Koninklijke Philips Corporation N.v.

Case Western Reserve University

Marconi Medical Systems, Inc.

Dee H Wu

Michael R Thompson

Wayne R Dannels

Kecheng Liu

David Leslie Foxall

Christopher K Anand

Jeffrey L Duerk

Jonathan S Lewin

Michael Burl

Jasjit S Suri

Francis H Bearden

Michael Wendt

John Carlon

Agus Priatna

Sara M Oberrecht

Laura M Reden

Sara Hagey

Troy K Havens

A magnetic resonance cardiac imaging method for imaging during a cardiac cycle interval includes monitoring an electrocardiographic signal () associated with the imaged heart for a first trigger event (). Responsive to the first trigger event, a data acquisition sequence () is applied, including a first preparation sequence block (), a first imaging sequence block () having at least one readout interval () that collects first data (), a second preparation sequence block (), and a second imaging sequence block () having at least one readout interval () that collects second data (). The data acquisition sequence () occupies an acquisition time interval which is less than the cardiac cycle interval of the imaged heart.

Multiple preparatory excitations and readouts distributed over the cardiac cycle

A magnetic resonance imaging (MRI) apparatus () acquires a plurality of parametric images () with at least one varying imaging parameter. A parametric map () is constructed from the plurality of parametric images (). At least one pilot parameter () is identified from at least the parametric map (). The at least one identified pilot parameter () includes at least a volume of interest for a diagnostic image. A contrast agent () is administered to the patient (). The identified volume of interest is imaged during influx of the administered contrast agent () into the identified volume of interest. The imaging uses the at least one identified pilot parameter ().

Method and apparatus for evaluation of contrast agent uptake based on derived parametric images

A two-dimensional slice formed of pixels () is extracted from the angiographic image () after enhancing the vessel edges by second order spatial differentiation (). Imaged vascular structures in the slice are located () and flood-filled (). The edges of the filled regions are iteratively eroded to identify vessel centers (). The extracting, locating, flood-filling, and eroding is repeated () for a plurality of slices to generate a plurality of vessel centers () that are representative of the vascular system. A vessel center () is selected, and a corresponding vessel direction () and orthogonal plane () are found. The vessel boundaries () in the orthogonal plane () are identified by iteratively propagating () a closed geometric contour arranged about the vessel center (). The selecting, finding, and estimating are repeated for the plurality of vessel centers (). The estimated vessel boundaries () are interpolated () to form a vascular tree ().

Angiography method and apparatus

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

Multiple contrast echo-planar imaging for contrast-enhanced imaging

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 ( ) 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. Thereafter, values for the pair of correction factors (&thgr;,&Dgr;) are derived from the image data.

EPI calibration method to minimize ghosting in reconstructed images

A magnetic resonance imaging (MRI) apparatus ( ) operator guidance system ( ) calculates monitor parameters and limit values for selectable parameters. The monitor values are displayed ( ) along with a sub-set of the selectable parameters ( ) and the limit values therefor. A curve is plotted ( ), comprising one of a desirability factor, a monitor parameter, and a selectable parameter as a function of a domain comprising at least one selectable parameter. Optionally, the desirability factor ( ) is optimized ( ) by adjusting at least one selectable parameter in accordance with a pre-defined mathematical optimization algorithm whereby the at least one selectable parameter is optimized. In another aspect, a data repository ( ) stores independent parameter value sets and associated images. Selected contents of the data repository are displayed ( ), and a stored imaging session is selected ( ) based on the displayed contents. Initial values for the selectable parameters corresponding to the stored selected imaging session are retrieved ( ) from the data repository ( ).

System and method of user guidance in magnetic resonance imaging including operating curve feedback and multi-dimensional parameter optimization

To image flowing materials, magnetic resonance preconditioning pulses are applied in an upstream region ( ). For scanning a subject, an RF pulse calibration sequence is performed by generating a corresponding magnetic resonance data line ( ) in each of a plurality of slices ( ) along a vessel. A processor ( ) determines a signal intensity for each slice ( ), fits the intensities for the family of slices to a curve ( ), and adjusts an RF pulse profile with spatial position in accordance with the curve which is dynamically dependent on the scanned subject. In a subsequent imaging sequence with the adjusted tip angles, data lines from each of the slices are received ( ) and reconstructed ( ) into an image representation stored in the memory ( ).

