摘要:
In a nuclear magnetic resonance tomography apparatus wherein imaging is implemented with hyperpolarized gases, a first magnet system having a high field strength for the pre-polarization of the nuclear spins is provided. A gradient system for generating magnetic field gradients and a radio-frequency arrangement for the excitation of nuclear spins in a subject as well as for the read-out of the arising nuclear magnetic resonance signals are provided in a second magnet system having lower field strength.
摘要:
In nuclear magnetic resonance tomography apparatus operable with a pulse sequence according to the echo-planar method, only a part of the k-space is scanned in the phase-coding direction per data acquisition, i.e., per radio-frequency excitation pulse. A phase-coding gradient is used such that regions of the k-space which are interleaved relative to each other are scanned in successive data acquisitions in the phase-coding direction. The number of echoes employed for the raw data matrix, and thus the resolution in phase-coding direction, or the length of the individual pulses of the read-out gradient, and thus the resolution in read-out direction, can thereby be enhanced.
摘要:
A method for determining a position of a mobile device relative to a B0 field magnet along a z-coordinate axis, and a device and a magnetic resonance tomography unit for performing the method are provided. The device includes a magnetic field strength sensor arranged in a fixed relative position. A characteristic magnetic field strength Bref of the B0 field magnet that emerges for a plurality of x-y coordinate pairs with a same reference z-coordinate zref is ascertained. The device is moved along the z-coordinate axis until the magnetic field strength sensor measures the characteristic magnetic field strength Bref.
摘要:
In a method and magnetic resonance (MR) apparatus to image a partial region of an examination subject by means of a multislice measurement, which partial region includes at least two measurement slices, and is located at least in part at the edge of a field of view of the magnetic resonance apparatus, for each voxel to be optimized that is located at the edge of the field of view, a gradient field is configured for each measurement slice of the partial region that is to be measured and is used to acquire magnetic resonance data in the multislice measurement. The gradient field is configured so as to cause a nonlinearity of the gradient field and a B0 field inhomogeneity to cancel at each of the aforementioned voxel to be optimized at the partial region at the edge of the field of view. An image of the partial region of the examination subject is determined from the magnetic resonance data acquired in this manner.
摘要:
Timing in a medical imaging system. The system comprises a magnetic resonance imaging (MRI) subsystem and a non-MRI subsystem. Operation of the non-MRI subsystem involves a timing signal within a radio frequency (RF) cabin of the MRI subsystem. Basing each non-MRI subsystem timing signal on a time base common between the MRI subsystem and the non-MRI subsystem. The non-MRI subsystem can be a medical imaging subsystem. The non-MRI medical imaging subsystem can be a positron emission tomography (PET) subsystem. Each non-MRI subsystem timing signal that based on the common time base can be created using the same model of equipment used for creating timing signals in the MRI subsystem. At least one stage of the non-MRI subsystem timing signal based on the common time base can be created using the same equipment used for creating timing signals in the MRI subsystem.
摘要:
A phantom for co-registering a magnetic resonance image and a nuclear medical image is disclosed. The phantom includes a longitudinal member having a first end cap and a second end cap and a chamber contained within the longitudinal member. The chamber contains a fluid for producing a first image using a first imaging modality. The phantom further includes a first rod disposed within the chamber of the longitudinal member. The first rod contains a radioactive substance for producing a second image using a second imaging modality.
摘要:
Example embodiments are directed to a method of correcting attenuation in a magnetic resonance (MR) scanner and a positron emission tomography (PET) unit. The method includes acquiring PET sinogram data of an object within a field of view of the PET unit. The method further includes producing an attenuation map based on a maximum likelihood expectation maximization (MLEM) of a parameterized model instance and the PET sinogram data.
摘要:
In a method for designing a gradient coil composed of multiple sub-coils, parameters representing the structure of the gradient coil are varied, and the variation that produces an optimized electrical field generated by the gradient coil is determined. The final design of the gradient coil embodies those parameters that produced the optimal electrical field. In a method for manufacturing a gradient coil, the gradient coil is manufactured according to the final design. A gradient coil manufactured according to the invention has a gradient conductor configuration that optimizes the electrical field generated by the gradient coil. A magnetic resonance apparatus, and a combined positron emission tomography/magnetic resonance apparatus, embodies such a gradient coil.
摘要:
Timing in a medical imaging system. The system comprises a magnetic resonance imaging (MRI) subsystem and a non-MRI subsystem. Operation of the non-MRI subsystem involves a timing signal within a radio frequency (RF) cabin of the MRI subsystem. Basing each non-MRI subsystem timing signal on a time base common between the MRI subsystem and the non-MRI subsystem. The non-MRI subsystem can be a medical imaging subsystem. The non-MRI medical imaging subsystem can be a positron emission tomography (PET) subsystem. Each non-MRI subsystem timing signal that based on the common time base can be created using the same model of equipment used for creating timing signals in the MRI subsystem. At least one stage of the non-MRI subsystem timing signal based on the common time base can be created using the same equipment used for creating timing signals in the MRI subsystem.
摘要:
The invention relates to calibration phantoms used in connection with medical imaging devices such as PET, MR, etc., and particularly in connection with hybrid systems such as MR/PET systems. In some cases, the phantoms have distinguishable, machine-readable identification features that allow the imaging system to identify them automatically, without operator intervention. In other cases, even where the phantoms do not have such distinguishable, machine-readable identification features, if the imaging system is appropriately configured with cameras and/or appropriate image analysis software, the imaging system can still identify the phantoms automatically.