General Electric Company

Michigan State University

Anthony Tienhuan Vu

Ersin Bayram

Charles Robert Michelich

Xiaoli Zhao

Ramesh Venkatesan

Hari Hariharan

Reed Frederick Busse

Wei Sun

David C Zhu

Agus Priatna

Ravi Bhardwaj

J Kevin DeMarco

Vijay Shivalingappa Nimbargi

Methods and systems are provided for modifying a pulse sequence. In one embodiment, a determination is made whether an estimated peripheral nerve stimulation (PNS) associated with a pulse sequence exceeds a PNS limit. If the estimated PNS exceeds the PNS limit, a slew rate associated with one or more axes of the pulse sequence may be reduced and the maximum gradient amplitudes for each axis of the pulse sequence may be adjusted. In one embodiment, adjustment of the maximum gradient amplitudes or local slew rate may be based upon a cost analysis performed on the pulse sequence.

Method and system for modifying pulse sequences

A method for acquiring magnetic resonance (MR) data for a three-dimensional (3D) dynamic study includes partitioning a k-kplane with a plurality of views into an inner region and a plurality of outer regions. The inner region includes a set of views in a central region of the k-kplane and each outer region includes a plurality of views outside of the central region of the k-kplane. The method also includes partitioning each outer region into a plurality of radial fan beam segments, defining a first view ordering for the inner region and defining a second view ordering for each outer region. Once the k-kplane is partitioned and the view orderings are defined, MR data is acquired for the set of views in the inner region and for all of the views in each of the outer regions in an alternating acquisition order where the set of views in the inner region are acquired more frequently than the views in each of the outer regions. At least one MR image is generated based on the acquired MR data.

Method and apparatus for view ordering of magnetic resonance imaging data for dynamic studies

A method for generating a susceptibility (or T2*) weighted magnetic resonance (MR) image includes defining a pulse sequence having a plurality of gradient echoes and acquiring MR data for each of the plurality of gradient echoes. A weighting function is applied to image data for each gradient echo such as MR data (e.g., k-space data) or magnitude images associated with each gradient echo. A susceptibility weighted image is generated by combining the image data for each gradient echo based on at least the application of the weighting function.

Method and apparatus for generating T2* weighted magnetic resonance images

A system and method for detecting atherosclerotic plaque hemorrhage includes a controller programmed to apply a non-selective inversion recovery RF pulse to a region of interest, apply a plurality of encoding sequences to the region of interest to cause generation of a plurality of echoes during application of each encoding sequence. The controller is further programmed to acquire three dimensional MR data from the region of interest during generation of each of the plurality of echoes, identify a hemorrhage based on the three dimensional MR data, characterize a type of the hemorrhage, and reconstruct an image based on the three dimensional MR data, the image comprising the characterized hemorrhage.

Apparatus and method for detecting and classifying atherosclerotic plaque hemorrhage

A system and method of MR imaging is disclosed that includes reconstruction of MR images with uniform or homogeneous fat suppression. An imaging process is performed using partial asymmetric acquisitions in conjunction with zero-filling of k-space for dynamic contrast-enhanced imaging. Data acquisition is carried out in a relatively short period of time which reduces scan time, reduces the likelihood of subject discomfort and motion-induced artifacts, and increases patient throughput.

System and method for MR data acquisition with uniform fat suppression

An imaging technique is disclosed to reduce ringing artifacts from amplitude decay in MR multi-echo acquisition. A flip angle train is determined to match scan parameters for an MR scan to acquire MR data from a given tissue. Reducing the effects of amplitude decay in the echo signal reduces ringing artifacts and thereby improves image quality.

Method and apparatus of multi-echo MR data acquisition with non-discrete flip angle train

A multi-shot three-dimensional (3D) magnetic resonance imaging (MRI) data view-ordering strategy for uniform or variable density k-space sampling schemes is presented. The k-kplane is partitioned into multiple wedge-shaped 'blades' (or radial fan beams). The angular size of individual blades may be adjusted according to the desired number of views for each blade. Each blade includes views near the origin that contain low-frequency information about the imaged object such that views having the most desirable characteristics may be used to fill the central portions of k-space.

Method and apparatus for acquiring magnetic resonance imaging data

A magnetic resonance imaging (MRI) apparatus includes an MRI system having a plurality of gradient coils positioned about a bore of a magnet. An RF transceiver system and an RF switch are controlled by a pulse module to transmit and receive RF signals to and from an RF coil assembly to acquire MR images. The MRI apparatus also includes a computer programmed to calculate a cost for each point to be acquired in k-space, acquire MR data based on the calculated cost for each point, and generate an MR image using the acquired MR data.

System and method of angular elliptic centric view ordering for 3D MR acquisitions

A technique embodied in a method and apparatus is disclosed for acquiring MR images in 2D and 3D using a common pulse sequence switchable in real-time. The technique includes identifying a 3D imaging volume and applying a 3D pulse sequence having the slice encoding and rewinder gradients disabled in one dimension. The technique then allows localizing and monitoring by acquiring 2D MR data. When it is desirable to enter a 3D imaging mode, the slice encoding and rewinder gradients are re-enabled in the common pulse sequence for acquisition of 3D MR data.

Real-time localization monitoring, triggering, and acquisition of 3D MRI

A pulse sequence for time-of-flight (TOF) magnetic resonance angiography (MRA) includes a fatsat segment, a magnetization transfer segment, and a spatial saturation segment that are applied by an MR apparatus to acquire MR data for image reconstruction with improved image quality. The pulse sequence is constructed such that at the beginning of each iteration of the inner loop of a 3D acquisition, a fatsat pulse is applied. After the fatsat pulse, MR data is acquired in a series of imaging segments with well-suppressed fat signal. Effective fat suppression is achieved by sampling central k-space data first, before signal from fat relaxes back to a pre-saturation level. Each imaging segment is immediately preceded by one of a MT pulse or a spatial saturation pulse and immediately followed by the other one of the MT pulse or the spatial saturation pulse.

Apparatus and method of simultaneous fat suppression, magnetization transfer contrast, and spatial saturation for 3D time-of-flight imaging

An MR imaging apparatus is presented and includes a plurality of gradient coils positioned about a bore of a magnet to impress a polarizing magnetic field. An RF transceiver system and an RF switch are controlled by a pulse module to transmit and receive RF signals to and from an RF coil assembly to acquire MR images. The MR imaging apparatus also includes a computer programmed to apply a 3D imaging sequence and acquire MR data using a segmented acquisition. The computer is further programmed to reconstruct an image from the MR data that is substantially free of eddy current induced artifacts.

Method and apparatus for acquiring MR data with a segmented multi-shot radial fan beam encoding order

The present invention provides a system and method of MR scan prescription to achieve in a fast, simple, and effective manner the optimal peak excitation field strength for a given pulse shape and flip angle such that the minimum TR for the MR scan can be optimized and based on SAR constraints. The present invention provides a technique to obtain optimal Bparameters for an arbitrary shape and flip angle of an excitation pulse in real-time while satisfying SAR and/or RF hardware limits to determine the minimum achievable repetition time for a pulse sequence. The present invention is particularly applicable with breath-hold and cardiac imaging techniques that are carried out at relatively high field strengths.

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Waukesha, WI, United States of America

Anthony Tienhuan Vu