A method and apparatus for accessing and imaging at least one body part of interest may position a subject in an imaging system to partially encloses the subject and partially expose the subject, and access at least one body part of the subject that is exposed outside the imaging system for a procedure. The at least one exposed body part is positioned to be imaged by the imaging system.

A nuclear magnetic resonance apparatus for estimating properties of an earth formation includes a carrier configured to be deployed in a borehole in the earth formation and at least one transmitting assembly disposed in the carrier and configured to generate an oscillating magnetic field in a volume of interest within the earth formation. The apparatus also includes at least one receiving assembly disposed in the carrier and configured to detect a nuclear magnetic resonance (NMR) signal originating in the volume of interest. In this apparatus, the receiving assembly includes at least a first longitudinal region with a loop coil and a butterfly coil, the loop coil central axis being located over a region of the magnet assembly where a static magnetic field is predominantly along an azimuthal direction to the carrier and the butterfly coil being at least partially overlapped with the loop coil to reduce mutual coupling.

Flow measurement of hydrogen density, volumetric concentrations, and longitudinal relaxation times and transverse relaxation times have all n components in pairs different to each other. The method has the steps of: enclosing a mixture inside a probe volume and polarizing the mixture with a magnetic field; measuring the mixture enclosed inside the probe volume in terms of its longitudinal or transverse relaxation behaviour by means of pulsed electromagnetic waves at least n times with a different volumetric share of its components to measure at least n different relaxation curves; obtaining the relaxation times from the relaxation curves; obtaining the thermal equilibrium magnetizations M.sub.0 of the individual components from the relaxation curves; and correlating yielded thermal equilibrium magnetizations M.sub.0 of the individual components to calculate the hydrogen densities and the volumetric share of the components for each relaxation curve.

A magnetic resonance imaging system comprises a field generation unit and a supporting structure for providing structural support for the field generation unit, wherein the field generation unit comprises at least one magnet for generating a B0 magnetic field and an opening configured to provide access to an imaging volume positioned in the B0 magnetic field along at least one direction and wherein the at least one direction is angled with respect to a main direction of magnetic field lines of the B0 magnetic field in the imaging volume.

A magnetic resonance imaging system comprises a field generation unit and a supporting structure for providing structural support for the field generation unit, wherein the field generation unit comprises at least one magnet for generating a B0 magnetic field and an opening configured to provide access to an imaging volume positioned in the B0 magnetic field along at least one direction and wherein the at least one direction is angled with respect to a main direction of magnetic field lines of the B0 magnetic field in the imaging volume.

A method for performing magnetic resonance imaging is provided. The method includes providing a magnetic resonance imaging system comprising: a radio frequency receive system comprising a radio frequency receive coil, and a housing, wherein the housing comprises a permanent magnet for providing an inhomogeneous permanent gradient field, a radio frequency transmit system, and a single-sided gradient coil set. The method also includes placing the receive coil proximate a target subject; applying a sequence of chirped pulses via the transmit system; applying a multi-slice excitation along the inhomogeneous permanent gradient field; applying a plurality of gradient pulses via the gradient coil set orthogonal to the inhomogeneous permanent gradient field; acquiring a signal of the target subject via the receive system, wherein the signal comprises at least two chirped pulses; and forming a magnetic resonance image of the target subject.

A method for performing magnetic resonance imaging is provided. The method includes providing a magnetic resonance imaging system comprising: a radio frequency receive system comprising a radio frequency receive coil, and a housing, wherein the housing comprises a permanent magnet for providing an inhomogeneous permanent gradient field, a radio frequency transmit system, and a single-sided gradient coil set. The method also includes placing the receive coil proximate a target subject; applying a sequence of chirped pulses via the transmit system; applying a multi-slice excitation along the inhomogeneous permanent gradient field; applying a plurality of gradient pulses via the gradient coil set orthogonal to the inhomogeneous permanent gradient field; acquiring a signal of the target subject via the receive system, wherein the signal comprises at least two chirped pulses; and forming a magnetic resonance image of the target subject.

The invention features methods for detecting the hydration state or vascular volume of a subject using a device capable of nuclear magnetic resonance (NMR) measurement. The methods involve exposing a portion of a tissue of the subject in vivo to a magnetic field and RF pulse from the device to excite hydrogen nuclei of water within the tissue portion, and measuring a relaxation parameter of the hydrogen nuclei in the tissue portion, the relaxation parameter being a quantitative measure of the hydration state or vascular volume of the subject as a whole. The invention also features devices and computer-readable storage media for performing the methods of the invention.

The invention features methods for detecting the hydration state or vascular volume of a subject using a device capable of nuclear magnetic resonance (NMR) measurement. The methods involve exposing a portion of a tissue of the subject in vivo to a magnetic field and RF pulse from the device to excite hydrogen nuclei of water within the tissue portion, and measuring a relaxation parameter of the hydrogen nuclei in the tissue portion, the relaxation parameter being a quantitative measure of the hydration state or vascular volume of the subject as a whole. The invention also features devices and computer-readable storage media for performing the methods of the invention.

In some aspects, a magnetic system for use in a low-field MRI system. The magnetic system comprises at least one electromagnet configured to, when operated, generate a magnetic field to contribute to a B.sub.0 field for the low-field MRI system, and at least one permanent magnet to produce a magnetic field to contribute to the B.sub.0 field.