Abstract: A reordering system for reducing respiratory artifacts in magnetic resonance images. The respiration cycle of the patient is measured and divided into N exclusive intervals. A different encoding amplitude is assigned to each interval in a first look-up table (LUT). The encoding pulses are selected by the first LUT responsive to measured respitory intervals. After M encoding pulses have been selected, a new LUT is constructed from the unused encoding pulse amplitudes using a new number (N-M) intervals. The new LUT is then used for another given number of encoding pulses. Other new LUT's are constructed after given numbers of encoding pulses are used until all encoding pulses are used.

Abstract: An RF probe for acquiring MR data comprising four loop means. There are first and second loop means that are substantially round, centered about a longitudinal axis of said probe and spaced apart substantially the length of said probe to define a cylindrical shape therebetween. There are third and fourth loop means being substantially saddle shaped spaced apart, oppositely disposed and extending between said first and second loop means. Conductors attached to said first and second loop means at points on said first and second loop means spaced apart by 180 degrees couple said third and fourth loop means to said first and second loop means to form a point of psuedo-saddle coils providing extremely homogenous signals.

Abstract: A data compression-expansion (decrease-increase) method for improving the signal-to-noise ratio of compressed-expanded data while retaining the fidelity of the original data comprises the steps of using a filter that can be separated into a smoothing portion and an enhancing portion. The selected filter is separated into the two portions: a first portion for smoothing prior to decreasing the data, and a second portion for enhancing after increasing the data whereby the filter has the maximal effect of decreasing noise while having a minimal effect on the data.

Abstract: A method of quantitatively determining the stenosis of the blood vessel using a digital subtraction angiographic image of the blood vessel. The method includes obtaining numbers proportional to the cross sectional areas of the blood vessel at stenosis portions and normal portions by obtaining density profiles less residual background from the images at those portions.

Abstract: A misregistration correction system that corrects for artifacts generated by the movement of a subject being imaged during the interval between temporally separated images. The system reduces the effects of secondary characteristics on the determination of a vector between a point on a first image and a point on a second image, which vector delineates the motion of the subject.