Abstract: A method of MR imaging and spectroscopy to reduce artifacts occurring due to the motion of an object to be represented, wherein the object position is determined quasi-continuously during the runtime of the MR acquisition, which includes one or more partial acquisitions (TA), and wherein motion correction is performed, which comprises dynamic adaptation of the frequency and phase settings of the RF system of the tomograph and of the orientation and amplitudes of the gradients during the runtime of the MR acquisition according to the current object position. The motion correction is thereby applied during a signal weighting period, during a signal read-out period, or between and/or during the two stated periods and the adaptations for motion correction are performed without interrupting or slowing the temporal progression of the MR acquisition. In this way, artifacts due to motion of the object to be represented can be further reduced.
Type:
Grant
Filed:
April 16, 2012
Date of Patent:
August 11, 2015
Assignee:
Universitaetsklinikum Freiburg
Inventors:
Michael Herbst, Maxim Zaitsev, Julian Maclaren, Matthias Weigel
Abstract: A method includes the acts of acquiring a blade of k-space calibration data; acquiring a set of T1-weighted k-space imaging data, the set of T1-weighted k-space imaging data having blades of undersampled k-space data rotated about a section of k-space. Each blade of undersampled k-space data includes first data points having acquired data and second data points that are missing data. The method also includes generating a set of reconstruction weights for the blades of undersampled k-space data using the blade of k-space calibration data; synthesizing k-space data for at least a portion of the second data points using the set of reconstruction weights; and generating a T1-weighted image using the T1-weighted k-space imaging data and the synthesized k-space data.
Type:
Grant
Filed:
April 18, 2012
Date of Patent:
August 11, 2015
Assignee:
GENERAL ELECTRIC COMPANY
Inventors:
James Hartman Holmes, Jean Helen Brittain, Reed Frederick Busse, Ajeetkumar Gaddipati, Xiaoli Zhao, Philip James Beatty, Zhiqiang Li, Howard Andrew Rowley
Abstract: Example apparatus and methods order projections in a 3D MRI acquisition to achieve improved equidistant spacing or to achieve improved adherence to a target distribution. The equidistant or target spacing may exist in k-space and/or in kt-space. In one embodiment, the improved equidistant spacing is a substantially uniform spacing. The substantially uniform spacing may be achieved using a modification of a charge repulsion analysis that treats points of projections that intersect the surface of a 3D volume to be imaged as point charges distributed on the 3D volume. In another embodiment, the target spacing may be uniform, non-uniform, uniform in parts and non-uniform in other parts, and other combinations.
Abstract: In a method for optimization of a flow coding with switching of an additional bipolar dephasing gradient pair, used in a magnetic resonance (MR) phase contrast angiography, the strength of the flow coding is selected depending on the flow velocity in the vessels that should be depicted. MR signals of an examination region are acquired with continuously running overview measurements, with an operator-selected flow coding strength. After the selected flow coding strength is adopted automatically for the next measurement of the continuously running overview measurements, and two partial measurements with different flow codings are implemented for each selected strength and a phase difference image from the two partial measurements is calculated and depicted in real time, and the selected flow coding strength is automatically adopted for the MR phase contrast angiography.