Abstract: A method that allows the quantification of the true mass of a calcium fragment located along a vessel is provided. The method is independent of the level of arterial contrast enhancement, does not require protocol-specific or scanner-specific calibration scans, and allows a detailed analysis of calcium distribution patterns. For each identified calcium fragment, the average intensity and volume is determined as a function of a plurality of intensity thresholds. Using these determined values brightness volume products are calculated for each of the plurality of intensity thresholds. The mass of a calcium segment is subsequently obtained from the calculated brightness volume products extrapolated at zero intensity and reference calcium parameters. The mass and volume of the calcium fragments could be visualized with respect to a vessel in a computer display.

Abstract: A method to define a curved slab region of interest that includes vessels while maximally excluding surrounding soft tissue and bone is provided. The thickness of the curved slab is automatically adapted to the thickness of the vessel and follows the tortuous vessel(s) so that an increase in tortuousity does not result in a disproportionate increase in the region of interest required to enclose the vessel. A plurality of boundary pairs is determined in the view plane to define a vessel. Vessel-intensities are determined for each one of the boundary pairs. The boundary pairs with associated intensities define the view of the vessel in the projection plane. Context-intensity could be defined in the area surrounding the boundary pairs in the projection and/or transverse plane. The method also includes several steps that will result in a better isolation and removal of non-vessel structures and view of the vessel(s) and its(their) branches.

Abstract: A method to quantify the vascular irregularity of aortoiliac arteries is provided. Inner wall and/or outer wall outlines of a vessel of interest are determined. The cross sectional area is determined for the area outlined by each outline. Using this cross sectional area a shape is selected that has substantially the same area as the outline. Subsequently, the shape is fitted to the outline. In one aspect, the irregularity index is calculated as the ratio of the outline and the outline of the fitted shape. In another aspect, the irregularity index is calculated as the ratio of at least a part of the outline and the outline of the fitted shape that corresponds to the same part of the outline. The irregularity index is visualized using a color scheme, a range of numbers, or a set of labels.

Abstract: A method for detecting and identifying structures of interest such as colonic polyps or similar structures like lung nodules in volumetric (medical) images data is provided. The method includes obtaining a heat diffusion field (HDF) by applying a heat diffusion scheme to a volume of interest that includes structures. The obtained heat diffusion field is then used for identifying a structure of interest from the structures in the volume of interest using a geometrical analysis of the heat diffusion field. The heat diffusion scheme is, at least partly, governed by non-linear diffusion parameters. The identification includes two parts: (i) the computation of a spherical symmetry parameter, and (ii) the performance of a local analysis of the volume of interest and computation of a triangulization parameter.

Abstract: A method to define a curved slab region of interest that includes vessels while maximally excluding surrounding soft tissue and bone is provided. The thickness of the curved slab is automatically adapted to the thickness of the vessel and follows the tortuous vessel(s) so that an increase in tortuousity does not result in a disproportionate increase in the region of interest required to enclose the vessel. A plurality of boundary pairs is determined in the view plane to define a vessel. Vessel-intensities are determined for each one of the boundary pairs. The boundary pairs with associated intensities define the view of the vessel in the projection plane. Context-intensity could be defined in the area surrounding the boundary pairs in the projection and/or transverse plane. The method also includes several steps that will result in a better boundary outline and view of the vessel.

Abstract: A method to quantify the radial endoluminal irregularity of aortoiliac arteries is provided. Radial endoluminal outlines of a vessel of interest are determined. The cross sectional area is determined for the area outlined by each endoluminal outline. Using this cross sectional area a shape is selected that has substantially the same area as the endoluminal outline. Subsequently, the shape is fitted to the endoluminal outline. In one aspect, the irregularity index is calculated as the ratio of the endoluminal outline and the outline of the fitted shape. In another aspect, the irregularity index is calculated as the ratio of at least a part of the endoluminal outline and the outline of the fitted shape that corresponds to the same part of the endoluminal outline. The irregularity index is visualized using a color scheme, a range of numbers, or a set of labels.

Abstract: A detection and classification method of a shape in a medical image is provided. It is based on generating a plurality of 2-D sections through a 3-D volume in the medical image. In general, there are two steps. The first step is feature estimation to generate shape signatures for candidate volumes containing candidate shapes. The feature estimation method computes descriptors of objects or of their images. The second general step involves classification of these shape signatures for diagnosis. A classifier contains, builds and/or trains a database of descriptors for previously seen shapes, and then maps descriptors of novel images to categories corresponding to previously seen shapes or classes of shapes.

Abstract: A method to detect and classify a structure of interest in a medical image is provided to enable high specificity without sacrificing the sensitivity of detection. The method is based on representing changes in three-dimensional image data with a vector field, characterizing the topology of this vector field and using the characterized topology of the vector field for classification of a structure of interest. The method could be used as a stand-alone method or as a post-processing method to enhance and classify outputs of a high-sensitivity low-specificity method to eliminate false positives.