Flow adaptive guided determination of imaging parameters for 3D magnetic resonance angiography

An RF coil construction ( ) includes removable, relocatable, and/or detachable sections ( ) that are inherently decoupled. The sections can be relocated, removed, or exchanged with sections having different coil sizes or coil configurations, allowing the coil configuration to be tailored to a desired imaging procedure and region of the brain. The coil construction provides space for stimulation devices and adjusting patient access and comfort. Since the operator can select coil removal or placement to reduce the amount of data outside the region of interest, the coil construction can also reduce scanning and reconstruction time, reduce artifacts, and provide increased temporal resolution and image throughput.

MRI RF coil systems having detachable, relocatable, and or interchangeable sections and MRI imaging systems and methods employing the same

A subject is disposed in an imaging region ( ) of a magnetic resonance imaging apparatus. An operator designates a steady-state imaging sequence and a sequence controller ( ) coordinates a gradient field controller ( ) and an RF pulse controller ( ) to generate the desired sequence. The gradient controller applies gradients that define a closed trajectory through k-space that starts at an origin point and follows a closed path to an end point. An analyzer ( ) analyzes data sampled at the beginning and end points. A gradient offset processor ( ) signals the sequence controller to apply additional gradients until the analyzer determines that the end point coincides with the origin point. A scaling circuit ( ) scales data sampled between the origin and end points for various anomalies in the steady-state magnetization, reconstructing scaled data into at least one image representation.

Steady-state imaging sequence

A method of MRI includes supporting a subject in an examination region of an MRI scanner, and setting up a spin system with a net magnetization. An inversion pulse is applied which inverts the magnetization of the spin system in a selected volume of the subject. As the magnetization re-grows, a first set of raw data is generated by acquiring MR signals from a series of regions within the selected volume. For the first set of raw data, the series of regions are acquired in a first temporal order with respect to the inversion pulse. The inversion pulse is re-applied, and as the magnetization re-grows, a second set of raw data is generated in similar fashion to the first. However, for the second set of raw data, the series of regions are acquired in a second temporal order with respect to the inversion pulse. The second temporal order is different from the first temporal order. From the first and second sets of raw data, respectively, first and second sets of complex image data are generated. A complex phase correction factor is then determined and applied to one of, or both, the first and second sets of complex image data to thereby phase match the same. A combined image is generated via a pixel by pixel complex combination of the phase matched first and second sets of complex image data.

Combination of fluid-attenuated inversion-recovery complex images acquired using magnetic resonance imaging

A magnetic resonance imaging (MRI) system ( ) performs optimized chemical-shift excitation. A computer system ( ) performs a constrained numerical optimization to determine radio frequency (RF) pulse amplitudes, phase angles, and interpulse intervals for a binomial-like RF pulse sequence that will excite magnetization ( ) of a selective one of two chemical species, such as water and fat for example, of a subject ( ) in relatively less time and that may therefore be used at lower magnetic fields. A static magnet ( ) produces a magnetic field along a predetermined axis relative to the subject Pulse sequence apparatus ( ) creates magnetic field gradients with the magnetic field, applies RF pulsed magnetic fields, and receives resulting RF magnetic resonance (MR) signals. Pulse sequence control apparatus ( ) controls the pulse sequence apparatus to apply the binomial-like RF pulse sequence to the subject. The computer system reconstructs an image from received RF MR signals resulting from application of the binomial-like RF pulse sequence.

Magnetic resonance imaging (MRI) optimized chemical-shift excitation

An MRI scanning method and apparatus provide increased efficiency by oversampling in the phase encoding direction. The oversampling is performed during one or more time periods (,) during the scanning sequence that would normally be unused. The addition phase encoding steps (,) can be used to enhance overall image resolution. In preferred embodiments, additional phase encoding steps reduce or eliminate N/2 ghost artifacts with no increase in imaging time. Image throughput is improved by obviating the need for ghost removal post-processing of the image data.

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Shaker Heights, OH, United States of America

Dee H Wu