Diffusion-weighted whole body MR imaging with background body signal suppression at 3.0 Tesla

Purpose: To provide a diffusion-weighted (DW) whole body MR imaging sequence with background body signal suppression (DWIBS) at 3.0 Tesla and to evaluate this sequence in first clinical applications.

Material and Methods: A DW spin-echo echo-planar imaging sequence (60 transversal slices, 4mm thickness, FOV/RFOV=400/314mm, matrix 112×86, bmax=1000s/mm² with NSA=6 and motion probing gradients in three orthogonal directions, SENSE factor 2, free breathing) was combined with the following methods of fat suppression: short TI inversion recovery (STIR), spectral attenuated inversion recovery (SPAIR), and spectral presaturation by inversion recovery (SPIR). Optimized sequences were implemented on a 3.0- and a 1.5-Tesla-system. From the isotropic DW images, gray scale inverted MIP images were reconstructed, and image quality was judged. Moreover, the best DWIBS sequence at 3.0 Tesla was evaluated in ten patients with various lesions in the neck, chest, and abdomen. In three patients with tumor metastases, DWIBS was compared to FDG-PET. Results: Best fat suppression and diagnostic image quality in all cases could be obtained at 3.0 Tesla with the STIR method. In comparison to 1.5 Tesla, DWIBS images at 3.0 Tesla provided a better lesion-to-bone tissue contrast. However, larger susceptibility and motion artifacts degraded the image quality at 3.0 Tesla. In comparison to FDG-PET images, on DWIBS images more metastases could be depicted with higher resolution. Conclusion: DWIBS at 3.0 Tesla is feasible and worth to be investigated in larger clinical settings.