Real-time reduction of motion artefacts using k-space weighting in magnetic resonance imaging

An improved version of motion-adapted gating useful in MR imaging is presented. Compared to other gating approaches, this advances method shows an improved ability to suppress motion artefacts at a reduced scan time. It is based on a k-space dependent weighting function and a realtime system feedback. During MR data acquisition patient motion is monitored and only those profiles are accepted whose respiratory motion induced displacements are below a pre-defined threshfold (gating) function. The displacements are measured relative to a reference position, which is automatically determined during the initial phase of the MR scan. While MR data are acquired, the object motion is statistically analysed in parallel by calculating the histogram of the displacement distribution for consecutive time intervals. This information can be used to interfere with the measurement process in the case that motion statistics changes during the scan. Initial in-vivo results are presented and compared to conventional techniques.