RICHARD L EHMAN, M.D.
Radiology at 1 St, Rochester, MN

2012027, Oct 25, 2012

Apr 23, 2012

13/453681

Richard L. Ehman - Rochester MN, US
Jun Chen - Rochester MN, US
Phillip J. Rossman - Rochester MN, US

A61B 5/055

600411

A flexible passive acoustic driver for use in an acoustic driver system which applies an oscillating stress to a subject undergoing a magnetic resonance elastography (MRE) examination which includes receiving acoustic pressure waves from an active driver through a tube and imparts pressure waves to a subject of an imaging procedure. In one configuration, the passive driver includes a flexible bag that forms the walls of an acoustic cavity, and a structure filling material located inside the acoustic cavity provides support for the flexible bag. The flexible bag conforms to the shape of the subject and may be held in place by an elastic band. The passive driver can have an integrated or detachable non-active push-on compartment which is rigid or semi-flexible to improve the human-driver mechanical coupling and the driver energy efficiency of converting acoustic pressure to mechanical vibration applied to a subject.

5952828, Sep 14, 1999

Aug 21, 1997

8/915828

Philip J. Rossman - Rochester MN
Raja Muthupillai - Rochester MN
Richard L. Ehman - Rochester MN

Mayo Foundation for Medical Education and Research - Rochester NY

G01V 300

324318

Devices for applying an oscillatory stress to an object positioned in a polarizing magnetic field of an NMR imaging system are used to perform MR elastography. The devices employ electrically energized coils which are connected to drive members and drive plates in a manner to provide various oscillatory forces to an object being imaged. The different oscillatory forces enable different body organs to be imaged using MR elastography methods.

6583624, Jun 24, 2003

Jun 15, 2000

09/595271

Raja Muthupillai - Rochester MN
Richard L. Ehman - Rochester MN

Mayo Foundation for Medical Education - Rochester MN

G01V 300

324309, 324307, 324306, 600410

A scan using an NMR imaging system is carried out while applying an oscillating voltage to the subject being imaged. The applied voltage may produce an electric field which moves charged particles in the subject, or it may produce a current that moves ions in the subject. An alternating magnetic field gradient synchronized with the applied voltage is employed in the NMR imaging pulse sequence to detect and measure synchronous spin motion throughout the field of view. The direction of the alternating gradient and/or the applied voltage may be changed to measure and image the properties of the subject.

5977770, Nov 2, 1999

Sep 25, 1996

8/719605

Richard L. Ehman - Rochester MN

Mayo Foundation for MEdical Education and Research - Rochester MN

G01V 300

324318

A scan using an NMR imaging system is carried out while applying an oscillating stress to the object being imaged. An alternating magnetic field gradient synchronized with the applied stress is employed in the NMR imaging pulse sequence to detect and measure synchronous spin motion throughout the field of view. The direction of the alternating gradient and/or the applied stress may be changed to measure and image the elastic properties of the object.

4937526, Jun 26, 1990

Jun 13, 1989

7/365632

Richard L. Ehman - Rochester MN
Joel P. Felmlee - Rochester MN

Mayo Foundation for Medical Education and Research - Rochester MN

G01R 3320

324309

An NMR data set which is acquired with applied phase encoding and read-out gradients is corrected to reduce motion artifacts and increase image sharpness. The acquired NMR data set is examined to detect bulk displacements of the object being imaged and phase displacements caused by motion. This information is employed to produce correction operators which are applied to the NMR image data set. One or more navigator signals may also be acquired during the scan to produce an NMR data set from which the corrective operators can more readily be derived.

6307369, Oct 23, 2001

Jul 12, 2000

9/614893

Joel P. Felmlee - Rochester MN
Kiaran P. McGee - Rochester MN
Richard L. Ehman - Rochester MN
Armando Manduca - Rochester MN

Mayo Foundation for Medical Education and Research - Rochester MN

G01V 300

324309

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.

5899858, May 4, 1999

Apr 9, 1998

9/058624

Raja Muthupillai - Decatur GA
Richard L. Ehman - Rochester MN

Mayo Foundation for Medical Education and Research - Rochester MN

A61B 5055

600410

The alternating magnetic field gradient used to sensitize an NMR signal to spin motion is modulated in amplitude with a window function to tailor it to the particular NMR measurement. In an MR elastography measurement, the gradient is a sinusoidal waveform having a frequency the same as an applied oscillatory stress, and the window function desensitizes the measurement to spin motions at other frequencies.

2012026, Oct 25, 2012

Apr 23, 2012

13/453646

Kevin J. Glaser - Rochester MN, US
Richard L. Ehman - Rochester MN, US
David A. Olsen - Rochester MN, US

G06K 9/36

382131

A dynamic magnetic resonance elastography (“MRE”) method for quantifying liver stiffness using intrinsic transient waveforms imparted on the liver by the beating heart is provided. The method includes synchronizing motion-encoding gradients in an MRE pulse sequence to the subject's cardiac cycle.

2010024, Sep 23, 2010

May 15, 2008

12/599721

Meng Yin - Rochester MN, US
Jayant A. Talwalkar - Rochester MN, US
Anthony J. Romano - Washington DC, US
Armando Manduca - Rochester MN, US
Richard L. Ehman - Rochester MN, US

A61B 5/021

600485

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.

2011006, Mar 10, 2011

May 1, 2009

12/990859

Richard L. Ehman - Rochester MN, US

A61B 5/055, A61B 5/00

600410, 600587

A method for detecting conditions in tissues that can lead to disease includes an in vivo measurement of the mechanical characteristics of the tissues using Magnetic Resonance Elastography (MRE). The deviation of mechanical characteristics such as tissue stiffness from a predetermined norm is determined and indicated on an image of the tissues.