Other

Image Analysis, Inc.

Ben A Arnold

Judd E Reed

Ping Xiang

Alan H Rowberg

A method automatically scores calcium in the aorta and other arteries of the body using calcium plaque definitions that include subject specific in vivo blood/muscle density measurements, subject specific voxel statistical parameters and 2D and 3D voxel connectivity criteria to automatically identify the plaques. The images are optionally calibrated with external phantoms or internal reference tissue. Aortic calcium is identified automatically without manual marking. Potential false plaques from bone are automatically excluded. A 3D coordinate system provides the specific coordinates of the detected plaques, which are displayed in a plaque map for follow-up exams or ease in plaque review.

Automated calcium scoring of the aorta

A method uses a computer and software to measure bone density and structure of the proximal femur of the hip from a volumetric set of images containing pixels representing x-ray attenuation of the subject which are acquired with three-dimensional X-ray imaging devices. The method automatically locates anatomical markers of the hip without operator interaction, automatically positions regions of interest (ROIs) for measurement, automatically determines bone density measures of the ROIs, and automatically reports the results for individual subjects. Bone density measurements of ROIs include the integral bone of the total hip and neck as well as trabecular bone. The method automatically identifies a three-dimensional region-of-interest (ROI) volume which includes the hip, determines a three-dimensional coordinate system referenced to the anatomy of the subject, analyzes the ROI volume to identify voxels in the volume which satisfy defined criteria, and determines a measure of bone structure.

Automatic method and system for measurements of bone density and structure of the hip from 3-D X-ray imaging devices

A method automatically detects and quantifies arterial plaque (hard plaque, soft plaque or both) in the coronary arteries of the heart from CT images. The method uses plaque definitions based on subject specific in vivo blood/muscle and fat density measurements, subject specific voxel statistical parameters and 2-D and 3-D voxel connectivity criteria to automatically identify the plaques. The locations of the major arteries are determined in a 3-D coordinate system; and the specific coordinates of the detected plaques are displayed in a plaque map for follow-up exams or ease in plaque review, editing and reporting the results.

Automatic detection and quantification of plaque in the coronary arteries of subjects from CT scans

A system and method enable calibration of CT scanners without using water phantoms. Tissue densities are expressed in either the Hounsfield Scale units (HU) referenced back to water or the proposed Gram Scale units (GU) with voxel intensities expressed in true density units. The fully automatic software-only method requires no interactions with the images. Routine calibration of CT scanners with water phantoms can be eliminated. The method further provides accurate calibrations that are patient, scanner, and scan specific and are repeatable over long time durations. The calibrations are based on the uniquely defined intensity of voxels with equal contributions of two tissues types. This calibration point is immune to the many variables found in ROI histogram measurements of mean, mode, SD or other measures of voxel intensities. The disclosed CT scanner system provides consistent CT image voxel intensities of the various tissues across a great variety of patients.

System and method for calibration of CT scanners and display of images in density units without the use of water phantoms

Calibration and reference samples with reduced cross-sectional areas encased within imaging tables or couch pads have low attenuation properties and provide patient comfort. The samples are stable and provide reproducible images without artifacts. The torso-length samples avoid positioning errors and misalignment. Sample density or mass calibration materials include calcium compounds representative of bone and calcifications, iodine compounds for contrast angiography, gadolinium compounds for MRI, and fat and tissue equivalent materials. Density corrections for variable patient scatter and imperfect image reconstructions improve quantitative measurement. Automated computer methods detect the samples and record readings on all images over the extent of the scans without operator interaction. Spatial references function as location references and enable spatial correction of device imperfections such as point spread function (PSF) or motion for improved images. Comparative analysis of backward and forward projections corrects images based on simultaneous imaging of the references of known properties.

Extended and fixed INTable simultaneously imaged calibration and correction methods and references for 3-D imaging devices

A method automatically segments the heart and abdominal aorta from volumetric images without the need to inject iodine contrast media into the subject. The method automatically quantifies arterial plaque (hard plaque, soft plaque or both) in the cardiovascular system. Plaque definitions include subject specific in vivo blood/muscle density measurements, subject specific voxel statistical parameters and 2-D and 3-D voxel connectivity criteria, which are used to automatically identify the plaques. The locations and outlines of the major arteries are determined in a 3-D coordinate system and the specific coordinates of the detected plaques are displayed in a plaque map for follow-up exams or ease in plaque review and reporting the results.

Automatic segmentation of the heart and aorta in medical 3-D scans without contrast media injections

An automated method measures coronary calcium in a living subject using x-ray computed tomography (CT). The method acquires at least one CT image containing voxels representing x-ray attenuation of the subject which may or may not be calibrated. The method of analysis may or may not require operator interactions and includes analyzing the images in a computer to identify the boundaries of the heart. The method further includes identifying the approximate location of at least one coronary artery without operator interaction. The method further includes placing a region-of-interest (ROI) surrounding the artery location automatically. The method further includes analyzing the ROI to identify voxels above a threshold value. The method further includes determining the calcium content in mass units.

