Abstract: A method of preparing a hydrogen-containing 13C compound test sample exhibiting an enhanced 13C nuclear magnetic resonance (NMR) signal when exposed to a 13C NMR pulse sequence is disclosed. In the disclosed method, the hydrogen-containing 13C compound is mixed with hyperpolarized 129Xe in the gaseous state, and the mixture is subsequently frozen within a magnetic field. The magnetic field strength is then reduced sufficiently so that spin polarization is transferred from the hyperpolarized 129Xe to the compound. The magnetic field strength is then increased, and the mixture is thawed to obtain the test sample.

Abstract: A method of preparing a hydrogen-containing 13C compound test sample exhibiting an enhanced 13C nuclear magnetic resonance (NMR) signal when exposed to a 13C NMR pulse sequence is disclosed. In the disclosed method, the hydrogen-containing 13C compound is mixed with hyperpolarized 129Xe in the gaseous state, and the mixture is subsequently frozen within a magnetic field. The magnetic field strength is then reduced sufficiently so that spin polarization is transferred from the hyperpolarized 129Xe to the compound. The magnetic field strength is then increased, and the mixture is thawed to obtain the test sample.

Abstract: A method and apparatus for suppressing electromagnetic fields induced in cables and electronic medical devices by a magnetic resonance imaging (“MRI”) system are provided. The apparatus includes a cable assembly constructed as a conductive wire wrapped around a paramagnetic core. The paramagnetic core may include a tube filled with a paramagnetic material, such as a gadolinium-based solution or a liquid in which iron oxide particles are suspended.

Abstract: A system and method for non-contrast imaging of pulmonary blood flow in a subject are described. In some aspects, the method includes acquiring, using a magnetic resonance imaging (“MRI”) system, image data from at least the subject's lungs during which little to no respiratory motion occurs in the subject, such as during a breath-hold. The method also includes assembling the image data into a plurality of time-series datasets representing temporal variations of magnetic resonance signals in a region of interest that contains all or part of the subject's lungs. The method further includes computing a statistical blood flow metric for each voxel in the region of interest, using respective time-series datasets, and generating at least one image representative of pulmonary blood flow in the subject using the computed statistical blood flow metrics.

Abstract: A portable magnetic resonance (MR) system for quantitatively measuring properties of a subject's lungs, such as regional ventilation and lung density, is provided. The portable MR system includes a magnet, radio frequency (RF) coil assembly, and spectrometer system. The magnet can be positioned near the subject's chest. The magnetic field of the magnet substantially homogeneous in a region-of-interest located at a distance from the surface of the magnet that localizes the region-of-interest in the subject's lung. The RF coil assembly includes one or more RF coils that are sized to be positioned near the subject's chest, and receives MR signals from the region-of-interest. The spectrometer system controls the RF coil assembly and computes from the acquired MR signals, a quantitative metric indicative of a characteristic of the subject's lung in the region-of-interest. An active noise cancellation system is provided so RF shielding of the portable MR system is not required.

Abstract: A system and method for producing a more accurate ventilation image, as compared to existing lung Fourier decomposition methods, and an image of ventilation dependent blood volume are provided. A time series of images depicting a subject's lungs during free-breathing are acquired and co-registered to a reference image. From the registration process, geometric information indicative proton density changes due to inhalation and exhalation of gas is obtained. This geometric information is used to correct the proton density values in the time series of image frames. These corrected proton density values are Fourier transformed to produce a Fourier spectrum, from which a signal peak occurring at the breathing frequency is extracted and Fourier transformed to produce a more accurate ventilation image. This more accurate ventilation image can be subtracted from a breathing frequency image produced by conventional lung Fourier decomposition methods to produce a ventilation dependent blood volume image.

Abstract: A system and method for producing a more accurate ventilation image, as compared to existing lung Fourier decomposition methods, and an image of ventilation dependent blood volume are provided. A time series of images depicting a subject's lungs during free-breathing are acquired and co-registered to a reference image. From the registration process, geometric information indicative proton density changes due to inhalation and exhalation of gas is obtained. This geometric information is used to correct the proton density values in the time series of image frames. These corrected proton density values are Fourier transformed to produce a Fourier spectrum, from which a signal peak occurring at the breathing frequency is extracted and Fourier transformed to produce a more accurate ventilation image. This more accurate ventilation image can be subtracted from a breathing frequency image produced by conventional lung Fourier decomposition methods to produce a ventilation dependent blood volume image.

