University of Utah Research Foundation

Wisconsin Alumni Research Foundation

James A Sorenson

Robert A Kruger

James A Nelson

Giles E Santyr

Mark M Bahn

Yi-Hsuan Kao

Ethan J Fairbanks

Oscillations in longitudinal magnetization as a spin system recovers from a 180.degree. inversion pulse in the presence of off-resonance spin-locking pulse are eliminated by tipping the magnetization prior to spin-locking by an amount .theta. and tipping it back by an amount -.theta. after spin-locking. A one-shot measurement of off-resonance relaxation constant T.sub.1.rho. employs the .+-..theta. pulses to improve accuracy and a T.sub.1.rho. enhanced imaging sequence employs the .+-..theta. pulses to reduce artifacts.

Suppression of oscillations in NMR measurement using off-resonance

A dual echo magnetic resonance imaging system produces two registered images of a patient in which the images have different contrast relationships between different tissue types. A two dimensional feature space histogram of the two images is produced and a separate centroid is located in the feature space histogram for each one of a pair of tissue types. A Cartesian coordinate system is defined in the feature space so that one axis of the system passes through the two centroids. Vector decomposition is employed to project each image element data point in the feature space onto a point on the one axis. The fractional quantity of each tissue type present in the image element is determined based upon the Euclidean distances from that axis point to the respective centroids. The fractional quantity is calculated for each element in the original images to form a pair of tissue images. The elements of a tissue image are processed to measure the amount of that tissue type in the imaged portion of the patient.

Method for segmenting features in an image

Method and apparatus for producing an enhanced radiographic image from a developed radiograph. The apparatus includes a support structure for supporting the radiograph in a stacked relationship with the radiographic film, a light source positioned in close proximity to the radiograph for directing a beam of light at the radiograph to sweep generally in a line from one side to the other, and an elongate light sensor aligned with the line of travel of the light beam to sense and signal the intensity of the light passing through the radiograph and film. A controller responds to the signals produced by the light sensor by producing light control signals which are applied to the light source to vary the intensity and/or the scanning speed of the light beam. As the scanning takes place, the support structure moves transversely of the line of travel of the light beam so that the radiograph is scanned by light substantially over its length and width. As a result, an enhanced radiographic image is created by reducing the density of the high density portions of the radiograph, and increasing the density of the low density portions. Also, the light beam width or spot size may be varied to further improve the detail enhancement of the radiograph.

Apparatus and method for enhancing radiographs and the like

A slit collimation system includes a signal absorptive plate assembly having a narrow slit located between a source of x-ray radiation and an object such as a patient undergoing a diagnostic imaging procedure. An image intensifier tube is located on the other side of the object and is optically coupled to an imaging device such as a television camera. The camera generates an image of the slit as well as x-ray scatter in succeeding TV frames as the slit is scanned, i.e. moved linearly over the object. Each TV frame is digitized and fed into a recursive loop including a digital memory adapted to store a complete TV frame which is comprised of an array of pixels. Pixel intensity values of successive frames are logically combined so that the video information in the shadow of the slit is accepted while the remainder of the video information which includes scatter and noise is rejected resulting in an x-ray image which is free of scatter.

Electronic slit collimation

A first x-ray film is made of an object which is of the type where the image on the film has underexposed portions with low optical contrast. An optical mask film is made from the first x-ray film by transferring the image of the object from the first x-ray film onto a photographically positive print film with duplicating means and an optical blurring means to produce an optically blurred positive image reflective of the object with exposed portions related to the underexposed portions of the first x-ray film. A second x-ray film is made of the object with the optical mask film positioned and registered with respect to the second x-ray film and with respect to the image reflective of the object to be formed on the second x-ray film by the x-ray means, to produce an optically masked image reflective of the object with the underexposed portions of the first x-ray film on the second x-ray film more exposed and with higher optical contrast with respect to the first x-ray film.

Growing community of inventors

Madison, WI, United States of America

James A Sorenson