Patents by Inventor Stephen J. Riederer

Stephen J. Riederer has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20120081118
    Abstract: A radio frequency (RF) coil array configured for use with a magnetic resonance imaging (MRI) system and that includes coil elements with a skewed coil geometry is provided. The coil elements are skewed with respect to a given direction, such as the slice-encoding direction of an MRI system, such that a variation in spatial sensitivity along that direction is provided. This spatial sensitivity variation allows for parallel imaging acceleration along the direction of the variation, which provides improved performance over standard rectangular geometries in performing acceleration along the slice-encode direction for three-dimensional axial acquisitions.
    Type: Application
    Filed: September 27, 2011
    Publication date: April 5, 2012
    Inventors: Ek T. Tan, Stephen J. Riederer
  • Publication number: 20110194746
    Abstract: A method for producing an image indicative of the time-of-arrival of contrast agent in a tissue of interest is provided. More specifically, a time-of-arrival is calculated for each voxel location in a time series of magnetic resonance (MR) images. The accuracy of the time-of-arrival presentation is enhanced when the underlying MR image acquisition is consistent, is done with compact sampling of the k-space center, has minimal temporal footprint for each image, and has a negligible anticipation artifact. The time-of-arrival presentation can be further enhanced by the suppression of signals from background tissue by using, for example, thresholding or by conversion of the time-of-arrival information into a color scale.
    Type: Application
    Filed: September 28, 2009
    Publication date: August 11, 2011
    Inventor: Stephen J. Riederer
  • Publication number: 20110184273
    Abstract: The present invention provides an MRI system for imaging of a subject over extended field-of-view (FOV) that employs both accelerated data acquisition, which is employed while the subject is stationary, and traditional data acquisition, which is employed while the subject is moved through the MRI system. This approach provides improved spatial resolution and time efficiency compared to traditional extended FOV imaging techniques.
    Type: Application
    Filed: September 29, 2009
    Publication date: July 28, 2011
    Inventor: Stephen J. Riederer
  • Publication number: 20110109314
    Abstract: The present invention is a coil array for an MRI system that is designed to improve 2D accelerated imaging of an object having significantly different fields of view in two phase-encoding directions. This is achieved by having a first set of coil elements whose sizes are tuned to optimize acceleration along a first phase-encoding direction and a second set of coil elements whose sizes are tuned to optimize acceleration along a second-phase encoding direction. Images acquired in accordance with the present invention exhibit improved signal to noise ratio at a given acceleration factor when compared to images acquired using a traditional MR coil array.
    Type: Application
    Filed: January 11, 2010
    Publication date: May 12, 2011
    Inventors: Stephen J. Riederer, Clifton R. Haider, Phillip J. Rossman
  • Publication number: 20100182008
    Abstract: An improved self-calibration method for accelerated magnetic resonance imaging (MRI) using inversion recovery pulse sequences allows calibration data for determining coil sensitivity profiles to be acquired by employing a calibration pulse sequence within the delay time of an inversion recovery pulse sequence. The calibration pulse sequence includes a constrained number of calibration pulses having small flip angles so that acceptable longitudinal magnetization recovery is provided.
    Type: Application
    Filed: January 20, 2010
    Publication date: July 22, 2010
    Inventors: Ek Tsoon Tan, Stephen J. Riederer
  • Patent number: 7610076
    Abstract: MRA data is acquired from an extended field of view by translating the patient through the bore of the MRI system as three-dimensional MRA data sets are acquired and time-resolved images reconstructed. The leading edge of a contrast bolus can be tracked in these images and parameters such as bolus velocity and bolus arrival time can be calculated to provide functional information in addition to anatomical information. Temporal resolution is improved by undersampling peripheral k-space and sampling the center of k-space at a higher temporal rate.
    Type: Grant
    Filed: March 5, 2004
    Date of Patent: October 27, 2009
    Assignee: Mayo Foundation for Medical Education and Research
    Inventors: Stephen J. Riederer, David G. Kruger, Ananth J. Madhuranthakam
  • Publication number: 20090238430
    Abstract: An MRI system produces a three-dimensional image by acquiring NMR signals that fully sample a central region of k-space and partially sample peripheral region of k-space. Specifically, k-space is arranged as a three-dimensional (3D) Cartesian grid of points that is divided into a central region of k-space and a peripheral region of k-space. Points are selected in k-space within a plurality of radial vanes that extend radially outward from the central region of k-space through the peripheral region of k-space as viewed in a plane sampled by two phase encoding gradients to create a plurality of gaps between the radial vanes that is substantially a factor of N times greater in area than the radial vanes. Using an MRI system having arrays of RF receiver coils, NMR signals are acquired from a subject to fully sample the central region of the 3D k-space and undersample the peripheral region of k-space by only sampling k-space within the plurality of radial vanes.
