Abstract: When performing repetitive scans of a patient using a magnetic resonance imaging machine or the like, patients often tend to move as they relax during a lengthy scanning session, causing movement in the volume or portion of the patient being scanned. A prospective motion correction component accounts for patient movement by calculating transformation data representative of patient movement in multiple planes, as well as rotational movement, and a host evaluates the change in position relative to a most recent scanning geometry of the patient or dynamic volume. In this manner, correction or adjustment to the scanning geometry employed by an associated scanner is made only for the differential between the current geometry and the most recent geometry, to mitigate redundant adjustment that can result in oscillatory over—and under—compensation during adjustments.

Abstract: An MRI MAP prescan data from a predetermined imaged patient volume is decomposed to produce a transmit RF field inhomogeneity map and a receive RF field inhomogeneity map for the imaged patient volume based on a three-dimensional geometrical model of the inhomogeneity maps. At least one of the transmit RF field inhomogeneity map and the receive RF field inhomogeneity map is used to generate intensity-corrected target MRI diagnostic scan image data representing the imaged patient volume.

Abstract: Frequency filtering of spatially modulated or “tagged” MRI data in the spatial frequency k-space domain with subsequent 2DFT to the spatial domain and pixel-by-pixel arithmetic calculations provide robust ratio values that can be subjected to inverse trigonometric functions to derive B1 maps for an MRI system.

Abstract: A variable flip angle (VFA) MRI (magnetic resonance imaging) spin echo train is designed and/or implemented. For example, a target train of detectable spin-locked NMR (nuclear magnetic resonance) echo signal amplitudes may be defined and a corresponding designed sequence of variable amplitude (i.e., variable NMR nutation angle) RF refocusing pulses may be determined for generating that target train of spin echoes in an MRI sequence (e.g., used for acquiring MRI data for a diagnostic imaging scan or the like). Such a designed VFA sequence may be output for study and/or use by an MRI system sequence controller.

Abstract: Frequency filtering of spatially modulated or “tagged” MRI data in the spatial frequency k-space domain with subsequent 2DFT to the spatial domain and pixel-by-pixel arithmetic calculations provide robust ratio values that can be subjected to inverse trigonometric functions to derive B1 maps for an MRI system.

Abstract: Frequency filtering of spatially modulated or “tagged” MRI data in the spatial frequency k-space domain with subsequent 2DFT to the spatial domain and pixel-by-pixel arithmetic calculations provide robust data that can be used to derive B1 and/or B0 maps for an MRI system.

Abstract: When scanning a patient to generate an image thereof, radio frequency (RF) coil modules are scalably coupled to each other using a plurality of clips to form flat or polygonal coil arrays that are placed on or around the patient or a portion thereof. A user assesses the volume to be imaged, identifies a coil array configuration of suitable size and shape and employs clips of one or more pre-determined angles to construct the identified coil array configuration, which is placed on or about the volume. Coil modules are coupled to a preamplifier interface box (PIB), which provides preamplified coil signal(s) to a patient imaging device, such as an MRI scanner. Small arrays are constructible to accommodate pediatric patients and/or smaller animals. Modules are hermetically sealed, can be sanitized between uses, and discarded at end-of-life. In one aspect, the modular coil array, clips, and PIB are maintained in an isolated contamination zone, separate from the patient imaging device.

Abstract: In a magnetic resonance imaging method, inner radial readout lines (100, 200, 300, 400) in an inner portion (102, 202, 302, 402) of k-space are acquired using a first readout magnetic field gradient profile (120, 220, 320, 420). Outer radial readout lines (104, 204, 304, 404) in an outer portion (106, 206, 306, 406) of k-space disposed substantially outside of the inner portion of k-space are acquired using a second readout magnetic field gradient profile (124, 224, 324, 424) different from the first readout magnetic field gradient profile. The acquired inner and outer radial readout lines are reconstructed to produce a reconstructed image.

