Abstract: A method and related apparatus are provided for correcting for a phase error in MRI observed values which represent a scan line which passes through the origin of Fourier space. The phase error is estimated by calculating the phase of the sum of the observed values. The observed values are then modified as a function of the estimated phase error. To minimize the effect of T.sub.2 decay, the phase error may be estimated by calculating the phase of the sum of the product of each pair of observed values on the scan line which have been relocated symmetrically, one on each side of the Fourier space origin.

Abstract: A quadrature antenna for magnetic resonance imaging systems is provided which includes first and second channels, each of these channels comprising a coil pair. Each of the four coils comprising the antenna is elliptical in shape and lies in a respective plane. The center point of each coil coincides with a reference point on the longitudinal axis of the antenna. The minor axes of the coils of the first channel coil pair are colinear. The minor axes of the coils of the second channel coil pair are also colinear with each other and are perpendicular to the minor axes of the coils of the first channel coil pair. Each of the four planes is inclined approximately forty five degrees (45.degree.) with respect to the longitudinal axis of the antenna.

Abstract: A two dimensional Fourier transform magnetic resonance imaging method produces a series of scan lines in Fourier space using quadrature demodulation of a series of radio frequency echo signals from an object being observed with a reference signal. Fourier transforming the scan line data provides visual image data through a section of the object. Limitations in the hardware performance introduces unknown, time varying, phase errors into the scan line data, proportional to the phase difference between the reference signal and the echo signals as each is demodulated. Improved visual imaging results from the introduction of an additional sensitive line scan through Y=0 in Fourier space, having a calculable phase error which is used to correct the unknown phase errors in the remaining scan lines. The phase term of the sensitive line data is corrected for the phase error which is known at Y=0. Magnetic resonance imaging scan line data are next generated for a slice through the object.

Abstract: A magnet for use in a magnetic resonant imaging device comprising pole pieces and a return magnetic path constructed of magnetic field conductive material and comprising activating coils, one located around each pole piece which, when activated, generate a magnetic field between the exposed faces of the pole pieces. To improve uniformity of the resultant magnetic field, the surface of the exposed face of each pole piece comprises a toroidal portion which may extend beyond the side surface of the cylinder of each pole piece and a concave portion surrounded by that toroidal portion. To further improve field uniformity, a plurality of projections extend from the exposed surface of each pole piece toward the exposed surface of the opposite pole piece with the distance each projection extends from the exposed surface of the respective pole piece being hydraulically adjustable.