A method is provided that includes applying at least one radiofrequency saturation pulse at a frequency or a range of frequencies to substantially saturate magnetization corresponding to an exchangeable proton in the ROI to generate magnetic resonance (MR) data. The MR data is then acquired using an echo-planar imaging readout, which is configured to sample a series of gradient echo pulse trains at a series of gradient echo times and a series of spin echo pulse trains at a series of spin echo times. One or more relaxometry measurement is then computed using the MR data sampled at the gradient echo times and the spin echo times. An oxygen-weighted image is then generated using the one or more relaxometry measurement, and a pH-weighted image is generated using MR data sampled at one or more of the spin echo times or gradient echo times.

The invention pertains to advances in constructing predetermined magnets from appropriate magnetic material that allows for focusing the magnetic field in a target region.

Described embodiments include an apparatus that includes an electrical interface and a processor. The processor is configured to receive via the electrical interface, from a plurality of sensors, a first signal that indicates a location of an intrabody tool inside a body of a subject, and a second signal that indicates a phase, of a physiological motion cycle of the subject, at which the first signal was acquired. The processor is further configured to acquire, using a magnetic resonance imaging (MRI) scanner, a set of multiple images at the location indicated by the first signal, over a portion, of a subsequent physiological motion cycle of the subject, that includes the phase indicated by the second signal. Other embodiments are also described.

Image-guided therapy of a tissue can utilize magnetic resonance imaging (MRI) or another medical imaging device to guide an instrument within the tissue. A workstation can actuate movement of the instrument, and can actuate energy emission and/or cooling of the instrument to effect treatment to the tissue. The workstation and/or an operator of the workstation can be located outside a vicinity of an MRI device or other medical imaging device, and drive means for positioning the instrument can be located within the vicinity of the MRI device or the other medical imaging device. The instrument can be an MRI compatible laser probe that provides thermal therapy to, e.g., a tissue in a brain of a patient.

A method, system and article of manufacture is disclosed. The method includes providing a spatial navigator outside of a thermal therapy region; receiving a plurality of analog-to-digital conversion (ADC) readouts from an MRI device at a plurality of time points, wherein the ADC readouts comprise a first ADC readout acquired at a first time point, and one or more additional ADC readouts acquired at subsequent time points; processing the ADC readouts to obtain a frequency of the spatial navigator at each of the time points; obtaining a main magnetic field (B.sub.0) drift of the MRI device based on the frequency of the spatial navigator at a particular time point and the frequency of the spatial navigator at the first time point; and obtaining the temperature change at the particular time point based on the B.sub.0 drift.

A system and method of use includes (a) directing a magnetic resonance (MR) system to perform a pulse sequences block in which radio frequency (RF) energy is applied to the subject to substantially saturate magnetization corresponding to an exchangeable proton. The method includes (b), following step (a), acquiring data from the subject with the MR system and (c) repeating step (a) a plurality of times where parameters of the pulse sequence sub-block differ in at least some pulse sequence sub-blocks by at least an amount of RF energy applied to saturate the magnetization. The method further includes (d), after each repetition of step (a), repeating step (b) to acquire data representing signal evolutions from the subject. Additionally, the method includes (e) comparing the signal evolutions with a dictionary database comprising a plurality of different signal evolution templates to determine quantitative chemical exchange or exchangeable proton information of the subject.

The present disclosure discloses a concentration and temperature measurement method for the magnetic nanoparticles based on paramagnetic shift, which measures magnetic nanoparticle concentration and temperature by utilizing a nuclear magnetic resonance device to measure chemical shifts of a liquid sample containing the paramagnetic particles, thereby efficiently achieving high-accuracy concentration and temperature measurement. Paramagnetic magnetic nanoparticles are added to the nuclear paramagnetic resonance sample reagent, and paramagnetic shifts of the sample are obtained by nuclear magnetic resonance. Resonance frequencies are obtained by the paramagnetic shifts, magnetic susceptibilities are obtained according to the relationship between the resonance frequencies and the magnetic susceptibilities of the magnetic nanoparticles, and then the concentration information and temperature information of the sample are obtained by inverse solution according to the relationship between the magnetic susceptibility and the concentration and temperature of the magnetic nanoparticles. From the simulation data, concentration measurement and high-precision temperature measurement of the magnetic nanoparticle samples can be effectively realized by the paramagnetic displacement information.

An MRI system uses a Cartesian-radial hybrid k-space trajectory to capture three-dimensional k-space data and reconstruct an image of an area of interest of a subject. The MRI system performs a series of k-space acquisitions to collect the data. A first k-space acquisition includes acquiring a two-dimensional EPI projection in a first plane parallel to a frequency-encoding direction and acquiring additional two-dimensional EPI projections in planes that are radially shifted about a center axis parallel to the frequency-encoding direction with respect to the first plane, until a selected number of projections are acquired. Each subsequent k-space acquisition includes acquiring an additional set of two-dimensional EPI projections in all of the planes in which an EPI projection was acquired during the first k-space acquisition, each additional set of EPI projections being shifted along a respective plane in a direction perpendicular to the frequency-encoding direction.

A system for guiding a medical intervention is disclosed. The system employs a device guide that operates on the surface of a sphere that is centered on a selected target.

Thermography of an ablation site is carried out by navigating a probe into contact with target tissue in the heart, obtaining a first position of a position sensor in the probe and acquiring a first magnetic resonance thermometry image of the target tissue. The method is further carried out during ablation by iteratively reading the position sensor to obtain second positions, and acquiring a new magnetic resonance thermometry image of the target tissue when the distance between the first position and one of the second positions is less than a predetermined distance. The images are analyzed to determine the temperature of the target tissue.