Abstract: A method and apparatus for correcting ghost artifacts that are related to orthogonal perturbation magnetic fields is disclosed. The technique includes acquiring MR data and an MR reference scan, each in the presence of orthogonal perturbation magnetic fields. However, the region of interest for the MR reference scan is limited to a relatively narrow band within the imaging subject. Preferably, the narrow band is selected in the vicinity of the magnet iso-center and parallel to the readout direction. Alternatively, the narrow band can also be selected in the limited region where the orthogonal perturbation fields are either minimal or constant along the phase encoding direction, and parallel to the readout direction. The selection of the relatively narrow band is accomplished by either spatially saturating surrounding regions, or using a two-dimensional spatially selective RF pulse.

Abstract: The present invention is directed to a method and apparatus for administering computed tomography (CT) imaging scans with reduced radiation dosage. The present invention includes an algorithm that allows for reduction of the sampling rate and tube current to acquire a first set of angular views. A second set of angular views is then created using interpolation from the first set of angular views. The sets of angular views are then combined to form a final set of angular views that are used to create an aliasing-free image of the scan subject. The present invention is particularly applicable for scanning centralized small objects such as the heart or the head and also is particularly useful in acquiring imaging data of pediatric patients.

Abstract: A system and method for optimally imaging the peripheral vasculature is disclosed which includes defining a given number of scan stations along a patient's peripheral vasculature and initially injecting a relatively small amount of contrast agent into the patient to pass a test bolus through the patient's peripheral vasculature, and thereafter tracking the test bolus through the patient and adjusting the patient on a moveable table within the MR imaging device from one scan station to a next station to determine a maximum travel time that the test bolus takes to travel through each of the given number of scan stations. Additional contrast agent is then injected into the patient to pass an exam bolus through the patient's peripheral vasculature, and using the test bolus travel time, MR data can be acquired from each scan station while it is known that the exam bolus is present in that station to optimize image resolution.

Abstract: A method and apparatus is disclosed to initially screen a patient's peripheral arterial vasculature for lesions, or stenotic vessels, using MR technology, and then grading the severity of any located stenosis. The invention includes tracking the passage of a contrast agent bolus through a patient, while acquiring a series of first MR images having low resolution. This initial examination uses flow sensitive bi-polar gradient waveforms with a gradient echo imaging pulse sequence to increase the sensitivity to lesion detectability. The bi-polar gradients generate a broad distribution of velocities in a large voxel. Relevant stenoses present in a voxel will result in intra-voxel flow dephasing in voxels immediate to and distal to the stenosis. After identifying a stenosis, a second MR image, having a higher resolution than the first, is used to grade the stenosis.