Abdominal T2-Weighted Imaging by Free-Breath PACE with a 3.0T MRI System

In a magnetic field of 3.0Tesla, motion artifacts are more serious, particularly in MRI of the moving upper abdomen, than those in a field of 1.5Tesla or lower. We carried out free-breathing Prospective Acquisition Correction (PACE) T2-weighted imaging of the upper abdomen in order to control the motion artifacts produced with a 3Tesla MRI System. We employed five volunteers for free-breathing T2-weighted imaging with various sequences on a whole-body 3.0-Tesla scanner. To each volunteer, Turbo SE with PACE (PACEJldquoSE), conventional Turbo SE (conv.TSE), HASTE with PACE (PACE_HASTE), and conventional HASTE (conv.HASTE) were applied. The TSE parameters were as follows: effective TE=66msec, spatial resolution in plane=1.4mm*l.lmm, slice thickness=6.0mm. The HASTE parameters were as follows: effective TE=85msec, spatial resolution in plane=1.4mm*l.lmm, slice thickness=6.0mm. Both HASTE data sets were MPR (Multi-Planar Reconstruction)-processed. Two observers evaluated image quality and the presence of artifacts. Moreover, the contrast of internal organs such as the liver and spleen were measured, and the results were compared. Motion artifacts of the moving upper abdomen were remarkably reduced with the PACE sequence, and image quality was greatly improved. In addition, to confirm the continuity of imaged body surfaces in three dimensions, both HASTE data sets (acquired as transverse slices) were reconstructed for coronal viewing. With the PACE sequence, the continuity of imaged body surfaces was dramatically improved in comparison with the conventional HASTE results. Among the four sequences, the two PACE sequences were the best in terms of both image quality and reducing respiratory motion artifacts in abdominal images.