EFFECTS BY PARAMAGNETIC AND DIAMAGNETIC MATERIALS IN A 1.5-TESLA HIGHFIELD MAGNETIC-RESONANCE-IMAGING SYSTEM (MRI)

This article shows the results of an experimental investigation of the interference by paramagnetic and diamagnetic materials on imaging in a closed 1.5 Tesla high field magnetic resonance imaging system (MRI). For different types of sequences (SE, GE, EPI) the effects of metal a nd non-metal profiles in producing artefacts were investigated. A phan tom (plastic trunk) filled with Gd-Mn-solution was used for representa tion of the artefacts. The materials analysed were placed parallel to the phantom at predetermined distances. The images were obtained in tr ansverse and sagittal planes and analysed with respect to the resultin g artefacts. The results show that aluminum and polymer profiles produ ce the weakest artefacts, even when the material is positioned close t o the phantom. A comparison of the sequence types shows that the SE-se quence has a low sensitivity to artefacts, despite the great profile v ariation in size and shape. The SE-sequence accordingly showed a highe r imaging stability as compared with the GE- and EPI-sequences. Steel and copper produced the strongest artefacts. The examination was begun after an intensive study of the literature (Internet, Medline, Medite c). So far have been few publications on this subject.