    Type: Application
    Filed: May 4, 2009
    Publication date: September 24, 2009
    Inventors: Clifton R. Haider, Stephen J. Riederer
  • Patent number: 7437188
    Abstract: MRA data is acquired from a large, longitudinal region of interest by translating the patient through the more limited longitudinal FOV of the MRI system as a three-dimensional MRA data set are acquired. Patient table movement is controlled to track a bolus of contrast agent as it passes through the region of interest. A seamless image of the entire region of interest is reconstructed after correcting the phase of acquired MRA data to reduce the signal falloff at abutting longitudinal FOVs. Phase corrections are determined from the central DC views acquired during the scan.
    Type: Grant
    Filed: February 18, 2005
    Date of Patent: October 14, 2008
    Assignee: Mayo Foundation for Medical Education and Research
    Inventors: Daivd G. Kruger, Stephen J. Riederer, Phillip J. Rossman
  • Publication number: 20080187196
    Abstract: An MRI system produces a three-dimensional image by acquiring NMR signals that fully sample a central region of k-space and partially sample peripheral k-space as a set of asymmetric radial sectors. The NMR signals are acquired with a plurality of receive channels and coils. An image is reconstructed using a homodyne reconstruction combined with SENSE processing.
    Type: Application
    Filed: May 2, 2006
    Publication date: August 7, 2008
    Inventors: Houchun H. Hu, Ananth J. Madhuranthakam, Stephen J. Riederer
  • Patent number: 7346383
    Abstract: MRA data is acquired from a large region of interest by translating the patient through the bore of the MRI system as a three-dimensional MRA data set are acquired. The pulse sequence is altered during the scan to change the lateral FOVL of the acquired image to better match the size of the region of interest along its length. Patient table movement is controlled to track a bolus of contrast agent as it passes through the region of interest. A seamless image of the entire region of interest is reconstructed after the acquired data is resampled in regions where the lateral FOVL is altered.
    Type: Grant
    Filed: December 22, 2004
    Date of Patent: March 18, 2008
    Assignee: Mayo Foundation for Medical Education and Research
    Inventors: Stephen J. Riederer, Houchun H. Hu, David G. Kruger
  • Patent number: 6967479
    Abstract: The present invention includes a method and apparatus to correct for gradient field distortions. The invention is particularly applicable in moving table imaging where a single extended image is desirable. The invention includes acquiring MR data in motion in the presence of gradient non-linearities, transforming the MR data acquired into the image domain, and then applying a warping correction function to the transformed MR data. The warp-corrected MR data is then corrected for motion induced during the MR acquisition. The data may be acquired point-by-point, line-by-line, or another sub-portion of the entire MR data acquired, and processed to minimize the amount of motion correction needed. Based on table velocity or acquisition sequence applied, the data is partitioned based on a common motion correction factor, and after correcting for motion, the data is accumulated to build up a final image.
    Type: Grant
    Filed: January 7, 2004
    Date of Patent: November 22, 2005
    Assignees: GE Medical Systems Global Technology Co., LLC, Mayo Clinic
    Inventors: Jason A. Polzin, Stephen J. Riederer, David G. Kruger
  • Patent number: 6912415
    Abstract: MRA data is acquired from a large region of interest by translating the patient through the bore of the MRI system as a three-dimensional MRA data set are acquired. Patient table movement is controlled to track a bolus of contrast agent as it passes through the region of interest. Fluoroscopic images may be acquired during the scan to enable accurate bolus tracking. A seamless image of the entire region of interest is reconstructed.
    Type: Grant
    Filed: November 26, 2001
    Date of Patent: June 28, 2005
    Assignee: Mayo Foundation for Medical Education and Research
    Inventors: David G. Kruger, Stephen J. Riederer
  • Patent number: 6853193
    Abstract: A method for the simultaneous acquisition of data from two transmit/receive “birdcage” coils is described. The coils are individually RF shielded, making them insensitive to signals generated outside of each coil's volume. Each coil is designed for imaging one leg, and when used together, both legs are imaged simultaneously. In coronal or axial orientations, a small FOV around each leg can be imaged without aliasing. This results in a two-fold scan time reduction compared to a large FOV acquisition with the same spatial resolution.
    Type: Grant
    Filed: May 8, 2003
    Date of Patent: February 8, 2005
    Assignee: Mayo Foundation for Medical Education and Research
    Inventors: Stephen J. Riederer, David G. Kruger, Phillip J. Rossman
  • Publication number: 20040210129
    Abstract: MRA data is acquired from an extended field of view by translating the patient through the bore of the MRI system as three-dimensional MRA data sets are acquired and time-resolved images reconstructed. The leading edge of a contrast bolus can be tracked in these images and parameters such as bolus velocity and bolus arrival time can be calculated to provide functional information in addition to anatomical information. Temporal resolution is improved by undersampling peripheral k-space and sampling the center of k-space at a higher temporal rate.
