A fat saturation method for a magnetic resonance imaging system having a main magnet providing a magnetic field B.sub.0 The method includes: driving a shim coil assembly with a first set of shimming currents to sufficiently alter a B.sub.0 field inhomogeneity of the magnetic field B.sub.0 within a region that includes a first imaging volume of interest such that water saturation inside the region is reduced from before the first set of shimming currents are applied; applying a fat saturation pulse to the region; identifying the first imaging volume of interest from the region; driving the shim coil assembly with a second set of shimming currents to alter the B.sub.0 field inhomogeneity of the magnetic field B.sub.0 within the first imaging volume of interest such that the B.sub.0 field inhomogeneity within the first imaging volume of interest is reduced; and obtaining magnetic resonance signals from the first imaging volume of interest.

The present invention relates to the locally resolved examination of objects by means of magnetic resonance (MR) and relates specifically to a less motion-artifact prone method for navigated multi-shot acquisition of diffusion-weighted image data using moment-nulled magnetic field gradients for diffusion encoding. The invention further relates to an apparatus for performing the method.

A diameter measurement device for measuring the diameter of a wireline cable dynamically during moving in and out of a borehole. The measurement device has a first pair of opposed shafts, a rotating roller on each shaft of said first pair of opposed shafts, a first resilient member mounted to urge at least one of the shafts of said first pair of opposed shafts toward the wireline cable to be measured, and a first intrinsic measuring unit operatively associated with the first resilient member to measure the displacement thereof. The measuring device further has at least a second pair of opposed shafts angularly displaced with respect to the first pair of opposed shafts, a rotating roller on each shaft of said second pair of opposed shafts, a second resilient member mounted to urge at least one of the shafts of said second pair of opposed shafts toward the wireline cable to be measured, and a second intrinsic measuring unit operatively associated with the first resilient member to measure the displacement thereof as the wireline cable is moved lengthwise between the rollers; each of said first and second intrinsic measuring devices outputting to a digitizer for generating digital measurements of the diameter at various positions on the circumference of and along the length of said wireline cable, which measurements are transmitted to and stored in a logging device. At least one of the first and second intrinsic measuring units can be an eddy current measurement device to measure deflection of at least one of the first and second resilient members using eddy currents.

Systems and methods for spinwave-based metrology in accordance with embodiments of the disclosure involve generating and detecting spinwaves in a sample having a ferromagnetic material; and determining a material thickness, a material integrity measure, a presence of a manufacturing defect, a categorical type of manufacturing defect, and/or a manufacturing process statistic corresponding to spinwave behavior in the sample. In an embodiment, spinwaves are generated by way of concurrent exposure of a target measurement site of the sample to each of a bias magnetic field and radiation (e.g., microwave or radio frequency radiation) produced by a first set of integrated waveguides. A response signal corresponding to a behavior of spinwaves within the target measurement site can be generated by way of a second set of integrated waveguides. Various embodiments of systems and methods for generating spinwaves, detecting spinwaves, and calculating, analyzing, or monitoring one or more sample properties can be automated.

A magnetic resonance apparatus corrects higher order B.sub.0 magnetic field inhomogeneities in the examination volume of an MR device. Currents through two or more coil sections (X.sub.1, X.sub.2) of at least one of a plurality of gradient coils (4) are independently controlled in such a manner that higher order field inhomogeneities of the main magnetic field B.sub.0 are compensated for by the magnetic field of the at least one gradient coil (4).

An interactive display of results obtained from the inversion of logging data is produced by obtaining and inverting the logging data using a Monte-Carlo inversion. An interactive plot having a percentile scale plotted against a location parameter is produced and a particular percentile is selected using the interactive plot. A cross-section plot for the particular percentile using the results of the Monte-Carlo inversion is produced. The particular percentile can be a curve representing a best-fit solution or a polyline representing selected solutions. Background color/shading can be displayed on the interactive plot to indicate user-defined constraints have been applied. Uncertain features can be plotted on a corresponding cross-section display using fading. Clusters of solutions that are substantially equally likely, given the measurements at a particular drill location, can be identified and plotted. A cross-section constructed from the layered models belonging to a particular cluster can be overlaid on another cross-section.

According to one embodiment, an MRI apparatus includes a data acquiring unit and processing circuitry. The data acquiring unit acquires MR signals for imaging according to data acquiring conditions for acquiring MR signals multiple times following one excitation. The data acquiring unit also acquires reference MR signals for phase correction of real space data for imaging. The real space data are generated based on the MR signals for imaging. The processing circuitry is configured to calculate a phase error, in a real space region, of reference real space data and generate MR image data based on the MR signals for imaging with the phase correction of the real space data for imaging based on the calculated phase error. The reference real space data are generated based on the reference MR signals. The real space region is determined based on conditions of acquiring the reference MR signals or the like.

In a method and apparatus for acquiring a magnetic resonance image data set of a scan area of an examination subject, the image data are acquired with a magnetic resonance apparatus having a transmitter coil that emits a radio-frequency signal having at least two transmission channels so that different polarizations of the radio-frequency signal are produced, and a magnetic resonance sequence is used to acquire raw data for the magnetic resonance image data set, wherein raw data are acquired during at least two scanning operations with the magnetic resonance sequence, with different polarizations of the radio-frequency signals being used for at least two of the at least two scanning operations, following which the magnetic resonance image data set is determined by averaging the raw data.

A method of validating a directional survey includes measuring the gravity and magnetic field vectors using a surveying tool and computing an overall statistical distance of the measurement. The statistical distance may be calculated from reference values associated with the surveying tool using corresponding surveying tool codes with error values. In a further aspect, an error covariance matrix may be used to determine whether the new errors in a survey are consistent or not with errors from one or more previous surveys.

A method of validating a directional survey includes measuring the gravity and magnetic field vectors using a surveying tool and computing an overall statistical distance of the measurement. The statistical distance may be calculated from reference values associated with the surveying tool using corresponding surveying tool codes with error values. In a further aspect, an error covariance matrix may be used to determine whether the new errors in a survey are consistent or not with errors from one or more previous surveys.