Wisconsin Alumni Research Foundation

Other

University of Illinois

Diego Hernando

Scott Brian Reeder

Xiaoke Wang

Bradley P Sutton

Samir Sharma

Anh Tu Van

Valentina Taviani

Yuxin Zhang

A system and method are provided for acquiring a plurality of differently-weighted images of a subject using a single pulse sequence. The method includes determining imaging parameters for a pulse sequence that includes a diffusion weighted module and an anatomical imaging module. The imaging parameters include at least a repetition time (TR), a mixing time (TM), an echo time (TE), and a diffusion weighting b-value, with at least two different values of at least TM, TE, and diffusion weighting b-value. The method also includes performing a pulse sequence using the imaging parameters to acquire MR image data from a subject. The different values of at least TM, TE, and diffusing weighting b-value are used to acquire the MR image data. Furthermore, the method includes reconstructing, from the MR image data, a plurality of images of the subject, including at least a T1-weighted image, a T2-weighted image, and a diffusion-weighted image.

System and method for stimulated echo based mapping (STEM) using magnetic resonance imaging (MRI)

Systems and methods for correcting phase errors in chemical shift encoded data are described. The technique is self-calibrated, without the need for specialized calibration data, and therefore may enable fat and iron quantification using data from clinical and research sites that do not have specialized pulse sequences.

Method for correcting phase offsets in quantitative chemical shift encoded magnetic resonance imaging

A phantom for use with magnetic resonance imaging ('MRI') and, in particular, for calibrating quantitative diffusion MRI is provided. In general, the phantom includes a solution composed of a solvent that has diffusivity value higher than that of water, and a solute that when added to the solvent reduces the diffusivity of the solution. By varying the combined concentration of the solvent and solute, the diffusivity of the solution can be controlled to fall within a range of diffusivity values found in biological tissues in a variety of different physiological conditions or tissue environments.

Phantom for quantitative diffusion magnetic resonance imaging

A system and method are provided for determining B1 inhomogeneities or creating a T1 map of a subject using a magnetic resonance imaging (MRI) system that is corrected for an influence of a presence of fat and a presence of iron in the subject on T1 weighting. The method includes controlling the MRI system using a single pulse sequence to acquire, from the subject, a plurality of datasets with varied T1 weighting created by varying at least one of a repetition time (TR) and a flip angle (FA) for repetitions of the single pulse sequence. The method also includes using an MR signal model and the plurality of datasets, estimating B1 inhomogeneities or generating a T1 map of the subject that is corrected for an influence of a presence of fat and a presence of iron in the subject on T1 weighting in the plurality of datasets.

System and method for confounder-corrected T1 measures using MRI

Phantoms for use in magnetic resonance imaging ('MRI') and, in particular, for use in quantifying fat concentration, iron concentration, or both, are provided. The phantoms are constructed to accurately reflect in vivo magnetic resonance signal behavior in the presence of both fat and iron. The phantoms described here can thus be used for phantom-based validation of MRI techniques for the joint quantification of fat and iron concentration, for phantom-based validation of MRI techniques for quantifying fat concentration in the presence of iron overload, and for phantom-based validation of MRI techniques for quantifying iron concentration given the confounding presence of fat.

Phantom for iron and fat quantification magnetic resonance imaging

A system and method for assessing magnetic susceptibility of tissue of a subject using a magnetic resonance imaging (MRI) system to acquire chemical-shift-encoded, water-fat separated data. From the water-fat separated data, separated water and fat images, as well as a magnetic field inhomogeneity map are used to estimate the magnetic susceptibility within tissue.

System and method for assessing susceptibility of tissue using magnetic resonance imaging

A method for producing an image of a subject with a magnetic resonance imaging ('MRI') system, in which relative signal contributions from a plurality of different chemical species are separated, is provided. A plurality of different echo signals occurring at a respective plurality of different echo times are acquired with the MRI system and a signal model that accounts for relative signal components for each of a plurality of different chemical species is formed for each echo signal. Those echo signals containing errors, such as phase errors, magnitude errors, or errors indicative of a corrupted echo signal, are identified. The relative signal components for each of the plurality of different chemical species are then determined by fitting the echo signals with the signal model. Particularly, those echo signals identified as containing errors are fitted to the signal models in a manner that discards the error-containing information.

