• Mathias Engström, Magnus Mårtensson, Enrico Avventi, and Stefan Skare.
• Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Neuroradiology, Karolinska University Hospital, Stockholm, Sweden.
• Magn Reson Med. 2015 Feb 1; 73 (2): 718-25.

PurposeThree-dimensional (3D) multislab diffusion-weighted echo-planar imaging (EPI) has been suggested as an alternative for high-resolution diffusion-weighted imaging. In this work, the key components of the sequence are investigated, optimal scan parameter settings suggested, and a signal-to-noise ratio (SNR) analysis, comparing 2D diffusion-weighted EPI and 3D multislab diffusion-weighted EPI, is performed.MethodsSlab profiles were measured using 3D multislab EPI to investigate slab profile saturation effects with respect to TR, T1 and overlap between slabs. For short TR values, two methods to reduce the slab banding artifacts are proposed. Moreover, the SNR for 2D and 3D multislab (3D-MS) DWI have been simulated for various anatomical coverages and slab thicknesses.ResultsSimulated 3D multislab scans were shown to be more SNR-efficient than a corresponding 2D scan, for all investigated anatomical coverages and slab thicknesses. Slab banding artifacts being negligible for long repetition times (TRs) were strong for a TR of 2000 ms, proving that they stem from T1 -saturation effects. This banding was largely reduced by the suggested correction methods.ConclusionIn the low TR regime, T1 -saturation effects between adjacent slabs need to be taken in consideration to avoid slab-banding artifacts for multislab sequences. With the proposed correction methods the difference between the SNR-optimal TR and the TR where slab-banding artifacts become acceptable is reduced.© 2014 Wiley Periodicals, Inc.

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