693 results about "Magnet resonance imaging" patented technology

Disclosed is an implantable or insertable medical device comprising (a) a substrate and (b) a hydrogel polymer coating at a least a portion of the surface of the substrate, wherein the hydrogel polymer is adapted to render the medical device visible under magnetic resonance imaging (MRI) upon insertion or implantation of the medical device into a patient. Also disclosed is the use of such a hydrogel coated implantable or insertable medical device in a medical procedure, wherein during or after insertion or implantation of the medical device in a patient, the position of the medical device is viewed under MRI. The use of a hydrogel polymer for coating a medical device wherein the hydrogel polymer is adapted to render a medical device coated with the hydrogel polymer visible under MRI and a hydrogel polymer adapted to render a medical device coated therewith visible under MRI are also disclosed.

A pole piece for a permanent magnet MRI system and a method for increasing the stability of a gradient field in an MRI system. The method includes: obtaining an MRI system comprising a magnet capable of providing a gradient magnetic field within an image volume in an air gap; and fixing a plurality of pole pieces within said MRI system, thereby defining the air gap, the raw material of construction of the pole piece being a material including a plurality of ferromagnetic particles coated with an electrically insulating substance. The fixing increases the stability of said gradient field by at least 10% relative to that of a gradient magnetic field in an MRI system identical except for the use of the material in the fabrication of the pole pieces.

A multicoil NMR data acquisition apparatus and processing method for performing three-dimensional magnetic resonance imaging in a static magnetic field without the application of controlled static magnetic field gradients. A preferred application relates specifically to the detection and localization of groundwater using the Earth's magnetic field. Multicoil arrays are used in both transmit and receive modes, and coherent data processing algorithms applied to the data to generate three-dimensional NMR spin density estimates. Disclosed are methods for acquiring NMR data using an array of at least two transmit and receive coils, and for processing such multicoil data to estimate the three-dimensional NMR spin density distributions.

A multicoil NMR data acquisition apparatus and processing method for performing three-dimensional magnetic resonance imaging in a static magnetic field without the application of controlled static magnetic field gradients. A preferred application relates specifically to the detection and localization of groundwater using the Earth's magnetic field. Multicoil arrays are used in both transmit and receive modes, and coherent data processing algorithms applied to the data to generate three-dimensional NMR spin density estimates. Disclosed are methods for acquiring NMR data using an array of at least two transmit and receive coils, and for processing such multicoil data to estimate the three-dimensional NMR spin density distributions.

The invention relates to NaYF4-based fluorescent nano particles with double effects and a preparation method thereof. The NaYF4-based fluorescent nano particles at least comprise a kernel and a shell, wherein the kernel is NaYF4: Er / Yb / Gd or NaYF4: Er / Yb, and the shell is NaGdF4. By introducing different luminous ion pairs into different layers, the single-excitation multi-color luminescence function of the single fluorescent particles is realized, and the fluorescent particles have magnetic resonance imaging function; and meanwhile, by introducing a wrapping layer, surface defects of the particles are reduced, and the fluorescent strength of the particles is improved.

Critical needs for MRI patient instruction, testing, comfort, motion control, and speech communication are provided for better imaging which leads to more effective medical care. An MRI Digital Video Projection System is disclosed which provides better quality display to the patient to better inform, instruct, test, and comfort the patient plus the potential to stimulate the brain with microsecond onset times to better diagnose brain function. An MRI Motion Tracker and Patient Augmented Visual Feedback System enables monitoring patient body part motion, providing real time feedback to the patient and / or technician to substantially improve diagnostic yield of scanning sessions, particularly for children and mentally challenged individuals. An MR Forward Predictive Noise Canceling Microphone System removes the intense MRI acoustic noise improving patient communication, patient safety and enabling coding of speech output. These systems can be used individually but maximum benefit is from providing all three.

The present invention relates to minimally invasive X-ray guided interventions, in particular to an image processing and rendering system and a method for improving visibility and supporting automatic detection and tracking of interventional tools that are used in electrophysiological procedures. According to the invention, this is accomplished by calculating differences between 2D projected image data of a preoperatively acquired 3D voxel volume showing a specific anatomical region of interest or a pathological abnormality (e.g. an intracranial arterial stenosis, an aneurysm of a cerebral, pulmonary or coronary artery branch, a gastric carcinoma or sarcoma, etc.) in a tissue of a patient's body and intraoperatively recorded 2D fluoroscopic images showing the aforementioned objects in the interior of said patient's body, wherein said 3D voxel volume has been generated in the scope of a computed tomography, magnet resonance imaging or 3D rotational angiography based image acquisition procedure and said 2D fluoroscopic images have been co-registered with the 2D projected image data. After registration of the projected 3D data with each of said X-ray images, comparison of the 2D projected image data with the 2D fluoroscopic images - based on the resulting difference images - allows removing common patterns and thus enhancing the visibility of interventional instruments which are inserted into a pathological tissue region, a blood vessel segment or any other region of interest in the interior of the patient's body. Automatic image processing methods to detect and track those instruments are also made easier and more robust by this invention. Once the 2D-3D registration is completed for a given view, all the changes in the system geometry of an X-ray system used for generating said fluoroscopic images can be applied to a registration matrix. Hence, use of said method as claimed is not limited to the same X-ray view during the whole procedure.

The present invention relates to a magnetic resonance imaging system and a corresponding method having a transmit phase and a receive phase. Further, the present invention relates to a detuning circuit and a corresponding detuning method for detuning an RF receive coil during the transmit phase in such a magnetic resonance imaging system. In high-field MRI systems the transmit mode operating frequency is higher than normal high breakdown voltage rectifiers can handle when they are used to forward bias a passive detuning circuit PIN diode switch. The proposed circuit uses a current-limiting capacitor (C5) in series with a fast (e.g. schottky) rectifier diode (V2) with a reverse breakdown voltage of e.g. 20 volts and a fast reverse recovery time to generate a DC current. The rectifying circuit is isolated from the PIN diode (V1) with a relatively high-value inductor (L2), which ensures that no harmful transient current spikes can flow from the PIN diode anode to the rectifying circuit. The inductor (L2) still passes and maintains the DC current generated by the rectifying circuit through the PIN diode, thus enabling the robust forward-biasing of the PIN-diode during transmit mode. The use of a fast (and thus low-power) rectifier results in less dissipation on the detuning circuit, and helps in fulfilling the surface temperature limits posed on receiver coils.