Self-navigated 3D Diffusion MRI using Simultaneous Multislab with multiband blipped-CAIPI

Brisbane Convention & Exhibition Centre 

High-resolution diffusion imaging can help depict small structures and complex fiber architectures. The resolution of 2D acquisitions is limited by SNR, particularly when using diffusion encoding. Additionally, the long TR required for full brain coverage, due to the large number of slices, results in low SNR efficiency. Simultaneous multislice imaging (SMS) (Setsompop, 2012) is widely used in 2D diffusion imaging to improve acquisition efficiency. As an alternative, 3D multislab (Engström, 2013; Frost, 2014; Wu, 2016) acquisition divides FOV into multiple slabs and achieve Fourier encoding along slice direction within each slab. Simultaneous multi-slab imaging (SMSlab) (Dai, 2021; Liu, 2023; Zhang, 2023) integrates SMS and 3D multislab techniques, exciting multiple 3D slabs simultaneously to increase the spatial coverage along the slice direction without extending the TR.

SMSlab has shown significant potential for achieving optimal SNR efficiency (TR=1-2s) in high resolution DWI (Liu, 2023; Zhang, 2023). However, the acquisition of an external navigator to correct for the inter-shot phase variations accounts for approximately 30% of the total acquisition time, which may compromise SNR efficiency due to prolonged TR. Inspired by a recently proposed self-navigated 3D multislab DWI (Li, 2024), we incorporated the kz-blip sampling technique into our SMSlab framework and proposed self-navigated 3D SMSlab DWI using blipped-CAIPI in the multiband dimension.