Abstract:
This invention relates generally to NMR systems for in vivo detection of analytes. More particularly, in certain embodiments, the invention relates to systems in which superparamagnetic nanoparticles are exposed to a magnetic field and radio frequency (RF) excitation at or near the Larmor frequency, such that the aggregation and/or disaggregation of the nanoparticles caused by the presence and/or concentration of a given analyte in a biological fluid is detected in vivo from a monitored RF echo response.
Abstract:
The invention relates to a method of 13 C-MR imaging and/or 13 C-MR spectroscopy of cell death using an imaging medium which comprises hyperpolarised 13 C-pyruvate.
Abstract:
MR receive (or reception) coil arrangements are disclosed which comprise at least one MR receive coil or coil element or coil system (9) which can be tuned and/or detuned in relation to an MR frequency, and which further comprise a transmission line (7) for electrically connecting the MR receive coil or coil element or coil system (9) with an MR receiver (10). Especially such MR receive coil arrangements are disclosed which are not provided for being stationarily (or permanently) installed or built in an examination zone of an MR imaging or examination system or apparatus (MRI system), like a whole-body coil system of such an MRI system, but which are mobile, like e.g. interventional or invasive devices, like catheters, or surface coils, e.g. in the form of (especially flexible) pads which are positioned on a surface of an examination object for examining a region of interest, or volume coils like birdcage coils for enclosing and examining a volume of interest. Finally, an MR imaging or examination system (MRI system) comprising such an MR receive coil arrangement is disclosed.
Abstract:
A system for using magnetic resonance to track a medical device, including an MR tracking device comprising one or more radiofrequency (RF) tracking coils adapted to receive a magnetic resonance MR response signal from nuclei excited by an RF pulse, the tracking device being attached to a medical device, wherein a dephasing gradient is applied perpendicular to the readout gradient before the RF response signal is received, thereby dephasing and attenuating any interfering signal emanating from remote nuclei, while the MR response signal is substantially unaffected. The system can also detect errors in tracking location by checking the amplitude of the signal from each coil and the detected distance between each coil, and correcting for such errors by ignoring data from coils having low amplitude or location deviating from known location relative to the other coils.
Abstract:
MRI compatible localization and/or guidance systems for facilitating placement of an interventional therapy and/or device in vivo include: (a) a mount adapted for fixation to a patient; (b) a targeting cannula with a lumen configured to attach to the mount so as to be able to controllably translate in at least three dimensions; and (c) an elongate probe configured to snugly slidably advance and retract in the targeting cannula lumen, the elongate probe comprising at least one of a stimulation or recording electrode. In operation, the targeting cannula can be aligned with a first trajectory and positionally adjusted to provide a desired internal access path to a target location with a corresponding trajectory for the elongate probe. Automated systems for determining an MR scan plane associated with a trajectory and for determining mount adjustments are also described.
Abstract:
Diagnostic MR images of the lung are segmented to distinguish the airway tree from lung parenchyma. Diffusion weighted images of the lungs are acquired using hyperpolarized gas MRI and a segmentation image is produced from the apparent diffusion coefficient (ADC) image calculated from the diffusion weighted images. Voxels in the diagnostic MR images having an ADC above a selected amount.are segmented as being in the airway tree.
Abstract:
The invention relates to a device for magnetic resonance imaging of a body (7), wherein the device (1) is arranged to a) generate a series of MR echo signals (20) by subjecting at least a portion of the body (7) to an MR imaging sequence comprising RF pulses and switched magnetic field gradients, b) acquire the MR echo signals for reconstructing an MR image (21) therefrom, c) calculate a susceptibility gradient map (22) from the MR echo signals or from the MR image (21), the susceptibility gradient map (22) indicating local susceptibility induced magnetic field gradients, d) determine the position of an interventional instrument (16) having paramagnetic or ferromagnetic properties from the susceptibility gradient map (22).
Abstract:
The invention relates to a device for magnetic resonance imaging of a body (7). The device (1) comprises means (2) for establishing a substantially homogeneous main magnetic field in the examination volume, means (3, 4, 5) for generating switched magnetic field gradients superimposed upon the main magnetic field, means (6) for radiating RF pulses towards the body (7), control means (12) for controlling the generation of the magnetic field gradients and the RF pulses, means (10) for receiving and sampling magnetic resonance signals, and reconstruction means (14) for forming MR images from the signal samples. In accordance with the invention, the device is arranged to a) generate a series of MR echo signals (20) by subjecting at least a portion of the body (7) to an MR imaging sequence of RF pulses and switched magnetic field gradients, b) acquire the MR echo signals for reconstructing an MR image data set (21) therefrom, c) calculate a gradient map (22) by computing echo shift parameters (SP x , SP y , SP z ) from subsets of the MR image data set, the echo shift parameters (SP x , SP y , SP z ) indicating magnetic field gradient induced shifts of the echo positions in k-space, wherein each subset comprises a number (n) of spatially adjacent pixel or voxel values of the MR image data set (21).