Image quality enhancement for MRT images

In this contribution a new combination of methods for noise and artifact reduction is presented. The new noise reduction system has successfully been applied to magnetic resonace tomography (MRT) sequences. For this purpose a system which is based on a nonlinear bandsplitting has been elaborated and optimized. In order to cope with motion artifacts and with ghosting effects, the motion detection is performed in only one of the resulting nonlinear subbands where noise, ghosting effects and objects can be effectively differentiated. This motion information is applied then to adjust the coefficients of subsequent recursive filtering processes. Furthermore, a coring is applied in each subband. The new system has been applied to a variety of MRT test sequences and yields a good noise and artifact reduction which is evaluated by Signal-to-Noise-Ratio (SNR) gains over a wide range of input SNRs. In this application, the new approach outperforms classical noise reduction techniques and achieves Peak-Signal-to-Noise Ratio gains of up to 7 dB for typical input sequences. Additionally, an implementation study has been performed in order to compare different implementation alternatives for this new method. Keywords— magnetic resonance tomography (MRT), image quality enhancement, motion adaptive noise reduction, nonlinear filter bank