Abstract: In a magnetic resonance imaging apparatus, a sensor (120, 122, 124, 126, 130) measures a displacement of a feature of interest. A magnetic resonance imaging scanner (10) acquires radial readout lines of magnetic resonance imaging data. A reconstruction processor (58) reconstructs the acquired readout lines into reconstructed image data A coordinating processor (134, 140) coordinates a direction of a radial readout line with the determined displacement. The coordinating processor (134, 140) biases at least one of the magnetic resonance imaging scanner (10) and the reconstruction processor (58) toward a selected relationship between readout magnetic field gradient direction and the determined displacement of the feature of interest.

Abstract: A magnetic resonance scanner includes a main magnet (20) that generates a static magnetic field at least in a scanning region (14), and a gradient system (26, 28) that selectively imposes selected magnetic field gradients on the static magnetic field at least in the scanning region. A structure (40) is provided for supporting a plurality of small subjects (80) in the scanning region. The structure includes a plurality of subject supports (82, 82?) each configured to support a small subject, and a plurality of solenoid coils (44, 44?, 44?) corresponding to the plurality of subject supports. Each solenoid coil is arranged with the corresponding subject support to operatively couple with a small subject supported by the corresponding subject support.

Abstract: When performing repetitive scans of a patient using a magnetic resonance imaging machine or the like, patients often tend to move as they relax during a lengthy scanning session, causing movement in the volume or portion of the patient being scanned. A prospective motion correction component (64) accounts for patient movement by calculating transformation data representative of patient movement in multiple planes, as well as rotational movement, and a host (38, 122) evaluates the change in position relative to a most recent scanning geometry of the patient or dynamic volume. In this manner, correction or adjustment to the scanning geometry employed by an associated scanner (10) is made only for the differential between the current geometry and the most recent geometry, to mitigate redundant adjustment that can result in oscillatory over- and under-compensation during adjustments.

Abstract: An imaging scanner (10) acquires imaging data. A reconstruction processor (30) reconstructs the imaging data into an unfiltered reconstructed image. A local noise mapping processor (64, 120, 136, 140, 142, 152) generates a noise map (68, 68?, 68?) representative of spatially varying noise characteristics in the unfiltered reconstructed image. A locally adaptive non linear noise filter (60) differently filters different regions of the unfiltered reconstructed image in accordance with the noise map (68, 68?, 68?) to produce a filtered reconstructed image.

Abstract: In a magnetic resonance imaging method, inner radial readout lines (100, 200, 300, 400) in an inner portion (102, 202, 302, 402) of k-space are acquired using a first readout magnetic field gradient profile (120, 220, 320, 420). Outer radial readout lines (104, 204, 304, 404) in an outer portion (106, 206, 306, 406) of k-space disposed substantially outside of the inner portion of k-space are acquired using a second readout magnetic field gradient profile (124, 224, 324, 424) different from the first readout magnetic field gradient profile. The acquired inner and outer radial readout lines are reconstructed to produce a reconstructed image.

Abstract: When scanning a patient to generate an image thereof, radio frequency (RF) coil modules are scalably coupled to each other using a plurality of clips to form flat or polygonal coil arrays that are placed on or around the patient or a portion thereof. A user assesses the volume to be imaged, identifies a coil array configuration of suitable size and shape and employs clips of one or more pre-determined angles to construct the identified coil array configuration, which is placed on or about the volume. Coil modules are coupled to a preamplifier interface box (PIB), which provides preamplified coil signal(s) to a patient imaging device, such as an MRI scanner. Small arrays are constructible to accommodate pediatric patients and/or smaller animals. Modules are hermetically sealed, can be sanitized between uses, and discarded at end-of-life. In one aspect, the modular coil array, clips, and PIB are maintained in an isolated contamination zone, separate from the patient imaging device.

Abstract: A dose of a contrast agent (44) is administered to the patient (42). A magnetic resonance is excited by an RF pulse (200) in a region of interest of the patient (42). An echo-planar imaging (EPI) readout waveform is implemented a preselected duration after the excitation to generate T2 or T2* weighted data. During the preselected duration, another echo planar readout waveform is implemented to generate T1 or proton density weighted data. The data is reconstructed (56) to generate a T2 or T2* weighted image and a T1 weighted image. The T1 and T2 or T2* weighted images are combined (62) to generate a contrast enhanced image.