Method for error compensated chemical species signal separation with magnetic resonance imaging

Described here is a system and method for estimating apparent transverse relaxation rate, R*, while simultaneously performing chemical species separation (e.g., water-fat separation) using magnetic resonance imaging ('MRI'). A homodyne reconstruction of k-space datasets acquired using a partial k-space acquisition is used and the chemical species separation of the resultant images takes into account the spectral complexity of the chemical species in addition to magnetic resonance signal decay associated with transverse relaxation. Full resolution maps of R* are thus capable of being produced while also allowing for the production of images depicting the separated chemical species that are corrected for transverse relaxation associated signal decays.

[object Object]

A method for producing parametric maps using a magnetic resonance imaging (MRI) system is provided. The MRI system is used to acquire k-space data from a field-of-view. A series of images is reconstructed from the acquired k-space data, and a confidence map is produced using the k-space data. The confidence map depicts regions in the field-of-view that are affected by error sources. A parametric map is produced using the reconstructed series of images and the produced confidence map. Values in the parametric map associated with regions in the field-of-view depicted in the confidence map as being affected by error sources are not computed, thereby reducing errors in the parametric map.

System and method for magnetic resonance imaging parametric mapping using confidence maps

A method for correcting motion-induced phase errors in diffusion-weighted k-space data acquired with a magnetic resonance imaging (MRI) system is provided. The MRI system is directed to acquire the following data from an imaging volume: three-dimensional diffusion-weighted k-space data, three-dimensional diffusion-weighted navigator data, three-dimensional non-diffusion-weighted k-space data, and three-dimensional non-diffusion-weighted navigator data. Initial estimates of k-space shift values and a constant phase offset value are calculated using the three-dimensional diffusion-weighted navigator data and the three-dimensional non-diffusion-weighted navigator data. These initial k-space shift values and constant phase offset value are then updated by iteratively minimizing a cost function that relates the phase of the diffusion-weighted k-space data to the phase of the non-diffusion-weighted k-space data, as shifted by the initial k-space shift values and constant phase offset value. The diffusion-weighted k-space data is then corrected for motion-induced phase errors using the updated k-space shift values and constant phase offset value.

Method for correcting motion-induced phase errors in magnetic resonance imaging

A magnetic resonance imaging ('MRI') system and method for producing an image of a subject with the MRI system in which signal contributions of water and fat are separated are provided. A plurality of in-phase echoes formed at a plurality of different echo times are sampled to acquire k-space data. The in-phase echoes include signal contributions from water and fat that are in-phase with each other. The signal contributions from water and fat are then separated by fitting only those echo signals that are in-phase echo signals to a signal model that models a fat spectrum as including multiple resonance peaks. From these signal contributions, an image of the subject depicting a desired amount of signal contribution from water and a desired amount of signal contribution is produced.

System and method for magnetic resonance imaging water-fat separation with full dynamic range using in-phase images

A method for measuring transverse relaxation rate, R*, corrected for the presence of macroscopic magnetic field inhomogeneities with a magnetic resonance imaging (MRI) system is provided. The method accounts for additional signal decay that occurs as a result of macroscopic variations in the main magnetic field, B, of the MRI system, and also mitigates susceptibility-based errors and introduction of increased noise in the R* measurements. Image data are acquired by sampling multiple different echo signals occurring at respectively different echo times. A Bfield inhomogeneity map is estimated by fitting the acquired image data to an initial signal model. Using the estimated field map, a revised signal model that accounts for signal from multiple different chemical species and for signal decay resulting from macroscopic variations in the Bfield is formed. Corrected R* values for the different chemical species are then estimated by fitting the acquired image data to the revised signal model.

Growing community of inventors

Madison, WI, United States of America

Diego Hernando