Real-time correction of MRS experiments
MRI and MRS experiments are often affected by subject motion and system imperfections arising from field inhomogeneities, field drifts and eddy currents. While MRI artefacts can usually readily be identified by the experienced radiologist, artefacts in MRS scans are much harder to recognize and can therefore give rise to false diagnoses in clinical examinations. Furthermore, MRS experiments are particularly susceptible to motion and system instabilities due to their long scan times. In our group we implement techniques aiming at the reduction of these artifacts. Lineshape distortions in MRS scans arising from hardware imperfections such as frequency drifts and eddy currents can be corrected with the interleaved reference scan method. Besides, we apply prospective motion correction to mitigate artifacts arising from subject motion. This method uses an optical camera for the acquisition of motion information, which is then fed back to the measurement control unit of the MR scanner where it is used to update RF pulses and gradients of the MRS sequence in real time.