Abstract: According to an aspect of the present inventive concept there is provided a method for quantifying isotropic diffusion and/or anisotropic diffusion in a sample, the method comprising: performing diffusion weighted magnetic resonance measurements on the sample using diffusion encoding magnetic gradient pulse sequences Gi=1. . . m, wherein each magnetic gradient pulse sequence Gi is generated such that a diffusion encoding tensor bi for the magnetic gradient pulse sequence Gi has one to three non-zero eigenvalues, where bi=Formula (I), qi(t) is proportional to Formula (II) and t is an echo time.
Type:
Grant
Filed:
February 10, 2015
Date of Patent:
February 13, 2018
Assignee:
CR DEVELOPMENT AB
Inventors:
Daniel Topgaard, Samo Lasic, Markus Nilsson
Abstract: The present invention describes a method for magnetic resonance (MR) and/or MR imaging, comprising acquisition of signals and MR images originating from a RF and gradient sequence causing isotropic diffusion weighting of signal attenuation, wherein the isotropic diffusion weighting is achieved by one time-dependent dephasing vector q(t) having an orientation, wherein the isotropic diffusion weighting is proportional to the trace of a diffusion tensor D, and wherein the orientation of the time-dependent dephasing vector q(t) is either varied discretely in more than three directions in total, or changed continuously, or changed in a combination of discretely and continuously during the gradient pulse sequence, 0?t?echo time, where t represents the time. The method may be performed during a single shot (single MR excitation).
Type:
Grant
Filed:
May 3, 2013
Date of Patent:
October 17, 2017
Assignee:
CR DEVELOPMENT AB
Inventors:
Daniel Topgaard, Samo Lasic, Markus Nilsson
Abstract: The present invention discloses a method for magnetic resonance (MR) imaging comprising: acquiring at least two MR images with different motion-weighting originating from a RF and gradient pulse sequence causing signal attenuation from diffusion but not flow (flow-compensated data); acquiring at least two MR images with different motion-weighting originating from a RF and gradient pulse sequence causing signal attenuation from diffusion and flow (non-compensated data); performing a model fit to the flow-compensated and non-compensated data in which at least one of the adjustable parameters are constrained to be the same for both sets of data; and obtaining quantitative information on microscopic flow by extracting at least one parameter of the intravoxel incoherent motion (IVIM) effect from the model fit, said method being directed to diffusion-perfusion.
Abstract: The present invention refers to a method for magnetic resonance imaging or nuclear magnetic resonance spectroscopy comprising emitting a radio frequency and gradient pulse sequence towards an object being subjected to a magnetic field, wherein said object comprises a molecule having an atom with a nuclear spin differing from 0, encoding, detecting and acquiring a magnetic resonance signal from said object corresponding to said emitted radio frequency and gradient pulse sequence, wherein the radio frequency and gradient pulse sequence comprises a first weighting block, a mixing block with duration tm and a second weighting block, and wherein encoding, detecting and acquiring the magnetic resonance signal from said object is limited to initial decay of the signal intensity I with increasing strength of at least one of the first weighting block and the second weighting block, wherein the variation of the initial signal decay rate with tm is analysed to obtain the apparent exchange rate AXR.