Automatic detection and quantification of coronary and aortic calcium

Methods to calibrate and display medical images with pixel values with known properties of one or more reference materials provide images which allow more accurate quantification of certain tissue properties. The images provide advantages in medical diagnosis by being standardized and independent of imaging devices or imaging techniques. The images are automatically displayed and/or filmed in optimum windows and levels. The images are calibrated with a variety of reference materials and displayed in a variety of measurement units. For example, CT images are displayed with pixel values in units of grams per cubic centimeter calibrated to a known reference which relate to but are quantitatively different from the customary Hounsfield scale based on water as the reference material. A novel more quantitative CT image display scale provides advantages in diagnosis, image recording and standardization. References with known magnetic properties imaged with MRI provide calibration and display standardization.

Display and analysis of medical images using calibrated pixel values in units of known properties of reference materials

A hybrid calibration method uses a calibration phantom (exterior reference) scanned simultaneously with the patient, and one or more known tissues of the subject (interior reference) to create a hybrid calibration reference that improves the measurement of tissue densities throughout the body. In addition, the calibration method is used to quantitatively define boundaries of tissue and organs for more accurate measurements of lengths, areas and volumes. Another aspect of the invention uses the calibrated images to quantitatively preset absolute window/levels for filming and image display, which provides standardized viewing for diagnostic purposes.

Calibration of tissue densities in computerized tomography

A hybrid calibration method uses an calibration phantom (exterior reference) scanned simultaneously with the patient, and one or more known tissues of the subject (interior reference) to create a hybrid calibration reference that improves the measurement of tissue densities throughout the body. In addition, the calibration method is used to quantitatively define boundaries of tissue and organs for more accurate measurements of lengths, areas and volumes. Another aspect of the invention uses the calibrated images to quantitatively preset absolute window/levels for filming and image display, which provides standardized viewing for diagnostic purposes.

The present invention relates to x-ray analysis apparatus for bone density measurements. Bone Densitometry is the preferred method of diagnosing low bone density such as osteoporosis. The invention is a low cost x-ray bone densitometer capable of measuring bone density in the human body. It is particularly designed to measure the extremities, phalanges, calcaneous or radius, but similar techniques and a modified device could measure in larger body parts. The device can also have application in small animals or animal parts. The use of photodiodes of larger size at fixed locations provides a mechanically positioned Region of Interest (ROI) which reduces software and hardware requirements. The low cost bone densitometer serves as a screening device in primary care physician's offices. The present invention provides a highly automated bone mineral density measurement achieved by simple positioning of the hand, and push button operation. The compact and low cost tabletop x-ray system is powered by line voltage or battery which exposes the body part and calibration phantom or phantoms simultaneously. The device provides exposures at multiple x-ray energies, here introduced as MEXA, (Multiple Energy X-ray Absorptiometry). The invention also utilizes an improved calibration method. This method uses calcium hydroxyapatite in a solid tissue equivalent matrix to form the reference calibration phantom, which is positioned adjacent to the fingers for simultaneous calibration on each exam.

Automated x-ray bone densitometer

A calibration phantom representative of human tissue containing variable concentrations of calcium serves as a calibration reference for quantifying calcium, bone mass and bone mineral density in radiography and CT imaging systems. The method of fabrication of the calibration phantom provides the long-term stable incorporation of calcium into a tissue equivalent material which allows accurate, standardized, and reproducible quantification of calcium and bone mineral density in radiography and CT imaging systems. A method of using the calibration phantom for quantifying calcium and bone includes placement of part of a patient's anatomy in a bolusing apparatus to provide uniform attenuation of the x-ray beam passing through and around the patient's anatomy. A x-ray filter plate may be used to predictably attenuate the x-ray beam.

Calibration phantom and improved method of quantifying calcium and bone

A calibration phantom for the quantitative computer tomography (QCT) system for bone or other tissue measurement in which a series of graduated reference solutions are retained within cavities formed in a translucent member having x-ray attenuation characteristics closely approximate to human tissue. In preferred embodiment, the reference solutions are sealed under pressure in direct contact with the material forming the base of the phantom. Only a very thin wall separates the solution from the upper and lower surfaces of the phantom. In addition, the cavities are closely adjacent one another. As a result, phantoms constructed in accordance with this invention minimize the size and mass of the phantom and thus minimize x-ray beam hardening, scatter and image are the facts.

Calibration phantom for computer tomography system

An automated image detail localization system for digital image systems, such as CT, MRI, digital radiograph, includes a calibration phantom having plural reference samples of materials having known, fixed imaging properties. The phantom is positioned with respect to a patient and scanned simultaneously to produce an image that includes a cross-section of the patient and a cross-section of the phantom. The cross-sectional image of the phantom includes cross-sectional images of the reference samples. The system automatically finds the phantom and the centers of the reference sample images and then positions regions of interest (ROIs) within the reference sample images to define the portions of the images that are included in a step of averaging the intensities of the reference sample images. The system further automatically places an ROI of regular (e.g., elliptical) or irregular shape in a specific region of the image of the patient's anatomy, such as the trabecular bone region of the patient's spine. The system automatically performs a histogram analysis of the tissue within an ROI to exclude tissue components that are undesirable in the calculation of tissue density. By using the phantom in combination with the histogram analysis, component tissues that cannot be readily separated spatially can be isolated by density or signal intensity and thus quantified in an automated manner. Small or irregularly-shaped tissues, such as lung nodules, can be accurately quantified without requiring precise placement of an ROI in the tissue image.

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Columbia, KY, United States of America

Ben A Arnold