Abstract: An MRI image from spiral trajectory scanning is arranged as complementary subsets of values in time-sampled k-space. These values are Fourier transformed to produce a spatial domain image. While holding the patient stationary, the contrast information is updated at the central portion of k-space, and the peripheral portion of k-space data can be filled during the whole image acquisition. The contrast information is combined with the peripheral portion of k-space (contributing to image resolution) to construct a full k-space data and to generate a spatial image. The technique is useful for providing short time interval sampling when analyzing the take-up and fade-away of a contrast agent over time.

Abstract: In NMR/MRI imaging, a location is noted for a point in the imaged space, and referred to a reference location so that the point in imaged space is known thereafter, without the need to locate the point again in further imaging steps. For breast cancer diagnosis and biopsy, a breast holding fixture immobilizes the breast. A volumetric image is taken encompassing a portion of the breast. In the same or a subsequent image, a fiducial mark is detected to determine the position of a holder for a biopsy tool or other modality. The tissue feature can be a tumor, cyst or tubal lesion, made temporarily visible in the image by perfusion with a contrast agent. After the contrast agent dissipates, the location of the tissue feature can still be determined by reference to the position of the fiducial marker, which is optional adjustable by post-imaging metered displacement.

Abstract: An MRI process and system image a volume of a sample in a magnetic field established by a biasing field magnet and an array of gradient magnet fields using a pulse sequence to obtain a response that is decoded into an image or images. A set of successive images is collected while the contrast associated with lesions and tumors is enhanced with a contrast agent. A non-spoiled reference image is acquired before the application of the contrast agent. The reference image is non-spoiled in that the pulse sequence for collecting a portion of the volume image is not randomized in phase in a manner that would reset the phase effects of a previous pulse sequence. At least one other one of the successive images collected using phase spoiling pulse sequences. The non-spoiled image data is registered with and subtracted from the successive images to enhance the appearance of selected compositions in the output image, such as the contrast agent and/or water to highlight lesions and cysts, or silicone from an implant, etc.

Abstract: A method and system estimate the risk of malignancy of a given region of interest using noninvasive MRI techniques. The determination of risk is based on the morphology and kinetic enhancement of a region of interest. In addition, the method and system use the type of the enhancement curve to determine the level of risk associated with a given region of interest. The region of interest can be a lesion, tumor, or other unknown. The imaging can be done with the aid of a contrast agent. Regions meeting component concentration criteria, time-change dynamic criteria and the like are distinctly colored and displayed on a single image. Different colors can be shown locally to identify predetermined levels of risk, and/or associated with predetermined compositions such as contrast agents, or to show the presence of silicone.

Abstract: To generate a magnetic resonance image of a region comprised of two species of nuclei that have non-identical Larmor frequencies, the nuclei are excited and two read-out gradient pulses are generated. The relative phase offset between the two species of nuclei is different at the center of the first pulse than at the center of the second pulse. Data acquired during the two read-out pulses are processed in accordance with these relative phase offsets.

Abstract: A magnetic resonance and apparatus in which an examination zone is exposed, preferably repeatedly, with a sequence in which the same RF pulse is both selective to fat, for acting in a fat suppression scheme within the sequence and is configured for inducing substantial magnetization transfer contrast. Design parameters are given for a 1-2-1 binomial RF pulse and a 1-2-1-1-2-1double binomial RF pulse having a 0.degree. net flip angle at the Larmor frequency of water protons and a nominal 180.degree. net flip angle at the Larmor frequency of fat bound protons. The partial derivatives of the latter nominal flip angle with respect to chemical shift and with respect to RF amplitude are each zero. Each of these RF pulse designs is implemented by a pulse which is substantially rectangular in amplitude, but which has alternations of phase between 0.degree. and 180.degree. during its duration to form the sub-pulses.