摘要:
An MRI image is corrected for motion artifacts using an iterative, autocorrection process in which corrections are tried and the quality of the resulting reconstructed image is measured. Different metrics for evaluating image quality are used during the autocorrection process to take advantage of their different attributes.
摘要:
A three-dimensional image data set is acquired with an MRI system and autocorrected to reduce artifacts caused by subject motion during image acquisition. Correction for motion along one or two axes is performed by selecting a 2D slice of data and autocorrecting it to produce phase corrections that are then made to the entire 3D image data set. This may be repeated by autocorrecting an additional 2D slice perpendicular to the first 2D slice to produce phase corrections for the 3D image data set for motion along the third axis.
摘要:
An MRI image acquired with a phase-array coil is corrected for motion artifacts using an iterative, autocorrection process in which corrections are tried and the quality of the resulting reconstructed image is measured. In one embodiment autocorrections are calculated for the data acquired with one coil element and the same corrections are made to data acquired with the other coil elements. In another embodiment autocorrections are calculated separately for the data acquired with each coil element. In either embodiment, the separate corrected images are combined to form the output image.
摘要:
A system and method for analyzing a subject using a magnetic resonance imaging (MRI) system is provided. The technique includes positioning a subject within the MRI system and coupling a driver to the subject to impart vibrational energy to the subject. The technique further includes using the MRI system and in coordination with operation of the driver, acquiring medical imaging data from the subject's brain and deriving stiffness information of the subject's brain from the medical imaging data. A report, such as an image, can be provided indicating the stiffness information of the subject's brain relative to baseline stiffness information to indicate a status of the subject with respect to a neurodegenerative disease.
摘要:
Navigator echo signals are acquired during an MRI scan in which image data is acquired. The navigator echo signals are used to estimate an initial correction of the acquired image data for patient motion during the scan. The initially corrected image data is then autocorrected in an iterative process which measures image quality and makes further corrections to the image data until the measured image quality is within tolerance.
摘要:
A method for magnetic resonance elastography (“MRE”) is described, in which an MRE inversion that accounts for waves propagating in a finite, bounded media is employed. A vibratory motion is induced in a subject and MRE is performed to measure one or more components of the resulting displacement produced in the subject. This displacement data is subsequently filtered to provide a more accurate and computationally efficient method of inversion. Wave equations based on the geometry of the bounded media are then utilized to calculate the material properties of the subject. Such a method allows for the performance of MRE on tissues such as the heart, eye, bladder, and prostate with more accurate results.
摘要:
The shear stiffness of a subject's spleen is measured using elastography techniques such as ultrasound elastography or a magnetic resonance elastography (MRE) acquisition with an MRI system. A relationship between splenic shear stiffness and portal venous blood pressure is modeled and is used to calculate portal venous blood pressure non-invasively from the measured splenic shear stiffness.
摘要:
An MRI image is corrected for motion artifacts using an iterative, autocorrection process in which corrections are tried and the quality of the resulting reconstructed image is measured. Metrics based on the gradient of the reconstructed image are employed to measure image quality.
摘要:
A method for calculating a mechanical property of a material using a magnetic resonance imaging (“MRI”) system is provided. The method is particularly robust to image data having low signal-to-noise ratio (“SNR”). An MRI system is used to acquire magnetic resonance elastography (“MRE”) data from a subject containing the material. Exemplary materials include lung tissue. Images are reconstructed from the MRE data and used to produce a wave image from which a spatial frequency spectrum is produced. A principal frequency of the spatial frequency spectrum is produced and used to calculate a mechanical property of the material. For example, shear stiffness may be calculated.
摘要:
The shear stiffness of a subject's spleen is measured using elastography techniques such as ultrasound elastography or a magnetic resonance elastography (MRE) acquisition with an MRI system. A relationship between splenic shear stiffness and portal venous blood pressure is modeled and is used to calculate portal venous blood pressure non-invasively from the measured splenic shear stiffness.