Abstract: An automatic method for the registration of prone and supine computed tomographic colonography data is provided. The method improves the radiologist's overall interpretation efficiency as well as provides a basis for combining supine/prone computer-aided detection results automatically. The method includes determining (centralized) paths or axes of the colon from which relatively stationary points of the colon are matched for both supine and prone positions. Stretching and/or shrinking of either the supine or prone path perform registration of these points. The matching and registration occurs in an iterative and recursive manner and is considered finished based on one or more decision criteria.

Abstract: Medical diagnostic ultrasound methods and systems for automated flow analysis are provided. Multiple cross-sectional areas along a vessel are determined automatically. A processor locates an abnormality as a function of the multiple cross-sectional areas, such as identifying a cross-sectional area that is a threshold amount less than an average cross-sectional area. The abnormal area is highlighted on the display to assist with medical diagnosis. For the carotid artery, the interior and exterior branches are labeled to assist medical diagnosis. The two branches are automatically identified. The branch associated with additional small branches is identified as the exterior carotid.

Abstract: A computer-implemented method for determining and characterizing, which portions or shapes of a medical image correspond to a shape of interest is provided. A candidate shape is obtained after which a visible surface is computed adjacent to this candidate shape. A visible surface includes one or more portions of the medical image that are visible by the candidate shape. Once the visible surface is determined, parameters of the visible surface are computed. Then the method further includes the step of determining whether the candidate shape corresponds to a shape of interest. The method further includes the step of computing features of the candidate shape and/or classifying the candidate shape. The advantage of the computer-implemented method is that it provides a high detection specificity, i.e. reducing false positives, without sacrificing sensitivity of the detection of a shape of interest.

Abstract: A computer-implemented method for automatically detecting shapes in a medical image is provided. The method is based on the concept that normals to a surface intersect or nearly intersect with neighboring normals depending on the curvature features of the surface. The method first locates a surface in a medical image after which normal vectors are generated to the located surface. Then the method identifies at least one intersection and/or near intersection of the normal vectors. The key idea is that the number of intersections identifies shapes such as potential malignant candidates. The method also includes the step of scaling normal vectors to provide additional robustness to the shape detection. The method eliminates viewing of large segments of images, thereby markedly shortening interpretation time and improving accuracy of detection. It also provides for an early detection of precancerous growths so that they can be removed before evolving into a frank malignancy.

Abstract: Segregating object images from an image is accomplished by a method that includes intensity thresholding and generating isolabel contour lines at image regions of constant image intensity. The shapes of the isolabel contours are quantified by calculating turning angle sequences. The turning angle sequences of contours compared to discern which contours to group and label as belonging to an object image. The method uses information obtained from intensity thresholding in combination with the inherent shapes of the object images to group isolabel contours and segregate the object images. The method is general and is used for segregating object images from continues images such as photographs and film. The method is extended to 3-dimensional image volumes and further includes modeling cross sections of object images as ellipses. An overlap criteria is used to group cross sectional object images in an images volume from 2-dimensional slices of the image volume.

Abstract: Methods are disclosed for assessing the condition of a cartilage in a joint, particularly a human knee. The methods include converting an image such as an MRI to a three dimensional map of the cartilage. The cartilage map can be correlated to a movement pattern of the joint to assess the affect of movement on cartilage wear. Changes in the thickness of cartilage over time can be determined so that therapies can be provided. Information on thickness of cartilage and curvature of cartilage or subchondral bone can be used to plan therapy. Information on movement pattern can be used to plan therapy.

Abstract: Each voxel is assumed to contain exactly two distinct materials, with the volume fraction of each material being iteratively calculated. According to the method, the spectrum of the X-ray beam must be known, and the attenuation spectra of the materials in the object must be known, and be monotonically decreasing with increasing X-ray photon energy. Then, a volume fraction is estimated for the voxel, and the spectrum is iteratively calculated.

Abstract: Disclosed is a method to correct the geometric distortion caused by field inhomogeneity in MR images such as images of patients wearing MR-compatible stereotaxic frames. A previous distortion correction method derives patient-dependent error maps by computing the phase-difference of 3D images acquired at different T.sub.E 's. The time difference (.DELTA.T.sub.E =4.9 ms at 1.5 T) is chosen such that the water and fat signals are in phase. However, .DELTA.T.sub.E is long enough to permit phase wraps in the difference images for frequency offsets greater than 205 Hz. Phase unwrapping techniques resolve these only for connected structures; therefore the phase difference for fiducial rods may be off by multiples of 2 .pi. relative to the head. This uncertainty is removed by using an additional single 2D phase-difference image with .DELTA.T.sub.E =1 ms (during which time no phase-wraps are typically expected) to determine the correct multiple of 2 .pi. for each rod.

Abstract: A method and apparatus to reduce the noise in three-dimensional phase contrast magnetic resonance velocity measurements exploits the property that blood is incompressible and therefore the velocity field describing its flow must be divergence-free. The divergence-free condition can be incorporated by the projection operation on Hilbert space where the velocity measurements are projected onto the space of divergence-free velocity fields. The reduction of noise is achieved since the projection operation eliminates the noise component that is not divergence-free. Higher quality angiograms are produced due to the noise reduction in the velocity measurement signals.