Norbert J Pelc

6353752, Mar 5, 2002

May 14, 1999

09/312027

Bruno Madore - Redwood City CA
Norbert J. Pelc - Los Altos CA

Board of Trustees of the Leland Standford Junior University - Palo Alto CA

A61B 5055

600410, 324307, 324309

In some dynamic applications of MRI, only a part of the field-of-view (FOV) actually undergoes dynamic changes. A class of methods, called reduced-FOV (rFOV) methods, convert the knowledge that some part of the FOV is static or not very dynamic into an increase in temporal resolution for the dynamic part, or into a reduction in the scan time. Although cardiac imaging is an important example of an imaging situation where changes are concentrated into a fraction of the FOV, the rFOV methods developed up to now are not compatible with one of the most common cardiac sequences, the so-called retrospective cine method. The present work is a rFOV method designed to be compatible with cine imaging. An increase by a factor n in temporal resolution or a decrease by n in scan time is obtained in the case where only one n of the FOV is dynamic (the rest being considered static). Results are presented for both Cartesian and spiral imaging.

4706026, Nov 10, 1987

Aug 16, 1985

6/766842

Norbert J. Pelc - Wauwatosa WI
Gary H. Glover - Waukesha WI

General Electric Company - Milwaukee WI

G01R 3320

324309

A method for reducing image artifacts due to periodic motion of a subject undergoing examination by nuclear magnetic resoance (NMR) techniques includes the acquisition of scan data for imaging the object. The scan data is composed of a number of views. The acquisition of each view includes the generation of an NMR signal and the application of a magnetic gradient along at least one dimensional axis of the object. The magnetic field gradient is characterized by a parameter value (e. g. , amplitude or direction) adjustable from view to view to encode spatial information into the NMR signal. The method includes the step of selecting the value of the adjustable parameter value for each view. A view order is then selected so as to attempt to obtain a predetermined relationship between the object motion and the adjustable parameter of the magnetic field gradient. The relationship is chosen to minimize artifacts in the reconstructed image.

6144873, Nov 7, 2000

Apr 17, 1998

9/062295

Bruno Madore - Redwood City CA
Gary H. Glover - Stanford CA
Norbert J. Pelc - Los Altos CA

Board of Trustees of The Leland Stanford Junior University - Palo Alto CA

A61B 5055

600410

MRI is used to monitor the time behavior or an organ of interest. Images of such organ may change in time due to physiological motion, and/or due to contrast-agent accumulation. Dynamic applications generally involve acquiring data in a k-t space, which contains both temporal and spatial information. In some dynamic applications, the t axis of the k-t space is not densely filled with information. A method is introduced which can transfer information from the k axes to the t axis, allowing a denser, smaller k-t space to be acquired, and leading to significant reductions in the acquisition time of the temporal frames. Results are presented for cardiac imaging and functional MRI (fMRI). In the case of cardiac imaging, the present method is shown to reduce the data requirement by nearly a factor two. In the case of fMRI, reductions by as much as a factor six can be obtained.

5469486, Nov 21, 1995

Nov 8, 1993

8/151456

Hui Hu - Waukesha WI
Norbert J. Pelc - Los Altos CA
Armin H. Pfoh - New Berlin WI

General Electric Company - Waukesha WI

A61B 603
G01N 23083

378 4

An x-ray computed tomography system for helically scanning a patient translates the patient as projections of the patient at various beam angles are obtained. The projection data are weighted prior to reconstruction to account for multiply measured projection data and the deviation of the cone beam from a parallel beam approximation.

4603428, Jul 29, 1986

Jan 4, 1985

6/688979

John M. Sandrik - Wauwatosa WI
Norbert J. Pelc - Wauwatosa WI

General Electric Company - Schenectady NY

G03C 146
G03B 4202

378174

X-ray energy-difference images are obtained simultaneously by exposing a body to a broad energy spectrum x-ray beam while a radiographic film package is disposed between front and rear x-ray intensifying screens. The film package has two superimposed films with a light-opaque sheet between them. The front screen, on which the polyenergetic image beam emerging from the body is incident, is excited to luminescence by x-ray photons predominantly in one energy band and the rear screen is excited predominantly by photons in another band. The light opaque sheet preferably contains x-ray filter material for additional filtering of photons to increase the fraction of photons at said other band to which the rear screen is sensitive. A shadowgraph of a marker is formed on the film emulsions during x-ray exposure to aid in matching congruent picture elements on each film when the developed films are being read out to obtain signals corresponding to their intensities. Notches in the edges of the films and sheet serve as a code for indicating the type of screens with which the package can be used.

5093620, Mar 3, 1992

Aug 9, 1990

7/564945

Norbert J. Pelc - Los Altos CA
Gary H. Glover - Menlo Park CA

General Electric - Milwaukee WI

G01R 3320

324306

In an NMR system a method for measuring the motion of spins moving in an unknown direction includes four separate measurement cycles. The first cycle establishes a reference phase and each of the subsequent three measurement cycles includes motion encoding field gradients for measuring motion along respective pairs of Cartesian coordinates. All four measurements are combined to calculate each of the motion components along x, y and z coordinates.

5697370, Dec 16, 1997

Jan 17, 1996

8/587409

Norbert J. Pelc - Los Altos CA
Stephen G. Hushek - Brookfield WI

General Electric Company - Waukesha WI
Board of Trustees of the Leland Stanford Jr. University - Stanford CA

A61B 5055

1286532

A method is described for increasing the temporal resolution of MR fluoroscopy procedures. A central portion of the image requiring a higher temporal resolution is updated more frequently using less-than-complete newly acquired NMR data. A running average of the signals produced by peripheral structures is used to form the periphery of the image and to remove artifact-producing data from the less-than-complete NMR data.

4653013, Mar 24, 1987

Nov 19, 1984

6/672609

Arthur K. Collins - Waukesha WI
Norbert J. Pelc - Wauwatosa WI
Susan T. Wallenslager - Waukesha WI

General Electric Company - Milwaukee WI

G01D 1514

364518

The values of pixels in a new image matrix are obtained by mapping pixels of the new matrix in the old matrix and then using polynomial interpolation of a plurality of values of pixels in the old matrix to obtain values of interim pixels in the new matrix and then using polynomial interpolation of a plurality of interim values to obtain final values of pixels in the new matrix. A precalculated table of weighting coefficients based on offset of a new pixel from an adjacent old pixel is used to expedite the polynomial interpolation.