple and convenient to synthesize, environmentally friendly, easy for surface functionalization, relatively high in longitudinal relaxation rate and X-ray attenuation rate, and excellent in biocompatibility and blood compatibility.

The invention discloses an MMT (montmorillonite)-Gd-DTPA (diethylenetriaminepentaacetic acid) compound, a synthetic method thereof and an application of the MMT-Gd-DTPA compound to magnetic resonance diagnosis for a digestive tract. The synthetic method is characterized in that MMT powder and GdCl3 are mixed in water and react, MMT-Gd compound powder is obtained and reacts with DTPA in water, and the MMT-Gd-DTPA compound is obtained. The MMT-Gd-DTPA compound is obtained through hydro-thermal synthesis, the method is simple and easy to implement, the obtained compound not only has good longitudinal relaxation rate r1 and good biocompatibility, but also has good effect of adhesion to the digestive tract wall, is a better T1 magnetic resonance molecular imaging oral contrast agent and has higher clinical application potential.

The invention relates to a T1-MRI and optoacoustic bimodal imaging contrast agent and a preparation method thereof. The contrast agent consists of ellagic acid, ferrum and polyvinylpyrrolidone, wherein the polyvinylpyrrolidone as a surfactant can control the particle diameter of an ellagic acid-ferrum coordination polymer and improve the water solubility of the ellagic acid-ferrum coordination polymer. The longitudinal relaxation rate of the ellagic acid-ferrum coordination polymer is 2.47mM-1S-1, which is apparently higher than that of ferrum coordination compound type contrast agents which are reported at present, and the contrast agent disclosed by the invention has excellent T1-MRI radiography. What's more, the polymer has strong near-infrared absorption properties as well, has excellent optothermal conversion properties, and presents obvious near infrared optoacoustic radiography properties. The reagent concurrently has T1-MRI radiography and optoacoustic radiography functions atthe same time, a necessary bimodal contrast agent can be provided for union of MRI and optothermal radiography techniques, and the diagnosing accuracy can be improved. Therefore, the bimodal contrastagent has good clinical application prospects.

The invention discloses a measuring characterization method for dynamical and pore-diameter characteristics of a micro-pore surface of a rock core. The method comprises the following steps: (1) preparing a sample; (2) performing low-field nuclear change field 1H NMRD measurement on the sample, thereby acquiring an evolving curve of longitudinal magnetization intensity in each field intensity alongwith the time; (3) calculating the distribution of longitudinal relaxation time T1; (4) calculating a distribution curve of all the field intensities and longitudinal relaxation rate R (R=1/T1), namely an NMRD curve; (5) adopting the NMRD curve for fitting a translation correlation time tau m and surface staying time tau s of liquid layer molecules of the micro-pore surface; (6) acquiring a kinetic parameter A of the micro-pore surface: A=tau s/tau m; (7) multiplying T1 by a factor, thereby acquiring the distribution of the pore diameter. The invention researches the micro-pore micro wettability of unconventional oil and gas reservoir by adopting a brand-new experimental method and a brand-new kinetic parameter. The distribution of T1 is utilized to realize the measurement on the distribution of the nanometer pore diameter of a compact rock core. As for the compact rock core, T1 is more stable and the signal thereof can be more easily acquired.

The invention discloses a chemical exchange saturation transfer quantitative method and device for magnetic resonance and a medium, and belongs to the field of biomedical engineering. The chemical exchange saturation transfer quantitative method comprises the following steps of: acquiring a longitudinal relaxation rate of water; presetting a deformation formula for calculating the spin lock relaxation rate of water on the basis of an unsteady-state experiment condition, wherein at least one deformation parameter of the deformation formula is a ratio of a saturation signal to an unsaturation reference signal under the unsteady-state experiment condition; acquiring a plurality of parameters under an unsteady state experiment condition, calculating a deformation formula according to the parameters, and acquiring the spin lock relaxation rate of water; based on the longitudinal relaxation rate of water and the spin lock relaxation rate of water, acquiring a magnetic resonance chemical exchange saturation transfer signal under a steady-state experiment condition; and acquiring the magnetic resonance chemical exchange saturation transfer effect under the steady-state experiment condition based on the signal. According to the chemical exchange saturation transfer quantitative method and the device, the steady-state CEST signal can be calculated and obtained based on the unsteady-state CEST signal, so that the influence of the imaging parameter on a CEST quantitative result is removed, and the accuracy of CEST quantification is improved.

The invention discloses an ultrasmall-particle-size nuclear magnetic resonance contrast agent as well as a preparation method and application thereof. The contrast agent is a MnSe nanocrystal. According to the preparation method of the contrast agent, staphylococcus aureus is used as a biological synthesizer, sodium selenite is reduced to obtain low-valence Se through the selenium-rich metabolism process of cells, the low-valence Se reacts with a manganese precursor Mn < 2 + > in the cells, and the MnSe nanocrystal which is good in monodispersity, small and uniform in particle size and high in longitudinal relaxation rate under the water phase condition can be obtained. The ultrasmall-particle-size nuclear magnetic resonance contrast agent provided by the invention has good biocompatibility and high contrast performance, can be passively gathered to a tumor part through high permeability and retention effect of a solid tumor, realizes high-contrast nuclear magnetic resonance imaging, and can be applied to living tumor imaging. In addition, the preparation method is simple and convenient, does not involve high-temperature, high-pressure and toxic solvents, is safe and green, and can be widely applied to the fields of chemistry and material science.