    Type: Application
    Filed: March 5, 2004
    Publication date: October 21, 2004
    Inventors: Stephen J. Riederer, David G. Kruger, Ananth J. Madhuranthakam
  • Publication number: 20040140804
    Abstract: The present invention includes a method and apparatus to correct for gradient field distortions. The invention is particularly applicable in moving table imaging where a single extended image is desirable. The invention includes acquiring MR data in motion in the presence of gradient non-linearities, transforming the MR data acquired into the image domain, and then applying a warping correction function to the transformed MR data. The warp-corrected MR data is then corrected for motion induced during the MR acquisition. The data may be acquired point-by-point, line-by-line, or another sub-portion of the entire MR data acquired, and processed to minimize the amount of motion correction needed. Based on table velocity or acquisition sequence applied, the data is partitioned based on a common motion correction factor, and after correcting for motion, the data is accumulated to build up a final image.
    Type: Application
    Filed: January 7, 2004
    Publication date: July 22, 2004
    Inventors: Jason A. Polzin, Stephen J. Riederer, David G. Kruger
  • Patent number: 6707300
    Abstract: The present invention includes a method and apparatus to correct for gradient field distortions. The invention is particularly applicable in moving table imaging where a single extended image is desirable. The invention includes acquiring MR data in motion in the presence of gradient non-linearities, transforming the MR data acquired into the image domain, and then applying a warping correction function to the transformed MR data. The warp-corrected MR data is then corrected for motion induced during the MR acquisition. The data may be acquired point-by-point, line-by-line, or another sub-portion of the entire MR data acquired, and processed to minimize the amount of motion correction needed. Based on table velocity or acquisition sequence applied, the data is partitioned based on a common motion correction factor, and after correcting for motion, the data is accumulated to build up a final image.
    Type: Grant
    Filed: May 17, 2002
    Date of Patent: March 16, 2004
    Assignees: GE Medical Systems Global Technology Co., LLC, Mayo Clinic
    Inventors: Jason A. Polzin, Stephen J. Riederer, David G. Kruger
  • Publication number: 20030214295
    Abstract: The present invention includes a method and apparatus to correct for gradient field distortions. The invention is particularly applicable in moving table imaging where a single extended image is desirable. The invention includes acquiring MR data in motion in the presence of gradient non-linearities, transforming the MR data acquired into the image domain, and then applying a warping correction function to the transformed MR data. The warp-corrected MR data is then corrected for motion induced during the MR acquisition. The data may be acquired point-by-point, line-by-line, or another sub-portion of the entire MR data acquired, and processed to minimize the amount of motion correction needed. Based on table velocity or acquisition sequence applied, the data is partitioned based on a common motion correction factor, and after correcting for motion, the data is accumulated to build up a final image.
    Type: Application
    Filed: May 17, 2002
    Publication date: November 20, 2003
    Inventors: Jason A. Polzin, Stephen J. Riederer, David G. Kruger
  • Publication number: 20030210048
    Abstract: A method for the simultaneous acquisition of data from two transmit/receive “birdcage” coils is described. The coils are individually RF shielded, making them insensitive to signals generated outside of each coil's volume. Each coil is designed for imaging one leg, and when used together, both legs are imaged simultaneously. In coronal or axial orientations, a small FOV around each leg can be imaged without aliasing. This results in a two-fold scan time reduction compared to a large FOV acquisition with the same spatial resolution.
    Type: Application
    Filed: May 8, 2003
    Publication date: November 13, 2003
    Inventors: Stephen J. Riederer, David G. Kruger, Phillip J. Rossman
  • Publication number: 20020173715
    Abstract: MRA data is acquired from a large region of interest by translating the patient through the bore of the MRI system as a three-dimensional MRA data set are acquired. Patient table movement is controlled to track a bolus of contrast agent as it passes through the region of interest. Fluoroscopic images may be acquired during the scan to enable accurate bolus tracking. A seamless image of the entire region of interest is reconstructed.
    Type: Application
    Filed: November 26, 2001
    Publication date: November 21, 2002
    Inventors: David G. Kruger, Stephen J. Riederer
  • Patent number: 6472872
    Abstract: An fMRI scan is performed with an MRI system in which a series of single shot EPI pulse sequences are performed to acquire a series of images. A shim navigator pulse sequence is interleaved with the EPI pulse sequence to acquire data with which the MRI system polarizing magnetic field can be measured. Measured changes in the polarizing field during the scan are employed to calculate corrective changes in the scan parameters that offset phase errors caused by changes in the polarizing field.
    Type: Grant
    Filed: June 29, 2001
    Date of Patent: October 29, 2002
    Assignee: Mayo Foundation for Medical Education and Research
    Inventors: Clifford R. Jack, Jr., Heidi A. Ward, Stephen J. Riederer