Multiple-angle, variable-interval, nonorthogonal MRI.

Abstract

Multiple-angle, variable-interval, nonorthogonal (MAVIN) MRI is a new, time-saving technique that allows for the independent choice of slice angle and position for each slice in a multiangle pulse sequence. By appropriate adjustment of the slice-select radiofrequency pulse and the slice-select and readout magnetic-field gradients, the interval and angle of each slice may be individually chosen. MAVIN can reduce examination time in studies of the lumbar spine, orbits, knees, and heart, where nonparallel oblique scanning may be necessary and would otherwise require the use of additional pulse sequences. Loss of signal in the region of intersection of multiple planes due to local changes in effective repetition time is a practical limitation. For this reason, scan planes are chosen so that the intersection does not overlie the region of interest.