Abstract: A method of preparing a hydrogen-containing 13C compound test sample exhibiting an enhanced 13C nuclear magnetic resonance (NMR) signal when exposed to a 13C NMR pulse sequence is disclosed. In the disclosed method, the hydrogen-containing 13C compound is mixed with hyperpolarized 129Xe in the gaseous state, and the mixture is subsequently frozen within a magnetic field. The magnetic field strength is then reduced sufficiently so that spin polarization is transferred from the hyperpolarized 129Xe to the compound. The magnetic field strength is then increased, and the mixture is thawed to obtain the test sample.

Abstract: A method of reconstructing an image from an MRI machine includes receiving a superposition of phase-weighted spin echoes. This is representative of a two-dimensional spin density that encodes the image. A partial spin density is then recovered from the superposition of spin echoes. This partial spin density is a PERL transform of the two-dimensional spin density. The two-dimensional spin density is then recovered from the partial spin density by analytically evaluating an inverse PERL transform of the partial spin density.

Abstract: A modular device with an injury pack holder (10) is shown for providing cooling and/or heating therapy to an injury, having a generally tubular shape and open first end (15) and an open second end (16). A plurality of module openings (55a, 55b and 55c) are cut through the injury pack holder (10) and covered with a retention mesh (60). A thermoelectric assembly (75) containing a Peltier device (85), fan (110), radiator (120), first plate (80) and second plate (88), transfers heat energy to a gel pack (95) which cools or heats an area, is installed in one of the module openings (55a, 55b, 55c). A battery pack (99) can be installed in another module opening (55a, 55b, 55c) or can be remotely located for operation of the thermoelectric assembly (75). The thermoelectric assembly (75) can be operated with other power supply devices such as a household adapter (160) or an auto adapter (170).

Abstract: A magnetic resonance imaging (MRI) probe having an external background magnetic field B.sub.o is described. The probe has a primary magnet having a longitudinal axis and an external surface extending in the axial direction and a rf coil surrounding and proximal to the surface. The magnet provides a B.sub.o field having an external region of substantial homogeneity proximal to the surface. Preferably, the B.sub.o field is provided by two magnets spaced axially and in axial alignment and wherein said region of homogeneity intersects a plane located between the magnets and perpendicular to the axis. For MR imaging, surrounding the primary magnet are r-, z- and .o slashed.-gradient coils to provide spatial encoding fields.

Abstract: Apparatus and methods for performing MRI are disclosed wherein the encoding field has a multidimensional, preferably periodic, dependence. Two dimensional image information can be obtained without the necessity for switching the encoding field. Further, velocity information can be obtained. Preferred coil structures for providing preferred encoding fields are described.

Abstract: An improved method for measuring very slow flow rates using nuclear magnetic resonance techniques is disclosed. The basic technique is that of steady state free precession, in which a sequence of radio frequency pulses are applied to nuclei in a magnetic field having a substantial gradient, so that a driven equilibrium state is obtained and which is characterized by a spatial periodicity in the magnetization response of the nuclei. Two images are generated. The two images may be generated using different time intervals between the application of the radio frequency pulses. Alternatively, the two images may be generated using different effective gradients. The spatial periodicity, and the NMR response of flowing nuclei to the spatial periodicity, is thus different during the two image formations. One image is subtracted from the other, which cancels signals from static nuclei in the signal, while relatively fast flowing nuclei, namely in the larger blood vessels or the like, never reach the equilibrium state.

Abstract: The present invention provides an NMR image in which the individual image element intensities are proportional to the amount of nuclei flowing within a window of velocities. The invention is predicated on the fact that static nuclei in a static reference frame provide the most intense portions of the NMR signal. A moving reference frame for image creation is created moving at the velocity of the nuclei to be imaged. Nuclei moving at the same velocity as the reference frame thus have zero velocity with respect to the reference frame, and hence provide maximum signal intensity. In the described embodiment, the moving reference frame is created by satisfaction of two conditions, which relate to tracking the Larmor frequency and phase of the nuclei of interest moving in a gradient. These conditions may be satisfied by variation of the main NMR magnetic field H.sub.o as a function of time. The field may be varied simply by addition of an additional coil to conventional NMR equipment.