Abstract: A method of magnetic resonance imaging is provided. It includes supporting a subject in an examination region of an MRI scanner (A), and applying an EPI pulse sequence with the MRI scanner (A) to induce a detectable magnetic resonance signal from a selected region of the subject. The magnetic resonance signal are received and demodulated to generate raw data. Applied to the raw data are a pair of ghost reducing correction factors (&thgr;,&Dgr;). The pair of corrections factors (&thgr;,&Dgr;) included a phase correction (&thgr;) and a read delay (&Dgr;). The phase correction (&thgr;) compensates for phase errors in the raw data, and the read delay (&Dgr;) effectively shifts a data acquisition window (120) under which the raw data was collected to thereby align the raw data in k-space. The correction factors affect how data is loaded into k-space to generate k-space data, and the k-space data is subjected to a reconstruction algorithm to generate image data.

Abstract: A main magnet assembly (12) creates a main magnetic field (Bo) through an imaging region (10). An operator selects sizes and locations of at least two intersecting slabs (72, 74) in a region of interest. A sequence controller (42) includes a gradient synthesizer (44) and an RF pulse synthesizer (46) that synthesize slab select gradient field pulses (80, 82) and magnetization tipping RF pulses (&agr;, &bgr;) to tip or rotate the magnetization in the slabs and an intersection region (70). A first RF pulse (&agr;) and slab select gradient tip the magnetization in the first slab and the intersection region out of alignment with the (Bo) field (FIGS. 5A, 7A). A second RF pulse (&bgr;) and slab select gradient tip the magnetization in the second slab out of alignment with the (Bo) field (FIG. 6B) and further manipulate the magnetization in the intersection region (FIG. 7B).

Abstract: A magnetic resonance imaging system includes a gradient hardware subsystem (36), a radio frequency transmission hardware subsystem (30), and a data sampling and digitization hardware subsystem (40) A sequence control processor (20) applies control signals or pulses to the hardware subsystems to cause the implementation of a selected EPI imaging sequence. Due to inductive loads, analog filters, and other circuit constructions within the hardware subsystems, each of the hardware subsystems has a different inherent delay between receipt of a control signal and actually achieving the controlled function such as applying a gradient or RF pulse or sampling data. Due to these different inherent delays, the imaging sequence occurs with timing variations from the intended sequence. Echo planar imaging sequences are very sensitive to phase errors caused by these relative delays, which phase errors manifest themselves in the form of Nyquist ghosts.

Abstract: A magnetic resonance imaging apparatus and method employ a magnet system (12) creating a temporally constant magnetic field through an examination region (14) in which at least a portion of an object to be imaged is placed. A radio frequency (RF) excitation system (24, 26) applies an RF excitation to a volume of interest of the object to be imaged, and a receiver system (32) detects and demodulates magnetic resonance data from the volume of interest. A magnetic field encoding system (20, 22, 40) applies encoding magnetic fields to provide spatial discrimination of magnetic resonance data from the volume of interest within a single radio frequency excitation period. The spatial encoding of the magnetic resonance signal data is performed and collected along a preselected k-space trajectory, the k-space trajectory covering a plurality of intersecting. planes or partial planes of k-space data.

Abstract: A method of calibrating pre-emphasis gradient pulse conditioning for long term eddy current compensation in an MRI system is provided. It includes positioning an object in the MRI system for imaging therewith. A long term eddy current generating pre-scan gradient pulse is applied, and after a delay, an EPI sequence is run such that a resulting image of the object is acquired. This process of applying the pre-scan gradient pulse followed by the EPI sequence is repeated while varying the delay therebetween. Size variations in the resulting images of the object are observed, and these size variations are fit to an exponential curve to obtain one or more time constants for the long term eddy currents. Next, a reference EPI sequence is run without applying the long term eddy current generating pre-scan gradient pulse such that a reference image of the object is acquired.